"TRB's Transit Cooperative Research Program (TCRP) Synthesis 73: AVL Systems for Bus Transit: Update explores the uses of computer-aided dispatch/automatic vehicle location (CAD/AVL) systems in fixed-route and demand-responsive services (bus AVL), as well as changes in agency practices related to the use of AVL systems."--Publisher's website.

Examines various aspects of developing and deploying automated vehicle location (AVL) systems over the last 20 years. Current practice; AVL architecture and technologies; and the institutional context of AVL defined in terms of funding, justification, staffing, and procurement are explored.

The synthesis describes the state of the practice in real-time bus arrival informations systems, including both U.S. and international experience. The panel for this project chose to focus on bus systems, rather than all transit modes, and on the following six elements of these systems: bus system characteristics; real-time bus arrival information system characteristics, including information about the underlying technology and dissemination media; system prediction, accuracy, and reliability; system costs; customer and media reactions; and institutional and organizational issues associated with the system.

This study explores the means through which automatic vehicle location (AVL) systems can be used to provide off-line data and reports for planning and management purposes. A review of the literature and discussions with transit system representatives determined that there are three distinct types of off- line activities that can benefit from the use of AVL data: planning and scheduling; line management information; and executive information. These three activities are found to generally use the same information, but require it to be presented in different formats and levels of aggregation. The system design guidelines are presented in the form of a checklist offering recommendations and suggestions to facilitate the use of AVL for planning and management information in transit properties designing or tendering new AVL systems. The guidelines cover organisational, systems, and reporting issues. The appendices contain a large selection of examples of reports generated using AVL, organised under the three types of information.