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Road Weather Information Systems:
Enabling Proactive Maintenance Practices
in Washington State

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by

Catherine Bradshaw Boon  
Senior Research Engineer  
Washington State Transportation Center  
Chris Cluett, Ph.D.
Senior Research Scientist
Battelle Transportation Division

Washington State Transportation Center (TRAC)
University of Washington, Box 354802
University District Building
1107 NE 45th Street, Suite 535
Seattle, Washington  98105-4631

Research Report
Research Project T1803, Task 39
Road Weather Info

Washington State Department of Transportation
Technical Monitor
William Brown
Road/Weather Information Systems Project Manager

Prepared for

Washington State Transportation Commission
Department of Transportation
and in cooperation with
U.S. Department of Transportation
Federal Highway Administration

March 2002

Disclaimer

The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein.  The contents do not necessarily reflect the official views or policies of the Washington State Transportation Commission, Department of Transportation, or the Federal Highway Administration.  This report does not constitute a standard, specification, or regulation.

Table of Contents

Figures

Tables

Executive Summary

Like many other states, Canadian provinces, and Scandinavian and European countries, the Washington State Department of Transportation (WSDOT) has invested in advanced technologies designed to monitor, report and forecast road related weather conditions. Collectively, these technologies are referred to as Road Weather Information Systems (RWIS). In Washington, deployed RWIS components include roadside sensor stations, a statewide communication network, data access tools for maintenance personnel, tailored weather forecasting services, advanced weather modeling, pavement temperature modeling and prediction, and an Internet website for maintenance decision making and traveler information. Implementation of these RWIS components serves primarily to help WSDOT maintenance personnel make timely and efficient winter maintenance decisions. It enables the use of cost‑effective, proactive snow and ice control practices that improve safety and the level of service provided to users of the state highway system. This same road condition and weather information is disseminated to the public as a way of helping travelers make informed decisions for safe and efficient travel. 

In 1998 WSDOT began a program to greatly expand and improve weather data available to both WSDOT maintenance personnel and the traveling public. The program, called rWeather, has resulted in a statewide network of weather stations that includes not only those sensor stations owned by WSDOT but also almost 400 other stations owned by nine other federal, state, and local agencies.

The objective of this research is to document the reported benefits of RWIS, assess the extent to which these benefits are being realized in Washington, and identify strategies and operational changes necessary to take full advantage of RWIS technology. The overall intent is to provide information to support future RWIS-related investment decision-making.

Winter Maintenance in Washington State

Snow and ice control practices are designed to keep roadways passable and as safe as possible during winter weather conditions. Of all the injury and fatality accidents in Washington from 1991 through 1996, nearly 8 percent (9000) occurred during conditions of snow and ice. Just in the past two years (1999 and 2000), 3,675 people have been injured and 64 people have died in accidents during conditions of snow and ice[1].

The costs of winter road maintenance are substantial. Over the last four winters annual costs for snow and ice control have climbed from $21 million to just over $26 million. Seventy percent of all snow and ice control expenses are borne by three WSDOT districts: the South Central Region, the North Central Region and the Eastern Region. Labor expenses generally account for 40 percent of the total costs, equipment for about 30 percent, and materials for roughly 25 percent[2]

The potential benefits of RWIS are substantial. Investments in RWIS can provide travelers with better information for safe and efficient travel, provide information useful for efficient scheduling of maintenance personnel, enable maintenance personnel to cost‑effectively provide a higher level of service, and provide higher quality observational data for improved weather forecasting. However, nearly all of these benefits result only when winter maintenance practices are significantly changed to take advantage of RWIS capabilities.

Without detailed, tailored, and targeted weather forecasts, winter maintenance decisions must be based on current weather conditions. Traditionally, winter maintenance managers have reacted to current conditions. In contrast, the information available from a fully deployed RWIS makes it possible to adopt new, proactive ways of doing business that can more efficiently and cost-effectively provide safer conditions for the traveling public. These RWIS-enabled practices include the following:

In Washington, the North Central Region reports benefits of anti-icing operations enabled to some extent by RWIS, including improved employee satisfaction and increased productivity as a result of eliminating most regular night shift assignments, as well as the ability to provide a higher level of service for the same cost.

The literature offers no comprehensive benefit-cost studies of implemented RWIS programs in the North America. Furthermore, no large-scale RWIS systems have yet to be fully incorporated into winter maintenance operations. However, several benefit/cost studies have been based on expected benefits in comparison to projected or actual costs.

WSDOT’s North Central Region has led the state in terms of adopting anti-icing and using tailored weather forecasts. The region’s maintenance staff have reported several benefits, including less sand used, less sand cleanup, less guardrail damage, elimination of weekend shifts, call-out and overtime savings, a lower accident rate, fewer tort claims, better level of service, fewer equipment hours, positive public feedback, and “happier environmentalists”.

RWIS-supported changes in snow and ice control practices are still too new to have achieved consistent region-wide application and to demonstrate clear trends. A review of maintenance expenditures and accident records reveals no clear evidence that these benefits are substantial enough to be detected in cost figures for snow and ice control. The number of accidents, in particular, is highly variable, with no clear trends visible in the short term. Region management has stressed that the most significant result to date has been an increase in the level of service offered to the public without an increase in cost.

WSDOT Maintenance Personnel Survey

WSDOT maintenance personnel were surveyed during May and June of 2001 about their use of, and attitudes toward, various sources of road weather information. Questionnaires were mailed to all 24 maintenance area superintendents with instructions to complete the questionnaire themselves and distribute copies of it to supervisors and lead technicians within their area. A total of 129 questionnaires were returned (a 51 percent return rate), of which 44 percent were superintendents or supervisors and 56 percent were lead technicians. The most significant results are listed below:

RWeather Customer Survey

Visitors to the rWeather website were invited to respond to a short on-line survey from March 6, 2001, to April 9, 2001. During that time 140 members of the public filled out the survey. The objectives of this survey were to better understand who used the site, what kinds of trips they were planning with information they derived from the site, the features of the site they used and how useful they found these features to be for their trip planning, and suggestions they might have for enhancing the overall value of the site.

The survey respondents were overwhelmingly positive in their assessment of the value of the rWeather website in helping them prepare for their travel and learn about weather and road conditions. Use of this site differs from that of many other traveler information sites in that users are predominantly focused on longer trips. More than twice as many users said they were most frequently planning recreational, business, and other personal trips of over 100 miles than those using the website to plan shorter trips.

Virtually all of the site’s informational features were used by most visitors, and their ratings of the usefulness of these features were high for all the main features, including weather conditions, mountain pass conditions, traffic cameras, road temperatures, and state-wide maps. About half the respondents offered specific suggestions that tended to cluster around several common topics, including a desire for more camera images, more current information, broader and more consistent geographic coverage, and some site design modifications. The great majority of users who responded to the survey said they considered the site well organized and generally easy to use, with information that is easy to find. Some concerns were reported regarding site usability, and evidence suggested that first-time users have more difficulties than experienced users. Overall, however, the response to this website was very positive. Comments such as, “The website is terrific,” and “One of the best sites that I have seen,” capture the opinion of many of the survey respondents.

Use of the rWeather website is growing. Overall use of the website increased 86 percent from 2000 to 2001(March through December), nearly doubling the number of rWeather users. The winter months experience the highest levels of use, as well as the most extremes of usage on a day-to-day basis, as shown on the figure below. (For example, February 2001 included a snowy Friday before a holiday weekend.)

Average Daily rWeather User Sessions

Average Number of User sessions per day

Findings and Recommendations

Major strides have been made recently in WSDOT’s implementation of RWIS as a result of the rWeather program. The most significant of these are equipment compatibility; development of a statewide RWIS network, including an extensive set of non-WSDOT weather sensors; access to statewide comprehensive weather information; weather training; and a successful public information website.

WSDOT maintenance personnel, however, are not taking full advantage of the state’s RWIS investment. At the same time, it is clear that enthusiasm for implementing advanced snow and ice control practices is growing and maintenance personnel have expressed extensive support for additional RWIS stations and weather interpretation training. The barriers to the full use of RWIS capabilities and the recommendations to address these barriers are summarized below.

Barriers

Recommendations

  1. Continue to share information about experiences with RWIS and advanced winter maintenance practices as a way to reduce barriers to expanded use.
  2. Document and review snow and ice control methods and results throughout the winter season.
  3. Document the reliability of rWeather pavement temperature forecasts and share the results with winter maintenance personnel.
  4. Require weather forecast service to meet defined performance criteria.
  5. Provide computers and Internet access in all maintenance sheds and ensure that computers with Internet access are available to all personnel tasked with making winter maintenance decisions.
  6. Provide training, particularly in the interpretation of weather information and the application of anti-icing strategies. Make an effort to focus the right training on the right people.
  7. Train maintenance personnel in the potential pitfalls of the multitude of Internet sources of weather information and the best way to take advantage of them.
  8. Provide strong management support for the need to adopt advanced winter maintenance practices and demonstrate a commitment to necessary training.
  9. Continue efforts to educate the public about the potential safety, cost, and environmental benefits of using anti-icing chemicals.
  10. Develop a well-documented plan for statewide uniform implementation of advanced winter maintenance practices to address liability concerns.
  11. Make a full review of the accuracy and reliability of all RWIS sensor station equipment.
  12. Ensure funding for ongoing maintenance of RWIS sensor stations.
  13. Consider ongoing funding of centralized RWIS technical support.
  14. Focus additional RWIS resources on areas where the potential to change snow and ice control practices exists and where additional sensor capability will contribute to improved weather forecasting.

Many of these recommendations are already being addressed through continued investments in RWIS sensor stations, Internet access, and additional weather-related training. In addition, current plans call for hiring a meteorologist to address the need for analysis of statewide forecast reliability and equipment performance.

RWIS enables cost effective, proactive winter maintenance practices that improve the level of service provided and lead to increased safety and mobility for the traveling public. Although proactive maintenance practices such as anti-icing can be implemented without a comprehensive RWIS, such implementations are very costly because use of labor, equipment, and materials is often beyond what is necessary. Expanding the use of RWIS and advanced winter maintenance practices will require management commitment and continued investment in equipment reliability, demonstration of forecast credibility, targeted training, and implementation planning.

Section 1: Introduction

Like many other states, Canadian provinces, and Scandinavian and European countries, the Washington State Department of Transportation (WSDOT) has invested in advanced technologies designed to monitor, report, and forecast road related weather conditions. Collectively, these technologies are referred to as Road Weather Information Systems (RWIS). In Washington, deployed RWIS components include roadside sensor stations, a statewide communication network, data access tools for maintenance personnel, tailored weather forecasting services, advanced weather modeling, pavement temperature modeling and prediction, and an Internet website for maintenance decision making and traveler information. Implementation of these RWIS components serves primarily to help WSDOT maintenance personnel make timely and efficient winter maintenance decisions. It enables the use of cost‑effective proactive snow and ice control practices that improve safety and the level of service provided to users of the state highway system.  This same road condition and weather information is disseminated to the public as a way of helping travelers make informed decisions for safe and efficient travel. 

Roadside RWIS station implementation in Washington began in the early 1980s. These sensor stations consist of equipment that constantly measures and reports atmospheric and road conditions such as temperature, wind speed, and humidity. WSDOT currently has just over 50 RWIS stations spread throughout the state. (The number of RWIS stations is expected to grow to more than 60 by next year.) In 1998 WSDOT began a program to greatly expand and improve weather data available to both WSDOT maintenance personnel and the traveling public. The program, called rWeather, has resulted in a statewide network of weather stations that includes not only those sensor stations owned by WSDOT but also almost 400 other stations owned by nine other federal, state, and local agencies.

With so much progress in the implementation of RWIS infrastructure it is timely to assess the extent to which the expected benefits of RWIS are being realized in Washington State.  As with many other new technologies, the benefits of RWIS are limited if business practices don’t change to take advantage of the opportunities provided by the technology.

Background

RWIS research and testing began in the United States as part of the Strategic Highway Research Program (SHRP). During the winter of 1990/1991, seven states participated in a test of RWIS that was documented in "Road Weather Information Systems Volume 1: Research Report" (Boselly 1993). The study concluded that “tailored and detailed forecasts based on a combination of RWIS sensor and thermal analysis can result in a return on investment of close to five hundred percent, and can significantly improve service levels and greatly decrease the frequency of decision errors,” with the following caveats:

Part of the intent of this research effort is to review and update these findings.

Purpose

The objective of this research is to document the reported benefits of RWIS, assess the extent to which these benefits are being realized in Washington, and identify strategies and operational changes necessary to take full advantage of RWIS technology. The overall intent is to provide information to support future RWIS-related investment decision-making.

The primary elements of this research effort are a literature review of benefits and previous benefit/cost ratio studies, a survey of WSDOT maintenance personnel regarding winter maintenance practices and attitudes, and an on-line survey of travelers who use the rWeather website to determine customer satisfaction with road weather information.

The next section provides background information about winter maintenance challenges in Washington and an overview of RWIS technologies and their implementation in the state. Section 3 describes the expected and experienced benefits of RWIS, and Sections 4 and 5 discuss the two survey activities and their results. Findings, recommendations, and conclusions are presented in Sections 6 and 7.

Section 2: RWIS in Washington State

Winter Road Maintenance in Washington

Winter weather, and the snow and ice control strategies necessary to deal with it, varies considerably throughout the state. The state can be divided into three areas: the Mountains which receive heavy snowfall and for which the primary winter maintenance activity is snow removal; the Coastal Lowlands, which experience occasional frost and rare snow events and require anti-icing and sanding for icy highways; and the Inland Plateau, which experiences numerous frost events and moderate snowfall for which the primary activity is management of icy roads using anti-icing and sanding (Baroga 2000).

