Detector vs. Trajectory Generated Automated Traffic Signal Performance Measures (ATSPMs)

Detectors such as loops, radar, or cameras have traditionally been used to collect ATSPMs data at intersections. These detectors require a connection to a high-resolution signal controller logger and communications between the controller and a centralized server, in order to collect and generate ATSPMs. Unlike physical detectors, high-resolution connected car (HRCC) trajectory data can provide the location, speed, and heading of a vehicle in <3-second intervals, meaning there is more available data for vehicle movement around the intersections to generate ATSPMs. This eliminates costly hardware and communication infrastructure requirements, making it a cheaper option for agencies looking to collect signal performance data.

This whitepaper will present the pros and cons of using these two data sources for generating ATSPMs.