Automatic vehicle location (AVL) for transit operation

The purpose of the AVL system is to monitor the location of buses. Knowing the location of a bus enables the operator to manage the bus fleet more efficiently and to provide their customers with up to the minute information on bus arrivals and departures. To monitor the location of the buses, it is necessary to have an adequate positioning device such as GPS and an accurate digital map such as a GIS. To ensure accurate information, the location (coordinates) of the bus must be consistent (or within a small tolerance) with those of the digital map. Employing an AVL system becomes especially important in an urban area where the system would be most valuable. In this paper the different aspects of AVL system implementation for a transit operator are discussed. Minimum requirements for different levels of AVL implementations are summarized, system evaluation procedures are suggested and results of an AVL evaluation are presented. Some of the challenges of such systems are discussed as well.