What are used to signalize specific movements that can occur while other phases of the cycle are active?

Overlaps are utilized in traffic signal systems to manage specific movements that can happen simultaneously with other signal phases. They allow for the safe and controlled operation of additional vehicle or pedestrian movements without necessitating a complete pause of all traffic signals. For instance, while a primary phase is green for the main direction of traffic, an overlap can permit turning movements or pedestrian crossings in the same intersection effectively.

This design helps in enhancing the efficiency of traffic flow and minimizes the delay for specific movements that can coexist safely. It is especially valuable in complex intersections where multiple routes intersect, and specific movements during certain phases can occur safely due to proper signal timing and lane configurations. This contrasts with the other options, which do not serve the same function of indicating additional movements during existing phases.