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Use of Videotape in HOV Lane Surveillance and Enforcement: Final Report





                            USE OF VIDEOTAPE
                                   IN
                                HOV LANE
                      SURVEILLANCE AND ENFORCEMENT
                              FINAL REPORT
                                    
             By John W. Billheimer Ken Kaylor Charles Shade
                                    
                                    
                              Submitted to
                                    
                           State of California
                      Department of Transportation
                                    
                         under Contract 55 G710
                                    
                                    
                                  D232
                               March 1990
                                    
                                    
          SYSTAN,INC.              in               ATD,INC.
       343 Second Street       Association   6431 Independence Avenue
          P.O. Box U              with      Woodland Hills, CA 91367
      Los Altos, CA 94023


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                      PREFACE AND ACKNOWLEDGEMENTS

   This report covers a six-month study designed to explore the use of
vidoetape in HOV lane surveillance and enforcement.  The study is an
extension of an earlier investigation of the effects of different
enforcement strategies and engineering designs on violation rates on
California's mainline HOV lanes.

   The report has been prepared in the Los Altos, California offices
of SYSTAN, Inc. under Contract No. 55 G71 0 with the California
Department of Transportation (CALTRANS).  The project was jointly
sponsored by the California Highway Patrol (CHP).  Mr. Philip Jang,
Chief of the HOV Systems Branch of CALTRANS Division of Traffic
Operations served as project administrator, while Scott McGowen of
CALTRANS acted as the project's technical monitor.

   A steering committee comprised of representatives from CALTRANS,
the CHP and the Federal Highway Administration (FHWA) was responsible
for overall project guidance and for approving the products of major
project tasks.  In addition to Mr. Jang and Mr. McGowen, other members
of the steering committee included: Assistant Chief N.K. Newman of the
CHP's Border Division; Mr. Robert Anderson and Mr. Bill Shoemaker of
CALTRANS District 4 (San Francisco); Mr. Glen Clinton of the FHWA; Mr.
Joe El Harake of CALTRANS District 12 (Orange County); Mr. Ron Klusza
of CALTRANS District 7 (Los Angeles); and Lieutenants Ron Phulps and
Shawn Watts of the CHP's Long Range Planning Section.

   SYSTAN's project manager and principal investigator was Dr. John W.
Billheimer.  Mr. Eric Lin of SYSTAN assisted with data coordination
and analysis.  Mr. Ken Kaylor of ATD Inc. was responsible for
developing, adapting, and coordinating the camera equipment and
monitors used in the study, while Mr. Charles Shade of ATD supervised
the field installation and operation of the equipment.  Ms. Fran Vella
of Phrasmaker Word Processing prepared the Final Report.

   Representatives of CALTRANS and the CHP who assisted in
coordinating the field tests at the heart of the current study
included:

                    Lt. Mike Howard, CHP (Santa Ana)
                    Mr. Andrew M. Miceli, CALTRANS (District 7)
                    Sgt.  John Steel, CHP (Santa Ana)
                    Lt. Ed Whitby, CHP (Westminster)

SYSTAN wishes to thank all those who provided information and insights
on the enforcement and operation of California's mainline HOV lanes,
and acknowledges full responsibility for the analysis, interpretation,
and presentation of the data they provided.


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                            TABLE OF CONTENTS
                                                                    PAGE
1.0     EXECUTIVE SUMMARY. . . . . . . . . . . . . . . . . . . . . . 1-1
  1.1   Introduction . . . . . . . . . . . . . . . . . . . . . . . . 1-1
  1.2   Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
  1.3   Experimental Findings. . . . . . . . . . . . . . . . . . . . 1-2
  1.4   Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . 1-7
  1.5   Recommendations. . . . . . . . . . . . . . . . . . . . . . . 1-8

2.0     INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 2-1
  2.1   Background . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
  2.2   Objective. . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
  2.3   Scope. . . . . . . . . . . . . . . . . . . . . . . . . . .   2-1
  2.4   Schedule of Field Trials . . . . . . . . . . . . . . . . . . 2-2

3.0     FIELD TESTS. . . . . . . . . . . . . . . . . . . . . . . . . 3-1

  3.1   Initial Camera Test. . . . . . . . . . . . . . . . . . . . . 3-1
  3.2   Initial Enforcement Test . . . . . . . . . . . . . . . . . . 3-7
  3.3   Eye-Level Camera Tests . . . . . . . . . . . . . . . . . . .3-14
  3.4   Final Enforcement Test . . . . . . . . . . . . . . . . . . .3-19

4.0     TEST FINDINGS. . . . . . . . . . . . . . . . . . . . . . . . 4-1

  4.1   Equipment Considerations . . . . . . . . . . . . . . . . . . 4-1
  4.2   Display Preferences. . . . . . . . . . . . . . . . . . . . . 4-5
  4.3   Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

5.0     POTENTIAL APPLICATIONS . . . . . . . . . . . . . . . . . . . 5-1
  5.1   Enforcement Applications . . . . . . . . . . . . . . . .     5-1
  5.2   Performance Monitoring . . . . . . . . . . . . . . . . . . . 5-5
  5.3   Unit Costs . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
  5.4   Public Relations . . . . . . . . . . . . . . . . . . . . . .5-12

6.0     CONCLUSIONS AND RECOMMENDATIONS. . . . . . . . . . . . . . . 6-1

  6.1   Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . 6-1
  6.2   Recommendations. . . . . . . . . . . . . . . . . . . . . . . 6-3

APPENDICES
  A     Bibliographical References
  B     Sample Press Coverage


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                            LIST OF EXHIBITS
  EXHIBIT No.                                                       PAGE

  1.1   Typical Field Test Set-Up and Monitor Output . . . . . . . . 1-3

  2.1   Schedule of Field Trials . . . . . . . . . . . . . . . . . . 2-3

  3.1   Initial Set-Up . . . . . . . . . . . . . . . . . . . . . . . 3-2
  3.2   Sample Video Monitor Output. . . . . . . . . . . . . . . . . 3-4
  3.3   Initial Enforcement Set-Up . . . . . . . . . . . . . . . . . 3-8
  3.4   Monitor Display Initial Enforcement Test . . . . . . . . . . 3-9
  3.5   Videotape Demonstration Photos . . . . . . . . . . . . . . .3-11
  3.6   Tests of Eye-Level Micro-Camera. . . . . . . . . . . . . . .3-15
  3.7   Positioning of Two Bridge Cameras and Eye-Level Camera . . .3-16
  3.8   Sample View From Eye-Level Camera. . . . . . . . . . . . . .3-18
  3.9   Final Set-Up . . . . . . . . . . . . . . . . . . . . . . . .3-20
  3.10  Occupancy Count Comparison . . . . . . . . . . . . . . . . .3-25
  3.11  Monitor View of Buffer Violator. . . . . . . . . . . . . . .3-29
  3.12  Monitor View of Suspected Violator with Undetected Child . .3-30
  3.13  Views from Eye-Level Camera. . . . . . . . . . . . . . . . .3-32

  4.1   Sample Camera Positions. . . . . . . . . . . . . . . . . . . 4-4
  4.2   Sample Views from Bridge Cameras . . . . . . . . . . . . . . 4-6

  5.1   Warning Letter to Seattle Drivers. . . . . . . . . . . . . . 5-3
  5.2   HOV Video Van Cost Estimate. . . . . . . . . . . . . . . . . 5-8


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                          1.0 EXECUTIVE SUMMARY


1.1   INTRODUCTION

1.1.1 Background

   Enforcement of California's HOV lanes currently requires
substantial commitments of California Highway Patrol (CHP) personnel
and equipment.  Personnel costs for enforcing the state's ten mainline
HOV lanes alone will exceed $400,000 in 1990.  HOV lane enforcement
has other costs as well.  These include the risks of high-speed
pursuit in lanes adjacent to stop-and-go traffic and the deterioration
of traffic flow when tickets are issued during peak commute periods.

   It has been suggested that using video equipment to assist in HOV
lane enforcement could reduce the requirements for patrol officers,
increase citation rates, and minimize freeway disruption.  The current
investigation has been designed to extend past studies of HOV lane
enforcement by testing both the feasibility and accuracy of the use of
video equipment in HOV lane surveillance.

1.1.2 Objective

   The objective of the current study has been to demonstrate and test
the use of video equipment in determining vehicle occupancy,
documenting violator identity, and aiding enforcement of HOV lanes.


1.2   APPROACH

   Six days of field tests were undertaken to explore the use of
videotape in HOV lane surveillance and enforcement.  Three days were
devoted to testing the effects of different camera positions, filter
adjustments, and monitor displays in the absence of enforcement
personnel.  Once a promising combination of camera positions and
displays had been identified, they were tested with enforcement
personnel present on specific HOV lanes in Southern California.  Two
days of HOV lane tests were undertaken on Los Angeles Route 91, with
one day on Orange County Route 55.  During these tests, personnel from
ATD Inc. set up cameras in different

                                   1-1

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configurations on and under freeway overpasses and established a
three-way monitor in a separate video control unit (See Exhibit 1.1).
CHP officers stationed downstream from the video control unit were
asked to observe selected video-identified violators to ascertain the
actual number of occupants in the vehicle.  At the same time, trained
CALTRANS observers were stationed on the overpass to provide manual
counts of violations.  The results of these tests were then analyzed
to determine the feasibility, accuracy, and cost-effectiveness of
using video cameras in HOV lane surveillance and enforcement.

1.3   EXPERIMENTAL FINDINGS

1.3.1 Equipment

   Field tests showed that it is technologically possible to record
several accurate views of vehicles traveling in mainline HOV lanes. 
Specifications and costs of the equipment needed for videotape
surveillance are summarized below.

   Cameras.  Best results are obtained with high speed color cameras
capable of achieving exposure times of 1/1000 of a second.  A 14:1
zoom lens is needed to focus on oncoming vehicles at distances of
approximately 1200 feet.  Cameras placed at eye-level on the freeway
itself should be small and unobtrusive.

   Auxiliary Equipment.  Two monitors with split screen capability are
required in the control van.  One monitor provides an on-line review
capability, while the other provides a permanent record of all camera
views.  A special effects generator should be used to make the exact
time and location a permanent part of the videotape record.

   Polarizing filters help to solve problems with glare from shiny
cars and windshields, although they reduce the light-gathering
capability of the cameras.  Infra-red cameras and light sources can be
used to document license plates after dark by videotaping the rear
license plates of departing cars.  However, it does not appear
feasible to videotape oncoming vehicles under conditions of darkness
or low visibility.  Results are not clear and the infra-red light
source can distract oncoming drivers.

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                               EXHIBIT 1.1
              TYPICAL FIELD TEST SET-UP AND MONITOR OUTPUT

                          1.Oncoming View
                          2.License View from Bridge
                          3.Driver's Eye Level View
                          4.License View from Roadway


Click HERE for graphic.


                                   1-3


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   Camera Positions.  For real-time decision making, viewers seemed to
prefer a monitor display showing three views of the suspect vehicles:
(1) An oncoming view; (2) A view of the license plate; and (3) An
oblique view downward into the passenger seat (camera positions 1, 2,
and 3 in Exhibit 1.1). When decisions regarding vehicle occupancy can
be delayed for a more leisurely review away from the freeway, the most
useful monitor display appears to be the one providing the most
information--that is, four views of the suspect vehicle.  To provide
these four views, an eye-level camera (Camera 4 in Exhibit 1.1) should
be added to the three-camera display.

   Cost.  The cost of purchasing a fully outfitted van carrying four
color cameras and the required monitors and auxiliary equipment is
estimated to be $108,000.  This includes the cost of the van itself
and California sales tax.  The van must be attended at all times by
two experienced operators, since frequent camera adjustments are
required to deal with glare and changes in ambient lighting.  The
services of a van and experienced operators can be leased for roughly
$5,000 per peak commute period.


1.3.2 Accuracy

   Buffer Violations.  Buffer violators, those drivers who enter or
leave the HOV lane illegally by crossing the double yellow line where
lane changing is not allowed, were easily identified by the camera
recording oncoming traffic.  Violator sightings were unambiguous, and
the license plates of those drivers entering the lane are recorded by
the video surveillance system.

   Occupancy Violations.  Videotape reviewers cannot currently
identify the number of vehicle occupants with enough certainty to
support citations for HOV lane occupancy violations.  In early tests
with three cameras located on an overpass, subsequent videotape review
produced a false alarm rate of 21%.  That is, 21% of those vehicles
identified as violators by videotape reviewers which had been checked
by officers on site actually had the required number of occupants. ln
later tests with the third camera moved to the freeway itself, the
false alarm rate rose to 51%.  The chief cause of false alarms
appeared to be small children and sleeping adults located out of the
view of all three cameras.

   Ambiguous Observations.  Ambient lighting conditions, glare, and
such vehicle design features as tinted windows, headrests, windshield
posts, and high windows also made it difficult to interpret the number
of videotaped vehicle occupants consistently.  Videotape

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reviewers reported that these conditions made it impossible to
estimate the occupancy of 11.4% of the vehicles passing by the video
cameras.  Even allowing for these uncertainties, individual reviewers
differed widely in their attempts to document vehicle occupancy
levels.  These differences suggest that tape reviewers must be well-
trained to ensure that certain conditions (i.e., glare) do not trigger
false alarms and that ambiguous views are treated consistently by all
reviewers.

   Roadside Occupancy Counts.  It is difficult to draw general
conclusions regarding the accuracy of roadside counters from the
observations of a small number of crews, since it is possible that the
observations of different roadside observers will vary as greatly as
those of different videotape reviewers.  It appears, however, that
roadside counters tend to overstate the number of HOV lane violators. 
In addition, one set of counters clearly understated the number of 3+
vehicles passing the observation point (this was the highest number of
occupants required by their count sheets).  Another set of counters
using different count sheets apparently overstated the number of 6+
vehicles.  Their count sheets included a space for 6+ vans, which they
filled by assuming that most of the vans passing their observation
point had six or more occupants.

   It appears that videotape, with the opportunity it affords for
rewinding and reviewing questionable vehicles, has the capability of
supporting more accurate occupancy counts than those provided by
roadside observers who must make decisions on the spot about cars
moving past at 50 or 60 miles per hour.


1.3.3 Potential Applications

   Although it is technologically possible to record a series of
accurate views of vehicles traveling in mainline HOV lanes, no
combination of recorded views currently provides enough information to
support prosecution for occupancy violators.  Even so, videotape
surveillance of HOV lanes can provide useful information for a variety
of other purposes.  These include:

   1. Support for on-line enforcement.  In cases where there are no
      refuge areas adjacent to mainline HOV lanes, videotape
      surveillance provides a means of alerting officers stationed
      downstream from the cameras to the presence of oncoming
      violators.

   2. Support for remote ticketing . Although videotape by itself does
      not appear to be accurate enough to provide a basis for
      citations, the combination of videotape and an observing officer
      could conceivably provide the accuracy needed for a system of
      mailed warnings and citations.  If a system of mailed warnings
      or citations

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      can be installed, the officer would not have to pursue
      violators, and a videotape record of driver, occupancy, and
      license plate would be available for court hearings.  Such a
      system would be more cost-effective than the current system of
      freeway pursuit and roadside citing, and will reduce the
      congestion caused by rubbernecking.

