Traffic signal priority (TSP) granted by communications between connected vehicles and the infrastructure has the potential to increase the mobility and efficiency of designated vehicles. Connected Vehicle to Everything (C-V2X) hardware can enhance the travel of traditional vehicles by granting them access to new technologies such as TSP. Signal control algorithms can detect approaching vehicles and shift to green phase to allow for the connected vehicles (CV) to pass through an intersection without stopping. As part of a pilot study conducted in Alpharetta, Georgia, two Fulton County School System (FCSS) Buses, one diesel and one propane-powered, were equipped with CV technology. In addition, 62 signalized intersections along the school buses routes were equipped with CV-enabled roadside units to support providing TSP to the school bus as it approached each traffic signal.1 The objective of the pilot was to improve safety and mobility for school bus drivers and students and to reduce the total fuel consumed by school buses and FCSS fuel costs.
The study collected data in 2022 for a month prior to deployment of the technology, and then another month while the CV technology was implemented. Data for the analysis was collected directly from the school buses and the FCSS data logger. In addition, the bus drivers were interviewed for qualitative data. Key performance metrics for the study included travel time, speed, number of stops, fuel efficiency in miles per gallon (MPG), and fuel consumption.
- Combined results for the two buses showed a 13.3 percent decrease in travel time, an 18 percent increase in speed, and a 40.4 percent decrease in number of stops.
- The propane bus saw a 6.7 percent improvement in MPG and a 7.4 percent decrease in fuel consumption, while the diesel bus saw a 13.4 percent improvement in MPG and a 12.4 percent decrease in fuel consumption.
- The drivers also reported that by reducing the number of times the bus make unscheduled stops along its route, the pilot program was able to reduce the likelihood that students stand up and engage unsafe behavior when the bus stopped, and generally created a safer environment onboard the school bus.