Snow and ice control practices are designed to keep roadways passable and as safe as possible during winter weather conditions. Of all the injury and fatality accidents in Washington from 1991 through 1996, nearly 8 percent (9000) occurred during conditions of snow and ice. Just in the past two years (1999 and 2000), 3,675 people have been injured and 64 people have died in accidents during conditions of snow and ice[3].

The costs of winter road maintenance are substantial. Over the last four winters annual costs for snow and ice control have climbed from $21 million to just over $26 million. Seventy percent of all snow and ice control expenses are borne by three of WSDOT’s districts: the South Central Region, the North Central Region, and the Eastern Region. See Figure 2-1. Labor expenses generally account for 40 percent of the total costs, equipment for about 30 percent, and materials for roughly 25 percent[4]

Figure 2-1: Washington State Regions

Washington State Regions

RWIS Components

The term RWIS refers broadly to a set of road-related weather observation, forecasting, and reporting technologies. Most generally, RWIS refers to the roadside sensor stations that report surface and atmospheric observations and the software and hardware that make these observations available to road maintenance staff.  However, the use of the term RWIS has expanded over time to mean an integrated system that includes detailed weather models and forecasts specifically tailored to the needs of road maintenance staff, in addition to public dissemination of travel-related road and weather condition information. The Federal Highway Administration (FHWA) is currently investing in research and development of even more sophisticated RWIS capabilities, referred to as Winter Maintenance Decision Support Systems. Each of these RWIS elements is briefly discussed below:

Sensor Stations

Nearly all of the more than 50 RWIS stations in Washington State are located along roadway right-of-way at locations, such as mountain passes and bridges, that typically experience the most severe weather-related road conditions. Figure 2-2 shows a typical RWIS sensor station[5]. In some cases the location of these stations is determined specifically to fill gaps in statewide weather modeling.

Figure 2-2: RWIS Sensor Station

Figure 2-2: RWIS Sensor Station

The capabilities of these RWIS stations vary. In Washington, all provide air temperature, wind speed and direction detection; many provide road surface and subsurface temperatures; and some detect the presence and concentration of snow and ice control chemicals on the road surface. Many also have cameras, providing a visual image of the conditions at the site. These sensor stations make it possible to determine, on the basis of current conditions, things such as whether ice can exist, whether ice or snow will bond to the pavement, and whether frost can form at that site.

The North Central Region Winter Maintenance Plan calls for installation of up to 20 additional RWIS sensor stations over the next four years, at a total cost of $1.4 million for installation, training and maintenance, as part of efforts to further implement proactive winter maintenance practices (Boselly 2000a).

Communication Network

In the past it was common for maintenance staff to have dial-up access to a limited set of nearby RWIS stations.  Recent hardware and software investments, as part of the rWeather program, have not only provided access to the statewide network of RWIS stations but also made the RWIS data easier to use through a service called SCAN Web[6]. The rWeather project has also integrated the data from the RWIS stations with nearly 400 other weather stations operated by other federal, state, and local agencies throughout the state.  This integrated set of information is available on the rWeather website, making it possible for maintenance personnel and travelers alike to get a broad perspective on current weather conditions and forecasts throughout the state.

Weather and Pavement Temperature Modeling

The extensive network of weather stations described above supports highly detailed weather and pavement temperature computer modeling that in turn supports high-resolution forecasts. Working with the Northwest Regional Weather Consortium and the University of Washington Department of Atmospheric Sciences, the rWeather program has been able to further enhance a high-resolution computer model known as MM5 (mesoscale model version 5) that encompasses all of Washington. This model is run twice each day and has a resolution of 4 square kilometers (Brown 2000).

The rWeather program has also funded the development of a sophisticated pavement temperature model that calculates current and predicted road surface temperatures. Representations of these pavement temperatures are displayed on the rWeather website.

Another tool that can be used for pavement temperature modeling is called thermal analysis. Thermal analysis requires that crews with specialized detection equipment go out and collect actual pavement temperatures along segments of highway in different weather conditions. This information is used to create temperature profiles for the highway that can be used to predict temperature pavement between sensor stations. Thermal analysis can also be used to determine the optimal location for RWIS sensor stations.

Thermal analysis has not been extensively used for forecasting pavement temperatures in Washington, which instead relies on highly sophisticated modeling techniques. However, a 2000 winter maintenance plan for the North Central Region recommends thermal analysis as a way to increase forecasting capability and thereby reduce winter maintenance costs (Boselly 2000a).

Tailored Weather and Pavement Temperature Forecasts

To be useful for winter maintenance operations, weather forecasts must be tailored to the needs of maintenance staff.  They must be targeted to specific areas, and they must be focused on the weather conditions relevant to predicting road conditions.  Specifically, weather forecasts must consider not only the predicted air temperatures but also road surface temperatures that will ultimately determine whether snow accumulates or black ice forms. NorthWest Weathernet, Inc., is an example of a private company that provides tailored weather forecasts under contract to some WSDOT maintenance areas.

A forecast tailored to winter road maintenance would indicate the type of precipitation to expect, how much to expect, where it will fall, when it will start, how long it will last, and whether it will “stick” to the road. Forecasts of this type are essential to cost-effective winter maintenance practices.

Even with sophisticated weather models and predictions, high quality forecasts are still the result of applying human judgment to computer-generated predictions.  Experience has shown that the highest success for tailored forecasts is achieved when the forecaster has an open line of communication with those who need to base decisions on those forecasts. rWeather program investments in weather data and modeling have contributed to improvements in the computer-generated predictions interpreted by the National Weather Service (NWS). NWS forecasts are made available to maintenance staff and the public on the rWeather website. 

Traveler Information

Travelers informed about the potential for adverse driving conditions can take precautions that will increase not only the safety of their own trip but also the safety and mobility of other users of the highway system. Travelers who are not prepared to encounter significant snow accumulations, for example, can cause incidents that close or otherwise reduce the capacity of the highway. In Washington, the rWeather website provides statewide weather-related road condition reports and forecasts. Figure 2-3 shows an rWeather web site example of the pavement temperature and weather conditions forecast for a stretch of US Highway 2.

Figure 2-3: Weather Pavement Temperature and Weather Forecast

Figure 2-3: Weather Pavement Temperature and Weather Forecast

Winter Maintenance Decision Support Systems

The FHWA’s Decision Support Requirements initiative has generated a needs analysis, operation concept description, and preliminary interface requirements for a winter road Maintenance Decision Support System (MDSS). Current efforts are focused on developing a prototype with the intent to test it in partnership with state departments of transportation. It is expected that WSDOT will play a role in this testing activity. The objective of the MDSS is to take advantage of recent advances in weather forecasting and understanding of pavement temperature behavior to provide information tailored specifically to support proactive decision-making by winter road maintenance managers (FHWA 2001).

Section 3: RWIS Benefits

The potential benefits of a comprehensive and integrated RWIS are substantial. Investments in RWIS can provide travelers with better information for safe and efficient travel, provide information useful for efficient scheduling of maintenance personnel, enable maintenance personnel to cost‑effectively provide a higher level of service, and provide higher quality observational data for improved weather forecasting. However, nearly all of these benefits result only when winter maintenance practices are significantly changed to take advantage of RWIS capabilities.

Many of the benefits of implementing these RWIS-enabled winter maintenance practices overlap; it is therefore useful to look at each practice individually to clarify the benefits that result from adoption of RWIS technologies.

Practices Enabled by RWIS

Without detailed, tailored and targeted weather forecasts, winter maintenance decisions must be based on current weather conditions. According to SHRP research, highway maintenance organizations have traditionally reacted to current conditions, or at best a forecast of winter weather obtained from the media. Patrols are sent to check conditions, and supervisors are notified that roads have become icy or snow has begun to accumulate. Crews are sent out to attack the problems as they occur and stay on the job until the problems have subsided. “This reactive response can be costly in both time and materials” (Boselly 1993).

In contrast, the information available from a fully deployed RWIS makes it possible to adopt new, proactive ways of doing business that can more efficiently and cost-effectively provide safer conditions for the traveling public. The following beneficial winter maintenance practices enabled by RWIS have been identified and are discussed below and summarized in Table 3-1:

Anti-icing

RWIS makes it possible for winter maintenance to be proactive. For example, the practice of anti-icing improves safety and mobility by keeping the road surface wet and slushy instead of icy. Anti-icing chemicals applied to the road surface either before or very early in a storm lower the temperature at which water freezes, prevent the bonding of snow, ice, or frost to the roadway. (Deicing, on the other hand, refers to using chemicals to break an existing bond between the roadway and ice or snow.) Preventing the bond of snow or ice to the roadway also allows the road to revert to bare pavement more quickly after a storm. Although anti-icing can be employed without RWIS, it is expensive because the costly deicing chemicals often get applied in excessive concentrations or when and where they are not needed.  It is far more efficient and effective to implement anti-icing with the support of advanced road and weather information. The use of RWIS to support anti-icing operations results in lower material and labor costs, a higher level of service, less environmental impact, and improved safety than the reactive practices of plowing and sanding (Boselly 1993).

The key to a successful anti-icing strategy is knowing which chemical to use, in what amount, and when. RWIS provides the detailed and targeted weather forecasts to do that. Without site-specific and tailored weather information, many highway agencies wait until a storm hits to send out their work crews to salt, sand, and plow.  By then the storm already has the advantage, and maintenance crews struggle to keep up and to clear pavements that are already covered with snow or frost (Mergenmeier 1995).

Pavement temperature forecasts are critical to effective anti-icing. Even if snow is forecast to accumulate or is accumulating in some areas, if the pavement temperature is forecast to remain above freezing, chemical applications may not be necessary and plowing may not be required.  In some cases, the most cost-effective decision is to do nothing (Boselly 1993).

Anti-icing requires less deicing material than that required to break the bond between the ice and the road later. Reduced amounts of sand and deicing chemicals provide cost savings and mitigate environmental damage. Roads that don’t ice up to begin with don’t require an application of sand for traction. Moreover, fewer labor hours are required for sand cleanup. 

Reductions in the amount of sand used are especially desirable in air-quality non‑attainment areas such as Spokane. In Oregon, the Department of Transportation found that 50 to 90 percent of the sand that is applied to pavements remains in the environment even after cleanup. Not only does the dust from road sanding operations contribute to air pollution, according to the United States Forest Service, sand sediment in streams and rivers is harmful to salmon (RoadSavers 1997).

In Washington, the North Central Region (NCR) has been expanding its use of anti-icing strategies over the last couple of years. Experience so far indicates that the region can increase the level of service it provides to the public (more time with roadways in the “bare” condition) at the same cost. Increased use of RWIS is expected to lower the cost of anti-icing because of the application of lower concentrations of chemicals, applying it at the right time, and in the right locations. In NCR’s experience, reductions in labor hours, equipment use, and the amount of sand that requires cleanup offsets the cost of the anti-icing program[7]

Because anti-icing prevents the buildup of ice and makes it easier to return roads to bare pavement condition after snow, anti-icing helps keep roadways at a higher level of service longer.  Theoretically, as a result of alleviating exposure to unsafe conditions, mobility and safety are improved.  Improved road conditions also enhance travelers’ choices and support business and tourism activities, particularly in rural communities.

Note that other states have experienced significantly higher cost savings as a result of anti-icing because they are allowed to use brine, which is far less expensive than the anti-icing chemicals that can be used in Washington. It is also important to note that, despite improved conditions due to anti-icing, the North Central Region has received some negative public reaction to the practice. In February 2001, nearly 900 residents of the Methow Valley submitted a petition to the Secretary of Transportation’s Office calling for an immediate end to use of liquid deicer for anti-icing operations.[8] The chemical used for anti-icing is mixed with an anti-corrosive agent that makes it brown, sticky, and hard to wash off. This is an advantage in keeping the anti-icer on road surfaces but it can be a great irritation to car owners. The anti-icing liquid is known to damage aluminum, a problem for wheels, other car components, trailers, and boats. In the North Central Region last winter, twelve people filed claims for damage. All were rejected. To date, WSDOT has maintained the position that the safety benefits of anti-icing far outweigh the inconveniences to drivers.[9]

Reduced Use of Routine Patrols

Accurate and timely weather observations from RWIS sensor stations at key locations can reduce the need for routine patrols, a common practice for monitoring or detecting conditions of roads. This is particularly true if a camera is also located at the sensor station site. RWIS information can make patrolling unnecessary in normal snow and ice conditions and can provide warnings about high wind and heavy rain that are likely to cause hazardous roadway conditions. Some RWIS sensor sites in critical locations such as mountain passes also have cameras that provide images of current conditions. RWIS sensors and cameras become the eyes and ears of supervisors instead of exclusive use of routine road patrols. The result is lower equipment use costs and improved labor productivity.  The only weather related reason to patrol becomes checking for downed trees or power lines or conducting other damage assessment activities (Boselly 1993).

Cost-Effective Allocation of Resources

A statewide survey conducted in 2000 measured customer satisfaction with WSDOT maintenance activities. Activities ranked as very important but for which customers expressed limited satisfaction included maintenance of roadway surfaces, pavement markings, drainage, and snow and ice removal (Pacific Rim Resources 2001). These results point to the need to allocate maintenance resources as effectively and as efficiently as possible.

RWIS can be used to optimize the allocation of labor, fleet, and material resources. Site-specific weather information and detailed weather and pavement condition forecasts make it possible to mobilize just the right amount of personnel and equipment at just the right time in just the right place to control snow and ice. Particularly within large geographic areas, this can greatly improve productivity.