   3. Performance Monitoring.  There are several applications in which
      videotape surveillance appears to provide a marked improvement
      over current practice.  These include:

      (a)   Freeway monitoring to document vehicle type and occupancy
            over time;

      (b)   HOV lane monitoring to document occupancy and violation
            rates as an aid for enforcement planning; and

      (c)   Project evaluation to document the impact of HOV lanes and
            other carpool incentives on occupancy rates.

   The cost of videotaping HOV lane activity is more than double the
   cost of monitoring operations manually.  However, videotape
   provides more accurate records, a consistent data base, and a
   permanent, verifiable record of traffic activity.  It also provides
   information on the vehicle mix, traffic speed, and the license
   plates of carpoolers and suspected violators.


1.3.4 Public Reaction

   In a state in which radar cannot legally be used to enforce speed
laws on state freeways, videotape surveillance of HOV lanes has
significant legislative and public relations implications.  These
implications are beyond the scope of the current study.  However, two
pieces of information related to the current study may shed some light
on the potential reactions of the public and the media to the
possibility of videotape surveillance.

   Focus Group Reactions.  In a previous study (Billheimer, 1990)
focus group participants were asked their opinions of a ticket-by-mail
system supported by video surveillance.  This possibility generated
heated discussion, and driver opinion split dramatically, but evenly,
on the desirability of videotape surveillance and tickets-by-mail. 
Opponents cited "big-brotherism" while proponents argued that freeway
ticketing caused significant traffic slowdowns.  Most drivers agreed
that the public would have to be educated regarding the need both for
HOV lanes and mail-out citations if such a procedure were to succeed.

   Press Coverage.  The field tests undertaken during the current
study attracted the attention of the Los Angeles media and resulted in
a limited amount of press coverage.  Articles in the Los Angeles Times
and Ontario Daily Report/Progress Bulletin were both balanced and

                                   1-6


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informative.  To the extent that these stories can be viewed as an
indication of press and public reaction to the use of videotape in HOV
lane enforcement, there was no suggestion that CALTRANS and the CHP
would be exposed to a massive public outcry if videotape proves to be
technologically and legally feasible as an enforcement tool. 
Furthermore, it can be assumed that the articles themselves made
potential HOV lane violators in the Los Angeles area more cautious.

1.4   CONCLUSIONS


1.4.1 Enforcement

   Videocameras operating alone cannot currently identify the number
of vehicle occupants with enough certainty to support citations for
HOV lane occupancy violations.  While certain HOV lane infractions,
such as illegal buffer crossings, can be identified unambiguously and
the license plates of violators can be recorded accurately, the rate
of false alarms encountered in using videotape records to document
occupancy violations is much too high to support enforcement actions. 
The chief problem encountered involves the size and positioning of
vehicle occupants.  Small children and sleeping adults can regularly
escape the camera's eye.

   Other problems encountered in attempting to document vehicle
occupancy through video surveillance included glare, ambient lighting
conditions, vehicle size and position, tinted windows, and sight-
obscuring headrests and windshield posts.  These other problems,
however, do not appear to be insurmountable.  Some (i.e. glare and
ambient lighting) can be solved technologically through the use of
filters and continuous camera adjustments.  Others simply lead to
indeterminate occupant counts which would not trigger a citation.  In
any case, these problems are not the kind which lead to the mis-
identification of violators.  They may cause some violators to escape
detection, but they should not produce false alarms so long as the
videotape is carefully interpreted.

   Video cameras operating in conjunction with officer observation may
provide sufficient accuracy to support mail-out citations for HOV lane
occupancy violations.  An officer stationed downstream from the video
cameras is in a position to verify the occupancy of vehicles which
appear suspect to observers monitoring camera output.  If a system of
mail-out warnings or citations can be installed, this officer would
not have to pursue violators, and a videotape record of driver,
occupancy, and license plate will be available for court hearings. 
This system is not foolproof, since the roadside officer may fail to
see a small child missed by the video monitor, but it appears to have
considerable promise.  Moreover, the presence of an observing officer
may remove some of the "Big Brother is watching" stigma from the use
of videotape.

   Analysis suggests that a combined system of video recording,
officer observation, and citations-by-mall is far more cost-effective
than the current system of freeway pursuit and roadside citing.  The
combined video/observation system should be able to produce the same
number of tickets for less than one-third the cost of special overtime
assignments to roadside enforcement.  Furthermore, by eliminating the
need to pursue and cite violators during rush hour, the combined
system improves the safety of both officers and drivers and reduces
the congestion caused by rubbernecking.

                                   1-7


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   -  The use of videotape as a real-time on-line enforcement aid
      appears to be limited to those locations lacking a median
      shoulder or enforcement area where an officer can be posted for
      observation purposes,

      The use of videotape as an aid in enforcement activities
      requiring officer pursuit and on-line citations appears to be
      somewhat limited.  An officer stationed beside an HOV lane in an
      enforcement area is in a better position to observe violators
      than an officer stationed in the control van watching a video
      monitor.  Furthermore, the roadside presence of an officer in an
      enforcement area can have a cautionary effect on drivers. 
      Either officer can radio ahead to pursuit units.

      The only locations where an officer in the videotape van might
      be better able to assist on-line enforcement than an officer on
      the freeway would be those locations where there is no refuge
      area adjacent to the HOV lane.  If there is no median shoulder
      or enforcement area where an officer can be situated for
      enforcement purposes (as in the case, for example, on Marin
      101), video-assisted enforcement stops might be considered as an
      option.


6.1.2 Surveillance

   -  Individual interpretation of occupancy levels by both roadside
      observers and videotape reviewers varies widely with the
      individual and the instrument used.  Evidence suggests that
      roadside observers overstate occupancy violations.  While some
      observers understated the number of vehicles with three or more
      occupants, others using different count sheets overstated the
      number of high occupancy vans carrying six or more people.

   -  Videotape provides a freeway monitoring tool which is
      potentially more consistent and accurate than existing
      techniques for documenting vehicle occupancy.  In addition,
      videotape provides a permanent, verifiable record of the vehicle
      mix, traffic speeds, and the license plates of violators and
      carpoolers.

1.5 RECOMMENDATIONS

   In view of the improved accuracy of videotape surveillance and the
potential promise of videotape as an enforcement tool if used in
conjunction with officer observation, it is recommended that CALTRANS
and the CHP take the following steps to explore further the potential
uses of videotape in HOV lane surveillance and enforcement.

   -  Test the relative accuracy of a four-camera set-up in
      conjunction with an observing officer.  Further field tests
      should be undertaken to explore the relative accuracy of a four
      camera set-up in a freeway setting.  As in past field tests, a
      downstream officer should verify the occupancy of suspect
      vehicles.  However, as an additional check on the accuracy of
      the officer/videotape combination, motor officers should be
      available to pursue and cite vehicles identified as violators by
      both the videotape observers and the verifying officer.

                                   1-8


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   -  Test the impact of mailed warnings on violation rates.  Video
      surveillance should be used in conjunction with a roadside
      officer to monitor several days of HOV lane operations.  Written
      warnings should be mailed to the registered owners of vehicles
      identified as violators by both the videotape monitors and
      roadside officers.  The impact of this activity on HOV lane
      violations should be documented through subsequent videotape
      surveillance and follow-up surveys.  Media support for the
      demonstration should be enlisted through a carefully designed
      program of public information.

   -  Explore the use of videotape on ramp meter by pass lanes.  The
      current study has tested and demonstrated the use of videotape
      in documenting violation activity on mainline HOV lanes. 
      Similar tests should be undertaken on ramp meter bypass lanes.

   -  Continue to explore the legislative/legal ramifications of mail-
      out citations.  The CHP should continue to explore the necessary
      legislative and legal steps necessary to support the use of
      tickets-by-mail for HOV lane infractions.

   -  Continue to explore the uses of advanced videotape technology in
      HOV lane surveillance and enforcement.  Two additional avenues
      of investigation identified through the current research
      include:

      1. The use of micro-cameras installed in the helmets of
         motorcycle officers; and

      2. The use of low level infrared lighting installed at freeway
         level to document the occupancy of departing vehicles under
         conditions of darkness or low visibility.

                                   1-9


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                            2.0  INTRODUCTION

2.1   BACKGROUND

   Enforcement of California's mainline HOV lanes currently requires a
substantial commitment on the part of the California Highway Patrol. 
A recent SYSTAN study (Billheimer, 1990) estimated that the personnel
costs required to enforce the mainline HOV lanes in place in January
1990 exceeded $400,000 per year.  HOV lane enforcement has other costs
as well.  Heavy enforcement during peak commute periods, when
violations are heaviest, leads to rubbernecking which can cause
traffic flow to deteriorate.

   It has been suggested that using video equipment to assist in HOV
surveillance and enforcement could reduce the requirements for patrol
officers, increase citation rates, and minimize freeway disruption. 
It is also possible that a videotape of HOV lane activities could
improve the accuracy of occupancy counts, provide a permanent record
of violations, document the identity of violators, and supply a basis
for mail-out warnings or citations.  Manufacturers of video equipment
claim that it is possible to videotape both the license plates and the
windows of vehicles using HOV lanes, even when those vehicles are
traveling at rapid rates of speed.  What is less well understood is
the ability of the video camera to document with certainty the exact
number of vehicle occupants.  The current investigation is designed to
extend past studies of HOV lane enforcement by testing both the
feasibility and accuracy of the use of video equipment in HOV lane
surveillance.

2.2   OBJECTIVE

   The current investigation has been designed to demonstrate and test
the use of video equipment in determining vehicle occupancy,
documenting violator identity, and aiding enforcement of HOV lanes.

2.3   SCOPE

   As many as four high-speed color video cameras operating from a
special mobile video unit were used in the demonstration.  This
equipment was installed by Advanced Technology Division (ATD), and was
adjusted to detect vehicle occupancy.  Preliminary experiments tested

                                   2-1


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the effect of different camera positions, filter adjustments, and
monitor displays.  Once a promising combination of camera positions
and displays was identified, they were tested in specific HOV lanes in
Southern California.  During the tests, trained observers were
stationed at the roadside to provide manual counts of violations at
the same time that the video equipment was recording.  In addition,
CHP officers stationed downstream from the Mobile video unit were
asked to observe selected video-identified violators to ascertain the
actual number of occupants in the vehicle and possibly issue a
citation.  The results of these tests were then analyzed to determine
the feasibility, accuracy, and cost effectiveness of using video
cameras in HOV lane surveillance and enforcement.

2.4   SCHEDULE OF FIELD TRIALS

   A schedule of the field trials undertaken in the current study
appears in Exhibit 2.1.  Chapter Three details the demonstration
activities undertaken during these trials, while Chapter Four analyzes
test results and lists the lessons learned from the field
demonstrations.  Chapter Five discusses potential applications of
video technology in HOV lane surveillance and enforcement.  Chapter
Six outlines recommendations resulting from the current study.

                                   2-2


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Click HERE for graphic.

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                             3.0 FIELD TESTS

   This section describes the field tests undertaken to test the use
of videotape in HOV lane surveillance and enforcement.  Each test is
described, findings from the field demonstrations and subsequent
analyses are documented, and results are summarized.

3.1   INITIAL CAMERA TEST

   The initial test of the use of video equipment in HOV lane
surveillance took place on the Winnetka Road overcrossing overlooking
the Simi Valley Freeway on August 22, 1989.  The test was designed to
explore alternative lens settings, camera positions, and monitor
displays.  Although there is no HOV lane on the Simi Valley Freeway,
the Winnetka Road overpass is unused and provided a good setting for
experimenting with a variety of camera positions trained on vehicles
in the number-one lane.

3.1.1 Test Equipment

   A mobile video van was employed in the tests.  This unit included
four high-speed video cameras operated from a control console having a
split screen capability.  An infra-red camera and light source were
also available.  Two 3/4" video recording units were used in
conjunction with two monitors to provide simultaneous playback and
recording capability.  A motor-generator supplied AC power for all of
the equipment.  The relative positions of the four cameras and the
control van are diagrammed in Exhibit 3.1.

3.1.2 Test Sequence

   Infra-Red Test.  The ATD crew began setting up equipment at
approximately 4:00 a.m. in order to test the feasibility of obtaining
videotape records under conditions of darkness and poor visibility. 
An infra-red camera and light source were used during this phase of
the test.

   Three-Camera Test. When daylight permitted, four cameras were set
up to record occupancy and license plate information simultaneously
(see Exhibit 3.1). Three cameras were initially deployed as follows:

                                   3-1


.


                               EXHIBIT 3.1

                             INITIAL SET-UP

                         1. Oncoming View
                         2. Oblique Oncoming View
                         3. License View
                         4. Oblique Departing View


Click HERE for graphic.


                                   3-2


.


   Camera 1:   One high-speed video camera was positioned on the
               overpass facing oncoming traffic to provide an oncoming
               view of vehicles traveling in the number 1 lane and
               their license plates.

   Camera 2:   A second high-speed camera was placed on the same side
               of the overpass to provide an oblique view of vehicles
               in the number one lane.  The angle of this camera was
               varied from 900 (right angles to the freeway) to 450 in
               order to determine the most advantageous position.

   Camera 3:   A third high-speed camera was placed on the opposite
               side of the overpass facing the rear of the vehicles
               traveling in the number one lane.  This camera provided
               a view of the rear window of the car as well as license
               plate data.

   Information from all three cameras was displayed simultaneously in
a split-screen format on a single monitor.  Sample split-screen
displays appear in Exhibit 3.2. In addition, a separate monitor
recorded the license plate images provided by Camera 3. Camera
positions were adjusted to determine the most advantageous
positioning, and a variety of split-screen presentations were tested
to determine the configurations best suited for observing vehicle
occupancy.
Four-Camera Test.  A fourth camera was ultimately added to the three-
camera configuration described above in order to provide an oblique
view of the rear of vehicles after they had passed by the observation
post.  Views from all four cameras were displayed in four quadrants of
a split screen monitor, and the position of the fourth camera was
adjusted to provide the most advantageous position.

3.1.3 Post-Test Analysis

   Sample Videotape.  A sample videotape was prepared from the footage
recorded at the Winnetka Road overcrossing to facilitate the
evaluation of different camera angles and monitor displays.  The
sample tape included fourteen different TV monitor displays involving
a combination of camera angles.  The fourteen displays were
characterized as follows:

1. Single camera, rear view         8. Three cameras, rear view
   (Display A in Attachment B)         horizontal
2. Single camera, front view        9. Four cameras, black and white
3. Single camera, rear view            front view
4. Single camera, side view         10. Four camera (Display C in
   (R to L)                             Attachment B)
5. Single camera, side view         11. Single camera, front view
   (L to R)                         12. Single camera, side view
6. Single camera, rear angle        13. Single camera, rear view (dark)
7. Three cameras, rear view         14. Four cameras, synchronized view
   vesticle (Display B in Exhibit 3.2)

                                   3-3


.


                               EXHIBIT 3.2
                       SAMPLE VIDEO MONITOR OUTPUT


Click HERE for graphic.


                                   3-4


.


   Procedure.  To test viewer reactions to the sample videotape, a
standard form was prepared that identified vehicles by description
(license numbers where available, size and color otherwise) and tape
location.  Five raters were asked to view the tape and assess the
occupancy of each vehicle and determine whether the driver was wearing
a seat belt.  Occupancy choices were 1, 2, 2+, 3, 3+ and "unknown."
Seat belt use was identified as "yes," "no," or "?".

   A maximum of 25 cars were rated in each of the fourteen sample
displays.  In all, a total of 232 cars were identified specifically on
the rating sheet.  All but one rater was able to locate all of the
vehicles identified on the sheet.  All of the raters reported that
they had no particular difficulty with the process.

