In a traffic signal cycle, phases are defined by their ability to allow or restrict movement for different directions or types of vehicles. Sequential phases are those that take place one after the other, meaning that when one phase is active, another phase cannot happen simultaneously. This is essential for maintaining safety and preventing conflicts among vehicles and pedestrians.
For example, a typical intersection may have a phase for north-south traffic and a separate phase for east-west traffic. When the north-south phase is active, the east-west phase is disabled, thus preventing potential accidents. This sequential organization of phases ensures that movements are managed in a safe and orderly manner.
Understanding the specifics of traffic signal phases is crucial for traffic signal technicians, as they need to be trained to configure and design signals that effectively manage the flow of traffic while minimizing risks. In contrast, concurrent phases allow different movements to occur at the same time, which can lead to conflicts. Overlapping phases refer to those that might occur together under certain conditions, while independent phases function without directly affecting each other. However, only sequential phases are specifically defined by their inability to operate simultaneously.