“Call-outs” to personnel to deal with a storm event can be very expensive.  Not only is call-out pay costly, but a minimum amount is guaranteed. RWIS sensor data and specialized forecasts make it possible to schedule staff for a storm or hold staff overtime, eliminating the need for call-out pay.

One of the benefits of RWIS already experienced in Washington is the ability to eliminate weekend and night shift work because of forecasts that make it possible to staff night and weekend shifts only when necessary. In the North Central Region, several shifts have been eliminated.  Instead, all employees are assigned to the day shift, reportedly resulting in increased employee job satisfaction. There is no appreciable cost saving since the shift differential savings are likely to be offset by overtime costs.  However, the assignment of all employees to the day shift greatly increases the department’s ability to perform other maintenance work that can only be done with multi-person crews and during daylight hours. In this way, WSDOT is able to address in a timely way the backlog of maintenance activities that customers have identified as important. In some cases, the need for extra seasonal workers has been eliminated. Substantial snow and ice control cost savings could be achieved by entirely eliminating night shift positions.

Provide Travelers Better Information

A fully integrated and comprehensive RWIS includes information delivery mechanisms (including website, automated phone system, kiosks, highway advisory radio and variable message signs) that make it possible to disseminate important weather and road condition information to the traveling public. The assumption is that more informed travelers will make better decisions about where, when, and how to travel. The result is a safer driving environment for everyone during difficult conditions.

In Washington, the rWeather website is where RWIS information is made available to the public. The results of the rWeather on-line customer survey (see Section 5) indicate that travelers are using RWIS information to better prepare themselves for travel, presumably resulting in safer travel behavior. It is too early to tell whether providing access to this information (rWeather has only been in full production for one winter season) will actually improve safety as measured by a reduction in crashes, injuries and fatalities in snow and ice conditions, but the rWeather users surveyed clearly indicated that they do feel safer as a result of having access to this information.

Cost-Effective Summer Maintenance Scheduling

Although directed primarily at winter maintenance operations, RWIS also can provide information that serves effective scheduling of maintenance crews during late spring, summer, and early autumn. Effective pavement marking and repaving operations need to be scheduled when road surface temperatures are conducive to getting the job done quickly and properly. By monitoring actual pavement temperatures, especially road surface temperature forecasts, maintenance crews can be scheduled accordingly.

The Wisconsin DOT reports that its pavement marking section and seal coat operations group use RWIS on a daily basis to determine work schedules (RoadSavers 1997). In Washington RWIS has not been reported to be used for this purpose. Although prediction of summer road temperatures in Washington is unlikely to be troublesome, the opportunity presented by RWIS may be the ability to start paving and pavement marking operations earlier in the spring and continue them later into autumn.

Share Weather Observation Data

Under the auspices of the rWeather project, WSDOT has become a participant in the Northwest Regional Weather Consortium, sharing RWIS data with weather observations collected by nine other local, state, and federal agencies (Brown 2000). The combined data are used to improve reporting of actual weather conditions and, perhaps more importantly, to improve the output of weather models and the ability of public and private forecasting services to provide more detailed and targeted weather forecasts. Theoretically at least, the more observational data, the better the weather models and the better the forecasts. 

The RWIS sensor station network is especially important because it generates data for the road surface temperature modeling done by the University of Washington Department of Atmospheric Sciences. Keeping the existing RWIS stations functioning properly and extending the network to additional locations will further improve the forecasted road surface temperatures that are critical to enabling proactive winter maintenance practices.

Case Studies

Table 3-1: Summary of RWIS-Enabled Winter Maintenance Practices and Benefits

RWIS-Enabled Practice

Associated Benefits

Anti-icing

  • Lower material costs
  • Lower labor costs
  • Higher level of service (improved road conditions), travel time savings, and improved mobility
  • Improved safety (fewer crashes, injuries, fatalities, property damage)
  • Reduced equipment use hours and cost
  • Reduced sand cleanup required
  • Less environmental impact (reduced sand runoff, improved air quality)
  • Road surfaces returned to bare and wet more quickly
  • Safe and reliable access, improved mobility

Reduced Use of Routine Patrols

  • Reduced equipment use hours and cost
  • Improved labor productivity

Cost-Effective Allocation of Resources

  • Increased labor productivity
  • Reduced weekend and night shift work
  • Improved employee satisfaction
  • Reduced maintenance backlog
  • More timely road maintenance
  • Reduced labor pay hours
  • Overall higher level of service
  • More effective labor assignments

Provide Travelers Better Information

  • Better prepared drivers
  • Safer travel behavior
  • Reduced travel during poor conditions
  • Fewer crashes, injuries, fatalities and property damage
  • Increased customer satisfaction and political support for WSDOT
  • Improved mobility
  • Safer, more reliable access

Cost-Effective Summer Maintenance Scheduling

  • Higher labor productivity
  • Improved roadway surface

Share Weather Data

  • Improved weather forecasts

In Washington, the North Central Region reports benefits of anti-icing operations that are supported to some extent by RWIS. As mentioned in the previous section, these benefits are improved employee satisfaction and increased productivity as a result of eliminating most regular night shift assignments, as well as the ability to provide a higher level of service for the same cost. Many other states have reported similar benefits that have been documented as RoadSavers case studies.

As a follow-up to the SHRP program, FHWA’s RoadSavers program contracted with the University of Nevada-Reno to coordinate and manage an assessment of the economic benefits of SHRP products, including RWIS and anti-icing. The first step involved collecting data on how state and local highway agencies were using SHRP products; this produced more than 100 case studies. Those case studies related to the use of RWIS and anti-icing are summarized in Table 3-2[10]. Case studies indicated particularly substantial cost savings can result from the implementation of both RWIS technology and an anti-icing strategy (Epps 1997).

Table 3-2: RoadSavers Case Studies as of July 10, 1997 (Anti-icing and RWIS)

Location

Reported Results

Kansas DOT

  • Reduced bonding – snow removal faster & easier
  • Improved safety
  • Reduced use of chemicals
  • Less adverse environmental impact
  • Average savings $1600 per storm

Missouri DOT

  • Clearer pavements, improved safety
  • Fewer chemicals, less environmental damage, saves money, less wear and tear on bridge decks and equipment
  • Labor and equipment savings

Oregon DOT

  • RWIS helped ensure right time and place for chemicals based on pavement temperatures
  • Will save $7 million over 25 years due to reduction in chemicals, more efficient scheduling of crews, less damage to vegetation
  • Improved environmental quality
  • Safer, more reliable access to recreational areas

Maryland DOT

  • Savings from reduced crew standby times expected to pay for the system in 5 to 7 years
  • Improved driving conditions
  • Lower costs for equipment and materials use and for labor expenses
  • Even greater improvements expected with anti-icing

California

  • Safer roadway
  •  More environmental protection
  • Reduced costs from lower requirement for staff, equipment and materials

Minnesota DOT

  • Better idea of how much chemical to apply when cutting costs and minimizing environmental impacts
  • Return on investment of 200% to 1300%

Montana DOT

  • Public benefits of faster response to weather-related emergencies
  • Better planned and executed maintenance activities
  • Reduced labor, material and energy costs
  • Enhanced road safety

North Dakota

  • Efficient and effective winter maintenance strategies
  • Clearer and safer roads
  • Save money by applying deicing materials only when needed
  • Know when to impose load restrictions

Massachusetts Highway Department

  • $53,000 savings in one winter
  • Reduced accident rates
  • Shorter travel times during winter storms
  • Reduced workplace absenteeism

Michigan DOT

  • Improved safety
  • Reduced costs for crew time and chemical use
  • Reduced wear on equipment and bridge decks

Wisconsin DOT

  • Clearer, safer roads
  • More efficient use of deicing materials
  • Increased awareness of anti-icing strategies
  • Lower cost for winter maintenance

Illinois DOT

  • Able to respond at the right time in the right place with the right reaction
  • More efficient plowing and anti-icing operations and improved driving condition information improves safety

Allows wiser use of salt and other material

Iowa DOT

  • Helps maintain ice-free roadways
  • Cuts down on labor costs
  • Reduces chemical use

West Virginia Parkways Authority

  • Cost savings of $6500 per storm due to less salt and other materials
  • Paid for itself in one year
  • More efficient winter maintenance has improved highway safety

District of Columbia DPW

  • Roads clearer of ice and snow
  • Use of deicing chemicals reduced
  • Determine where to do winter maintenance
  • Ensure safe driving conditions

New Jersey DOT

  • Cut snow and ice control costs by 10 to 20 percent
  • Reduced use of salt and other chemicals
  • Roads clearer of snow and ice, improved travel conditions

Texas DOT

  • Reduced winter maintenance costs
  • Improved service for motorists
  • Improved scheduling of highway construction work

Colorado DOT

  • Improved scheduling of winter maintenance crews
  • Able to adopt anti-icing strategy that reduces sand use
  • Improved safety on mountain passes

South Dakota DOT

  • Better safety, less material used and lower costs as a result of being more timely
  • Better scheduling of crews

Benefit/Cost Studies

The literature offers no comprehensive benefit-cost studies of implemented RWIS programs in the North America. Furthermore, no large-scale RWIS systems have been fully incorporated into winter maintenance operations for many of the reasons outlined in the next section. However, several benefit/cost studies have been based on expected benefits in comparison to projected or actual costs.

The first significant benefit-cost modeling work was done by Boselly et. al. as part of the SHRP program (Boselly 1993). In fact the report projected results specifically for Washington State, indicating a benefit/cost ratio of 5.0 due primarily to the assumption that improved weather information would eliminate the need for routine road patrols (and the associated labor and equipment hours).

Boselly refers to his model as a “cost-reduction simulation model.” "Cost reductions" are defined as the difference in direct snow and ice control expenditures produced by alternative RWIS options, and the costs required to implement various the RWIS options. An important finding was that the winter maintenance cost reductions due to RWIS sensor stations and pavement temperature models used by themselves are significantly lower than those that can be achieved by using detailed weather and pavement condition forecasts to mobilize resources before snow and ice problems accumulate. Furthermore, the most cost-effective reason for using forecast information is to take no action. 

Somewhat more recently, a life cycle benefit/cost model for RWIS was developed at the University of Texas and applied as a case study for an RWIS station planned in Abilene, Texas (McKeever 1998). The model resulted in a net present worth for the planned RWIS station of $900,000 over a 50-year period.

The McKeever model was based on a synthesis of previous RWIS benefit/cost work, as well as data collected from various agencies. Like the Boselly model, it was based on some significant assumptions, including the elimination of routine patrols and the associated labor and equipment costs, and reducing labor hours by 15 percent for each storm event as a result of reducing the number of passes required to clear the roadway. On the basis of findings from other studies, McKeever assumed that reductions in liability expense, pollution costs, and travel delay costs would be negligible in comparison to other RWIS costs and savings. However, McKeever did assume a reduction in fatal, injury, and property damage accidents, given the assumption of reduced exposure to snow and ice conditions as a result of RWIS.

More recently a draft benefit/cost study of RWIS and anti-icing technologies attempted to document benefits experienced by states involved in early testing of RWIS and anti-icing. Most states reported snow and ice control efficiencies (primarily based on employee feedback) but little in the way of documented dollar savings (Boselly 2000b). The findings indicated that the lack of a formal methodology for documenting savings and annual variability made the task even more difficult. Reports were found of site‑specific accident reductions (although some increase in severity due to higher speeds), reductions in overtime, virtual elimination of sand disposal costs, and fewer road closures.

The North Central Region Winter Maintenance Plan includes a high-level benefit/cost analysis for that region. The plan notes that “forecasts have the potential for the highest return on the investment if precision in the forecasts can be established.” The North Central Region plan assumes a 10 percent savings in direct snow and ice control expenditures, merely citing that such an estimate has been used elsewhere. On the basis of this assumption, a benefit/cost ratio of 1.4 is projected over four years. The plan further assumes that the addition of thermal mapping would reduce the number of RWIS stations needed and thereby increase the benefit/cost ratio to 1.6. An increase in forecasting capability could push the cost/benefit ratio to 2.0. With continued expansion of the RWIS program, the plan projects a $2,500,000 savings over ten years (Boselly 2000a).

Results in Washington State

WSDOT’s North Central Region has led the state in terms of adopting anti-icing and using tailored weather forecasts. As part of the draft study report mentioned above (Boselly 2000b), Washington’s North Central Region’s maintenance staff reported the following at the end of the winter of 1999/2000:

RWIS-supported changes in snow and ice control practices are still too new to have achieved consistent region-wide application and to demonstrate clear trends. A review of maintenance expenditures and accident records reveals no clear evidence that these benefits are substantial enough to be detected in cost figures for snow and ice control. The number of accidents, in particular, is highly variable, with no clear trends visible in the short term. Region management has stressed that the most significant result to date has been an increase in the level of service offered to the public without an increase in cost[11].

Snow and Ice Control Expenditures

RWIS-supported changes in snow and ice control practices are still too new to have achieved consistent region-wide application and to demonstrate any clear trends. A review of maintenance expenditures and accident records reveals no clear evidence that these benefits are substantial enough to be detected in cost figures for snow and ice control. This analysis is complicated by limited weather condition information and a current lack of level of service measurements. (The lack of level of service information is being addressed by incorporation of winter maintenance into the Maintenance Accountability Process discussed at the end of this section.)

WSDOT uses a “winter frost index” to reflect the severity of each winter and compare conditions from region to region and from year to year. WSDOT set out to use the Winter Index developed by the Strategic Highway Research Program, however the winter index calculation requires statewide snowfall data, which is not available for Washington State. As a surrogate measure, the frost index was developed and analysis showed a good correlation with the winter index. The frost index is calculated from temperature observations provided by the National Weather Service (Baroga 2000).