   Raters were provided with stop-motion and rewind controls and
allowed to take as much time as they wished in identifying vehicles. 
They were instructed to make sure that they reviewed all views of a
vehicle in the multiple camera displays before completing the rating. 
The amount of time raters took to review and record their responses to
232 vehicles ranged from one hour and thirty minutes to three hours
and fifteen minutes.

   Results.  Appendix A summarizes the five rater evaluations for each
of the fourteen displays.  A review of this information and
observation of the rating process suggests that:

   -  Vehicle occupancy was easier to observe than seatbelt use;

   -  No single display produced unanimity of results among raters;

   -  Single-occupant vehicles were easiest to identify;

   -  In considering the multi-camera displays, raters tended to
      prefer three-camera displays to four-camera displays, since they
      felt the views provided in the four-way split were too small;

   -  The various displays produced wide variations in rater
      consistency.  Raters provided the most consistent responses to
      the three-camera and four-camera displays (#8 and #9).  The
      least consistent responses were obtained in rear-view shots (#1
      and #3), right-angle shots (#1 2), and the synchronized four-way
      shot (#1 4).

   Raters were asked to comment on the advantages and disadvantages of
each alternative, but few had specific comments.  By the time they had
finished their task, the individual displays had run together in their
minds.


                                   3-5


.


3.1.4  Preliminary Findings

   The field tests and subsequent tape review led to the following
tentative conclusions.

   1. After-Dark Videotaping. Although it is possible to videotape
      license plates from the rear using an infra-red camera and light
      sources, it does not appear feasible to document occupancy under
      conditions of darkness or low visibility.  Results are not clear
      and the light source can be a distraction to oncoming drivers.

   2. Playback Necessity. Under real-time viewing conditions, it is
      usually necessary to play back the videotape to make sure that a
      vehicle suspected of violating HOV requirements actually has too
      few occupants.  The playback/conformation action can take from
      30 seconds to one minute, so that any officers responding to
      broadcast descriptions of violators will have to be at least one
      to two miles downstream from the taping site.

   3. Number of Cameras. During the field test, the four-camera set-up
      appeared to provide the most useful information on vehicle
      occupancy.  However, viewers reviewing the tape after the fact
      preferred the three-camera setup, feeling that the images
      provided in the four-way split were too small.

   4. Camera Angles.  During the initial trial, it appeared that the
      camera facing the oncoming vehicles (Camera 1 in Exhibit 3.1)
      should be set at a shallow angle (with the horizon) to keep
      vehicles in the frame as long as possible.  The oblique camera
      (Camera 2) should be aimed to cover the same field of vision as
      the camera facing traffic directly.  In this way, the two views
      of the vehicle (head on and oblique) appear simultaneously on
      the split screen, providing a visual cue to the monitor viewer. 
      As a practical matter, the amount of occupancy information
      provided by the oblique camera appeared to increase as the angle
      between the camera and the roadway decreased (i.e. as the camera
      was aimed farther down the roadway).  Very little useful
      information was transmitted when the camera was set at right
      angles to the roadway.

      The two cameras trained on the rear of departing cars should be
      focused at sharper angles to the freeway to provide clearer
      license plate definition.  As with the forward-facing camera,
      the oblique camera (Camera 4 in Exhibit 3.1) should be trained
      on the same segment of freeway as the camera directly over the
      departing cars (Camera 3).

   5. Missed Observations.  Although the four-camera system provided
      conclusive occupancy information on most vehicles, car design,
      camera angles, glare, tinted windshields, changing light
      conditions and a variety of other problems made it impossible to
      obtain occupancy information on 1 00% of the vehicles
      videotaped.

   6. Simultaneous Display.  Although it is possible to acquire video
      equipment capable of introducing an on-line time delay in the
      monitoring system so that all four images of a single vehicle
      are displayed simultaneously, the expense of this equipment
      (currently estimated at roughly $50,000) does not appear to be
      justified.  Furthermore, the on-line delay would have to be
      adjusted constantly as vehicle speeds change.  The on-site
      observer will have to review the tape under most circumstances,
      and can quickly review the separate images produced by the two
      forward-facing cameras and the two rear-facing cameras.  Any
      requirement for simultaneous hard-copy records can be
      manufactured in the studio after the initial data have been
      recorded.

                                   3-6


.


   7. License Plate Documentation.  License plates can be captured
      with sufficient accuracy on the quarter-screen display of the
      multiple-image monitor.  They need not have a separate dedicated
      full-screen monitor.

3.2   INITIAL ENFORCEMENT TEST

   On October 19, the first of a series of tests using CHP officers
and on-line video displays to identify possible violators was
undertaken.  The test took place at the Wilmington Avenue overpass
overlooking the eastbound HOV lane on LA 91.  As the demonstration was
initially set up, a single officer in the control van monitored the
video display and radioed descriptions of suspected violators ahead to
two motor officers.  The two motor officers verified the number of
occupants in the vehicle and, at their discretion, issued citations to
drivers violating the HOV lane's occupancy requirements.

3.2.1 Demonstration Set Up

   Equipment.  Three cameras were set up on the Wilmington Avenue
overcrossing and linked to two video monitors in the observation van. 
The location of the camera is diagrammed in Exhibit 3.3. Two cameras
focused on oncoming traffic in the HOV lane, while the third camera
recorded license plates of departing vehicles.  One of the monitors in
the van provided an ongoing, time indexed record of the three camera
views.  Exhibit 3.4 shows the three views displayed on the monitor. 
The second monitor provided the viewing officer with a stop-action and
review capability which made it possible to replay and reexamine the
images of suspected violators before making a final decision on the
number of occupants.

   Officer Participation.  The video equipment was in place and
running by 12:00 noon.  At that time two motor officers took up
positions at on-ramps roughly one-and-a-half miles downstream from
Wilmington Avenue.  A third officer was stationed in the observation
van and given a brief run-down on equipment operations.  The three
officers then experimented with the too[ during the relatively light
midday traffic.  When the observing officer spotted a potential
violator, she would review the tape, note the license number, and
radio the vehicle description ahead to the two motor officers, who
would pursue the suspect and verify the violation.  Even during the
light midday traffic, some suspected violators went unverified if the
motor officers were busy pursuing previous calls.

                                   3-7


.


                               EXHIBIT 3.3
                       INITIAL ENFORCEMENT SET-UP

                         Three Cameras On Bridge
                         1. Oncoming View
                         2. License View
                         3. Oblique View


Click HERE for graphic.


                                   3-8


.


Click HERE for graphic.


                               EXHIBIT 3.4

                             MONITOR DISPLAY
                        INITIAL ENFORCEMENT TESTS

.


   At 2:00 p.m. the CHP shifts changed, and a new set of officers
replaced the initial participants.  The incoming officer quickly
learned videotape operations, and the new team of officers was in
place by 2:19.

   As the evening commuter traffic built up, it became increasingly
difficult for motor officers to pursue violators from positions near
freeway ramps.  When it became apparent that more and more suspects
were escaping unverified, the officers repositioned themselves at an
enforcement area being constructed about 1500 feet downstream from the
observation point. (See Exhibit 3.5.) From this stationary position
next to the HOV lane, they were able to observe most of the suspected
violators identified by the officer viewing the videotape.


3.2.2 Analysis of Results

   Field Test Findings.  A summary of the traffic observations made by
the second team of officers during the evening commute period appears
below:


   TIME         SUSPECTED     VIOLATOR    VIOLATOR       VERIFICATION RESULTS
                VIOLATORS   DESCRIPTIONS DESCRIPTION  VIOLATOR  SUSPECT  UNABLE TO
                OBSERVED        SENT    ACKNOWLEDGED  VERIFIED   NOT A    OBSERVE
                                                               VIOLATOR   SUSPECT

INITIAL TIME       12            12          11           1        5         5
2:15-3:25 (Motor
officers pursuing)


OFFICERS           29            29          28          18       10         0
REPOSITIONED
3:30-4:20 (Motor
officers stationary
in enforcement
area)


CAMERA             18            18          16           8        6         2
REPOSITIONED
4:29-5:00 (Motor
officers stationary)


TOTAL              59            59          55          27        2        17


                                  3-10


.

Click HERE for graphic.


                               EXHIBIT 3.5
                     VIDEOTAPE DEMONSTRATION PHOTOS


.


   Motor officers were able to observe 48 of the 59 (81%) suspected
violators whose descriptions were broadcast by the observing officers. 
Of the suspects actually observed, 27 of 48 (56%) were verified as
violators.  However visual observation at freeway level showed that
44% of the suspects turned out to have the required number of
occupants.  This rate of false alarms is far too high for any mail-out
warning scheme.  However, the rate represented the results of a first
trial, and several adjustments were identified to improve future
accuracy.

   Both of the officers assigned to the van were able to master the
use of the video monitor quickly and with no difficulty.  At first,
both tended to try to review the tape on potential violators before
the violator had passed by the third (rear-view) camera, but this
tendency was quickly remedied.

   The position of the oblique camera was adjusted at 4:30 p.m. to
provide a more direct view downward view into the passenger seat of
the oncoming vehicles.  The observing officer felt that this view
"...improved things 110%" but it did not noticeably reduce the false
alarm rate.

   Data Reduction. In order to check the relative accuracy of the
officers making decisions during peak commuting hours against the
accuracy of office workers reviewing the videotape under more relaxed
conditions, office personnel subsequently screened the October 19 tape
record for the hour between 3:30 p.m. and 4:30 p.m., classifying
vehicle occupancies.  The occupancy records documented by reviewers
during that period are listed below.


   LA 91: 10/19/89
  Vehicle Occupancy        1      2       3     3+   Can't Tell  Total
3:30 p.m. to 4:30 p.m.

       Number             86     947     111    45       58      1247

       Percent           6.9%   75.9%   8.9%   3.6%     4.7%     100%


   Thus the office reviewers counted 86 violators during the one-hour
period, a violation rate of 6.9%. Over the same period, the CHP
officer viewing the videotape on the scene had identified 29 potential
violators.  When field officers assigned to the freeway checked these
29 vehicles, they found that 19 actually were violators, while 10 had
at least two occupants.  This represented a success rate of 66%.

                                  3-12

.

   Only fourteen of the twenty-nine vehicles verified by officers at
the time of the field trial were identified as potential violators by
the office reviewers.  Of these, eleven vehicles had been identified
as actual violators, while three had the required number of occupants,
even though they escaped the camera's eyes.  This represented a
success rate of 79% for the off ice reviewers.

   As would be expected, reviewers identified more potential violators
than the officer on the scene, who needed to make decisions in real
time and was often reviewing videotape or conferring with field
officers as other violators passed before the camera.  It is also not
too surprising that the office reviewers, who enjoyed the luxury of
unlimited screening time, had a higher percentage of accuracy (79% vs.
66%) than the field officer.  Because of the relatively small sample
size this higher accuracy percentage is not statistically significant
(at the 5% significance level).

3.2.3  Preliminary Findings

   The following preliminary conclusions and observations were made
following the initial videotape/enforcement demonstration on LA 91. 
These observations and findings would be tested further in subsequent
demonstration runs.

   1. Real-Time Enforcement Efficacy.  The use of videotape as a real-
      time enforcement aid appeared to be somewhat limited.  The
      officer in the van radioed descriptions of more potential
      violators than the two motor officers could apprehend, but he
      could easily have made the same observations from a roadside
      enforcement area, where his presence might have had a cautionary
      effect on drivers.  The only locations where an officer in the
      videotape van might be better able to assist on-line enforcement
      than an officer on the freeway would be those locations where
      there is no refuge area adjacent to the HOV lane.  If there is
      no median shoulder or enforcement area where an officer can be
      situated for enforcement purposes, video-assisted enforcement
      stops might make more sense.  The Marin 101 HOV lane is a good
      example of such a location.  In the previous test of enforcement
      tactics on Marin 101, it was virtually impossible to find an
      adjacent location where a motor officer could safely observe
      traffic (Billheimer, 1990).

   2. Camera Positioning.  The ability of officers stationed beside
      the HOV lane to sight violators that escaped detection by the
      overcrossing camera suggested that an unobtrusive freeway-level
      micro-camera might be used to good advantage in HOV lane
      surveillance.

   3. Technical Difficulties.  A few technical problems were noted
      which would be corrected in future runs.

      -  At certain times of day, windshield glare prevented viewers
         from observing the number of vehicle occupants.  On future
         runs, polarized filters would be used to combat this effect.

                                  3-13


.


Different lengths of cable leads from the control van made it
difficult to synchronize the color and images provided by the three
cameras.  On future runs, cable leads would be reconfigured to balance
line resistance and minimize this problem.

3.3   EYE-LEVEL CAMERA TESTS

   Since officers in the enforcement area alongside the HOV lane on LA
91 were able to detect occupancy violations with more success than
cameras and observers stationed on overpasses above the HOV lane, ATD
undertook the development of a camera that could record the same view
as that seen by the roadside officers.  Since this camera would be
located alongside the HOV lane, it was essential that it be
unobtrusive enough to avoid distracting passing drivers.  To that end,
they developed a micro-camera and mount capable of being installed on
the median divider.

3.3.1 Field Testing

   Three field tests were made to develop, test, and demonstrate the
roadside micro-camera.

   (1)   On December 12, 1989, ATD tested the installation of a micro-
         camera along the Simi Valley freeway at the Winnetka
         overcrossing.  Various camera levels were tested, and best
         results were obtained from a camera position slightly higher
         than the car roof, angled downward to provide a view of the
         passenger seat and right rear seat.  Exhibit 3.6-A shows the
         camera-tripod arrangement tested on the Simi Valley Freeway.

   (2)   On December 14, 1989, ATD tested the use of polarized filters
         in conjunction with the micro-camera.  The test was conducted
         on DeSoto Avenue near ATD headquarters, and resulted in the
         development of a tiny filter capable of reducing the effect
         of glare when the micro-camera is recording.

   (3)   On December 19, 1989, the team tested the eye-level micro-
         camera on LA 91 with CHP officers present to review the
         videotape and verify violations on the freeway itself. 
         Exhibit 3.6-B shows the micro-camera installation on a fence
         post rising from the LA 91 center divider, while Exhibit 3.7
         shows the relative positions of the three cameras used in the
         demonstration.  Two experienced CALTRANS freeway observers
         were also on hand to count vehicle occupants from the bridge
         level and provide a basis for comparing manual and videotape
         counts.

                                  3-14

.

                               EXHIBIT 3.6
                     TESTS OF EYE-LEVEL MICRO-CAMERA


Click HERE for graphic.


Click HERE for graphic.


                                  3-15


.


                               EXHIBIT 3.7

                         Two  Bridge Cameras And Eye-Level Camera
                         1.Oncoming View
                         2.License View
                         3.Drivers Eye Level View


Click HERE for graphic.


                                  3-16


.


3.3.2  Test Results

   Camera Functioning. The primary purpose of the series of tests
undertaken in December 1989 was to develop and demonstrate a micro-
camera suitable for roadside installation.  From this technological
standpoint, the tests were successful.  The micro-camera was small
enough to avoid distracting drivers and still provide useful
information to the control van monitor.  Exhibit 3.8 shows one of the
views provided by the eye-level micro-camera.  The camera provided a
good view of rear-seat occupants, particularly those in the right rear
passenger seat.  Occupants in the left rear seat whose heads were
below window level might still escape detection.  Depending on car
design and shutter-timing, riders in the passenger seat next to the
driver could be obscured by the windshield post.

