The objective of this research project is to evaluate the safety and effectiveness of different signal displays and phasing for Protected/Permissive Left-Turn (PPLT) control through lab and field studies. These studies will gather, analyze, and interpret data that will provide a basis for recommendations for uniform display(s) for protected/permissive control. The research will consider both leading and lagging operations associated with protected/permissive control, and other situations where the yellow trap occurs, and typical configurations.

NOTE: It is important to note that this research project will not develop any guidelines, warrants, or recommendations for the use of protected/permissive left-turn phasing. The underlying assumption is that the traffic engineer has decided that protected/permissive control is the most appropriate left-turn treatment. The goal of this research study is to identify the most effective display(s).