Figure 3-1 shows the frost index for the last four winters only for the three regions with the highest winter maintenance expenses. (The North Central Region, South Central Region and Eastern Region account for 70 percent of total snow and ice control costs in the last four years.). The index uses a scale from –50 to 50, with –50 being the most severe[12] In the following figure the scale has been reversed so that more severe winters show as higher on the chart than less severe winters.

Figure 3-1: Winter Frost Index

Winter Frost Index

As shown in Figure 3-1, the frost index for the last four years for the three regions shows the same pattern at different levels of severity.

Snow and ice control costs for the same three regions are shown in figures 3-2 through 3-4[13]. Without snowfall and level of performance information it is difficult to draw conclusions from the expense data. Trends should begin to show themselves more clearly after two or three more winters. It does appear that there may be already some leveling off of material and equipment costs in the North Central Region, which uses anti-icing strategies extensively[14].

Figure 3-2: Snow and Ice Labor Cost

Snow and Ice Labor Cost

Figure 3-3: Snow and Ice Equipment Cost

Snow and Ice Equipment Cost

Figure 3-4: Snow and Ice Materials Cost

Snow and Ice Materials Cost

Safety

Accident data are reported by calendar year, so it is difficult at this time to see any accident trends as a result of anti-icing operations. Regardless, accident numbers are highly variable and with only one year of extensive use, it is too early to see any definitive evidence that anti-icing has reduced accidents. A further impediment to the analysis is that data on vehicle miles traveled during ice and snow conditions are not available, making it impossible to calculate accident rates. For the North Central Region and the South Central Region, figures 3-5 and 3-6 show the number of injury accidents and fatal accidents that occurred in conditions of snow and ice [15] . Accident data are not available for 1997 and 1998.

Figure 3-5: Injury Accidents

Injury Accidents

Figure 3-6: Fatal Accidents

Figure 3-6: Fatal Accidents

Level of Service Performance Measures

WSDOT has been pilot testing a method of measuring snow and ice control performance for the past two winters and has made final recommendations for incorporating these measures into the Maintenance Accountability Process (MAP). When implemented, the new performance measurement technique should provide some very useful information, particularly with respect to the level of service outcomes for anti-icing and sanding strategies. It will also then be possible to compare level of service performance with snow and ice control expenditures.

Section 4: Maintenance Personnel Survey

WSDOT maintenance personnel were surveyed during May and June of 2001 about their use of, and attitudes toward, various sources of road weather information. Questionnaires were mailed to all 24 maintenance area superintendents with instructions to complete the questionnaire themselves and distribute copies of it to supervisors and lead technicians within their area. A copy of the questionnaire and a summary of the responses are included in Appendix A.

A total of 129 questionnaires were received, overall a 51 percent return rate. Supervisory staff (superintendents and supervisors) had a higher return rate than lead technicians and some WSDOT regions had much higher return rates than others as shown in Figure 4-1. Forty-four percent of the respondents were superintendents or supervisors and 56 percent were lead technicians. Responses were received from every WSDOT region although the Southwest Region was poorly represented with a response rate of only 17 percent. As a result, throughout this report responses from the Southwest Region are included in statewide results but not shown in comparison with results from other regions.

Figure 4-1: Survey Return Rates by Region and Job Class

Survey Return Rates by Region and Job Class

Winter Maintenance

Winter Maintenance Issues

Supervisory staff (superintendents and supervisors) were asked to indicate their first and second most common winter maintenance issues. The most common winter maintenance issues were black ice (first or second most common for 66%), followed closely by frost (63%), as shown in Figure 4-2. Snow accumulation was ranked as either the first or second most common winter maintenance issue by 43 percent of the supervisory staff respondents. Not surprisingly, the most common winter maintenance issues varied considerably by region. For the Eastern Region, frost was reported as the most common winter maintenance issue. In the North Central Region the issue was frost and snow accumulation. In the South Central Region it was snow accumulation and in the Northwest and Olympic regions it was black ice.

Figure 4-2: Most Common Winter Maintenance Issues

Most Common Winter Maintenance Issues

Snow and Ice Control Practices

Supervisory personnel were asked how extensively they used each of the following snow and ice control practices during the 2000/2001 winter season: patrols, plowing and sanding, anti-icing (to prevent an ice/road bond), and de-icing (to break an ice/road bond). As shown in Figure 4-3, patrols were used extensively by nearly half of the respondents. About one third reported using anti-icing or plowing and sanding extensively, and less than 15 percent reported using de-icing extensively. Use of these techniques varied considerably by region, as shown in Figure 4-4.

Figure 4-3: Statewide Use of Snow and Ice Control Practices

Statewide Use of Snow and Ice Control Practices

Figure 4-4: Snow and Ice Practices Used Extensively, by Region

Snow and Ice Prctices Used Extensively, by region

Weather Information

Weather Information Sources

Respondents were asked to indicate how frequently they consulted various sources of weather information to make snow and ice control decisions. Figure 4-5 indicates the number of respondents who answered that they consulted a particular source of information on either a daily or weekly basis. Overall, the most used weather information resources were routine road patrol reports, local broadcast TV, local broadcast radio, and the Internet/Web.

Figure 4-5: Most Frequently Used Sources of Weather Information

Most Frequently Used Sources of Weather Information

Supervisory staff were more likely to rely on less traditional sources of information than were lead techs, as shown in Figure 4-6. Twice as many supervisory staff as lead techs use SCAN Web, and more than twice as many supervisory staff as lead techs used rWeather.

Figure 4-6: Weather Information Source Use, by Job Class

Weather Information Source Use

Figure 4-7 shows that private sector weather forecasting services were used more in the North Central Region than in any other region.  The North Central Region also reported using rWeather more than the other regions. The Eastern Region used SCAN Web much less frequently than any other region[16].

Figure 4-7: Weather Information Sources Used Frequently, by Region

Figure 4-7: Weather Information Sources Used Frequently, by Region

Respondents who reported using anti-icing extensively also reported relying on NorthWest Weathernet and SCAN Web more than those who reported extensive use of plowing and sanding and little or no use of anti-icing, as shown in Figure 4-8.

Figure 4-8: Daily Weather Information Sources and Winter Maintenance Practices

Figure 4-8: Daily Weather Information Sources and Winter Maintenance Practices

Nearly half (46%) of the respondents consulted road patrol reports from outside of their own maintenance areas and 20 percent consulted SCAN Web for RWIS stations outside of their areas.  Use of these external resources varied by region, with the Olympic Region using external road patrol reports the least and the North Central Region making the most use of SCAN Web for external RWIS sites (see Figure 4-9).

Figure 4-9: Use of Weather Information Sources Across Boundaries

Figure 4-9: Use of Weather Information Sources Across Boundaries

Internet Websites Used for Weather Information

Just over three quarters (77%) of the respondents indicated that they used at least one Internet website on a daily or weekly basis for weather information. The National Weather Service was used most often (by just over half of the respondents), followed by WSDOT’s rWeather website, as shown in Figure 4-10. The Weather Channel website is used by 36 percent of the respondents, and nearly 40 percent indicated that they used some other Internet website for weather information.

Figure 4-10: Websites Used for Weather Information

Websites Used For Weather Information

Satisfaction with Available Weather Information

Figure 4-11 shows that just over 65 percent of respondents indicated that they were very or generally satisfied with the weather information they had available for winter maintenance decisions during the winter of 2000/2001. An additional 20 percent indicated that they were somewhat satisfied. Only 2 percent indicated that they were not at all satisfied with the weather information they had available to them.

Figure 4-11: Satisfaction with Available Weather Information

Figure 4-11: Satisfaction with Available Weather Information

Respondents in the Eastern and North Central regions indicated a slightly lower level of satisfaction with the weather information they had available to make winter maintenance decisions than in the South Central, Olympic, and Northwest regions (see Figure 4-12).

Figure 4-12: Average Satisfaction with Weather Information, by Region

Figure 4-12: Average Satisfaction with Weather Information, by Region

Savings from Detailed Weather Information

Respondents were asked whether they had experienced any of a list of savings as a result of the use of detailed weather information. More efficient use of labor was cited by nearly 65 percent of supervisory staff. Between 40 and 50 percent of supervisory staff also indicated that they had experienced labor hour and equipment hour reductions and lower material costs. Ten percent indicated that they had not experienced any of these benefits (see Figure 4-13).

Figure 4-13: Savings from Detailed Weather Information, by Job Class

Savings from Detailed Weather Information

Savings experienced varied by region, with labor efficiency reported more often by the Northwest and North Central regions, labor hour reductions reported more often by the North Central and Olympic regions, equipment hour reductions reported more often by the North Central Region and lower material costs reported more often by the Olympic Region (see Figure 4-14).

Figure 4-14: Savings from Detailed Weather Information, by Region

savings From detailed weather Inofmraiton

Improvements to Weather Information

Respondents were asked which improvements to the weather information they received would be valuable to them. Figure 4-15 shows that improved reliability and more detailed forecasts targeted to specific areas topped the list of valuable improvements.

Figure 4-15: Valuable Improvements to Weather Information

Valuable Improvements to Weather Information

Potential to Reduce Routine Patrols and Increase Anti-icing

Reducing routine road patrols and increasing the use of anti-icing strategies are the two primary ways that RWIS can generate safety and cost effectiveness benefits for WSDOT. More (73%) respondents reported the potential for improved weather information to increase the use of anti-icing than those (43%) who reported its potential to reduce routine road patrols. Supervisory staff were more likely than lead techs to expect these outcomes, especially regarding routine patrols. Results varied by region as well, with the North Central and Olympic regions seeing the most potential and the Northwest and Eastern regions seeing the least (see figures 4-16 and 4-17).

Figure 4-16: Expected Results of Improved Weather Information, by Job Class

Expected Results of Improved Weather Information

Figure 4-17: Expected Results of Improved Weather Information, by Region

Expected results of Improved Weather Information

Weather Information Source Ratings

Respondents were asked to rate SCAN Web, the rWeather website and weather forecasting services such as NorthWest Weathernet in terms of ease of use, usefulness for making maintenance decisions, and level of confidence in the information.  All sources of weather information ranked at medium or just below in terms of level of confidence in the information. In terms of ease of use and usefulness, forecasting services ranked the highest, as shown in Figure 4-18.

Figure 4-18: Ratings for Weather Information Sources

Figure 4-18: Ratings for Weather Information Sources

Usefulness of Information for Winter Maintenance Decisions

Respondents were asked to indicate how useful each of several site-specific types of information (many of which are available from RWIS sensor stations) are for making snow and ice control decisions. The results are shown in Figure 4-19. Nearly all respondents reported that road condition (icy, wet, etc.) was very or somewhat useful information. Of interest is the fact that most of the pieces of information available from RWIS stations were viewed as very useful by only about 40 percent of the respondents. Surprisingly, camera images were viewed as not useful by nearly 30 percent of the respondents.

Figure 4-19: Usefulness of Information for Winter Maintenance Decisions

Usefulness of Information for Winter Maintenance Decisions

Internet Access

One hundred percent of the supervisory staff responding to the survey reported having Internet access at work. In contrast, less than 70 percent of the lead tech personnel reported having Internet access at work. The North Central and Northwest regions had the highest percent of lead techs with access (86% and 85%).  The Eastern Region had the lowest rate of Internet access, with only 40 percent of lead techs reporting having access at work (see Figure 4-20).

Figure 4-20: Lead Techs with Internet Access, by Region

lead techs with Internet access

Comfort with Internet and Pagers

Respondents were asked to indicate how comfortable they were at getting information from the Internet and text message pagers. Of those who had used these technologies, nearly half reported being very comfortable with both. However, 16 percent indicated that they were not at all comfortable getting information from pagers, while only 1 percent indicated the same about the Internet (see Figure 4-21).

Figure 4-21: Comfort Level with Internet and Pagers

Comfort Level with Internet and Pagers

As shown in Figure 4-22, nearly twice as many supervisory staff as lead techs reported being very comfortable using the Internet; however just over one quarter of the lead tech staff had never used the Internet.

Figure 4-22: Comfort Level with Internet, by Job Class

Comfort Level with internet

Adequacy of Training

Most (74 percent) of the respondents who had received training in interpreting weather information reported that the training was adequate for making snow and ice control decisions. However, more than half (54 percent) indicated that they had not had any training in interpreting weather information at all. Just over 60 percent of lead techs reported having received no weather interpretation training along with 45 percent of the supervisory staff respondents. Most of those reporting that they had not received training were from the Eastern Region. Those most likely to have received training were from the North Central Region (see figures 4-23 and 4-24).

Figure 4-23: Adequacy of Training, by Job Class

Adequacy of Training

Figure 4-24: Lack of Training, by Region

Lack of training

RWIS Stations

Satisfaction with RWIS

Forty-one respondents indicated that they had an RWIS sensor station in their maintenance area. These respondents were asked to indicate their satisfaction level with RWIS data accuracy, location of existing stations, equipment reliability, and availability of training. The results are shown in figures 4-25 through 4-27. The majority of respondents indicated that they were only somewhat satisfied with these RWIS aspects.  Respondents from the Eastern Region indicated the highest dissatisfaction with these aspects of RWIS, with a full 50 percent indicating they were not at all satisfied with RWIS equipment reliability and data accuracy. Among those with RWIS stations, satisfaction with RWIS training varied considerably by region, as shown in the adjacent chart. Half or more of the respondents in the Eastern, Northwest, and South Central regions indicated that they were not at all satisfied with the availability of RWIS training. Satisfaction with the availability of training also varied somewhat by job class, with nearly half of lead techs indicating they were not at all satisfied.