   Enforcement Support.  Attempts to document the accuracy of the
three-camera set up on LA 91 on December 19 were marred by several
problems.

   1. Shortly after the cameras were in place, a truck overturned at
      the freeway ramp linking eastbound LA 91 to southbound LA 710.    
      This accident occurred downstream from the test overpass, and
      the participating officers were called away to deal with the
      emergency.

   2. When the officers returned, they experienced problems
      establishing a communications frequency separate from the
      Westminster area's dispatch frequency.

   3. The license plate camera failed intermittently, as did a
      replacement camera.

   4. The control van monitor was not fitted with a timer unit, making
      it difficult to document ongoing activities for future
      reference.

   All officers had returned and established a working communication
channel by 4:00 p.m., and were able to verify suspect violations for a
half-hour, before it became too dark to proceed.  Unfortunately, the
intermittent failure of the license plate camera made it difficult to
undertake a subsequent analysis of the tape to compare reviewer
observations with on-line verifications.

3.3.3 Observations

   On-Line Accuracy.  The officer viewing the monitor in the van
tended to rely on a single camera view, the view of oncoming traffic
provided by Camera #1, in determining whether or nota vehicle was a
violator.  He rarely experimented with the monitor controls to get the

                                  3-17


.


                               EXHIBIT 3.8
                    SAMPLE VIEW FROM EYE-LEVEL CAMERA


Click HERE for graphic.


                                  3-18


.


benefits of the eye-level camera.  This may have been because the
motor officers observing traffic were located in an enforcement area
only 1500 feet downstream from the overcrossing, so that decisions had
to be made rapidly.  During the period between 4:00 p.m. and 4:30, the
officer in the control van radioed the descriptions of 24 suspected
violators to the motor officers downstream.  Eight of these 24
suspects were found to have the required number of passengers, eight
were identified as violators, and eight were not located.*  Of the
sixteen suspects verified by close-up observation, therefore, only 50%
turned out to be actual violators.  This high false-alarm rate can't
be taken as a comment on the accuracy of the eye-level camera,
however, since in most cases the van officer did not wait to consult
the eye-level camera before radioing suspect descriptions.

   Counter Accuracy.  During the same 4:00 to 4:30 period that the van
officer identified 24 suspect violators, CALTRANS observers positioned
on the overpass counted 32 violations.  While CALTRANS counters
observed every vehicle, the van officer sometimes took time to rewind
the tape and take a second look at a suspect vehicle.  Hence it is not
surprising that the observers would count more violators than the van
officer.  However, the fact that only half of the suspects identified
by the van officer turned out to be violators suggested that the
observers may also be overstating the actual number of violators. 
This possibility would be further tested in the final videotape
demonstration.

3.4   FINAL ENFORCEMENT TEST

   The final test of videotape technology in enforcement took place on
January 4, 1990 at the Warner Avenue overcrossing on OR 55.

3.4.1    Demonstration Set-Up

   Cameras.  Exhibit 3.9 shows the locations of the four cameras used
in the demonstration.  The cameras were installed and ready for use at
2:00 p.m. Between 2:00 p.m. and 4:00 p.m. three camera views were fed
to the monitor: The oncoming scene recorded by Camera 1 of Exhibit
3.9, license plate data revealed by Camera 2, and an eye level view of
passing
______________________________

   * Reasons for the lack of verifications varied.  Some suspects
bailed out of the lane when the downstream officers came into view. 
In other cases, the suspect description arrived too late, after the
vehicle had already passed the enforcement area.


                                  3-19


.


                               EXHIBIT 3.9
                              FINAL SET-UP

                         1.  Oncoming View
                         2.  License View from Bridge
                         3.  Driver's Eye Level View
                         4.  License View from Roadway


Click HERE for graphic.


                                  3-20


.


traffic provided by Camera 3. At four o'clock, Camera 4 was switched
into the system to provide a freeway-level record of license plate
information, replacing that of Camera 2. The views of Cameras 3 and 4
were synchronized to provide a simultaneous image of a car's interior
and its license plate.

   Enforcement. Three motor officers from the Santa Ana office were
assigned to assist with the demonstrations.  At two o'clock, the three
officers took up positions at an enforcement area about 2,000 feet
downstream from the overcrossing.  Between two and three-thirty, the
officers verified the occupancy levels of vehicles identified as
potential violators by an ATD employee seated in the control van.  At
3:30 one of the officers took over in the control van.  Whereas the
ATD employee was more adept at reviewing the tape to determine the
license numbers of potential violators, the officer was better able to
describe the suspect vehicles from their profiles ('Check out the
white Camaro") and communicate his descriptions to his fellow
officers.

   Between 3:45 and 4:00, the officers left the enforcement area to
cover an accident which occurred just downstream from the Warner
Avenue overcrossing.  There was no way to verify the occupancies of
potential violators during this period.  Aside from this single
instance, however, the demonstration went smoothly.

3.4.2 Analysis of Results

   Field Test Findings.  A summary of the traffic observations made by
the van occupants and field officers during the OR 55 demonstration
appears on the following page:

                                  3-21


.


                                                                   ADDITIONAL
    TIME/     SUSPECTED    VIOLATOR      VERIFICATION RESULTS       VIOLATORS
 START/END/   VIOLATORS  DESCRIPTIONS  VIOLATOR SUSPECT UNABLE TO    SPOTTED
VAN OBSERVER* OBSERVED   ACKNOWLEDGED  VERIFIED  NOT A   OBSERVE     BY FWY.    TOTAL
                                               VIOLATOR  SUSPECT    OFFICERS  VIOLATORS

 2:15-2:30/C      6            5           3       2        1           0         3
 2:30-2:45/C      8            5           3       2        3           1         4
 2:45-3:00/C      7            6           3       3        1           0         3


 3:00-3:15/C      4            4           2       2        0           2         4
 3:15-3:30/C      2            2           1       1        0           1         2
 3:30-3:45/O      3            3           0       3        0           0         0
Officers Called
Away at 3:45


 4:00-4:15/O      3            3           1       2        0           1         2
 4:15-4:30/O      2            2           0       2        0           4         4
 4:30-4:45/O      9            9           4       5        0           1         5
 4:45-5:00/O      9            8           2       6        1           2         4


                 53           47          19      28        6          12        31

   *C = Civilian Observer in Van
    O = Police Officer in Van

   During the demonstration, field officers verified the occupancy of
forty-seven vehicles identified as suspects by the van occupants.  Of
these forty-seven vehicles, nineteen (40.4%) turned out to be
violators, while twenty-eight (59.6%) had the required number of
occupants.  These field results should not necessarily be used to
gauge the accuracy of the video monitoring system, since the van
occupants were under pressure to call out the identity of suspect
vehicles before they passed the field officers 2,000 feet downstream. 
As a result, they sometimes identified suspects from the first view
seen (the view provided by the single. head-on camera) without
checking other views.

   In this regard, the performance of the two observers was remarkably
different.  The monitoring observer in the van from 2:15 to 3:30 was a
civilian employee of ATD familiar with the playback system and its
controls.  He was much more likely to check the view from the eye-
level camera before alerting the field officers to the presence of a
possible violator.  On the other hand, the motor officer who took over
at 3:30 was more likely to single out a potential violator on the
strength of a single view from the head-on cameras.  The relative
accuracy of the two observers reflects their difference in approach:
Of the twenty-two suspects identified by the civilian

                                  3-22


.


observer, twelve (54.5%) actually turned out to be violators.  In the
case of the second observer, only seven of twenty-five suspects (28%)
were found to be violators.

   The on-line performance of both observers could undoubtedly have
been improved if the enforcement area used as an observation post by
the field officers had been further downstream.  Both van operators
were rushed to identify potential violators before they had passed the
observation post.*

   Data Reduction: Accuracy.  In order to check the ability of
reviewers to identify violators using the videotape alone, five
observers reviewed different segments of the videotape and identify
occupancy violators.  Each observer was instructed in the use of the
monitor and asked to identify those vehicles which they felt should
receive citations for occupancy violations based solely on the
videotape evidence.

   The results of the review are summarized below:


                    Violator   Vehicles                            False
Observer   Time     Suspects    Checked   Violator      Suspect    Alarm
 Number   Period   Identified  In Field   Verified  Not a Violator Rate

    1    2:18-3:45     15          4          3            1        25%
         4:05-4:30      2          1          1            0        0%

    2    2:18-3:45     89         19          9           10       52.6%

    3    2:48-3:20     22          5          2            3        60%
         4:30-5:00     27          9          4            5       55.6%

    4    2:45-3:00     18          5          2            3        60%

    5    3:00-3:20      3          0          0            0        0%

  TOTAL                176        43         21           22       51.2%

   * The selection of monitor views may also have contributed to the
   tendency of the van operators to rely on a single image in
   identifying violators.  During the first enforcement test on LA 91,
   the second image presented in the van was an oblique shot of the
   passenger seats taken from the overcrossing.  This image followed
   the initial oncoming shot closely in time and the van officers
   tended to wait for it before judging a vehicle occupancy.  The eye-
   level view of suspects did not appear on the screen until roughly
   seven seconds after the first view of the vehicle had disappeared,
   and the van observers appeared to be less likely to wait for this
   delayed view.


                                  3-23


.


   Forty-three of the 176 suspect vehicles identified by the videotape
reviewers had been checked by field officers at the time the videotape
was made.  When these vehicles were compared with the officer reports,
22, or 51.2% were found to have the required number of occupants. 
Thus the false alarm rate for the eye-level camera was actually
greater than that experienced with the bridge-level camera.  Although
the sample sizes were not large enough to be statistically
significant, the high error rate suggests conclusively that videotape
cannot currently be used as the sole means of identifying violators
for enforcement purposes.

   Data Reduction: Occupancy Counts.  To obtain further insights into
the relative accuracy of videotaped occupancy counts, three observers
were asked to monitor videotapes of three different fifteen-minute
periods of HOV lane activity, and record the number of occupants of
each vehicle passing by the camera during each period.  The occupancy
counts recorded by each of the three videotape viewers are tabulated
along with counts made by roadside observers in Exhibit 3.10.

   The tabulations of Exhibit 3.10 show that the occupancy counts
recorded by the three videotape viewers not only differ from those
recorded by the roadside observer, but also from each other. 
Videotape observer #1 recorded occupancy rates that were consistently
higher than those recorded by the roadside counter, while videotape
observer # recorded consistently lower occupancy rates.*  A three-way
analysis of variance showed that the observers differed significantly
among themselves in two key judgments: 1) identification of violators;
and 2) identification of vehicles with three or more occupants.

   Because of the marked differences in the results obtained from the
three different videotape observers, it is difficult to draw any
general conclusions regarding the relative accuracy of videotape vs.
roadside observations in documenting vehicle occupancy.  A careful
check of the tape suggests that the roadside observers consistently
understated the number of vehicles with
______________________________

* The first observer displayed a tendency to understate violations and
produce a relatively high number of 3+ vehicle sightings.  She was
reluctant to label a vehicle as a violator until she had carefully
examined all three views of the vehicle, and searched each view
thoroughly for evidence of a third passenger.  Observer number 3 went
through the videotape more quickly, requiring less evidence to label a
suspected violator and spending less time searching for additional
passengers.  During the third fifteen-minute time period, where the
sun's angle darkened the view from the eye-level camera, the
tendencies of these two observers were magnified.  Observer number 1
recorded only one violator during the period.  She couldn't be sure
there wasn't a second occupant out of her view.  Observer number 3
found 26 possible violations during this same period, but only two
vehicles with three or more occupants.  Without the eye-level camera,
he couldn't identify a third occupant with sufficient certainty.

                                  3-24


.


                              EXHIBIT 3.10

                       OCCUPANCY COUNT COMPARISONS


 Time Period   Buses   Motorcycles     Vehicle Occupancy      Computation
                                                Don't     Violation Occupancy
             1/2 Full                1   2   3+ Know Total  Rate      Rate

  2:45-3:15
   COUNTER       1          6       10  242  21   0   280   3.57%     2.10

 Observer 1      2          7        7  203  50  20   289   2.60%     2.32
 Observer 2      1          7       26  160  40  27   261   8.45%     2.17
 Observer 3      1          7       21  188  10  39   266   9.25%     2.00


  3:00-3:15
   COUNTER       0         11       11  234  10   0   266   4.14%     1.97

 Observer 1      0         10        4  159  38   9   220   1.90%     2.20
 Observer 20     9         18       159 27   20  233 7.84%  2.06
 Observer 3      0          9        8  170  15  21   233   3.91%     1.93


 4:15-4:30*
   COUNTER       1          9        7  218  23   0   258   2.71%     2.12

 Observer 1      1          6        1  139  27  43   217   0.57%     2.27
 Observer 2      1          5       16  160  22  22   226  11.11%     2.12
 Observer 3      2          6       26  128   2  44   208  15.85%     1.97
______________________________

   * During this time period, the angle of the sun was such that the
   eye-level camera provided very few views inside passing vehicles.

                                  3-25


.


three or more occupants, and therefore, presumably understated
occupancy levels.  This finding is not surprising, since it is easy to
overlook some occupants and roadside observers must make instantaneous
judgments without the benefit of the replay knob available to
videotape viewers.  Given the differences observed among videotape
viewers, however, it is dangerous to extend this observation from the
specific CALTRANS observers watching traffic on January 4 to the more
general class of roadside observers.  It is possible that another set
of roadside observers might have overstated the number of vehicles
with three or more occupants.*  If there is one lesson to be learned
from these comparisons, it is that different observers can produce
widely different estimates of the occupancy levels of the same flow of
vehicles.  Consequently, when reviewing trends in traffic
observations, sudden jumps in violation rates or occupancy levels
should, be viewed with some skepticism if different observers were
responsible for successive counts.


3.4.3 Preliminary Findings

   Camera Positioning.  Dropping the license plate camera to freeway
level was viewed as a positive move at the time, since it synchronized
the views from two of the cameras and took some of the guesswork out
of the on-line review process.  However, office personnel using the
tape to identify violators preferred the license plate view generated
by the overhead camera, since it often provided a view into the
backseat of the vehicle as well.

   Verification of Manual Counts.  During the last two videotape
demonstrations (December 19 on LA 91 and January 4 on OR 55), CALTRANS
provided personnel who counted
______________________________

* This actually appears to have happened during the December 19 field
test on LA 91.  There CALTRANS counters from Division 7 used different
forms from those used by the Division 12 counters observing OR 55. 
The headings on the two count sheets are reproduced below:

District 7 (LA 91):  1 2 3 4 5 6+  6+ Vans  M/C  Full Bus  1/2 Bus  1/4 Bus  Empty Bus
District 12 (OR 55):   1/2 Bus  Full Bus    M/C  1  2  3+

The availability of a counting slot for 6+ vans in the district 7
count sheets resulted in many entries being made in that category.  A
review of the videotape for that day suggested that many vans were
being classified as 6+ occupants when it was impossible to see inside
the van or when a van actually had far fewer than six occupants.  In
this case, therefore, the roadside observers undoubtedly overstated
actual occupancy rates on LA 91.  There is no way of knowing whether
this tendency extends beyond the count crew assigned to the videotape
field test.  The current study was not designed to explore the
accuracy of count crews in detail.  However, the limited findings
suggest that CALTRANS should standardize its count forms, train
counters carefully, and check for differences among individual
counters.

