Traffic Signal Priority Implementation in Oakland County, Michigan Demonstrated Potential Cost Savings of $0.25 per Vehicle per Intersection
The Road Commission for Oakland County's SMART Grant Project Evaluated the Financial Benefits of Traffic Signal Priority for Commercial Vehicles
Michigan, United States
Leading in Economically Sustainable Safety with V2X Technology in Oakland County Michigan
Summary Information
Vehicle-to-Everything (V2X) communication is emerging as a key enabler for safer and more coordinated transportation networks. To enhance roadway safety, mobility, and efficiency across Oakland County, this project prototyped a connected vehicle (CV) system that was built for scalability, interoperability, and financial sustainability. The system integrated multiple technologies, including V2X roadside units (RSUs), advanced traffic controllers, edge computing devices, an enhanced V2X hub with modular plug-ins, on-board units (OBUs), human–machine interfaces, upgraded antennas, a Security Credential Management System (SCMS), and a V2X authorization server along with intelligent, sensor-based infrastructure such as cameras, AI-enabled vulnerable road user (VRU) detection models, and dual-mode RSUs.
Stage One deployed five equipped intersections and 10 Road Commission of Oakland County maintenance vehicles to test traffic signal priority, vulnerable road user (VRU) detection, and multi-band communication. Field testing began in mid-2024, accompanied by detailed planning for future deployment. A proposed Stage Two would scale the system to 112 intersections and more than 1,000 vehicles across the county.
METHODOLOGY
The project team evaluated the financial benefits of traffic signal priority by measuring time savings for vehicles passing through equipped intersections. The team used the American Transportation Research Institute's reported hourly operating cost of $91.27 for trucking to calculate the potential cost savings. The evaluation was based on field testing with a test vehicle at four intersections where traffic signal priority was fully implemented.
FINDINGS
The analysis showed that traffic signal priority provides an approximate 10-second reduction in travel time at an intersection on average each time a vehicle passes through, regardless of whether the TSP request is granted. Using the American Transportation Research Institute's reported hourly operating cost of $91.27 for trucking, this translates to an estimated cost savings of $0.25 for each traffic signal priority intersection that a vehicle passes through.
The study demonstrated that these savings scale significantly when applied across fleets and entire signal networks. For example, a single vehicle passing through a 10-equipped intersection corridor twice per day would save $5.07, which increases to $25.35 over a 5-day work week, and $1,318.34 over a full year.