Figure 4-25: Satisfaction with RWIS Stations

Satisfaction with RWIS

Figure 4-26: Satisfaction with RWIS Training, by Region

Satisfaction with RWIS Training by Region

Figure 4-27: Satisfaction with RWIS Training, by Job Class

Satisfaction with RWIS Training by Job Class

Of those respondents with an RWIS station in their area, a majority (56%) indicated that they did not use SCAN Web; however this percentage varied considerably by region, as shown in Figure 4-28. Respondents with RWIS stations in the South Central and North Central regions reported using SCAN Web twice as often as those in the Olympic and Northwest regions. Less than 20 percent of the respondents in the Eastern Region reported using SCAN Web if they had an RWIS station in their area.[17]

Figure 4-28: Have RWIS and Use SCAN Web

Have RWIS and Use SCAN Web

Additional RWIS Stations

The results of the survey indicate extensive support for additional RWIS stations. Overall, 84 percent indicated that additional RWIS stations in their maintenance area would be useful in making snow and ice control decisions. Support varied by region, as shown in Figure 4-29.

Figure 4-29: Support for Additional RWIS, by Region

Support for Additional RWIS by Region

rWeather

Overall, 79 percent of the respondents indicated that they were aware of the rWeather website, and of those, 78 percent had used it. Awareness and use varied by region and job class, as shown in figures 4-30 and 4-31, with awareness and usability highest in the North Central and South Central regions and among supervisory staff.

Figure 4-30: Weather Awareness and Use, by Region

Weather Awareness and Use by Region

Figure 4-31:r Weather Awareness and Use, by Job Class

weather awareness and use ;by Job Class

National Weather Service warnings, satellite and radar images, and the statewide weather map were cited as the most valuable features of rWeather. Nine of the ten statewide features were rated as very useful or somewhat useful by over half of the respondents. Of concern is that less than half of the respondents viewed pavement temperature features as useful. Since pavement temperatures are key to winter maintenance decisions, this suggests that emphasis should be placed on training related to the credibility and usefulness of this information (see Figure 4-32).

Figure 4-32: Usefulness of rWeather Features

Usefulness of rweather features

Additional Road Weather Information Investments

Respondents were asked to indicate the RWIS-related activities in which they would like to see WSDOT invest additional resources. The results are shown in Figure 4‑33. Two of three activities most often selected for additional investment were related to training. Nearly 70 percent indicated that they would like to see more investment in training related to interpreting weather data. Additional RWIS stations and training related to anti-icing strategies were cited by just about half of the respondents. Additional resources for RWIS station maintenance and operations and additional investment in providing weather and road condition information to the public followed at more than 40 percent. Less than one quarter of the respondents requested improved Internet access and additional office computers. Although low, this number reflects that access to computers and the Internet is a priority for those who do not already have it.

Figure 4-33: Activities for Additional Investment

Activities for Additional Investment

Comments

Sixty of the respondents (46%) shared additional comments about weather information and winter maintenance decision–making. These comments (a copy of which can be found in the questionnaire example in Appendix A) can be categorized as shown in Table 4-1.

Table 4-1: Maintenance Survey Comments

Comment Summary

Number of Comments

Improvements in forecast reliability are essential in order to use forecasts for winter maintenance decision-making.

8

Additional computers and Internet access are necessary in order to take advantage of weather information resources.

8

Support for the importance of advanced road weather information.

8

Having a good forecast is not enough; road patrols are necessary for responsible decision-making.

8

Miscellaneous

8

RWIS information is inaccurate or not timely.

6

Additional training is necessary.

5

Need improved road condition information for the public.

3

Winter maintenance staffing is inadequate.

2

In this region an accurate enough forecast is not possible.

2

Additional camera sites are needed.

2

The following comments are representative of the comments in the first four categories:

“At Pullman we just go out over the sections if there is any question of frost or worse.  After taking care of the same sections for 23 winters you begin to see a pattern in areas that are hardest hit so you just naturally check them.  For instance, in Pullman you might have clear skies but south of downtown it could be 6" of snow and drifting.  If we had some sort of weather information system it would have to be able to pin point specific areas and then it would have to prove itself before we would stop going out every time to see for ourselves.”

“Some maintenance sheds do not have computers, all of this technology is a great help but we can only use it if we are at home.”

“With the advent of the RWIS sites and NorthWest Weathernet, it has made decision making easier.  More accurate information, gives us time to respond in a more proactive way to each situation.  This brings about a greater reduction in wasted movements and equipment time.”

“Most winter maintenance decisions should be made by crews on the road and in my area at least they are.  I think that major decisions should involve the crews and sometimes that doesn't happen.  Major decisions that include new equipment, new product distribution, types of equipment used should be run by people that use them.”

“We still find that common sense, road patrols and experience are the most reliable current methods.  We have several different weather patterns within our area no one piece of equipment could possibly give as valid and current a report as actually being out there.” 

Section 5: rWeather Customer Survey

Visitors to the rWeather website were invited to respond to a short on-line survey from March 6, 2001 to April 9, 2001. During that time 140 members of the public filled out the survey.  In addition, 12 WSDOT personnel also responded to the survey.  The objectives of this survey were to better understand who used the site, what kinds of trips they were planning with information they derived from the site, the features of the site they used and how useful they found these features to be for their trip planning, and suggestions they might have for enhancing the overall value of the site.  A replica of the survey that was placed on-line is shown in Appendix B.

In interpreting findings from this survey, it is important to point out that respondents were self-selected; that is, the results of this survey reflect the opinions of only individuals who decided on their own to respond. Since the sample of respondents was not scientifically selected, their opinions do not necessarily reflect the opinions of all rWeather site users or of the general population of highway users in the Northwest.  Nevertheless, these respondents reflect a diverse and interested group of private and commercial users of road-weather information available on the Internet, and their opinions can be very helpful in better understanding the types of road-weather information that are most useful, how that information is being used, and how websites like rWeather can potentially be improved so that they can better serve the general traveling public.

Analysis of Survey Results

While somewhat over half (54.4%) of the respondents were frequent users of the rWeather website (more than three times a month), one-third of the respondents said they were visiting for the first time when they answered the survey questions.  For many of the survey questions, it will be useful to focus on the responses of the more experienced users of the site, so this analysis will look at differences between the comments of the first time and the more frequent site users (see Figure 5-1).

Figure 5-1: Frequency of Use

Freqency of the Website

The second question on the survey asked respondents to indicate how frequently they used the site for various reasons. Figure 5-2 excludes the first time users, and shows the percentage of experienced site users who said they used the site “sometimes,” “frequently” or “always” for five different reasons.  Ninety percent of the respondents indicated that they frequently or always used the site to help them prepare for driving conditions along their route, and 86 percent said they frequently or always used the site to find out about weather conditions in general.  Two-thirds used it to check weather conditions for a specific recreational activity, and fewer still primarily used the site for trip timing or route selection purposes.  Use of the site for trip timing and route selection occurred mainly on an occasional basis, though some always use the site for these purposes.  However, as indicated in Figure 5-2, a significant portion of frequent site users said they frequently or always used the site for one or another of these reasons; thus, it seems fair to conclude that the site offers a variety of different high value benefits for different users.

Figure 5-2: Frequency and Reason for Use

Frequency and reason for use

While deciding which highway to take was the least frequently cited reason for visiting the website over all, respondents from Central Washington and outside Washington state were somewhat more likely to select this option (frequently or always) than respondents from Western or Eastern Washington (45.2 percent versus 32.4 percent).  However, there were very few site visitors from outside Washington (10 visitors or 7.2 percent of the 140 visitors), so it is difficult to draw conclusions about this group because of the small number of respondents. The visitors from Central Washington and outside Washington State also were somewhat more likely to cite preparing for driving conditions along their route. Western and Central Washington site users were more likely than users from other locations to indicate frequent use of the site to check for weather conditions for a specific recreational activity.

Use of the rWeather site has increased significantly over the past year. Figure 5-3 shows the average number of user sessions per day between March 2000 and December 2001. This chart also shows the variability in usage of the site in each month in terms of the range from the heaviest day of use to the lightest day of use in that month.[18]  The winter months experienced the highest levels of use as well as the most extremes of usage on a day-to-day basis. In February 2001, for example, a daily average of 3,741 user sessions was recorded for the site, but on February 16th, usage exploded to almost 13,000 user sessions that day, about three and a half times the average for the month.  In fact February 16, 2001, was the Friday before the three-day President’s Day holiday, and furthermore those days experienced particularly bad winter weather in the passes and other parts of the state. 

As a general matter, use of the rWeather site is growing over time, though another year of usage data is needed to sort out longer term growth trends from the seasonal factors that impact use levels. For the ten consecutive months of March through December, overall use of the website increased 86 percent from 2000 to 2001, nearly doubling the number of rWeather users. Growth in site use is also implied by the fact that new users seem to be visiting the website in significant numbers, as about one-third of the respondents to the web survey were first time visitors to the site.

Figure 5-3: User Sessions Per Day

Average Number of User Sessions Per Day

As shown by the data in Figure 5-4, the site is used most frequently to plan recreational and other personal trips of more than 100 miles. About half of the respondents to the survey indicated that this was their main use of the site, and younger respondents to the survey were more likely to indicate the use of the site for recreational trips than older respondents.  The site is also more frequently used to plan for longer rather than shorter business trips.  Those who use the site to plan for trips of 100 miles or less were fairly equally distributed over commuting trips, recreational trips, and other personal trips (between 18.6 percent and 24.3 percent of users plan these types of trips frequently).

Figure 5-4: Kinds of Trips

Kinds of Trips

Visitors to the website were asked to rate 13 different features of the site. For those features that they actually used, they rated the level of usefulness, and for those they didn’t use, they indicated whether they were aware that each feature was available to them on the site. Figure 5-5 shows the overall level of usage reported for these features. The frequently used features include weather and pass conditions, traffic cameras, and road temperatures. Less frequently used features include construction activities, traffic incidents, audio highway advisories, and marine weather information. However, even for the less frequently used features, at least half of the respondents reported using them.

Figure 5-5: Use of Website Features

use of Website Features

As can be seen in Figure 5-5, most of the respondents reported themselves as users of most of the features of the site. Those who didn’t use a particular feature were typically about evenly split between those who said they were aware of the feature but don’t use it and those who say they are not aware of the feature. The detailed data on this split can be seen for Question 4 in Appendix B. There were higher portions of the first time users among those who reported that they were not aware of a particular feature. Presumably, their level of awareness of what is available on this website would grow as they gain more experience over successive visits to the site.

Figure 5-6: Usefulness of Website Features

Usefulness of Website features

Figure 5-6 shows the reported usefulness of various site features for those who reported using each feature.  Weather conditions and mountain pass conditions were judged to be the two most useful features.  Traffic cameras, road temperatures, highway conditions and the state-wide weather map were evaluated as very useful by about eighty percent of those who said they used these features of the website.  Note that at least half of all the users of these features said that each feature was very or somewhat useful.  Given the self-selected nature of this sample, however, respondents who may have used particular features and stopped using the site because they didn’t find them useful would not be represented here.  That is, users of each feature were likely to be those individuals who found a measure of usefulness in it or at least continued to visit the website because it was useful to them.  Nevertheless, the range of evaluations of usefulness offers a picture of which features are the more highly valued by the user community.

Respondents were asked to evaluate the site in terms of their level of agreement or disagreement with various attributes. Figure 5-7 shows the proportion of respondents who said they “strongly agree” or “somewhat agree” with each attribute, arranged in terms of declining overall support for the statements, which are shown in their full wording in Appendix B. About 90 percent or more of these site visitors agreed that the site is well organized, that the site helps them be better prepared for road and weather conditions when they travel, that their use of the site makes their trips safer, and that they feel confident about the accuracy of the information about both current and forecast conditions. In terms of strength of agreement, the site is most valued for its ability to prepare travelers for road and weather conditions.  Users also felt more confident (stronger agreement) in the accuracy of reported current conditions than forecast conditions.

Figure 5-7: Agreement with Site Attributes

Agreement

Slightly over one-third of the users agreed that it took them too long to access some of the information on the site, and about one-quarter of them said that important information was missing from the site that should be made available. Responses to the open-ended comments offered some additional discussion and suggestions regarding these concerns. Only 7 percent of respondents agreed that the site was confusing and difficult to use (81 percent disagreed with this statement). Overall, this is a very positive reaction to these important aspects of the rWeather website.

The perceived usability of the rWeather site is an important issue for WSDOT, and four of the attributes of the website examined bear on how useable respondents find it. Figure 5-8 compares the opinions on site usability of first time users with those of frequent users.  The figure compares the percentage of first time users and frequent users who said they “strongly agree” with each of these four usability indicators.  While the differences between these two groups are not very large, each of the four comparisons supports the interpretation that first time users find the site somewhat more difficult to use than experienced users.  First time users are less likely to strongly agree that the site is well organized, and more likely to agree that accessing information on the site takes too long, that important information is missing from the site, and that the site is confusing and difficult to use.

Figure 5-8: Usability Indicators

Figure 5-8: Usability Indicators

Obviously, as can be seen in the figure, very few respondents, regardless of experience with the site, said they strongly agree that the site is confusing and difficult to use.  For this question, it is helpful to look at the percentage who strongly disagree.  Fifty-eight percent of the first time users said they strongly disagreed that the site was confusing, but 75 percent of the experienced users strongly disagreed. So while many first time users clearly find the site perfectly usable, some do not, and more of these were in this first timer group than in the experienced group of users.

