Railroad Preemption
Similar to traffic signals, railroad signals can allocate signal timing based on trains approaching the crossing. The US 90A traffic signals are programmed to receive an advance warning signal from the approaching train. The signal controller (receiving the preemption call) will provide green time to the approach with the railroad crossing and allow vehicles to clear the track. Once the crossing gates go down, the US 90A signals will serve the other approaches until the train clears the crossing. Then the signals will transition back to synchronized signal timing along the corridor.