                                  3-26


.


occupancy rates from their normal positions on the overcrossing.  Two
counters were available on both occasions.  Preliminary results
suggest that manual counts made from overcrossings may overstate the
number of HOV lane violators.

   The table below compares manual counts with the observations of
roadside officers tallying violators downstream from the overcrossing.

   FREEWAY:                        OR 55              LA 91

   TIME PERIOD:                1415 to 1530       1600 to 1630

   VIOLATIONS OBSERVED BY
   COUNTERS                         38                 32

   SUSPECTED VIOLATIONS
   OBSERVED BY MONITOR
   VIEWER                           27                 24

       - Violations Verified        12                  8
       - Legitimate Vehicles        10                  8
       - Vehicle Not Sighted         5                  8

   ADDITIONAL VIOLATIONS
   SPOTTED BY FIELD OFFICERS         4                  0

   TOTAL VERIFIED VIOLATIONS        16                  8


   In both cases, the viewer in the control van registered fewer
suspected violators than the observers on the bridge.  This is not
surprising, since the van viewer had the ability to rewind the tape
and take a second look at a suspect vehicle.  Sometimes violators
drove by while this review was taking place.  However, the downstream
officers were instructed to report on all violators they saw passing
them, whether or not the viewer in the control van had alerted them to
check a particular vehicle.

   Only 50% of the suspect vehicles actually checked by the officers
stationed beside the LA 91 HOV lane turned out to be violators.  In
the case of OR 55, 54.5% of the suspects identified by the monitor
operator were violators.  As noted, these figures should not
necessarily be used to gauge the accuracy of the video monitoring
system, since the van occupants were under pressure to call out the
identity of suspect vehicles before the vehicles passed the police
officers

                                  3-27


.


downstream.  However, the results do indicate that manual counts
probably overstate the actual violation rate, perhaps even doubling
it.*

   While theoretically interesting, this knowledge may have little
practical impact.  Even if suspects turn out not to be violators
(usually because there is a child out of the view of the camera and
the CALTRANS counters), the fact that they look like violators can
affect the public perception of the HOV lane.

   HOV lane critics have accused CALTRANS in the past of understating
actual violation rates.  These critics are not likely to believe that
the rates have actually been overstated, particularly when many
vehicles which are actually legal carpools look like violators.  In
this regard, one of the positive aspects of the use of videotape in
HOV lane surveillance is that it provides a permanent record of HOV
lane activity.  Critics who doubt reported violation rates can be
provided with copies of the relevant tape as a rebuttal.

   Unambiguous Violator Identification: Buffer Violations. Although
many suspected occupancy violations identified on videotape turned out
to be false alarms, one type of violator could be unambiguously
identified one hundred percent of the time.  This was the buffer
violator who entered the HOV lane illegally by crossing the double
yellow line at a place where lane changing was not allowed.  Exhibit
3.11 shows an example of one such violator.

   Buffer violators can be easily identified, even when fast-
forwarding through the videotape.  So long as the violators are
entering the lane (rather than leaving it), moreover, the appearance
of the driver and the license plate of the vehicle will be recorded by
the video surveillance system.

   Accuracy and Ambiguity: Missing-Children.  Infants or children
hidden from the camera's view were the most common causes of violator
misidentification by videotape viewers.  Exhibit 3.12 shows three
views of a taxi cab videotaped in the OR 55 HOV lane on January 4. The
______________________________

* In all, the freeway officers on LA 91 saw eight violators in the
same span of time that the counters tallied thirty-two.  On OR 55, the
freeway officers saw sixteen violators while the counters tallied
thirty-eight.  Heisenberg's principle affects these findings to a
certain extent, since some violators left the lane when they saw
officers in the enforcement area.  However, when the violators were
first under the scrutiny of the van occupants and the CALTRANS
counters, they were well out of range of the officers in the
enforcement area.  The fact that the field officers found that only
half of the suspects identified by the van occupants were actually
violators, coupled with the relative number of sightings reported by
the van observers and bridge counters, suggests strongly that the
counters on the bridge were no more accurate than the observers in the
control van.

                                  3-28


.


                              EXHIBIT 3.11
                     MONITOR VIEW OF BUFFER VIOLATOR


Click HERE for graphic.


                                  3-29


.


                              EXHIBIT 3.12

                   MONITOR VIEWS OF SUSPECTED VIOLATOR
                          WITH UNDETECTED CHILD

                            (Yellow Cab #51)


Click HERE for graphic.


                                  3-30


.


observer in the control van, along with four subsequent videotape
viewers, independently identified the taxi as an HOV lane violator. 
However, the motor officer observing traffic in the lane downstream
from the taping point reported that there was a small child in the
cab's backseat.  Yet four different observers failed to identify the
child in repeated viewings and reviewings of the videotape.

   Accuracy and Ambiguity: Tinted Windows. Exhibit 3.13 shows three
views from the eye level camera.  In the first view, the rear seat
contains a passenger, the second vehicle is a violator (verified by
the roadside observer), and the third vehicle has tinted windows,
making a judgment on the occupancy of the rear seat impossible.  Such
problems as tinted windows, sight-obscuring headrests, windshield
posts, and ill-positioned vehicles generally caused the videotape
viewers to list the occupancy as unknown or guess at the occupancy
from a single front view.  Most test viewers were reluctant to
identify vehicles as potential violators when one or more of the
supporting views was obviously obscured.  While tinted windows can
produce indeterminant or biased occupancy counts, therefore, they are
not likely to trigger false violation alarms, so long as the videotape
viewers are well trained.

   Certain vision-obscuring problems could potentially bias occupancy
counts.  The vehicles most likely to have windows out of range of the
eye-level camera were buses and vans, precisely those vehicles which
are likely to carry a high number of occupants.  If videotape viewers
ignore these vehicles because they can't see into the rear windows,
occupancy rates will be artificially low.  As noted, moreover,
ambiguous views can cause different viewers to react in different
ways.  Faced with a large number of obscure views from the eye-level
camera, one viewer understated violation rates because she shouldn't
be sure there wasn't a second occupant somewhere in the car.  Another
viewer understated the number of vehicles with three or more occupants
because he couldn't be sure the back seat was occupied.

                                  3-31


.

                              EXHIBIT 3.13
                   VIEWS FROM EYE-LEVEL CAMERA SHOWING

   1 - Rear Seat Occupant
      2 - Empty Rear Seat
         3 - Tinted Windows


Click HERE for graphic.


                                  3-32


.


                            4.0 TEST FINDINGS

   This chapter summarizes the findings of the various field tests. 
Technical considerations related to camera selection and positioning
are discussed, display preferences are outlined, and issues of
accuracy are addressed.

4.1   EQUIPMENT CONSIDERATIONS

4.1.1 Illumination

   Ambient Sunlight.  The only lighting used during the enforcement
tests was the ambient light from the sun.  Thus every recording
session presented a challenge, because the light intensity and angle
of incidence was changing throughout the daytime hours.  For instance,
if the early-morning sun is directly behind the camera and the
sunlight is directed downward into the front passenger compartment,
then the passengers in the front seat will be well-illuminated and
considerable detail can be recorded.  However, late in the afternoon,
the opposite condition will exist and the passengers will be seen in
silhouette.

   Clean, well-polished vehicles can also present a problem for the
camera.  As these vehicles move down the highway under the sun's rays,
bright reflections can bounce off of the bumpers and chrome trim.  On
occasion, these reflections have been severe enough to mask the
occupants of the vehicle.

   Filters.  Problems with glare were partially solved by using
polarizing filters.  The effect of these filters varied considerably,
depending upon the angle of the sun in relationship to the passing
cars.  The polarizing filters had the undesirable effect of reducing
the light-gathering capability of the cameras by one complete "f"
stop.

   The most undesirable filters encountered were the privacy screens,
or tinted windows, installed in many new vehicles.  These tinted
screens keep both cameras and roadside observers from viewing the
interior of vehicles.

   Infrared Possibilities.  HOV lane surveillance must take place when
the majority of HOV lane users are in transit.  This usually means the
early morning and late evening hours.  Since peak traffic periods can
start before dawn and extend after dusk, ATD tested the use of
infrared

                                   4-1


.


lamps to augment ambient light from bridge-top camera positions.  The
infrared lamps made it possible to record license plates after dark. 
No attempts were made to illuminate oncoming traffic using infrared
lamps, however, since it was feared that the lamps might prove to be a
distraction for drivers.

   It also appears feasible to use infrared lighting in conjunction
with a low-level camera to extend the hours of operation of the
surveillance system after dark.  This approach would focus infrared
lamps and a near-infrared sensitive camera on the windows of the car
after it had passed, so that the light source could be shielded from
the view of the driver.  These lamps will illuminate the interior of
the car from the low-elevation camera positions.  This should make
high-speed recording possible under night-time conditions, although
ATD did not undertake a low elevation test employing infrared lamps.

4.1.2 Camera Specifications

   Contrast Ratio. The NTSC television signal is limited to a contrast
ratio of approximately 10:1. That means that ten shades of gray can be
resolved when looking at the TV screen.

   Unfortunately, the ratio between the bright unfiltered sunlight and
the light in the interior of a moving vehicle may exceed 100:1.  Very
careful adjustment of the camera system must be made to compensate for
these wide ranging light levels.  For instance, it may be necessary to
let the sky "wash-out" in order to pick up the interior of the
vehicle.  As previously mentioned, highlights from windows or bright
work will further complicate the recording of high-contrast images.

   Motion Blur.  HOV lane traffic typically moves at speeds from 50 to
65 mph.  When using close-up images, the "blur" at a standard 1/60th
of a second exposure rate will be unacceptable.  At these speeds,
tests were made at 1/100th, 1/500th, 1 /1000th and 1/2000th of a
second.  These tests showed that an exposure time of 1/1000th of a
second are required.  This exposure rate reduces the light
availability by four "f" stops.  In order to compensate for the light
loss, a modified color NTSC camera should be used that has at least
24db of gain boost.  It is preferable to have an automatic gain
circuit as well as a manually selected gain capability.

   Lens Selection. Since high speed exposures are required, very low-
light-level cameras must be used.  Field tests showed that it was
desirable for the observer to have five-to-ten seconds to determine
the number of occupants in the front seat of an oncoming vehicle.  To
accomplish this, a lens with a long focal length must be focused on
oncoming vehicles that are

                                   4-2


.


approximately 1/4 mile away.  Experimentation led to the selection of
a 14:1 zoom lens having a focal length from 20 mm to 280 mm.

   Monochrome or Color Capability.  Tests were run with both
monochrome (black and white) and color cameras.  Although the
monochrome system seems to have slightly better contrast and
resolution capability, the advantages of using color in identifying
vehicles far outweigh the slight loss in resolution when a color
system is used.  However, careful technical alignment of the cameras
is required to satisfy the stringent timing requirements needed to
synchronize color cameras.  Slight timing imperfections can cause
significant changes in the perceived color of the same vehicle
displayed in different quadrants of the same picture.

   Resolution.  In order to see sufficient detail in the interior of a
moving vehicle, adequate resolution must be achieved by the camera,
the recording medium, and the viewing monitors.  A color system having
the resolving capability of 300 tv lines is desirable.  It is
necessary to record multiple images within one frame of view.  The
recorded resolution is reduced by about 25% in each quarter/frame
image.  In order to resolve the license plate numbers, the field-of-
view must be limited to no more than an eight foot segment of the
traffic lane.  This makes it possible to resolve five horizontal dots
across each letter or number on the license plate.

4.1 .3   Camera Positions

   Many tests were conducted with cameras situated in different
locations on top of overcrossings and at various locations in the
median shoulder alongside HOV lanes.  Four camera views appeared to
provide the maximum amount of information about vehicle occupancy. 
These views are diagrammed in Exhibit 4.1.

   Bridge Cameras.  As shown in this exhibit, one camera is set up to
observe oncoming traffic at approximately 1/4 mile from the
overcrossing.  The long range view provided by Camera #1 does not
allow the observer to look down into the front seat to see a rider who
is resting in a reclining seat, or a child who is below the level of
the dashboard.  To overcome this defect, a second camera is positioned
to look down into the vehicle at a much steeper angle.  This camera
should be aimed so that the vehicle is picked up shortly after it
disappears from the view of the first camera.  If the views of cameras
1 and 2 are tightly synchronized, monitor observers have an easier
time picking up the second image, and are more likely to rely on it in
making on-line decisions.

                                   4-3


.


                               EXHIBIT 4.1

                         SAMPLE CAMERA POSITIONS

                         1.  Oncoming View
                         2.  Oblique Oncoming View
                         3.  License View
                         4.  Eye-Level View


Click HERE for graphic.


                                   4-4


.


   Eye-Level Camera.  A third camera is set up in the median barrier
approximately 1 00 feet from the overcrossing.  It is located
approximately five feet above the level of the road and is pointed at
an angle approximately 300 from the perpendicular to the traffic. 
This camera provides a view of the rear seat occupants and a second
check on the occupants of the seat next to the driver.  Best results
were obtained from the eye-level camera when it was positioned under
the overpass itself.  The shadow of the overpass minimized ambient
light changes and maximized the contrast available in shots inside the
vehicle.

   License Camera.  The fourth camera is set up to document license
plate numbers.  If the plates are being recorded primarily for
subsequent off-line reviews, the license plate camera should be
located on the overcrossing and aimed downward at a steep angle.  This
downward angle often provides additional information on the occupants
of the rear seat.

   If license plates are being recorded primarily as an aid for on-
line enforcement, the license plate camera should be located
approximately five feet above the roadway about 125 feet from the
overcrossing.  This license plate camera should be aimed to record the
vehicle at the same time that the eye-level camera is documenting
occupancies.  In this way, both images will be on the screen at the
same time, and the task of identifying the particular vehicle is
simplified.

4.1.4 Cable Requirements

   Recent introduction of some color high-speed video cameras that
allow power to be transmitted down the Video cable have simplified the
set-up of HOV cameras.  These units can be used up to 500 feet from
the control van without the use of additional power cables.  This
allows the use of only one small (1/4" diameter) cable for each
camera.  In addition, cameras that are powered from one simple control
are relatively easy to time correctly from the van location.

4.2   DISPLAY PREFERENCES

4.2.1 Real Time Decisions

   For real-time decision-making, viewers seemed to prefer a monitor
display showing three views of the suspect vehicles: (1) An oncoming
view; (2) An oblique view downward into the passenger seat; and (3) A
view of the license plate.  Exhibit 4.2 shows a sample of these three

                                   4-5


.


                               EXHIBIT 4.2
                    SAMPLE VIEWS FROM BRIDGE CAMERAS


Click HERE for graphic.


                                   4-6


.


views.  The view from the oncoming camera is displayed vertically on a
full half screen in order to provide as much time as possible for an
initial judgment regarding the number of occupants in a particular
vehicle.  The remaining views are each displayed on a quarter of the
monitor screen.

   When making real-time decisions, viewers tended to pay more
attention to the oblique view of the passenger seat, because it
followed closely after the oncoming view and was somewhat easier to
locate in a review mode.  If the first two views showed a potential
violator, the monitor viewer would ultimately stop the tape to
document the license number of the vehicle.

   When the eye-level camera was used, the view from that camera
tended to be delayed until about seven seconds after the image of the
vehicle had left the screen, so that the viewers were forced to wait
and stop the tape to obtain a second view of suspect vehicles, then
search for the license number.  The need to search for the second view
proved so bothersome in an on-line environment that some viewers
ignored the second view and made decisions solely on the basis of the
view from the initial camera.

