What is the term for the time during which all traffic signals display red?

The term for the time during which all traffic signals display red is known as an all-red clearance. This phase is crucial in traffic signal operation as it allows for the safe transition of vehicles and pedestrians by ensuring that all traffic movements are halted. The primary purpose of the all-red clearance is to clear the intersection of any vehicles or pedestrians before the next phase of traffic signals changes, thus reducing the potential for accidents during the switch from one traffic phase to another.

An all-red clearance phase typically lasts for a brief period, just long enough to ensure that vehicles have ceased movement and pedestrians can safely navigate across the intersection. This phase is particularly important at busy intersections where traffic flow needs to be regulated to prevent conflicts between different movements.

The other terms provided do not accurately describe the condition where all signals are red. For instance, a full-stop phase generally refers to a situation where all vehicles must stop, but it does not specifically convey the aspect of coordinated signal changes. Clear phase often refers to the movement of vehicles out of the intersection rather than the status of the traffic signals. Lastly, the yellow phase indicates a warning to drivers that the signal is about to change to red, not a situation where all signals are indeed red. Understanding the function and timing of these