Abstract: Controlling traffic signal preemption includes inputting to a conditional preemption circuit, values of incident parameters that include at least a vehicle unit identifier of a vehicle unit and an incident priority that describes an incident. The conditional preemption circuit determines a vehicle class based on one or more of the plurality of incident parameters. In response to a preemption request communicated from the vehicle unit, the conditional preemption circuit determines whether or not the vehicle unit qualifies for preemption at one or more intersections based at least on the vehicle class, location of the vehicle, and heading of the vehicle unit specified in the preemption request. Phase selection signals are communicated to traffic signal control circuitry at the one or more intersections in response to determining that the vehicle unit qualifies for preemption at the one or more intersections.

Abstract: Controlling traffic signal preemption includes inputting to a conditional preemption circuit, values of a plurality of incident parameters that include at least a vehicle unit identifier of a vehicle unit and an incident priority that describes an incident. The conditional preemption circuit determines a preemption mode for a vehicle associated with the vehicle unit identifier based on one or more of the plurality of incident parameters. The preemption mode is one of a first mode or a second mode. Traffic signal preemption is enabled for the vehicle unit in response to the conditional preemption circuit determining the first mode. Traffic signal preemption is disabled for the vehicle unit in response to the conditional preemption circuit determining the second mode.