4.2.2 Delayed Decisions

   When decisions regarding vehicle occupancy could be delayed for
more leisurely review away from the freeway, the most useful monitor
display appeared to be one which provided the most information - that
is, four views of the suspect vehicle.  The four recommended views are
the four views produced by the camera positions sketched in Exhibit
4.1: (1) An oncoming view of the vehicles; (2) A view of the license
plate; (3) An oblique view downward into the passenger seat; and (4)
An eye-level view through the side windows.

   These four views were not tested simultaneously in an enforcement
setting in the current study.  However, such a test should be part of
any future research program.

                                   4-7


.


4.3   ACCURACY

4.3.1 Buffer Violations

   Buffer violators, those drivers who enter or leave the HOV lane
illegally by crossing the double yellow line where lane changing is
not allowed, were easily identified by the camera recording oncoming
traffic.  Violator sightings were unambiguous, and the license plates
of those drivers entering the lane are recorded by the video
surveillance system.

4.3.2 Occupancy Violations

   Videotape reviewers cannot currently identify the number of vehicle
occupants with enough certainty to support citations for HOV lane
occupancy violations.  In early tests with three cameras located on an
overpass, subsequent videotape review produced a false alarm rate of
21%.  In later tests with one of the three cameras moved to the
freeway itself, the false alarm rate rose to 51%.  The chief cause of
false alarms appeared to be small children and sleeping adults located
out of the view of all three cameras.

   Ambient lighting conditions, glare, and such vehicle design
features as tinted windows, headrests, windshield posts, and high
windows also made it difficult to interpret the number of videotaped
vehicle occupants consistently.  Videotape reviewers differed widely
in their attempts to document vehicle occupancy levels.  These
differences suggest that tape reviewers must be well-trained to ensure
that certain conditions (i.e., glare) do not trigger false alarms and
that ambiguous views are treated consistently by all reviewers.

4.3.3 Roadside Occupancy Counts

   It is difficult to draw general conclusions regarding the accuracy
of roadside counters from the observations of two crews, since it is
possible that the observations of different roadside observers will
vary as greatly as those of different videotape reviewers.  It
appears, however, that roadside counters may overstate the number of
HOV lane violators.  One set of counters clearly understated the
number of 3+ vehicles passing the observation point (this was the
highest number of occupants required by their count sheets).  Another
set of counters apparently overstated the number of 6+ vehicles using
count sheets with a heading for 6+ vans passing their observation
point by assuming that most vans had six or more occupants.


                                   4-8


.

                       5.0 POTENTIAL APPLICATIONS

   This chapter discusses potential applications of videotape
technology in HOV lane surveillance and enforcement in the light of
the field test findings.  Issues of cost-effectiveness and public
attitudes are addressed, and future research directions are
identified.

5.1   ENFORCEMENT APPLICATIONS

   Videotape can be used to support HOV lane enforcement in at least
two ways:

   1. On-Line Assistance. Video cameras can serve as enforcement eyes,
      identifying and recording the identity of potential violators
      who are then pursued and cited by officers located downstream
      from the control monitor.

   2. Remote Ticketing. Videotape records might potentially be used to
      trigger a system of mailed warnings or citations, reducing the
      need for on-line enforcement.

5.1.1 On-Line Assistance

   The use of videotape as an on-line enforcement aid appears to be
somewhat limited.  An officer stationed beside an HOV lane in an
enforcement area is in a better position to observe violators than an
officer stationed in the control van watching a video monitor. 
Furthermore, the roadside presence of an officer in an enforcement
area can have a cautionary effect on drivers.  Both officers can radio
ahead to pursuit units and are likely to see far more violators than a
team of two pursuit units can handle (larger enforcement teams are
likely to cause rubbernecking and traffic breakdowns).

   The only locations where an officer in the videotape van might be
better able to assist online enforcement than an officer on the
freeway would be those locations where there is no refuge area
adjacent to the HOV lane.  If there is no median shoulder or
enforcement area where an officer can be situated for enforcement
purposes, video-assisted enforcement stops might make more sense.  The
Marin 101 HOV lane is a good example of such a location.  In the
previous test of enforcement tactics on Marin 101, it was virtually
impossible to find an adjacent location where a motor officer could
safely observe traffic (Billheimer, 1990).

                                   5-1


.


5.1.2    Remote Ticketing

   From an enforcement standpoint, the real promise of videotape is
its potential use as a triggering mechanism for a system of mailed
warnings or citations.  The successful implementation of such a system
could save officer time, reduce the number of hazardous pursuits
needed to apprehend HOV lane violators, and improve traffic flow by
eliminating much of the rubbernecking which follows ticketing
activities during peak commute hours.

   How It Might Work. If such a system were implemented, a four-camera
set-up could be used to document HOV lane use.  Videotapes of peak
commute hours would be screened by trained observers, the license
plates of violators would be noted, hard photographic copies
documenting the violation would be produced, and warning letters or
citations would be mailed to the registered owner of the violating
vehicle.  Photographic evidence of the violation would not be
forwarded to the vehicle owner.  However, this evidence would be
available in the event that the citation is appealed in court.

   Although California cannot currently issue warnings or tickets by
mail to registered owners, a few states have instituted such
procedures.  Exhibit 5.1 contains a copy of the letter sent to Seattle
drivers as part of that city's HERO program to discourage the illegal
use of HOV lanes.

   Implementation Problems.  A number of hurdles need to be cleared
before HOV tickets by mail could become a reality in California. 
These include:

   1. Demonstration of the technical feasibility and accuracy of
      videotape as an enforcement tool;

   2. Clearing of the legal impediments to citing the registered owner
      of a vehicle by mail;

   3. Consideration of the public information issues associated with a
      ticket-by-mail campaign and the campaign's impact on the public
      acceptance of HOV lanes.
______________________________

* Two such states are Washington and Virginia.  Seattle has relied on
other drivers for descriptions of violating vehicles as part of their
HERO program (Reference, 1).  Virginia relies primarily on the
observations of police officers in identifying violators who are sent
citations through the mail (Tollett, 1990).

                                   5-2


.


                               EXHIBIT 5.1
                    WARNING LETTER TO SEATTLE DRIVERS

              JOHN SPELLMAN                 DUANE BERENTSON
                Governor                       Secretary

                           STATE OF WASHINGTON
                      DEPARTMENT OF TRANSPORTATION
                   Office of District  Administration
     D-1, 6431 Carson Ave. So., C-81410 - Seattle, Washington 981O8

                                  Date

Name
Address
City, State, Zip

Dear:

     At approximately time on date your vehicle, license
number ORH606 was observed in violation of-the bus/carpool
lane restrictions on Location.

     State law restricts usage of these lanes to buses,
motorcycles or vehicles carrying three or more persons. 
This restriction is in effect 24 hours a day.  If your
vehicle is observed again in violation of the bus/carpool
lane restrictions, the State Patrol will be notified.

     We are concerned with the unauthorized use of the
bus/carpool lanes.

     More new freeways cannot be built because of high cost,
environmental factors, and land consumption.  Therefore,
alternative means of travel must be found to relieve present
congestion and to accommodate future growth in the Seattle
area.

     The bus/carpool lanes increase the people-moving
capacity of Interstate 5. Running at only a quartet of their
capacity, the bus/carpool lanes carry 2700 people in the
peak hour.  The other lanes each carry 2200 people in four
times as many vehicles and run virtually at capacity.

     Because there are fewer vehicles in the bus/carpool
lanes. speeds are higher than in the other lanes.  Higher
speeds provide the commuter with a shorter travel time -- an
incentive to carpool or take a bus.  Each time someone
shares a ride, everyone benefits since fewer vehicles are
competing for space in the other freeway lanes.

     If you did not violate the bus/carpool lane
restrictions, or would like to discuss the bus/carpool lanes
or our actions, please call me at (206) 764-4376.

                                 Sincerely,


                                 Traffic Systems Management
                                 Washington State Department
                                 of Transportation

                                   5-3


.


   This study has focused on the first aspect, the technical
feasibility and accuracy of videotape as an enforcement tool.  Legal
issues are beyond the study scope, as are public information concerns,
which are addressed briefly in a later section.

   Based on field test findings to date, videotape technology by
itself does not appear to be sufficiently accurate for use in a system
of mail-out warnings and citations.  Although the technology is
capable of providing accurate views of vehicle windows and license
plates when traffic is moving at top speed, and certain offenses (i.e.
illegal buffer crossings) can be unambiguously recorded on tape, the
false-alarm rate caused by children and adults out of camera range is
too great to support citations for occupancy violations.

   The problem of accuracy is further exacerbated by the need to deal
with ambient lighting.  As a day's shooting progresses, the movement
of the sun can cause the view provided by a particular camera to be
obscured by glare or to lose definition.  Filters and aperture
adjustments can sometimes overcome these problems, but camera crews
need to remain alert to make such adjustments.

   Promising Configurations.  Although videotape by itself does not
appear to be accurate enough to provide a basis for citations, the
combination of videotape and an observing officer could conceivably
provide the accuracy needed for a system of mailed warnings and
citations.  Such a system could work in much the same way as the
recent field tests.  That is, an officer would be posted far enough
downstream from the video cameras to verify the occupancy of suspect
vehicles and identify violators who escaped the notice of observers in
the control van.  Warnings or citations would be mailed only to
vehicles which were identified as violators by the observing officer
and by a review of the videotape.

   This process is not foolproof, since it is possible that the
observing officer could fail to see a child or sleeping adult who also
escaped the notice of the camera's eyes.  However, such mistakes
should be relatively rare, and the officer would have the videotape
record to back up any required court testimony.  The proposed
procedure also fails to free officers entirely from special overtime
assignments to HOV lane enforcement.  However, a single officer used
in conjunction with a videotape set-up should be able to identify
nearly all of the violators passing both the video camera and the
officer's observation post.  This would result in the issuance of far
more citations than the officer could possibly write on his own. 
Furthermore, a mail system would eliminate the need to pursue and cite
violators during rush hour, thereby improving officer safety and
reducing congestion caused by rubbernecking.

                                   5-4


.

   Future Research Needs.  Future videotape research should explore
the use of four camera views in an enforcement setting.  Although the
current research experimented with four views, the most promising
combination of views (long shot of oncoming vehicles, oblique view of
passenger seat, eye-level view of rear seat, and downward shot of
license plate) was never tested.

   Future research should also test the concept of mailed warnings by
using the combination videotape and observing officer to identify
violators.  Lane activity should be monitored on several successive
days, warnings should be mailed to suspected violators (i.e.,
violators identified by both the officer and videotape reviewers), and
the impact on freeway violations and public response should be
monitored.  By using videotape to monitor HOV lane operations in this
fashion, it should also be possible to develop a better understanding
of the incidence of repeat violators on violation totals.

   Other uses of videotape technology should also be explored.  For
example, a microcamera installed in the helmet of a motorcycle officer
could document vehicle occupancy at the same time that the officer
does.  The camera would provide a record of both vehicle occupancy and
driver identity, and could even document the license plate as well. 
If the legal obstacles to mail-out tickets could be overcome, the
micro-camera could provide a videotape record in support of a mailed
citation.  This would make it unnecessary for officers to pull
vehicles over during commute-hour traffic, thereby improving their
efficiency and avoiding the congestion resulting from rubbernecking.

   Virginia has established a system of mail-out warnings based on the
visual observation of officers (Tollett, 1990).  However, registered
owners are currently able to escape prosecution by claiming they
weren't driving their vehicle or asserting that a small child was
aboard at the time.  A videotape record provided by a micro-camera
could counter this line of defense.

5.2   PERFORMANCE MONITORING

   Although videotape systems do not currently appear to provide
enough accuracy to support occupancy citations, there are several
applications for which such systems are ideally suited and provide a
marked improvement over current practice.  These include:

                                   5-5


.


   1. Freeway Monitoring to document vehicle type and occupancy over
      time.

   2. HOV Lane Monitoring to document occupancy rates as an aid for
      enforcement planning; and

   3. Project Evaluation to document the impact of HOV lanes and other
      carpool incentives on occupancy rates.

5.2.1 Freeway Monitoring

   The task of documenting vehicle occupancy and vehicle type in
monitoring freeway performance over time is new to most operating
agencies.  In many areas of California, there are no historical
records of vehicle occupancy rates which can provide a basis for
tracking carpool trends or assessing the likely impact of proposed
carpool incentives.  With the increased emphasis on air quality
control and ridesharing, it is important that freeway operations
personnel begin to document not only the number of vehicles using
freeway segments, but also vehicle mix and occupancy levels.  Current
tests suggest that video cameras can provide a more consistent and
accurate record of vehicle occupancy rates than roadside counters. 
Moreover, the tape supplies a permanent record of freeway activity
which can be consulted long after the initial counts were made.

5.2.2  HOV Lane Monitoring

   Intelligent planning of HOV lane enforcement requires, at a
minimum, annual monitoring of violation rates so that appropriate
levels of overtime enforcement can be allocated.  This is especially
important in the case of ramp meter bypass lanes, which rely almost
exclusively on special overtime enforcement.  Recent experience in
California suggests that monitoring activities have fallen behind or
been set aside as bypass lanes have proliferated.  Video surveillance
provides a technique for obtaining and maintaining consistent and
accurate records of the use of ramp bypass lanes and other HOV
facilities for planning purposes.  Furthermore, this availability of
license plate data can identify the incidence of repeat violators. 
The permanent record provided by the videotape can also help to
silence skeptics who challenge figures cited in support of HOV lane
operations.

                                   5-6


.


5.2.3 Project Evaluation

   Objective evaluation of HOV projects requires careful measurement
of vehicle occupancies before and after the installation of a new HOV
lane.  If proper occupancy measurements are not made (or are made
inconsistently) before a lane is installed, the lane's impact can
never be documented adequately.

   Even if many manual counts are made, the inconsistencies of
individual counters can color results.  On the Santa Monica Diamond
Lanes, for example, one observer responsible for counting vehicle
occupancies before the lanes were installed consistently understated
the number of vehicle occupants.  When this observer was replaced
following the lane installation, subsequent counts showed steep (but
overstated) carpooling increases (Billheimer, 1978).  Similarly, early
occupancy counts on the separate HOV lane on San Diego 1-15 proved to
be inaccurate because one particular observer consistently understated
violation rates.  The use of videotape records provides a consistent
and verifiable approach to documenting occupancy rates before and
after the installation of an HOV project.


5.3   UNIT COSTS

5.3.1 Equipment

   Purchase Cost. The cost of outfitting a van with four color cameras
capable of recording HOV lane activity at the same level of detail as
the field tests documented in this study is estimated to be $108,000. 
Exhibit 5.2 itemizes the individual components of this cost.  The
largest components are the van itself ($36,000), three U-Matic three-
quarter-inch video recorders ($14,500), four high-speed color cameras
with telephoto lenses ($10,800), a special effects generator
($10,000), and California sales tax ($6,828).

   Contracting/Licensing Costs. For jurisdictions which do not have
sufficient surveillance needs to invest in a fully equipped van and
train personnel to record and reduce data, ATD Incorporated has set
the cost of videotaping a peak period of HOV lane activity at $5,000. 
This price includes the use of the equipment listed in Exhibit 5.2,
along with the services of trained operators.  It does not, however,
include the costs of reducing the videotaped data.

