How do overlaps differ from other phases in a traffic signal?

Overlaps in traffic signals are unique features that allow certain movements to advance concurrently with the main signal phases. The correct response highlights that overlaps cannot be independently called into action, which distinguishes them from other signal phases. Typically, signal phases are designed to operate based on specific vehicle or pedestrian demands, often relying on detection systems that activate them when needed. In contrast, overlaps are inherently tied to the primary signal indications and only engage when those specific phases are active. This integration ensures that movements permitted during an overlap phase complement the primary flow of traffic without causing confusion or conflicts.

While the other choices imply characteristics about overlaps, they do not align with the fundamental nature of how overlaps function within the signal system. Notably, overlaps are not designed to operate independently; they essentially enhance the efficiency of movement in coordination with the main phases, which contributes to their classification and functionality in traffic signal timing.