Intelligent Transportation Systems

This paper describes the activities in developing and applying improved computer techniques in traffic signal management, performed in the technical center established at the Institute of Transportation Studies (ITS), as part of the Fuel Efficient Traffic Signal Management (FETSIM) project. The center provides technical support to local agencies, develops software and conducts research for most efficient use of the state of the art computer programs. A description of the available programs is given and how these tools can be used in the various phases of a signal retiming study. Selected...

This study focuses on the problem of measuring the queue discharge flow rates for a nonbottleneck freeway section and on developing an approach for estimating the impacts of intelligent transportation system (ITS) measures on the mean and variance of the queue discharge flow rate. The whole-year mean and variance of the queue discharge flow rates for the subject section of freeway are computed on the basis of measured 5-min congested flow rates over the course of a year. The flow data are categorized into congested and uncongested flows on the basis of a speed threshold that separates...

Several issues must be addressed when establishing intelligent vehicle-highway system (IVHS) communication standards, particularly for the most advanced of these systems, the advanced vehicle control system (AVCS). Each of the three stages of AVCS evolution have separate issues that must be addressed in order to define communication standards. It is recommended that measured progress toward the development of IVHS communication standards be based on a solid foundation so that they do not risk becoming impediments to progress. Given the current state of development of IVHS technology, more...

The technical issues that the Advanced Vehicle Control Systems (AVCS) Committee of the Intelligent Vehicle Highway Society (IVHS) of America has identified as necessary to improve the performance of the surface transportation system are discussed. AVCSs represent the application of sensors, computers, and electromechanical actuators to provide drivers with warnings of hazards, assistance in controlling their vehicles, or fully automated control of vehicle motions. The constraints under which AVCS enabling technologies must be brought to maturity, such as cost, reliability, fault tolerance...