What is the term for phasing where the left turn gets a green arrow before the opposing through movement?

Lead/lag left turn phasing is a term used to describe a specific type of signal phasing that effectively manages the flow of traffic at intersections, particularly for vehicles making left turns. In this configuration, the left turn movement is given a green arrow before the opposing through movement, allowing vehicles to clear the intersection safely and efficiently. This phasing optimizes traffic flow and enhances safety by reducing the chances of conflicts between left-turning vehicles and oncoming traffic.

In contrast, delayed left turn phasing would imply that the left-turning vehicles must wait for the through traffic to clear before receiving a green light, which does not maximize the safe and efficient use of the intersection. Simultaneous left turn phasing could suggest that left turns and opposing traffic movements occur at the same time, increasing potential conflict points. Contrary left turn phasing does not accurately describe this concept, as it refers to a different traffic scenario. Lead/lag left turn phasing is, therefore, the correct choice for this question.