                                   5-7


.

                               EXHIBIT 5.2
                       HOV VIDEO VAN COST ESTIMATE

Item Description                      Qty.     Cost     Extended

01  Motor Van with Toilet and Cab-bed   1   $36,000.00   $36,000.00
02  Air Conditioner                     1     1,500.00     1,500.00
03  Motor Generator (4Kw)               1     2,500.00     2,500.00
04  Awning                              1     2,000.00     2,000.00
05  Trailer Hitch                       1       350.00       350.00
06  Custom Equipment Racks              1     2,000.00     2,000.00
07  Mobile Phone                        1     1,500.00     1,500.00
08  Emergency Light/Generator           1       800.00       800.00
09  Fire Extinguishers (2)              2       100.00       200.00
10  Battery Powered Work Lights         3        50.00       150.00
11  Portable Lantern                    1        25.00        25.00
12  Safety Cones                       24        25.00       800.00
13  Safety Signs, Stands and Flags      2       100.00       200.00
14  Walkie/talkie Radio                 2       300.00       600.00
15  Sand Bags                          12        25.00       300.00
16  Tool Kit                            1       300.00       300.00
17  Hard Hats                           4        50.00       200.00
18  Safety Vests                        4        25.00       100.00
19  Equipment Storage Case              4       200.00       800.00
20  Hi Speed Color Camera               4     1,500.00     6,000.00
21  Telephoto Zoom Lens                 4     1,200.00     4,800.00
22  CCU with Genlock                    1       600.00       600.00
23  Heavy Duty Tripod with Arm          4       450.00     1,800.00
24  Fluid Pan/Tilt Head                 4       300.00     1,200.00
25  Quick Release Plates                4        25.00       100.00
26  Portable Viewfinder (4")            2       300.00       600.00
27  U-Matic "B" VCR                     2     4,000.00     8,000.00
28  U-Matic "B" Edit VCR                1     6,500.00     6,500.00
29  Edit Controller                     1     1,900.00     1,900.00
30  13' Hi Res monitor, Color           3       500.00     1,500.00
31  Quad B/W Monitor                    1       950.00       950.00
32  Quad Split Device, Color            1     2,900.00     2,900.00
33  Special Effects with Dual TBC       1    10,000.00    10,000.00
34  Video Cable Reels (150')            5       150.00       750.00
35  Video Cable Reels (300')            5       300.00     1,500.00
36  Power Cable Reels (50')             3        25.00        75.00
37  Power Cable Reels (150')            3        50.00       150.00
38  Video Cam-Corder with Case          1     1,500.00     1,500.00
39  Mounting Clamp Set                  1       100.00       100.00
40  Wheel Chocks and Ramps              2        50.00       100.00

    Total Mobile Vehicle Price                          $101,150.00

    California State Sales Tax                             6,827.62

    TOTAL COST OF VAN AND EQUIPMENT                     $107,977.62


                                   5-8

.

5.3.2 Personnel

   Recording.  Two experienced operators are required to set-up and
operate the video equipment.  The amount of personnel time required to
cover one four-hour peak period is roughly sixteen hours, or eight
hours for each operator.  This includes set-up and tear-down time, as
well as the time consumed in traveling to and from the site.

   Data Reduction.  Data reduction time can vary widely from
individual to individual.  Current experience in reducing test data
suggests that the following ranges apply:

   -  Personnel time required to identify violators: 2 to 4 hours per
      hour of videotape

   -  Personnel time required to identify violators and document
      vehicle occupancy: 4 to 8 hours per hour of videotape

   Personnel Costs.  Assuming personnel costs of $30.00 per hour,* the
following costs would be incurred in recording and reducing.


                PERSONNEL COST OF RECORDING AND REDUCING
                    FOUR PEAK HOURS OF HOV LANE DATA

           VIOLATIONS ONLY                          VIOLATIONS AND OCCUPANCY

Recording

  2 people, 8hrs = 16hrs @ $30 = $480.00    2 people, 8hrs = 16 hrs @ $30 = $480.00

Reducing

  1 person, 12hrs = 12hrs @ $30 = $360.00   1 person, 24hrs = 24 hrs @ $30 = $720.00

Total
                    28 hrs @ $30 = $840.00                    40 hrs @ $30 = $1,200.00


   Data reduction costs will drop as trained personnel learn to
perform the tasks and become more efficient.  Data reduction costs
could also be lowered by sampling occupancy rates rather than
recording precise occupancy counts for each vehicle during the four
hour period.
______________________________

* This represents the high range of fully loaded costs for ordinary
time, and the low range of overtime costs for CALTRANS personnel at
the level needed for field observations.


                                   5-9


.


5.3.3    Relative Cost Effectiveness

   Enforcement Costs. Although video technology has not yet proven
itself capable of supporting a system of mail-out citations, it is
instructive to consider the potential cost effectiveness of such a
system.  The most promising system identified in the current research
would use a video van in combination with a roadside officer to
provide the license plate information needed for mailing out
citations.  Such a system would not replace the routine enforcement
activity currently in place on California's mainline lanes, but it
might reasonably be expected to replace the overtime assignments
needed to augment this routine enforcement.

   Concurrent research suggests that a program aimed at ticketing 2.5%
of HOV lane violators can be expected to keep overall violation rates
within an acceptable 10% level (Billheimer, 1990).  There are
currently roughly 500 peak commute periods in California each year
(two periods during each of 250 weekdays).  Covering 2.5% of these
periods would require enough personnel to ticket every violator during
12.5 peak periods.  However, experience has shown that routine
enforcement is responsible for well over half of the citations issued
for mainline HOV lane violations in California.  Thus special overtime
enforcement needs to pick up less than half of the total citations
needed, say enough citations for all violators encountered during six
peak periods on each project.

   The personnel cost of covering a single peak period on one of
California's mainline HOV lanes with a combination of video recording
and officer observation can be approximated as follows:

  One motor officer on overtime           6 hours @ $50/hour =      $300
  Van personnel - 2 people                8 hours @ $30/hour =       480
  Data reduction - 1 person              12 hours @ $30/hour =       360
                                                               ---------
  Total Personnel Costs                                           $1,140

  Allocating these personnel costs to each of California's ten
mainline HOV lanes and allowing for equipment depreciation produces
the following annual cost:

  Personnel Costs - $1140 x (54 peak periods                     $61,560
  Equipment Depreciation ($107,977.62  4**)                      26,994
                                                               ---------
                                                                 $88,554
______________________________

* Eight of California's ten mainline lanes operate during both am and
pm peaks.  Two (SF 280 and LA 91) effectively operate only during one
peak, producing a total of 54 peak periods of special enforcement (six
for all lanes operating during both peaks, and three each for LA 91
and SF 280.)

** Assumes that the equipment is fully depreciated over four years.


                                  5-10


.


   Thus the annual costs of supplementing routine enforcement with a
system of mail-out citations supported by a combination of video
documentation and officer observation would be $88,554.  Since the CHP
currently allocates at least $334,000 to the special overtime
enforcement of HOV lanes, this represents a considerable savings.  In
addition, a video-based surveillance system would obviate the need for
pursuit and citation by special enforcement units during peak commute
periods and therefore would be both safer for CHP officers and
motorists and less likely to cause congestion than the current
approach.

   Accordingly it appears that the prospect of video-based enforcement
is sufficiently attractive so that the CHP should continue to attempt
to develop a system capable of supporting mail-out citations.

   Monitoring Costs.  The personnel costs of recording and reducing
four peak hours of HOV lane data using a three-camera video display
have been estimated at $840 if the data reduction activity focuses
only on violations, and $1200 if both violations and occupancy are
recorded for every car. (See Section 5.3.2.) To these personnel costs
must be added an allowance for equipment depreciation.  If every
mainline HOV lane in California were monitored twice yearly during
each peak period, the cost of video monitoring could be computed as
follows.

Annual cost of monitoring violations only:

  Personnel Costs:                  $840 x (36 peak periods) =   $30,240
  Equipment Depreciation                   ($107,977.62  4) =    26,994
                                                               ---------
                                                                 $57,234

Annual cost of monitoring violations and occupancy:

  Personnel Costs:                   $1200 x (36 peak periods)   $43,200
  Equipment Depreciation                                          26,994
                                                               ---------
                                                                 $70,194

On the other hand, the cost of obtaining the same data through manual
observation, as it has historically been obtained, is considerably
cheaper:

  Personnel Time:

     On-Site Recording:                     2 people x 6 hours  12 hours
     Data Reduction:                        1 person x 2 hours   2 hours
                                                               ---------
     Total                                                      14 hours

Annual Cost of Manual Observation

  Personnel Costs:       14 hours x $30/hour x 36 peak periods   $15,120

                                  5-11


.


   Thus manual monitoring of HOV lanes is considerably less expensive
than videotape monitoring.  While these figures are rough estimates,
and the annual depreciation charged to mainline HOV lane monitoring
could be much less (if, for example the video equipment were applied
to other uses such as the surveillance of ramp meter bypass lanes or
freeway monitoring in support of air resource board calculations), the
personnel costs involved in videotaping lane activity and reducing the
taped data will always be at least double the cost of manual
observation.

   The videotape observations, to be sure, provide far more
information than the manual records provided by roadside counters. 
Videotape provides more accurate records, a consistent data base, and
a permanent, verifiable record of traffic activity.  It also provides
information on the vehicle mix, traffic speeds, and the license plates
of violators and carpoolers.

   Officials contemplating the use of videotape in monitoring HOV lane
performance must ask themselves whether the added benefits provided by
the videotaped data are worth the added cost.  If the data can be used
as a basis for enforcement, of course, the question is moot.  As noted
earlier, the cost of videotaping and reducing mainline HOV lane data
appears to be more than justified if that data can be used as a basis
for citing violators and offsetting the need for overtime enforcement
activity.

5.4   PUBLIC RELATIONS

   In a state in which radar cannot legally be used to enforce speed
laws on state freeways, videotape surveillance of HOV lanes has
significant legislative and public relations implications.  These
implications are beyond the scope of the current study.  However, two
activities occurring during the study may shed some light on the
possible reactions of the public and the media to the possibility of
videotape surveillance.

   (1)   In a previous segment of the study (Billheimer, 1990), focus
         group participants were asked their opinion of a ticket-by-
         mail system supported by video surveillance.

   (2)   The field tests undertaken during the current segment of the
         study attracted the attention of the Los Angeles media and
         resulted in a limited amount of press coverage.

                                  5-12


.


5.4.1 Focus Group Reactions

   During an investigation of HOV lane violations (Billheimer, 1990),
six focus group discussions were conducted with drivers on four
freeways having HOV lanes: Orange County Route 55 (two groups), Los
Angeles Route 91 (two groups); Santa Clara Route 101; and Marin Route
1 01.  These focus groups probed drivers' perceptions of and attitudes
toward HOV lanes, violations, and enforcement activities.  In five of
the six focus groups, the possibility of video surveillance and
tickets-by-mail was suggested by members of the group.  At the close
of all six group discussions, this possibility was outlined and
participants were asked their opinion of the concept.  Discussions
were invariably heated, with strong feelings on either side of the
issue.  In the end, participants in three focus groups favored using
mail-out citations, while participants in the three remaining groups
were opposed.  A summary of the arguments for and against the concept
appears below:

   (1)   Arguments For.  One OR 55 driver noted that "Mail-out tickets
         is the best way (to enforce HOV lanes).  Pulling violators
         over is almost out of the question ... It really messes up
         the traffic pattern." Another OR 55 driver felt that mail-out
         tickets would "...free police for more important duties.  But
         that doesn't mean the CHP should disappear.  That visibility
         is important." Several drivers made the point that before
         mailing out tickets, the state "...needs to educate the
         public first." The public needs to understand both the need
         for compliance with HOV regulations and, in particular, the
         need for video surveillance.

   (2)   Arguments Against.  "Shades of Big Brother" was the most
         frequently cited argument against mail-out citations.  Many
         drivers expressed concern over the technological problems
         involved in making sure that the camera hadn't missed a baby
         or a sleeping adult.  Even when the majority of the group
         favored mail-out tickets, there was generally a vocal
         minority which felt strongly that they were an invasion of
         privacy.

   In short, driver opinion split dramatically on the desirability of
videotape surveillance and tickets-by-mail.  Opponents cited "big-
brotherism" while proponents argued that freeway ticketing caused
significant traffic slowdowns.  Most drivers agreed that the public
would have to be educated regarding the need both for HOV lanes and
mail-out citations if such a procedure were to succeed.


5.4.2  Press Coverage

   The Los Angeles Times took an interest in the videotape tests and
sent a reporter and cameraman to the Warner Avenue overcrossing on the
day of the final field test.  The reporter,

                                  5-13


.


Eric Bailey, interviewed most of the participants in the test, as well
as representatives from the Orange County based Drivers for Highway
Safety.  The text of Bailey's story, which ran in the Times on January
9, appears in Appendix B. Although the story predictably raised the
specter of Big Brother, it was balanced and informative, and has
evidently generated remarkably little negative reaction.  A follow-up
piece by John Rezendes-Herrick of the Daily Report/Progress Bulletin
in Ontario, California was similarly balanced (see Appendix B).  To
the extent that these stories can be viewed as an indication of press
and public reaction to the use of videotape in HOV lane enforcement,
there was no suggestion that CALTRANS and the CHP would be exposed to
a massive public outcry if videotape proves to be technologically and
legally feasible as an enforcement tool.  Furthermore, it can be
assumed that the articles themselves made potential HOV lane violators
in the Los Angeles area more cautious.

                                  5-14


.


6.0   CONCLUSIONS AND RECOMMENDATIONS

6.1   CONCLUSIONS

6.1.1 Enforcement

   -  Videocameras operating alone cannot currently identify the
      number of vehicle occupants with enough certainty to support
      citations for HOV lane occupancy violations.  While certain HOV
      lane infractions, such as illegal buffer crossings, can be
      identified unambiguously and the license plates of violators can
      be recorded accurately, the rate of false alarms encountered in
      using videotape records to document occupancy violations is much
      too high to support enforcement actions.  The chief problem
      encountered involves the size and positioning of vehicle
      occupants.  Small children and sleeping adults can regularly
      escape the camera's eye.

      Other problems encountered in attempting to document vehicle
      occupancy through video surveillance included glare, ambient
      lighting conditions, vehicle size and position, tinted windows,
      and sight-obscuring headrests and windshield posts.  These other
      problems, however, do not appear to be insurmountable.  Some
      (i.e. glare and ambient lighting) can be solved technologically
      through the use of filters and continuous camera adjustments. 
      Others simply lead to indeterminate occupant counts which would
      not trigger a citation.  In any case, these problems are not the
      kind which lead to the misidentification of violators.  They may
      cause some violators to escape detection, but they should not
      produce false alarms so long as the videotape is carefully
      interpreted.

   -  Video cameras operating in conjunction with officer observation
      may provide sufficient accuracy to support mail-out citations
      for HOV lane occupancy violations.  An officer stationed
      downstream from the video cameras is in a position to verify the
      occupancy of vehicles which appear suspect to observers
      monitoring camera output.  If a system of mail-out warnings or
      citations can be installed, this officer would not have to
      pursue violators, and a videotape record of driver, occupancy,
      and license plate will be available for court hearings.  This
      system is not foolproof, since the roadside officer may fail to
      see a small child missed by the video monitor, but it appears to
      have considerable promise.  Moreover, the presence of an
      observing officer may remove some of the "Big Brother is
      watching" stigma from the use of videotape.

