Investigating Road User's Compliance of Yellow and Clearance Time Intervals for Signal Timing Design (Phases 1 - 2)

PM: Simon Ramos, P.E.

In the Phase I of this collaborative project, the University of Arizona (UArizona) research team examined whether implementing the updated ITE 2020 yellow time intervals could help reduce the number of red-light running (RLR) violations. In the first phase, the research team selected 12 intersections in the City of Phoenix and developed a before-and-after experimental design for yellow interval change. In Phase II of this collaborative project, the UArizona team will investigate whether implementing the updated ITE 2020 red clearance intervals could reduce the number of RLR violations. The team will focus on identifying the relationship between red clearance intervals and the RLR frequency of the left-turn phase. The outcome of the second phase of this project will further help the City of Phoenix (COP) engineers to understand, the correlation between clearance time interval with RLR frequency.