Transit Signal Priority Experiment in a Connected Vehicle Technology Environment

Abstract

Connected vehicle (CV) technology allows developing next-generation transit signal priority (TSP) that is based on cooperation between signals (change signal timing) and buses (alter speed). In this study, a CV-based TSP that was previously developed and evaluated through a computer simulation was tested in the field. The field experiment at the Smart Road testbed at the Virginia Tech Transportation Institute (Blacksburg, Virginia) validated the feasibility of CV-based TSP and evaluated its performance. The proposed TSP algorithm properly delivered TSP green times to buses with a 100% success rate. In addition, it reduced delays—between 32 and 75%—for a bus traveling approximately 72.4 km/h (45 mi/h) and a traffic signal with a 90-s cycle length with 30-s green time. Moreover, the field experiment showed that regular and differential global positioning system (GPS) devices demonstrate no statistically significant difference in performance. This finding could facilitate large-scale implementation of the TSP logic based on connected vehicle technology (TSPCV) because the regular GPS devices are readily available and much cheaper than differential GPS devices.