Traffic assignment models are an important component in analyzing the relationship between demand and supply in the transportation network for design, planning, and control purposes. The static traffic assignment model has been used in practice for several decades. With the latest development in the area of Advanced Traffic Management Systems (ATMS) and Advanced Traveler Information Systems (ATIS), there is an increasing demand for dynamic traffic assignment models to serve as a basis for studying various issues in these areas.

Existing dynamic user-equilibrium traffic assignment (DUETA) models are mostly expanded from the static user-equilibrium traffic assignment model by intro- ducing the time dimension along with a group of additional constraints. Whereas the equivalency between the solution to the traffic assignment model and the user-equilibrium condition as defined by Wardrop is well established in the static case, the same may not be true for the dynamic case. This paper examines the general form of DUETA models as proposed in previous research and shows that, if queuing behavior is represented in the model at a minimal level, the solution to conventional DUETA models with an objective function of the form Et Xi Jti(t) f(w)dw may not necessarily converge to or approximate the Wardropian user-equilibrium condition in the dynamic sense as defined by many researchers.

This paper poses two key questions regarding ATMIS implementation: how are ATMIS services successfully implemented?, in what circumstances are ATMIS strategies cost-effective? The authors attempt to find answers by examining case studies of twelve jurisdictions. The answers should help others judge where and how ATMIS should be implemented. The first section of the paper identifies the requirements for successful ATMIS implementation and operation based on the case study findings. The second describes a diffusion pattern found in the case studies. The final section concludes that more is known about how to implement ATMIS than about whether implementation will be cost-effective and suggests devoting more resources to evaluation. The first requirement for successful ATMIS implementation is a need for improved traffic management. Given this need, there must also be leadership to initiate and organize a project. This leadership is most often found at the staff level. The leaders must have information. Information is obtained from reading, contact with other transportation professionals, and from consultants, who generally participate at some point in the implementation process. Funding is also needed, and many combinations of sources of funding are possible. Given these basic requirements, community support, multi-agency cooperation, and technical resources can be generated. ATMIS is first implemented in large, congested cities, particularly those with frequent surges of traffic due to sports or entertainment events. Smaller, nearby cities, seeing the success of ATMIS in these cities, subsequently implement ATMIS. More evaluation of actual ATMIS implementation is needed to provide a basis for determining the circumstances in which ATMIS is likely to be cost-effective.

Transportation Management Centers (TMCs) are focal points for monitoring and operating traffic management systems. As new technologies are developed through research in Intelligent-Vehicle- Highway Systems (IVHS), these TMCs will assume increasingly more importance as command and control centers for transportation operations. This study is aimed at developing visions for how the TMC of the future will exploit the capabilities of IVHS. Part 1 of this study, reported herein, is an assessment of existing TMC capabilities in the State of California. Part 2, to be reported later, will develop the future visions, considering present capabilities, ongoing research and transportation needs. The Part 1 report includes a brief overview of TMC development efforts, and results of in-depth interviews with personnel at all seven Caltrans TMCs, as well as interviews with three city TMCs (Anaheim, Los Angeles and San Jose). The interviews assessed: existing TMC functions, coordination among TMCs, coordination with other agencies, facilities, software and databases, and communication media. Detailed survey results are provided in Appendix B, on a site by site basis. Major study conclusions include: (1) California has made great strides in developing its TMCs, especially through the close coordination of the California Highway Patrol (CHP) and Caltrans. These efforts have laid the groundwork for major advances in traffic management. (2) Despite California's accomplishments, the TMCs have not yet fulfilled their potential for being the nerve centers for the vast array of trafpic management functions. Effort is needed to determine the best way to integrate a greater scope of advanced IVHS functions into TMC operations. (3) Effort is needed to develop California's TMCs into a distributed network of closely coordinated agencies, to ensure that their combined talents can be applied in the most effective manner.

In this paper, the authors, although agreeing that deployment is the ultimate goal of Intelligent Transportation Systems (ITS) research and funding, believe that there is not sufficient knowledge of how, why and when to deploy specific ITS functions They contend that continued research and testing (R &T) is still necessary to assure effective future deployment. The article identifies critical needs for R & T and is based to a large degree on the authors' experience in the California PATH research program.

The objective of this study is to evaluate alternative frameworks for Computer Integrated Transportation (CIT) from an institutional perspective. This was accomplished through site visits and interviews at existing Transportation Management Centers (TMCs), along with focus group sessions in which strategies for CIT were presented to TMC managers and staff for their comments and discussion. The study found that four factors: 1) time-frame, 2) linking information to actions, 3) broadcast orientation, and 4) embracement of new technologies have profound implications for Intelligent Transportation Systems' (ITS) implementation and research. Each demands careful deliberation at the strategic level, and possibly changes in how transportation agencies are organized.The objective of this study is to evaluate alternative frameworks for Computer Integrated Transportation (CIT) from an institutional perspective. This was accomplished through site visits and interviews at existing Transportation Management Centers (TMCs), along with focus group sessions in which strategies for CIT were presented to TMC managers and staff for their comments and discussion. The study found that four factors: 1) time-frame, 2) linking information to actions, 3) broadcast orientation, and 4) embracement of new technologies have profound implications for Intelligent Transportation Systems' (ITS) implementation and research. Each demands careful deliberation at the strategic level, and possibly changes in how transportation agencies are organized.

This report defines a framework for comparing dynamic traffic models. It emphasizes four dimensions: functionality, traffic dynamics, route choice dy namics, and overall network performance. The first dimension compares the models through a check-list of model functions. Regarding the last three comparison dimensions, a total of five networks and twelve scenarios are defined. These test scenarios are designed to accentuate model properties and differences. Also included in the report are a list of performance measures for comparison purpose, and a discussion of the interpretation of results.