The release of the National Cooperative Highway Research Program (NCHRP) Synthesis 659: Automated Traffic Signal Performance Measures: Management, Operation, and Maintenance (2026) captures a turning point in how state DOTs manage traffic signals. The report documents national practices around both traditional high-resolution Automated Traffic Signal Performance Measures (ATSPMs) and crowdsourced Signal Performance Measures (SPM) platforms. “It is exciting to see signal performance measures progress from research products into everyday tools for practitioners. What was once experimental is now enabling state and local transportation agencies to generate actionable insights across entire networks.” — Chris Day, Iowa State University Author of NCHRP Synthesis 659 While traditional ATSPMs remain foundational, the synthesis makes clear that crowdsourced solutions are now a meaningful part of the signal performance ecosystem. Platforms like INRIX Signal Analytics emerged early in this space, helping agencies expand performance visibility beyond intersections equipped with high-resolution hardware. The Challenge: Scaling Signal Performance Traffic signal performance is a cornerstone of modern mobility management. Agencies increasingly want quantitative measures such as delay, split failures, arrivals on green to diagnose issues and evaluate improvements. Traditional ATSPMs help deliver intersection-level insights, but they depend on: - Compatible controllers - High-resolution detection - Reliable communications - Skilled staff and data integration infrastructure For many agencies, achieving full traditional ATSPM coverage statewide has proven difficult. The synthesis documents this challenge across the U.S., highlighting consistent roadblocks such as limited staffing, outdated hardware, and funding constraints that slow comprehensive deployment of high-resolution systems. Even when traditional systems exist, they tend to be concentrated on individual corridors. Agencies struggle to expand performance monitoring to corridors and networks, yet those broader views are essential for planning, investment prioritization, and before/after performance evaluation. The Solution: Crowdsourced Analytics to Bridge the Gap A growing number of agencies have turned to Signal Analytics. Signal