What is a preemption system in traffic signals?

A preemption system in traffic signals is designed primarily to give priority to emergency vehicles, such as ambulances, police cars, and fire trucks. When an emergency vehicle approaches an intersection equipped with a preemption system, the traffic signals will respond by changing to provide a clear path for the emergency vehicle. This typically results in other traffic signals turning red, allowing the emergency vehicle to proceed without delay, which is crucial for responding to urgent situations quickly.

The preemption mechanism often relies on specific devices like transponders or sensors that recognize the presence of emergency vehicles, ensuring that emergency responses are not impeded by regular traffic patterns. This system significantly enhances safety and efficiency in emergency responses, making it a vital component of traffic management in urban environments.

The other options, while relevant to traffic management and signal operation, do not accurately describe the function of a preemption system. For example, pedestrian signals and speed control methods relate to different aspects of traffic signaling, while tracking traffic flow involves data collection and analysis rather than prioritizing emergency vehicles.