Signal Preemption

A signal preemption system interrupts traffic signal timing to allow critical vehicles to pass through the intersection without stopping. Usually used for emergency vehicles, the signal is turned green when requested by the vehicle, and conflicting traffic is prevented from crossing the intersection. Using roadside and on-board V2I technology, UDOT provides signal priority to its snow plows on certain corridors when they are actively plowing. Using other types of technology, some cities provide preemption to emergency vehicles.