One explanation for this difference in the sample could be that the experienced users had figured out the site and continued to use it, whereas those who tried it and had difficulty very likely had given up and no longer use it. Those who had problems may have stopped using the site and thus would not be in the self-selected sample. Another explanation can be inferred from the users who were not sure about this question. Four times as many first time users as experienced users (21.1 percent versus 5.6 percent) said that they are neutral on the question of site difficulty (i.e., neither agreed nor disagreed), which suggests that they hade not had time to make up their minds and wanted more experience with the site to make a judgment.

Comments Provided by Users

Just over half of the respondents (71 or 50.7 percent) offered comments when asked to suggest how the website could be improved to better meet their needs.  Suggestions tended to cluster around several common topics, including a desire for more camera images, more current information, broader and more consistent geographic coverage, and some site design concerns that mostly centered on the way frames were being used to present information. Many of the problems that some users experienced seemed to be related to the use of Macintosh computers and the Netscape browser, causing loading delays and problems with graphic images.[19]  Some respondents related some interesting, and somewhat unusual, uses of the rWeather site, and many others simply wanted to offer their gratitude for a site they found very useful. These comments are summarized below.

Suggestions

Problems Experienced

Creative Uses of Site

Positive quotes (with minor paraphrasing)

Summary

In the month that the survey was posted on the rWeather website, 140 users of the site responded, offering their opinions and suggestions. Overall, use of the site has been growing over the past year, perhaps by a factor of three during this period, though more time and data are needed to distinguish long-term growth trends from the wide seasonal variation in use experienced at this site. About one-third of the respondents were first-time users and over half were frequent users. They were overwhelmingly positive in their assessment of the value of the site in helping them prepare for their travel and learn about weather and road conditions. Use of this site is different from many other traveler information sites in that users are predominantly focused on longer trips.  More than twice as many users said they were most frequently planning recreational, business, and other personal trips of over 100 miles in comparison to those using the website to plan shorter trips.

Virtually all of the site’s informational features were used by most visitors and their ratings of the usefulness of these features were high for all the main features, including weather conditions, mountain pass conditions, traffic cameras, road temperatures, and state-wide maps.  About half the respondents offered specific suggestions that tended to cluster around several common topics, including a desire for more camera images, more current information, broader and more consistent geographic coverage, and some site design modifications. A few Mac and Netscape users reported problems. The great majority of users who responded to the survey said they found the site well organized and generally easy to use, with information that is easy to fine Some concerns were reported regarding site usability, and evidence suggests that first-time users had more difficulties than experienced users. Overall, however, the response to this website was very positive.  Comments such as, “The website is terrific,” and “One of the best sites that I have seen,” capture the opinion of many of the survey respondents.

Section 6: Findings and Recommendations

Major strides have been made recently in WSDOT’s implementation of RWIS as a result of the rWeather program. The most significant of these are equipment compatibility; development of a statewide RWIS network, including an extensive set of non-WSDOT weather sensors; access to statewide comprehensive weather information, weather training; and a public information website.

However, WSDOT maintenance personnel are not taking full advantage of the state’s RWIS investment. At the same time, it is clear that enthusiasm for implementing advanced snow and ice control practices is growing, and maintenance personnel have expressed extensive support for additional RWIS stations and weather interpretation training.

Barriers to Full Use

The barriers to full use of RWIS capabilities can be grouped under the following headings:

Findings and recommendations associated with each of these barriers are presented below.

Lack of Experience

Findings

The learning curve itself is a barrier to the implementation of advanced winter maintenance practices. It is difficult to take full advantage of technologies for which there has been little experience, as is the case for RWIS in most of Washington.  As with any change in tools and procedures, expectations become more realistic with use. 

To some extent the lack of confidence in weather forecasts, RWIS sensor stations, and the performance of anti-icing chemicals are all directly related to a lack of experience with these data sources and materials. The results of the maintenance personnel survey clearly indicate that those with the most experience with RWIS capabilities and proactive maintenance practices are the most optimistic about the potential of these technologies and strategies. These employees also use more sophisticated sources of weather information, and they are the most interested in improvements to weather forecasts that will help them more effectively and efficiently implement advanced snow and ice control practices. It is also clear that adequate training and access encourage use of more sophisticated sources of weather information such as SCAN Web, rWeather, other Internet websites and commercial forecast services. 

Those without experience relying on weather forecasts view them as insufficient for good maintenance decision-making, with more than half of the survey respondents citing the need to continue routine patrols despite improvements in weather forecasting. As noted by Boselly (1993), “DOTs tend to base their assessment of the utility of forecasting services on perception and intuition rather than generating even simple statistics such as percentage of correct forecasts.”

Recommendations

The push to use more advanced (and expensive), proactive snow and ice control strategies will force the use of RWIS as a means to control the cost of these strategies. Already, experience with RWIS and anti-icing in the North Central Region is reducing the barriers to implementation in the other regions. Weather data archiving and monitoring of snow and ice control performance will become increasingly important as a way to learn from experience. The winter maintenance plan developed for the North Central Region includes a mechanism to document snow and ice control performance for each storm or storm segment, and it recommends a post-storm analysis as part of a total storm management strategy (Boselly, 2000a).

Lack of confidence

Findings

For the purposes of implementing proactive winter maintenance practices, reliable and tailored forecasts of weather and pavement temperature are essential. A lack of confidence in these forecasts is a major barrier to using them to support changes in snow and ice control practices. WSDOT maintenance personnel express very little confidence in weather forecasts and virtually no confidence in pavement temperature forecasts. There is even concern about the reliability of RWIS station weather observations.

Outside of the North Central Region, which contracts for tailored weather forecasts, winter maintenance personnel rely on the same high-level forecasts that are provided to the general public by the National Weather Service.  These forecasts cannot provide the level of detail necessary to implement advanced snow and ice control practices, and they do not address pavement temperatures at all. In addition, as with most information sources, people are far more likely to remember poor forecasts than good ones. 

Less than half of the maintenance personnel who reported having used rWeather viewed the pavement temperatures and forecasts as useful. This appears to be partly due to a lack of knowledge about the importance of pavement temperature forecasts and partly due to a lack of confidence in these forecasts, especially at the detail level that is useful for maintenance decision-making. It is important to note that thanks to increases in computing power and additional detection technology, tremendous advances are being made in the ability to forecast weather.

Maintenance personnel have a great interest in weather forecasts with improved reliability and more detail, and most respondents in the survey thought they would increase their use of anti-icing strategies if they had better weather information.

Recommendations

It is important to be able to demonstrate to maintenance personnel the reliability of the rWeather pavement temperatures and forecasts being generated by computer models at the University of Washington. Comparisons between forecast and actual pavement temperatures and atmospheric weather conditions need to be made and shared with maintenance personnel.

The reliability of tailored, vendor-provided weather forecasts needs to be determined by keeping records of forecast and actual conditions. A simple framework useful for summarizing weather forecast performance is shown in Figure 6-1. This framework was developed as a tool for evaluating the FORTELL project, a multi-state weather information field operational test. (Battelle 1998).

Figure 6-1: FORTELL Weather Forecast Evaluation Model

Figure 6-1: FORTELL Weather Forecast Evaluation Model

WSDOT’s contracts for forecasting services should be performance based.  Several state DOTs have started to require stated levels of reliability from contractors providing tailored weather forecasts.  For example, Wisconsin DOT (WisDOT) decided that maintenance personnel had to have a forecast product that they had confidence in and could rely on if Wisconsin was going to forge ahead with plans to use anti-icing techniques and if it was going to continue intensive efforts to reduce salt use while still maintaining a high level of service.  In 1997 WisDOT awarded its first contract for new forecast services to a vendor that was required to meet WisDOT's service and reliability requirements. 

The new contract contains language requiring the forecast agency to notify Wisconsin counties 4 hours before snowfalls of more than 1 inch or freezing rain events are forecast to start and 2 hours before other snowfall events are expected.  It also requires the forecast agency to immediately notify the county when the forecast changes during storm events. The new forecast services contract includes similar specific language for pavement temperature forecasts. 

WisDOT has undertaken an effort to verify the weather and pavement temperature forecasts using common meteorological techniques to determine the accuracy of the vendor's forecasts, including timing error, percentage of correct determination for snow, freezing rain, and air and pavement temperatures dropping below freezing. The forecast verification rate is expected to be 85 percent or better.  An average forecast verification rate of less than 85 percent is grounds for the customer to cancel the contract (Adams 1998). 

Lack of Access

Findings

Access to RWIS information is essential in order for that information to be used to support advanced winter maintenance practices.  The findings of the maintenance personnel survey indicate that a large percentage of maintenance sheds and lead techs do not have access to the Internet, the primary method of accessing RWIS and other weather information.

Somewhat surprisingly, the level of comfort in using the Internet is very high (87 percent are very or moderately comfortable), indicating that an investment in Internet access would be worthwhile.

Recommendations

Provide computers and Internet access in all maintenance sheds and ensure that computers with Internet access are available to all personnel tasked with making winter maintenance decisions. 

Lack of Training

Findings

The survey of maintenance personnel clearly shows a need for, and an interest in, training in several areas. The survey also indicates that personnel who have received more training are more open to the use of RWIS and advanced snow and ice control practices. Specific findings include the following:

Recommendations

Provide training, particularly in the interpretation of weather information and the application of anti-icing strategies.  Make an effort to focus the right training on the right people.

Multiple Internet resources are available and heavily used by maintenance personnel for weather information. It would be advantageous to train maintenance personnel in the potential pitfalls of these sources and the best ways to take advantage of them.

Resistance to Change

Findings

Winter maintenance crews have a high degree of pride in the work that they perform, and RWIS isn’t necessary to continue the reactive approaches to snow and ice control. However, significant changes in business practices are required to achieve the operating cost savings promised by RWIS. Specifically, routine road patrols need to be eliminated and staffing strategies need to be revised.   

The elimination of routine road patrols is probably the most problematic.  Patrols are heavily relied upon as a source of weather and road condition observations, and they are an integral part of how business is done.  In fact, many believe that even with improved weather information, patrols would be necessary.

As mentioned earlier, areas in the North Central Region have already made changes in crew staffing that have resulted in the elimination of routine night and weekend shifts, a change reportedly well received by the employees.

Another aspect of resistance to change is the desire to avoid risk.  In the case of anti-icing, the cost of applying anti-icing chemicals where they are not needed is very high. In addition, some maintenance personnel are not sure of the safety of anti-icing chemicals, which if applied incorrectly can actually make the road slippery. 

Even some members of the public are resistant to change, as evidenced by the petition against anti-icing submitted by residents of the Methow Valley.

Recommendations

A statewide transition to more cost-effective winter maintenance practices will require a strong management stance on the need to make change and a commitment to training. In addition, WSDOT should continue its efforts to educate the public about the potential safety, cost, and environmental benefits of using anti-icing chemicals.

Liability Concerns

Findings

There are two concerns related to liability.  The first is a concern that the use of anti-icing chemicals will generate vehicle damage claims.  The second concern is that not using anti-icing will generate accident-related lawsuits claiming negligence on the part of WSDOT.

According to the Risk Management Office[20], WSDOT has been “steadfast” in denying claims of damage related to anti-icing chemicals and sand, citing that the DOT’s duty to provide safe roads overrides the duty to protect individual property. In the case of damage from sand, claims are rarely paid and if they are, the payments are small. However, liability has been an issue in cases in which improperly applied anti-icing chemicals have led to slippery conditions.

The demonstrated capabilities of RWIS could constitute the state-of-the-art in snow and ice control technology. Such a view could make highway agencies liable if they did not acquire and properly use the technology. However, information from a representative in the Washington State Attorney General’s Office (who is also a longtime member of the Transportation Research Board’s Tort Liability and Risk Management Committee)[21] indicates that, although snow and ice is a significant area of liability for WSDOT, charges of negligence for not using RWIS and advanced maintenance practices have not become an issue for Washington. Furthermore, they have not been an issue for any other state DOT, most of which are not required to mitigate the consequences of weather the way that Washington is. However, he cautioned that tort liability related to the use of RWIS capabilities and anti-icing strategies may very well become an issue if part of the state adopts improved methods and others do not. A lack of consistent implementation of advanced winter maintenance practices and uniform compliance with associated procedures could definitely weaken the state’s ability to defend itself against claims.

If WSDOT adopts more sophisticated approaches and a new standard of care, travelers can be expected to raise their level of service expectations. A change to the use of advanced winter maintenance practices needs to have a well planned and documented, staged implementation. Anti-icing efforts to date have been characterized as experimental.

Recommendations

Development of a well-documented implementation plan is essential to address liability concerns related to non-experimental use of RWIS and advanced winter maintenance practices.

RWIS Equipment and rWeather Website Issues

Findings

The maintenance personnel survey results indicated that between 70 and 75 percent of the respondents were somewhat or not at all satisfied with the accuracy, reliability, or location of the RWIS sensor stations in their area. 

The rWeather website has proven itself as a valuable tool for travelers (especially for long distanced trips), and as it has evolved it has continued to address traveler information needs. According to the maintenance personnel survey, 50 percent of those surveyed use the rWeather website. For maintenance staff this is the only resource that provides access to the network of non-WSDOT weather station information and the only place to find pavement temperatures and forecasts.

One issue no doubt responsible for the relatively low level of use is the lack of Internet access by many of the survey respondents. In addition, however, maintenance personnel have expressed dissatisfaction with the lack of detail available on the site. The RWIS sensor station reports lack some important detail that is available on SCAN Web, and the pavement temperatures are too general to support winter maintenance decision-making. These design decisions were made out of concern for minimizing WSDOT’s liability for information provided to the public. As a result of trying to address both audiences, the rWeather website has become a better tool for travelers than for maintenance staff.

As of late 2001 the rWeather website has become the corner stone of integrated traveler information on the WSDOT website, taking advantage of rWeather’s success in providing road and weather information to travelers.

