Performance Evaluation of Automated Vehicle Locator and Digital Map Accuracy in Transit Application

Abstract

New Jersey Transit (NJT) is investigating acquisition of an automated vehicle locator (AVL) system. The purpose of the AVL system is to monitor the location of buses. Knowing the location of a bus allows the operator to manage the bus fleet more efficiently and to provide customers with up-to-the-minute information on bus arrivals and departures. To monitor the location of the buses, their positional information (as determined by the AVL) is displayed on a digital map such as a geographic information system. To ensure accurate information, the location (coordinates) of the bus must be consistent (or within a small tolerance) with those of the digital map. If this is not the case, the system can yield incorrect information. This problem might become especially critical in an urban area where the system would be most valuable. The methodology that was developed for testing and evaluating the accuracies of AVL systems and available digital maps is described. The AVL system analyzed is the continuous positioning system by Andrew Corporation. Digital mapping products evaluated were TIGER, Navtech, and Digital Orthophotos. These data sets were evaluated with an accurate network of control points measured by a global positioning system. Some recommendations on the appropriateness of the tested AVL system and NJT’s digital mapping data are made.