This section presents the transportation community's perspective regarding the more general system development objectives for ATIS and CVO, as well as the more specific system performance objectives, performance measures, and performance requirements. The term development objective is used to refer to general factors or benefits envisioned to result from ATIS and CVO development. The term performance objective is used to refer to a specific objective that is related to ATIS or CVO performance, but that does not include the specification of particular measures of system performance. The term performance measure is used to refer to a quantifiable index of system effectiveness. The term performance requirement is used to refer to specific quantitative values of individual measures that serve as goals or requirements for system performance. The primary goals in ascertaining the transportation community's views on these topics are:

• To convey the underlying objectives for system development
• To help ensure that subsequent project work maintains a perspective that is consistent with the transportation community.
• To provide an initial basis upon which to develop dependent measures to be employed in the subsequent research phases of this project.

IVHS-wide development objectives have been stated in very broad, institutional terms in the Strategic Plan for Intelligent Vehicle-Highway Systems in the United States (Intelligent Vehicle Highway Society of America, 1992) as summarized below:

• Improved safety.
• Reduced congestion.
• Increased and higher quality mobility.
• Reduced environmental impact.
• Improved energy efficiency.
• Improved economic productivity.
• Development of a viable U.S. IVHS industry.

For the purposes of the present discussion, we have combined the objectives of "reduced environmental impact" and "improved energy efficiency." These two objectives were combined because of their commonality of goals and performance objectives. Additionally, we have not systematically considered the objective of "development of a viable U.S. IVHS industry". Although this objective is an important and pervasive goal, it has limited relevance to the scope of the present project.

The general IVHS objectives cited in the Strategic Plan for Intelligent Vehicle-Highway Systems in the United States tend to be repeated with only minor variations throughout the transportation community when referring to either IVHS or ATIS development. This consistency is due to the guiding role that has been played by the government-industry team represented by IVHS America. However, there are differences in the relative importance of these objectives when private and commercial applications are considered. Figure 2 depicts the mean importance ratings and 95% CI (represented by vertical bars) of the importance of five development objectives in meeting overall ATIS technology objectives for private and commercial vehicle applications. Review of this figure suggests that for private applications, traffic congestion, safety, and mobility are all considered to be relatively more important than environment & energy and economic productivity. Review of the 95% CI for these data (see appendix A, table 36) indicate substantial variability among the ratings, resulting in significant differences between only traffic congestion and environment & energy, even though the trend indicated by review of the figure is supported by statistical analysis. Review of the ratings for commercial applications reveal that the least important objective for private applications, economic productivity, was rated the most important for commercial applications. However, we again find that environment & energy are given the lowest ratings for commercial applications. Review of CI indicates that there was also substantial variability among respondents' ratings of commercial applications, resulting in economic productivity receiving significantly higher ratings than all groups, and safety being rated significantly higher than environment & energy.

Figure 2. Mean importance ratings for five development objectives in meeting overall ATIS technology objectives for private and commercial vehicle applications.

The five general development objectives identified above provide a very useful focus for government and industry in the current effort to develop a common framework for IVHS development. These objectives can be associated with various performance objectives, measures, and requirements that can be used to assess the overall effectiveness of IVHS, ATIS, and CVO systems. For example, the development objective of traffic congestion can be associated with several performance requirements which generally address such factors as increased traffic volume and reduced excess travel. Such performance objectives represent broad institutional benefits from system development. However, as pointed out in many of the interviews, including all interviews with private industry representatives, the perspective of the individual consumer must also be specifically considered in identifying performance objectives, measures, and requirements. As noted repeatedly by interview respondents, the individual consumer will ultimately determine the success or failure of ATIS technologies. Respondents noted that the individual consumer has a limited concern for traffic volume. The individual's concerns associated with traffic congestion revolve around reducing personal travel times and minimizing traffic delays personally experienced. These two perspectives are both associated with traffic congestion, and it is likely that correlations between the two measures will be found to be substantial when large-scale operational tests are conducted. However, the distinction is important, in terms of recognizing the relative roles of institutional and individual performance objectives, measures, and requirements associated with the separate development objectives. This distinction will be explicitly addressed throughout this section.

CVO system development objectives are also associated with both institutional and individual user performance objectives, measures, and requirements. However, as pointed out by CVO representatives during project interviews, the CVO community is quite heterogeneous in terms of its concerns regarding the separate performance benefits. Two important factors in considering CVO system objectives are the type of service being provided and the size of the commercial operation responsible for the vehicles. For the purposes of the present paper, CVO services have been divided into three categories: public service, local commercial, and interstate trucking. Each of these types of operations have substantially different operational requirements, which can be translated into ATIS and CVO system performance objectives, measures, and requirements. The size of the commercial operations can generally be categorized as large operations, with 100 or more vehicles owned by the operation; smaller operations, with less than 100 vehicles; and individual owner/operators.

When considering the basic ATIS objective of providing the traveler with more complete and accurate information, many commonalities and differences can be seen in comparing private and commercial vehicle operations. Much of the information ATIS will be designed to provide can be useful to all drivers, regardless of the type of vehicle they use. However, CVO drivers require more specialized information. For example, interstate trucks cannot be operated on all roads for various reasons, such as low clearances, restrictive geometry, hazardous materials limitations, and bridge weight restrictions. Therefore, interstate truck operators require accurate, detailed information about any changes to their normal routes or unfamiliar routes.

The remainder of this section is divided into five subsections, each of which discusses one of the five broad development objectives: traffic congestion, safety, mobility, environment & energy, and economic productivity. Each of these subsections is further divided into an introduction and three brief discussions. The introductions include a consideration of the relationship between ATIS subsystems and the development objective; and provide an overview of the specific performance objectives, measures, and requirements found to be associated with each general development objective within the transportation community. The sets of three brief discussions address the sources and types of specific performance objectives, measures, and requirements that correspond to the goals of government institutions, private vehicle drivers, and commercial vehicle operators.