Recommendations

The rWeather program has upgraded many RWIS station sites over the last couple of years, and many concerns about sensor reliability may have been addressed by now. However, a full review of the accuracy and reliability of all RWIS sensor station equipment would ensure that the equipment is able to adequately support improvements in winter maintenance practices. Funding for ongoing maintenance of these stations is also necessary. Consideration should also be given to ongoing funding of centralized RWIS technical support.

WSDOT should consider adding RWIS detail and pavement temperature detail components to the site formerly known as rWeather, accessible only to WSDOT personnel through the WSDOT Intranet as a way of heightening the sites usefulness for winter maintenance decision making. Looking to the future, a WSDOT-only portion of the website could also be used for tracking where and when anti-icing chemicals have been applied, currently a critical missing piece in the electronic information available for snow and ice control.

Limitations of Existing Technology

Findings

The following list highlights some limitations to existing technologies that are currently barriers to more extensive use of RWIS:

Recommendations

The potential value of RWIS varies from region to region as a result of the type of weather and road conditions that need to be addressed and the ability to reliably forecast conditions. Only with reliable forecasts can advanced winter maintenance practices be efficiently implemented. Additional RWIS resources need to be focused on areas where the potential to change snow and ice control practices exists and where additional sensor capability will contribute to improved weather forecasting.

All of these technology limitations are being addressed and will be resolved over time.

Summary of Recommendations

Many of the recommendations identified above, and summarized below, are already being addressed through continued investments in RWIS sensor stations, Internet access, and additional weather-related training. In addition, current plans call for hiring a meteorologist to address the need for analysis of statewide forecast reliability and equipment performance.

  1. Continue to share information about experiences with RWIS and advanced winter maintenance practices as a way to reduce barriers to expanded use.
  2. Document and review snow and ice control methods and results throughout the winter season.
  3. Document the reliability of rWeather pavement temperature forecasts and share the results with winter maintenance personnel.
  4. Require weather forecast service to meet defined performance criteria.
  5. Provide computers and Internet access in all maintenance sheds and ensure that computers with Internet access are available to all personnel tasked with making winter maintenance decisions.
  6. Provide training, particularly in the interpretation of weather information and the application of anti-icing strategies. Make an effort to focus the right training on the right people.
  7. Train maintenance personnel in the potential pitfalls of the multitude of Internet sources of weather information and the best ways to take advantage of them.
  8. Provide strong management support for the need to make change and demonstrate a commitment to necessary training.
  9. Continue efforts to educate the public about the potential safety, cost, and environmental benefits of using anti-icing chemicals.
  10. Develop a well-documented plan for statewide, uniform implementation of advanced winter maintenance practices to address liability concerns.
  11. Make a full review of the accuracy and reliability of all RWIS sensor station equipment.
  12. Ensure funding for ongoing maintenance of RWIS sensor stations.
  13. Consider ongoing funding of centralized RWIS technical support.
  14. Focus additional RWIS resources on areas where the potential to change snow and ice control practices exists and where additional sensor capability will contribute to improved weather forecasting.

Section 7: Conclusion

RWIS enables cost effective, proactive winter maintenance practices that improve the level of service provided and lead tech to increased safety and mobility for the traveling public. Although proactive maintenance practices such as anti-icing can be implemented without a comprehensive RWIS, such implementations are very costly because use of labor, equipment, and materials is often beyond what is necessary.

In Washington, the rWeather program has significantly improved the RWIS resources available for winter maintenance decision-making. The rWeather program has also resulted in development of a weather and road condition website highly valued by long-distance travelers.

This research has shown that WSDOT maintenance personnel have not taken full advantage of the capabilities of RWIS, in part because these capabilities are not necessary to continue traditional, reactive winter maintenance strategies. Expanding the use of RWIS and advanced winter maintenance practices will require management commitment and continued investment in equipment reliability, demonstration of forecast credibility, targeted training, and implementation planning.

Section 8: References

Adams, Michael J., Martinelli, Thomas J. Innovative Uses of RWIS Technologies in Wisconsin's Winter Maintenance Operations. Prepared for Transportation Research Board Annual Meeting, Washington D.C., January 1998.

Baroga, Enrico, V. Performance Measurement for Snow and Ice Control Activities: A Pilot Project in Washington State, Washington State Department of Transportation, May 18, 2000

Battelle. Evaluation of the FORTELL Consortium Operational Test: Weather Information for Surface Transportation, Evaluation Strategy, Prepared for USDOT Joint Program Office, Washington D.C., July 1, 1998.

Boselly, S. Edward, Doore, G. Stanley, Thornes, John E., Ulberg, Cyrus, Ernt, Donald D. Road Weather Information Systems Volume 1: Research Report, Prepared for the Strategic Highway Research Program, National Research Council, Washington D.C., 1993.

Boselly, S. Edward. North Central Region Winter Maintenance Plan, Washington State Department of Transportation, October 2000(a).

Boselly, S. Edward. Benefit/Cost Study of RWIS and Anti-icing Technologies, DRAFT prepared for the National Cooperative Highway Research Program (20-7,117), November 2000(b).

Brown, W., Legg, B., Coss, G., and O’Brien, A. rWeather: Real-Time Statewide Road and Weather Information Network, Washington State Department of Transportation, August 2000.

Epps, Jon. A., Ardila-Coulson, Maria. Summary of SHRP Research and Economic Benefits of Snow and Ice Control, Prepared for FHWA, Washington D.C., December 1997. (FHWASA-98-015)

Federal Highway Administration. Maintenance Decision Support System Project: MDSS Prototype Development Plan. June 2001. (Abridged Version)

Mergenmeier, Andrew. New Strategies Can Improve Winter Road Maintenance Operations, Public Roads, Spring 1995.

McKeever, B. A Life Cycle Cost-Benefit Model for Road Weather Information Systems, Proceedings of the Transportation Research Board 77th Annual Meeting, Washington D.C., January 1998.

Pacific Rim Resources. WSDOT Maintenance Customer Survey - Summary Report, Prepared for Washington State Department of Transportation, January 2, 2001.

RoadSavers Case Studies. Federal Highway Administration, 1997. (http://www.fhwa.dot.gov/winter/roadsvr/index.html).

Appendix A: Road Weather Information Questionnaire

This questionnaire is part of a study of the road weather information resources available to maintenance staff within the Washington State Department of Transportation.  The answers you provide will help guide further WSDOT investments in road weather information.  Please return the completed questionnaire by May 1st, 2001 to:

                Catherine Boon

                Washington State Transportation Center

                1107 NE 45th Street, Suite 535

                Seattle, WA 98105-4631

Name:  __________________________________________

Date:  ___________________________________________

Position:  __Supervisory staff (57), Lead techs (72)__________

Section(shed):  __Eastern Region (26), North Central Region (24), Northwest Region (26), Olympic Region (24), South Central Region (23), Southwest Region (6)_______

1.        Please indicate your first most common winter maintenance issue:

Other__________________________________________________________      

2.        Please indicate your second most common winter maintenance issue:

3.        Please indicate the extent to which you used each of the following snow and ice control practices during the 2000/2001 winter season:

 

Used Extensively

Used Moderately

Used Minimally

Not Used

At All

Patrols

(68)

(39)

(18)

(3)

Plowing and sanding

(43)

(56)

(29)

(0)

Anti-icing (chemicals to prevent ice/road bond)

(33)

(61)

(25)

(7)

Deicing (chemicals to break ice/road bond)

(14)

(25)

(43)

(40)

4.     Please indicate how often you consulted the following sources of weather information to make winter maintenance decisions during the winter of 2000/2001: 

 

Daily

Weekly

Monthly

Annually

Never

SCAN Web - only for your RWIS* stations

(22)

(10)

(3)

(1)

(79)

SCAN Web - for RWIS stations outside your section

(11)

(15)

(9)

(2)

(73)

WSDOT's rWeather website

(34)

(31)

(6)

(2)

(41)

National Weather Service website

(30)

(37)

(8)

(2)

(34)

Weather Channel website

(24)

(22)

(9)

(1)

(56)

Other Internet website

(27)

(23)

(10)

(3)

(42)

Forecasting service such as Northwest Weather Net

(52)

(10)

(3)

(1)

(47)

Local broadcast radio

(92)

(10)

(3)

(2)

(12)

NOAA radio

(18)

(14)

(7)

(2)

(68)

Local broadcast TV

(95)

(11)

(0)

(0)

(15)

Cable TV weather station

(46)

(13)

(3)

(3)

(45)

Road patrol reports within your section

(103)

(7)

(1)

(0)

(6)

Road patrol reports from areas outside your section

(36)

(23)

(6)

(3)

(36)

Other:
______DTN____________________

(4)

       

*RWIS - Road Weather Information System

5.        During the winter of 2000/2001, how satisfied were you with the weather information you had available for making winter maintenance decisions?

6.        Have you experienced any of the following as a result of the use of detailed weather information?

7.        Which of the following improvements to your weather information, if any, would be valuable to you: (select all that apply)

8.      Do you think that improvements in the weather information you have available to you would encourage you to increase your use of anti-icing strategies?

9.     Do you think that improvements in the weather information you have available to you would encourage you to reduce your use of patrols?

10.     For the following weather services, please rate each one in terms of ease of use, availability (works when you need it), usefulness for making maintenance decisions, and your level of confidence in the information. Circle your rating as High, Med (medium) or Low.

 

Don't Use

Ease of Use

Availability

Usefulness

Confidence

SCAN Web

(70)

High (19)  Med (20) Low (7)

High (21)  Med (19) Low (6)

High (16) Med (23) Low (6)

High (8) Med (31) Low (6)

WSDOT's rWeather website

(49)

High (34) Med (28) Low (9)

High (39) Med (20) Low (11)

High (20) Med (38) Low (11)

High (10) Med (42) Low (14)

Weather forecasting service*

(39)

High (54) Med (24) Low (4)

High (52) Med (21) Low (5)

High (32) Med (40) Low (3)

High (7) Med (52) Low (14)

*NorthWest Weathernet for example.

11.     How useful to you is each of the following site-specific information for making snow and ice control decisions?

 

Very
Useful

Somewhat Useful

Not

Useful

Air temperature

(108)

(16)

(1)

Changes in air temperature over last 24 hours

(42)

(65)

(12)

Wind speed and direction

(43)

(67)

(13)

Pavement temperature

(93)

(26)

(6)

Changes in pavement temperature over last 24 hours

(44)

(54)

(20)

Dew point, relative humidity

(54)

(53)

(13)

Road surface condition (dry, wet, ice)

(109)

(14)

(1)

Road subsurface temperature

(44)

(56)

(20)

Precipitation/snowfall

(103)

(17)

(5)

Chemical presence

(55)

(46)

(19)

Chemical concentration

(49)

(48)

(23)

Visibility

(49)

(57)

(14)

Camera images on the web

(39)

(48)

(33)

12.     Is the training you have received in interpreting weather information adequate for you to make snow and ice control decisions?

13.     Do you personally have access to the Internet at work?

14.     What kind of connection do you have to the Internet at work?

15.    In your workplace, is Internet access limited because of security and abuse concerns?

16.   How comfortable are you getting information from each of the following sources?

 

Have Never Used

Very Comfortable

Moderately Comfortable

Marginally Comfortable

Not at all Comfortable

Internet

(18)

(53)

(41)

(14)

(1)

Internal WSDOT network (Intranet)

(19)

(63)

(34)

(8)

(1)

Electronic Mail

(18)

(85)

(15)

(3)

(4)

Pager (text messages)

(69)

(26)

(12)

(5)

(8)

Voice Mail (telephone answering machine)

(39)

(43)

(22)

(9)

(9)

FAX

(19)

(65)

(28)

(8)

(5)

TV/Radio

(5)

(79)

(27)

(13)

(2)

17.    Do you have any RWIS sensor station in your maintenance section?

18.    Please indicate the capabilities your RWIS stations had available (working) during most of this winter (2000/2001) season:

 

All stations had this

Some stations had this

No stations had this

Don't

Know

Air temperature

(32)

(0)

(1)

(8)

Pavement temperature

(29)

(0)

(3)

(7)

Sub-surface temperature

(20)

(2)

(6)

(10)

Visibility

(10)

(3)

(12)

(9)

Chemical presence

(14)

(1)

(10)

(11)

Chemical concentration

(11)

(0)

(13)

(12)

Precipitation

(28)

(1)

(2)

(9)

Wind speed and direction

(30)

(2)

(1)

(8)

19.     Please indicate your satisfaction with the following aspects of your RWIS stations:

 

Very
Satisfied

Somewhat Satisfied

Not at all Satisfied

Equipment reliability

(10)

(26)

(6)

Data accuracy

(12)

(24)

(6)

Location of existing stations

(12)

(21)

(10)

Availability of training

(4)

(22)

(15)

20.  Would additional RWIS stations in your maintenance section be useful to you in making snow and ice control decisions?

