Advanced BRT Volume II: Innovative Technologies for Dedicated Roadways

Presented herein is a novel approach to vehicle positioning using RFID technology (Vehicle Positioning System, or VPS). By installing in the road RFID tags encoded with road name or other designation, the specific lane, the direction of travel, and the longitudinal distance from a known reference, a vehicle outfitted with an RFID tag reader can determine its position each time it passes over and reads a tag, thus, providing precisely the information needed for many ITS applications – the longitudinal position of a vehicle in a particular lane on a particular road of the transportation network. Knowledge of lane of travel and distance from a known reference provided by VPS enables many transit applications, including headway control of bus platoons, merge/lane change assistance, rear-end collision avoidance, and bay markup applications. For lane assist systems, VPS and a lateral positioning system can augment DGSP in urban areas, providing seamless operation where DGPS accuracy is insufficient for lane keeping. This research focused on designing and building a prototype VPS using existing third party RFID hardware. The hardware was evaluated and characterized to determine if it could be used to create a viable, robust VPS. After the development and characterization of the positioning system, an implementation of a rear-end collision avoidance system was built to demonstrate the use of VPS. Finally, a more sophisticated rear-end collision avoidance system was designed and simulated, after which its implications to the accuracy specifications for VPS were analyzed. The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. This document is disseminated under the sponsorship of Government do not endorse products or manufacturers. Trade or manufacturers' names appear herein solely because they are considered essential to this report. The authors would like to thank Metro Transit, in particular, Steve McLaird and Lenny Pawlek for keeping the Technobus Research Vehicle clean and in terrific working order long past its typical service life. Steve has allowed the use of the bus for numerous demonstrations and meetings, allowing the IV Lab to show that this technology is really viable for transit applications. Lenny and his staff in the Heywood Maintenance Garage have kept the bus in working order, fueled, and clean for both research activities and demonstrations. Without their help, this program would have never made it to the next step.