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
The Road Commission for Oakland County (RCOC) implemented a Vehicle-to-Everything (V2X) technology system as part of a USDOT SMART Grant project. The project deployed traffic signal priority (TSP) at four intersections where equipped and enrolled vehicles could make requests as they approached the intersection. TSP allows for signal extensions of the requested phase or reductions of opposing phases, which is less disruptive than emergency vehicle preemption. The implementation was designed with a conservative approach, with a maximum timing adjustment set to 10 percent of the cycle length to minimize disruption to normal traffic patterns.
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 TSP was fully implemented.
FINDINGS
The analysis showed that TSP 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 TSP 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.