                                   6-1


.


      Analysis suggests that a combined system of video recording,
      officer observation, and citations-by-mail is far more cost-
      effective than the current system of freeway pursuit and
      roadside citing.  The combined video/observation system should
      be able to produce the same number of tickets for less than one-
      third the cost of special overtime assignments to roadside
      enforcement.  Furthermore, by eliminating the need to pursue and
      cite violators during rush hour, the combined system improves
      the safety of both officers and drivers and reduces the
      congestion caused by rubbernecking.

   -  The use of videotape as a real-time on-line enforcement aid
      appears to be limited to those locations lacking a median
      shoulder or enforcement area where an officer can be posted for
      observation purposes

      The use of videotape as an aid in enforcement activities
      requiring officer pursuit and on-line citations appears to be
      somewhat limited.  An officer stationed beside an HOV lane in an
      enforcement area is in a better position to observe violators
      than an officer stationed in the control van watching a video
      monitor.  Furthermore, the roadside presence of an officer in an
      enforcement area can have a cautionary effect on drivers. 
      Either officer can radio ahead to pursuit units.

      The only locations where an officer in the videotape van might
      be better able to assist on-line enforcement than an officer on
      the freeway would be those locations where there is no refuge
      area adjacent to the HOV lane.  If there is no median shoulder
      or enforcement area where an officer can be situated for
      enforcement purposes (as in the case, for example, on Marin
      101), video-assisted enforcement stops might be considered as an
      option.

6.1.2 Surveillance

   -  Individual interpretation of occupancy levels by both roadside
      observers and videotape reviewers varies widely with the
      individual and the instrument used.  Evidence suggests that
      roadside observers overstate occupancy violations.  While some
      observers understated the number of vehicles with three or more
      occupants,

                                   6-2


.


      others using different count sheets overstated the number of
      high occupancy vans carrying six or more people.

   -  Videotape provides a freeway monitoring tool which is
      potentially more consistent and accurate than existing
      techniques for documenting vehicle occupancy.  In addition,
      videotape provides a permanent, verifiable record of the vehicle
      mix, traffic speeds, and the license plates of violators and
      carpoolers.

6.2   RECOMMENDATIONS

   In view of the improved accuracy of videotape surveillance and the
potential promise of videotape as an enforcement tool if used in
conjunction with officer observation, it is recommended that CALTRANS
and the CHP take the following steps to explore further the potential
uses of videotape in HOV lane surveillance and enforcement.

   -  Test the relative accuracy of a four-camera set-up in
      conjunction with an observing officer.  Further field tests
      should be undertaken to explore the relative accuracy of a four
      camera set-up in a freeway setting.  As in past field tests, a
      downstream officer should verify the occupancy of suspect
      vehicles.  However, as an additional check on the accuracy of
      the officer/videotape combination, motor officers should be
      available to pursue and cite vehicles identified as violators by
      both the videotape observers and the verifying officer.

   -  Test the impact of mailed warnings on violation rates.  Video
      surveillance should be used in conjunction with a roadside
      officer to monitor several days of HOV lane operations.  Written
      warnings should be mailed to the registered owners of vehicles
      identified as violators by both the videotape monitors and
      roadside officers.  The impact of this activity on HOV lane
      violations should be documented through subsequent videotape
      surveillance and follow-up surveys.  Media support for the
      demonstration should be enlisted through a carefully designed
      program of public information.

   -  Explore the use of videotape on ramp meter bypass lanes.  The
      current study has tested and demonstrated the use of videotape
      in documenting violation activity on mainline HOV lanes. 
      Similar tests should be undertaken on ramp meter bypass lanes.

                                   6-3


.


   -  Continue to explore the legislative/legal ramifications of mail-
      out citations.  The CHP should continue to explore the necessary
      legislative and legal steps necessary to support the use of
      tickets-by-mail for HOV lane infractions.

   -  Continue to explore the uses of advanced videotape technology in
      HOV lane surveillance and enforcement.  Two promising avenues of
      investigation identified through the current research include:

   1. The use of micro-cameras installed in the helmets of motorcycle
      officers; and

   2. The use of low level infrared lighting installed at freeway
      level to document vehicle occupancy under conditions of darkness
      or low visibility.

                                   6-4


.


                               APPENDIX A
                       BIBLIOGRAPHICAL REFERENCES


.

                       BIBLIOGRAPHICAL REFERENCES

Billheimer, John W. HOV Lane Violation Study, prepared for the
   California Department of Transportation and the California Highway
   Patrol by SYSTAN, Inc., Los Altos, California, January, 1990.

Billheimer, John W., Juliet McNally and Robert Trexler, TSM
   Profficient Violation Rate Final Report prepared for the California
   Department of Transportation and the California Highway Patrol by
   SYSTAN, Inc., Los Altos, California, 1981.

Billheimer, John W., and Gail Fondahl, TSM Project Violation Rates:
   Study Design, prepared for the California Department of
   Transportation and the California Highway Patrol by SYSTAN, Inc.,
   Los Altos, California, June, 1979.

Billheimer, John W., Evaluation of the 1986 Public Information
   Campaign to Reduce Driving Under the Influence, prepared for the
   California Highway Patrol by SYSTAN, Inc., Los Altos, California,
   September, 1987.

Billheimer, John W., and Douglas S. Solomon, 55 MPH Public Information
   Campaign Evaluation, Final Report prepared for the California
   Highway Patrol by SYSTAN, Inc., Los Altos, California, September,
   1987.

Billheimer, John W., and J.B. Moore, THE DRIVER: A Public Education
   Project by Law Enforcement, Vol. 1: Technical Report and Vol.  II:
   Planning, Implementation and Evaluation Guidelines, prepared for
   the California Department of Transportation, National Highway
   Traffic Safety Administration by SYSTAN, Inc., Los Altos,
   California, January, 1987.

Billheimer, John W., and Robert Trexler, Evaluation Handbook for
   Transportation Impact Assessment, Report No. UMTA-IT-06-0203-81-1,
   prepared for the Urban Mass Transportation Administration,
   Washington, D.C., December, 1980.

Billheimer, John W., Robert Bullemer and Carolyn Fratessa, The Santa 
   Monica Freeway Diamond Lanes: An Evaluation, SYSTAN, Inc., Los
   Altos, California, April, 1977.

Billheimer, John W. San Tomas Expressway Data Review and Requirements,
   prepared for the Santa Clara County Transportation Agency by
   SYSTAN, Inc., Los Altos, CA, April, 1982.

California Department of Transportation, Guidelines: Bus and Carpool 
   Lanes, Park-and-Ride, Draft, Sacramento, California, February,
   1981.

California Department of Transportation, Caltrans District 07, Route 
   55 Newport Costa Mesa Freeway Commuter Lane 18 Month Report, Los
   Angeles, July, 1987.

California Department of Transportation, Caltrans District 07, Route 
   55 Newport Costa Mesa One Year Report of Commuter Lane Use, Los
   Angeles, December, 1986.

California Department of Transportation, Caltrans District 07, Route 
   91 Artesia Freeway Operational Report Based on 18 Months of
   Commuter Lane Use, Los Angeles, December, 1986.

California Department of Transportation, Caltrans District 07,
   Evaluation of High Occupancy Vehicle (HOV) Strategies, Unreleased
   Report, Los Angeles, April, 1978.

                                    1

.

California Department of Transportation, Caltrans District 11,
   Interstate Route 15 Reversible Roadway for High Occupancy Vehicles
   Operational Plan, San Diego, July, 1984.

Cechini, Frank, Operational Considerations in HOV Facility
   Implementation, prepared for Transportation Research Board Task
   Force ASTS1 (HOV Systems) Federal Highway Administration,
   Sacramento, CA, October, 1988.

Freedman, Mark, et al., Public Opinion Regarding Photo Radar,
   Insurance Institute for Highway Safety, Arlington, VA, October,
   1989.

Institute of Transportation Studies, University of California, Irvine,
   Results of Preliminary Study of Accidents on the SR-55 Freeway,
   prepared for Orange County Transportation Commission by ITS. 
   Irvine, California, November, 1986.

Law, C.S., A Photographic System for Auto Occupancy Counting and
   Vehicle Identification, Volume 1. Principle Findings and
   Conclusions, Report No. FHWA-RD-82-000 prepared for the Federal
   Highway Administration by the Naval Surface Weapons Center,
   Dahlgren, VA, November, 1981.

Newman, Leonard, Cornelius Nurworsoo, and Adolf D. May, Operational
   and Safety Experience with Freeway HOV Facilities in California,
   Submitted to Transportation Research Board for Publication,
   January, 1988.

Newman, Leonard, Cornelius K. Nurworsoo, and Adolf D. May, Design of 
   Bus and Carpool Facilities: A Technical Investigation, Research
   Report UCB-ITS-RR-87-15.  Institute of Transportation Studies,
   University of California, Berkeley, November, 1987.

Orange County Transit District, Memorandum for Debra Irizarry to Gary
   Edson on "Non-Traditional Approaches to Enforcement on HOV
   Facilities," May 29, 1987.

Orange County Transportation Commission, Commuter Attitudes Toward
   Proposed High Occupancy Vehicle Lanes in Orange County, August,
   1985.

Raub, R.A., Summary and Critique of the Literature Pertaining to the 
   Effects of Increased Enforcement of Traffic Lanes on Improving
   Traffic Safety (Reducing Accidents, Illinois Department of Law
   Enforcement, Springfield, Illinois, December, 1979.

SYSTAN, Inc., Santa Clara County Commuter Lane Performance Evaluation,
   prepared for Santa Clara County Transportation Agency, Los Altos,
   CA, March, 1989.

SYSTAN, Inc., HOV Lane Violation Study: Study Plan, prepared for the 
   State of California Department of Transportation, Los Altos, CA,
   October, 1988.

Tollett, David L., "Virginia's Ticket-by-Mail Program for HOV
   Offenses," presented at the 69th Annual Meeting of the
   Transportation Research Board by the Virginia Department of State
   Police, Richmond, VA, January, 1990.

                                    2

.


                               APPENDIX B
                          SAMPLE PRESS COVERAGE


.

Click HERE for graphic.

.

Click HERE for graphic.

.


01582942                 35128
Video Patrol of Car-Pool Lanes Gets Tryout in D.C.

Los Angeles Times (LT) - MONDAY January 8, 1990
By:ERIC BAILEY; TIMES STAFF WRITER
Edition: Orange County Edition    Page: 1  Pt. A  Col. 5
Story Type: Full Run
Word Count: 1,475

TEXT:
   It could be the traffic cop of the future.

   Across the country, from the Washington beltway to the streets of
Pasadena, transportation officials are turning to the camera to crack
down on motorists guilty of everything from speeding to running stop
lights.

   Now the concept could be coming to California in an even bigger
way.  Authorities at the California Department of Transportation and
the California Highway Patrol are looking at using video cameras to
nab motorists who violate car-pool-lane rules on freeways up and down
the state.

   The new video technology, which features cameras as tiny as a
lipstick tube and super-slow-motion replay machines, has already had a
dry run on the Artesia and Simi Valley freeways in Los Angeles County
and was tested again last Thursday in Orange County along the Costa
Mesa Freeway's car-pool lanes.

   For the CHP, the idea has particular allure.  If the video
technique proves feasible, it could help shrink violation rates in
car-pool lanes and relieve officers of the dangerous task of pulling
scofflaws across three or four lanes of freeway traffic to issue a
ticket.

   "We're interested in testing any kind of technique that could help
out," said Lt. Shawn Watts of the CHP's transportation planning unit
in Sacramento.  "This looks pretty good because it would possibly save
a lot of officer time, reduce their exposure to traffic out there and
hopefully catch more violators."

   While transportation officials agree that the idea shows promise,
obstacles remain.  Technological hurdles must be overcome, and
logistical changes might be necessary before tickets could be
delivered to motorists via the mail.

   But the biggest roadblock, experts say, may be legal.  As they have
in other parts of the country, some residents and civil liberty groups
may conjure Orwellian images of "Big Brother," saying the cameras
infringe on the privacy of motorists.

   "Speaking for myself, the Big Brother aspect of it is a little
disturbing," said Bill Ward, a leader of Drivers for Highway Safety, a
small Orange County-based group opposed to car-pool lanes.  "I think
they'll have some problems getting it to stand up in court . . . I
just don't see this going very far."

   Transportation officials, however, insist that the benefits of such
an approach would far outweigh the risks.

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   "I think those kinds of arguments, the Big Brother thing, can be
overcome and has to be overcome," said Steve Albert, a Texas-based
expert on the use of video cameras for monitoring traffic.  "it
(currently) just takes too many man-hours to enforce these facilities. 
It's too costly.  Like every other technological advancement, it will
come in time."

   Most authorities in California estimate it could be as long as five
years before the video cameras could become a fixture along car-pool
lanes in the state.

   A host of difficulties must first be addressed.

   Initial tests, which are being conducted as part of a larger study
of car-pool enforcement, have been hampered by the tedious task of
positioning cameras just right so they can peer down into a car to
spot the less-obvious passenger--a baby on board or someone lying down
on the back seat.  Tinted windows, sun glare, morning mist on the
windshield and other environmental factors could also obscure the
camera's view.

   Assuming those sorts of troubles can be ironed out, state
authorities would still have to deal with the problem of angry
motorists, who might reject the idea of receiving a ticket through the
mail.  Laws would probably have to be adjusted so the burden of a
ticket falls on the owner of a vehicle instead of the driver, a
regulation that might irk any parent whose teenager got caught by the
camera driving solo down the car-pool lane in the family car.

   Even the issue of who monitors the cameras and videotape could
prove vexing.  Though some cities have hired outside firms to pluck
violators from the pictures and search the records for vehicle owners,
California authorities envision a system that would probably employ
sworn peace officers to determine who has broken the law.

   Whatever is decided, the concept promises to engender a fair amount
of debate.  Surveys conducted as part of the car-pool violation study
found motorists "equally divided" over camera-patrolled car-pool
lanes, according to John Billheimer, vice president of Systan Inc., a
Los Altos-based transportation planning firm doing the study for
Caltrans.

   Despite that reaction, the concept has been in use for years in
other parts of the world.  West Germany has had an active "photo-
radar" program for about two decades, and the technique is used to nab
speeders elsewhere in Europe, Asia and South America.

   Photo-radar, which combines still photographs with radar to
determine a motorist's speed, has only recently made an appearance in
the United States.  Although some residents quickly dubbed it
"robocop," the technique has been used successfully in Paradise
Valley, Ariz., since 1987.  Pasadena began issuing citations with the
same Swiss-made device in June, 1988.

   Since then, more than 14,000 speeding tickets have been issued in
Pasadena for motorists caught by the photo-radar, according to Sgt. 
Gene Gray of the Pasadena police.  Nearly 300 people fought their
tickets, but the city prevailed in 90% of those cases, he said.

   Still, there have been problems.  Pasadena recently tried enlisting
a similar

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device that would photograph motorists who run red lights, but the
machine proved largely ineffective.  The same device was installed at
several intersections in New York that have been plagued with
accidents involving cars hitting pedestrians.

   Then there are the troubles in Texas.  A small suburban community
outside Houston adopted photo-radar a few years ago, but discontinued
use of the device after about six months.  Though the official excuses
were legal problems and public discontent, transportation planners say

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