Pilot Deployment of a GPS Data-Informed Traffic Signal System in Michigan Yielded Up to a 30 Percent Reduction in Delay and 40 Percent Reduction in Stops.
A Multi-Corridor Pilot Deployment Evaluated Signal Timing Changes at Intersections in Oakland County after Implementing the Signal Timing System.
Michigan, United States
Faster commutes in Oakland County – rollout underway for U-M-designed traffic flow system
Summary Information
Efficient traffic signal timing at signalized intersections plays an important role in reducing delays. Many traffic signals use preset time-of-day timing plans, these plans are often only reassessed every two to five years, or they rely on physical detectors for adaptive operations. In this study, researchers at the University of Michigan (U-M) developed a new traffic signal timing system designed to reduce unnecessary stopping leveraging global positioning system (GPS) data from vehicles. Every few weeks, the system could recalibrate using GPS data from as little as five percent of all vehicles on the road.
METHODOLOGY
Two primary measures were used to evaluate the performance of the traffic signal timing system: reductions in delays and stops at intersections. Additionally, deployment-related benefits were assessed by comparing performance with installations of other signal systems.
FINDINGS
- Along an eight-mile roadway in Farmington Hills, four signalized intersections between Orchard Lake Road and Brentwood Street experienced a 30 percent reduction in vehicle delays and a 40 percent reduction in stops.
- Along a 12-mile road in Royal Oak, nine signalized intersections between Vinsetta Boulevard and North Connecticut Avenue recorded a 20 percent reduction in both vehicle delay and stops.
- Over an 18-month period beginning in 2023, deployment of the system at 34 intersections in Birmingham, Michigan produced a 20 to 30 percent decrease in vehicle stops.
- The U-M system was estimated to cost approximately $2,500 per intersection per year, much less than conventional traffic count collection and signal retiming efforts (up to $4,500 per intersection) and installation of roadside vehicle detection and real-time signal reprogramming systems (up to $50,000 per intersection for installation). The proposed system could yield an estimated cost savings of approximately $2,000 to $47,500 per intersection.
