Multipath signal phase and timing broadcast project

Abstract

The Multipath Signal Phase and Timing (SPAT) Broadcast Project demonstrates a Safe Green Passage traffic signal application that provides speed guidance to an approaching driver so that a vehicle may safely pass through the green phase of an upcoming traffic signal. This is accomplished by the signal system’s ability to send SPAT information to approaching vehicles even when they are several miles or multiple signals away. This project was developed in partnership with the Institute for Information Industry, a Taiwan ITS consortium, the Michigan Department of Transportation (MDOT), and the University of Michigan Transportation Research Institute (UMTRI). The Institute for Information Industry provided system components, software and a related Traffic Signal Violation Warning application. UMTRI provided a Paramics system simulation of the multipath SPAT application, functional requirements, and overall coordination of the project. The implementation at two signalized intersections was supported by the Road Commission of Oakland County. The system was developed and demonstrated on August 8, 2011. While the functional demonstration was successful, the traffic simulation of 25,000+ vehicles did not show the expected statistical increase in flow-through efficiency. Further, the Dedicated Short Range Communications (DSRC) technology requires line-of-sight placement, which significantly limits the ability to maximize the distance from the signal to the vehicle, and therefore limits the effectiveness of the application.