What are the two main types of emergency vehicle preemptions?

The two main types of emergency vehicle preemptions are indeed categorized as stationary and mobile. Stationary preemption systems are those that are installed along fixed locations, such as traffic signals at intersections. These systems are activated when an emergency vehicle, such as a fire truck or ambulance, approaches the intersection, allowing the traffic signal to change to green for the emergency vehicle while ensuring red signals for the other directions to minimize the risk of accidents.

Mobile preemption systems, on the other hand, are designed to work with emergency vehicles that are in motion. They utilize technologies that can communicate with the existing traffic signal infrastructure as the vehicle approaches. This allows for dynamic adjustments to the traffic signal settings based on the vehicle's location and speed, enhancing the effectiveness and response time for emergency services.

This distinction is crucial in understanding how traffic management systems can improve emergency response times and reduce conflicts at intersections. Knowing this helps traffic signal technicians implement and maintain these systems effectively, ensuring they function properly when needed most.