The Utah Department of Transportation’s (UDOT) vision to “Keep Utah Moving” includes strategic goals to Optimize Mobility and achieve Zero Crashes, Injuries and Fatalities. Connected vehicle (CV) technology is the tool to enable the next leap forward in transportation safety and mobility. CV will also improve air quality and quality of life.
The Utah Smart Transit Signal Priority project uses CV technology to enable conditional priority of transit vehicles at traffic signals, with the objective to improve the reliability of bus service while optimizing the use of available green time. UDOT partnered with the Utah Transit Authority (UTA) on the project. It is UDOT’s first connected vehicle project and is intended to pave the way for other applications in Utah.
This Connected Vehicle project uses Dedicated Short Range Communication (DSRC) radios to allow interactive communication between UTA buses and traffic signals. In this project, DSRC radios have been installed at 30 intersections along Redwood Road, from 400 South to 8020 South. When the buses are behind schedule, the signal grants available additional green time to the bus so it can get back on schedule. Through the DSRC radios, the traffic signal controller and a small computer in the signal cabinet communicates back and forth with similar radios and computers installed in UTA buses. The project developed the schedule-checking module and built upon the Multi-Modal Intelligent Traffic Signal Systems (MMITSS) software created at the University of Arizona.
This deployment is one of the first, if not the very first, DSRC system in regular operation in the United States. To date, transit reliability on this corridor for bus route #217 has improved by 12 percent. Late bus arrivals have also been reduced by 40 percent.