Final answer:
A gap is the distance between approaching vehicles in which to cross an intersection or join traffic. Pedestrians should wait for a sufficient gap between vehicles to ensure their safety.
Step-by-step explanation:
A gap, in the context of crossing an intersection or joining traffic, refers to the distance between approaching vehicles that allows a pedestrian to safely cross the road. It is important for pedestrians to wait for a sufficient gap between vehicles to ensure their safety. For example, if the distance between two approaching vehicles is too short, it may not be safe for a pedestrian to cross.