What is an Automated Traffic Signal Performance Measure (ATSPM)? 

There are more than 330,000 traffic signals operating in the United States, and highway agencies typically retime these signals on a three- to five-year cycle at a cost of approximately $4,500 per intersection. For the vast majority of these signals, citizen complaints are the primary measure of performance. Not having performance data drives retiming costs up by requiring software modeling to simulate performance, along with detailed, manually collected traffic data.

When agency professionals and consultants conduct retiming projects, they perform an ad hoc comparison of limited before and after travel-time data to demonstrate the effectiveness of optimization efforts. Typically, no ongoing performance measurement capability exists, and agencies rely on citizen complaints to reactively detect maintenance or operational deficiencies. This lack of active performance management compromises safety and efficiency and contributes to congestion. It also institutionalizes public dissatisfaction with the operation and maintenance of signalized intersections.

ATSPMs can revolutionize the management of traffic signals by providing the high-resolution data needed to actively manage performance. High-quality service can be delivered to customers with significant cost savings to agency maintenance and operations. A number of implementation options are available, ranging from a low-cost, open-source code framework to a fully integrated traffic signal system.