The OCTA (Orange County Transit Authority) Transit Probe Project is a field operational test of an automatic-vehicle-location (AVL) system operating in Orange County, California. This report presents the final evaluation results for the project, concentrating on the operational period from June 1, 1998 to May 30, 1999. The report provides a detailed description of the system and the motivation for its design. It provides analyses of data reliability and accuracy, and analysis of the usefulness of transit probe data for predicting automobile travel times. Institutional issues are evaluated...