Map

21.  Are you aware of WSDOT's rWeather Internet website? (See sample screen at right.)

22.  Have you ever used WSDOT's rWeather Internet website?

23.  Please rate each of the rWeather site's features in terms of its usefulness for maintenance decision making:

 

Very
Useful

Somewhat Useful

Not

Useful

Haven't Used this Feature

Statewide weather map (shown above)

(19)

(54)

(5)

(4)

RWIS station weather conditions

(28)

(26)

(10)

(14)

Other weather station conditions

(22)

(41)

(8)

(9)

Camera images

(22)

(43)

(6)

(9)

Highway radio advisories

(20)

(35)

(13)

(13)

Construction activities

(10)

(34)

(21)

(13)

Current statewide pavement temperatures

(10)

(27)

(24)

(19)

Current and forecast pavement temperatures for I-90 and SR2

(10)

(24)

(24)

(22)

Weather radar images

(39)

(32)

(5)

(4)

Weather satellite images

(37)

(35)

(5)

(3)

National Weather Service warnings

(37)

(37)

(1)

(6)

Marine information (Ferry Weather)

(7)

(9)

(31)

(32)

24.  In which of the following would you like to see WSDOT invest additional resources?

25.  Please share any comments you have about the weather information and winter maintenance decision making:

________________________________________________________________________

Appendix B: rWeather Customer Survey

Questionnaire

RWeather Customer Survey Results

1.   How often do you visit this website?

 

Frequency

Percent

This is my first visit

46

33.8%

I visit the site one to three times a month

16

11.8%

I visit the site more than three times a month

74

54.4%

Totals:[22]

136

100.0%

2.   How often have you used this site for each of the following reasons?

      a.  To decide which highway to take.

 

Frequency

Percent

Never

27

25.7%

Sometimes

40

38.1%

Frequently

29

27.6%

Always

9

8.6%

Totals:

105

100.0%

      b.  To make sure it is a good time to make my trip.

 

Frequency

Percent

Never

13

11.8%

Sometimes

37

33.6%

Frequently

34

30.9%

Always

26

23.6%

Totals:

110

100.0%

      c.  To prepare myself for driving conditions along my route.

 

Frequency

Percent

Never

7

6.0%

Sometimes

15

12.9%

Frequently

34

29.3%

Always

60

51.7%

Totals:

116

100.0%

      d.  To check weather conditions for a specific recreational activity.

 

Frequency

Percent

Never

27

23.7%

Sometimes

17

14.9%

Frequently

31

27.2%

Always

39

34.2%

Totals:

114

100.0%

      e.  To find out about weather conditions in general.

 

Frequency

Percent

Never

7

5.9%

Sometimes

19

16.1%

Frequently

43

36.4%

Always

49

41.5%

Totals:

118

100.0%

3.   Considering all the times you have used this site, indicate the kinds of trips you most frequently plan.

      a.  Commuting for school or work.

 

Frequency

Percent

Trips of 100 miles or less

29

20.7%

Trips of more than 100 miles

13

9.3%

      b.  Business trips

 

Frequency

Percent

Trips of 100 miles or less

16

11.4%

Trips of more than 100 miles

39

27.9%

      c.  Recreational trips

 

Frequency

Percent

Trips of 100 miles or less

34

24.3%

Trips of more than 100 miles

71

50.7%

      d.  Other personal trips.

 

Frequency

Percent

Trips of 100 miles or less

26

18.6%

Trips of more than 100 miles

67

47.9%

      e.  Freight hauling or goods/services delivery

 

Frequency

Percent

Trips of 100 miles or less

7

5.0%

Trips of more than 100 miles

14

10.0%

4.   Rate the usefulness of each of the features of this website that you have used at least once.  For each feature that you have not used, please indicate whether you were aware of this feature before taking this survey.

      a.  State-wide weather map

 

Frequency

Percent

Use this feature

117

92.9%

         Very useful

91

72.2%

         Somewhat useful

24

19.0%

         Not very useful

2

1.6%

Don’t use this feature

9

7.1%

         Aware of it

4

3.2%

         Not aware of it

5

4.0%

Totals:

126

100.0%

      b.  Mountain pass conditions

 

Frequency

Percent

Use this feature

127

96.9%

         Very useful

122

93.1%

         Somewhat useful

4

3.1%

         Not very useful

1

0.8%

Don’t use this feature

4

3.1%

         Aware of it

3

2.3%

         Not aware of it

1

0.8%

Totals:

131

100.0%

      c.  Weather conditions

 

Frequency

Percent

Use this feature

129

98.5%

         Very useful

120

91.6%

         Somewhat useful

7

5.3%

         Not very useful

2

1.5%

Don’t use this feature

2

1.5%

         Aware of it

0

0.0%

         Not aware of it

2

1.5%

Totals:

131

100.0%

      d.  Traffic cameras

 

Frequency

Percent

Use this feature

123

96.1%

         Very useful

97

75.8%

         Somewhat useful

21

16.4%

         Not very useful

5

3.9%

Don’t use this feature

5

3.9%

         Aware of it

2

1.6%

         Not aware of it

3

2.3%

Totals:

128

100.0%

      e.  Audio highway advisories

 

Frequency

Percent

Use this feature

73

61.9%

         Very useful

33

28.0%

         Somewhat useful

30

25.4%

         Not very useful

10

8.5%

Don’t use this feature

45

38.1%

         Aware of it

18

15.3%

         Not aware of it

27

22.9%

Totals:

118

100.0%

      f.  Construction activities

 

Frequency

Percent

Use this feature

97

78.9%

         Very useful

55

44.7%

         Somewhat useful

34

27.6%

         Not very useful

8

6.5%

Don’t use this feature

26

21.1%

         Aware of it

14

11.4%

         Not aware of it

12

9.8%

Totals:

123

100.0%

      g.  Traffic incidents

 

Frequency

Percent

Use this feature

85

71.4%

         Very useful

37

31.1%

         Somewhat useful

39

32.8%

         Not very useful

9

7.6%

Don’t use this feature

34

28.6%

         Aware of it

18

15.1%

         Not aware of it

16

13.4%

Totals:

119

100.0%

      h.  Road conditions (temperature)

 

Frequency

Percent

Use this feature

123

95.3%

         Very useful

100

77.5%

         Somewhat useful

22

17.1%

         Not very useful

1

0.8%

Don’t use this feature

6

4.7%

         Aware of it

4

3.1%

         Not aware of it

2

1.6%

Totals:

129

100.0%

      i.  Weather radar images

 

Frequency

Percent

Use this feature

102

83.6%

         Very useful

51

41.8%

         Somewhat useful

41

33.6%

         Not very useful

10

8.2%

Don’t use this feature

20

16.4%

         Aware of it

10

8.2%

         Not aware of it

10

8.2%

Totals:

122

100.0%

      j.  Weather satellite images

 

Frequency

Percent

Use this feature

100

82.0%

         Very useful

50

41.0%

         Somewhat useful

42

34.4%

         Not very useful

8

6.6%

Don’t use this feature

22

18.0%

         Aware of it

10

8.2%

         Not aware of it

12

9.8%

Totals:

122

100.0%

      k.  National Weather Service warnings

 

Frequency

Percent

Use this feature

107

85.6%

         Very useful

61

48.8%

         Somewhat useful

46

36.8%

         Not very useful

0

0.0%

Don’t use this feature

18

14.4%

         Aware of it

4

3.2%

         Not aware of it

14

11.2%

Totals:

125

100.0%

      l.  Marine information (Ferry Weather)

 

Frequency

Percent

Use this feature

63

54.3%

         Very useful

15

12.9%

         Somewhat useful

28

24.1%

         Not very useful

20

17.2%

Don’t use this feature

53

45.7%

         Aware of it

33

28.4%

         Not aware of it

20

17.2%

Totals:

116

100.0%

      m.  Current and forecast highway conditions (I-90, SR2)

 

Frequency

Percent

Use this feature

118

93.7%

         Very useful

95

75.4%

         Somewhat useful

19

15.1%

         Not very useful

4

3.2%

Don’t use this feature

8

6.3%

         Aware of it

5

4.0%

         Not aware of it

3

2.4%

Totals:

126

100.0%

5.   Based on your experience using this site, please evaluate the site in terms of the following aspects.  Indicate your level of agreement with each of these statements.

      a.  The site is well organized.

 

Frequency

Percent

Strongly agree

89

67.9%

Somewhat agree

35

26.7%

Neither agree nor disagree

3

2.3%

Somewhat disagree

4

3.1%

Strongly disagree

0

0.0%

Totals:

131

100.0%

      b.  I am confident about the accuracy of the information about current conditions.

 

Frequency

Percent

Strongly agree

77

60.2%

Somewhat agree

39

30.5%

Neither agree nor disagree

8

6.3%

Somewhat disagree

2

1.6%

Strongly disagree

2

1.6%

Totals:

128

100.0%

      c.  I am confident about the accuracy of the information about forecast conditions.

 

Frequency

Percent

Strongly agree

53

41.7%

Somewhat agree

60

47.2%

Neither agree nor disagree

10

7.9%

Somewhat disagree

4

3.1%

Strongly disagree

0

0.0%

Totals:

127

100.0%

      d.  My use of this site makes my trips safer.

 

Frequency

Percent

Strongly agree

90

70.3%

Somewhat agree

30

23.4%

Neither agree nor disagree

7

5.5%

Somewhat disagree

1

0.8%

Strongly disagree

0

0.0%

Totals:

128

100.0%

      e.  It takes me too long to access some of the information on this site..

 

Frequency

Percent

Strongly agree

18

14.0%

Somewhat agree

27

20.9%

Neither agree nor disagree

29

22.5%

Somewhat disagree

25

19.4%

Strongly disagree

30

23.3%

Totals:

129

100.0%

      f.  There is important information missing from this site that should be made available here.

 

Frequency

Percent

Strongly agree

14

11.4%

Somewhat agree

15

12.2%

Neither agree nor disagree

44

35.8%

Somewhat disagree

25

20.3%

Strongly disagree

25

20.3%

Totals:

123

100.0%

      g.  The information I get from this site helps me avoid travel delays.

 

Frequency

Percent

Strongly agree

40

32.0%

Somewhat agree

55

44.0%

Neither agree nor disagree

24

19.2%

Somewhat disagree

6

4.8%

Strongly disagree

0

0.0%

Totals:

125

100.0%

      h.  This site helps me to be better prepared for road and weather conditions when I travel.

 

Frequency

Percent

Strongly agree

105

81.4%

Somewhat agree

17

13.2%

Neither agree nor disagree

6

4.7%

Somewhat disagree

0

0.0%

Strongly disagree

1

0.8%

Totals:

129

100.0%

      i.  I find this site confusing and difficult to use.

 

Frequency

Percent

Strongly agree

3

2.3%

Somewhat agree

6

4.7%

Neither agree nor disagree

14

10.9%

Somewhat disagree

19

14.8%

Strongly disagree

86

67.2%

Totals:

128

100.0%

      j.  The information I get from this site makes me more relaxed on my trips.

 

Frequency

Percent

Strongly agree

52

41.3%

Somewhat agree

47

37.3%

Neither agree nor disagree

25

19.8%

Somewhat disagree

2

1.6%

Strongly disagree

0

0.0%

Totals:

126

100.0%

6.  Please also indicate, in your own words, how this website could be improved to better meet your needs.  Consider information content, ease of use of the site, ability to understand what is presented, and anything else that could make this site better.  Be as specific as you can.

Comments were provided by 72 out of 140 respondents (51.0%).  See text for an overview analysis of these comments.

7.  Please indicate the region in which you live.

 

Frequency

Percent

Western Washington

77

55.8%

Central Washington

27

19.6%

Eastern Washington

24

17.4%

Outside of Washington state

10

7.2%

Totals:

138

100.0%

8.  Please check your age category.

 

Frequency

Percent

16 years of younger

0

0.0%

17 to 24

1

0.7%

25 to 34

14

10.2%

35 to 44

34

24.8%

45 to 54

45

32.8%

55 to 64

33

24.1%

65 years or older

10

7.3%

Totals:

137

100.0%


[1] Data provided by the Transportation Data Office.

[2] Data provided Highway Maintenance, Field Operations Support Service Center.

[3] Data provided by the Transportation Data Office.

[4] Data provided Highway Maintenance, Field Operations Support Service Center.

[5] Copyrighted by Office of the New Jersey State Climatologist. Used with permission.

[6] SCAN Web is a trademark of Surface Systems, Inc.

[7] Conversation with Bob Stowe, Assistant Regional Administrator for Maintenance, North Central Region, January 22, 2001.

[8] Conversation, Jennette Ingham WSDOT Ombudsman, February 6, 2001.

[9] Conversation, Jeff Adamson, NCR Communications Manager, February 6, 2001.

[10] Case studies can be found at http://www.fhwa.dot.gov/winter/roadsvr/casehome.htm.

[11] Conversation with Bob Stowe, Assistant Regional Administrator for Maintenance, North Central Region, January 22, 2001.

[12] Frost index information provided by Mike Ellis, WSDOT Maintenance Office 10/22/01.

[13] Snow and ice control expenses provided by Lee Wlazlak, WSDOT.

[14] Per Jack Manicke, WSDOT Maintenance Office, test de-icing materials and stock pile maintenance used in the Eastern Region during the FY’01winter resulted in substantially lower materials cost.

[15] Accident data provided by Kathy Tanner, Transportation Data Office

[16] According to Bill Brown, RWIS Program Manager this is due to the limited availability of SCAN Web in the Eastern Region during the 2000/2001 winter season.

[17]According to Bill Brown, RWIS Program Manager this is due to limited availability of ScanWeb in the Eastern Region during the 2000/2001 winter season.

[18] The daily number of user sessions was not available to estimate the range of use for the months of March 2000 to June 2000. Daily ranges for the other months were estimated based on monthly graphics generated by WSDOT and made available on their website.

[19] The rWeather website was not specifically developed and tested for use in a Macintosh environment.

[20] Phone conversation, Bill Henselman, WSDOT Risk Management, February 12, 2001.

[21] Phone conversation, Mike Tardif, State Attorney General’s Office, February 12, 2001.

[22] Total responses for each question in the survey reflect only the number of individuals who actually answered the question.  Since some respondents skipped one or more questions, the total number of responses for each question is typically somewhat less than 140.