1. A traffic preemption system, comprising: a vehicle equipped with an onboard computer system configured to: capture diagnostic information; estimate the location of the emergency vehicle using information provided by a GPS receiver connected to the onboard computer system; and transmit the captured diagnostic information and estimated location using a wireless transmitter connected to the onboard computer system via a first wireless network; a fleet management computer system connected to a wireless receiver, where the fleet management computer system and wireless receiver are configured to: receive information transmitted by the on-board equipment; determine whether the received information is from a vehicle requiring intersection preemption; provide the estimated location of vehicles requiring intersection preemption to a traffic management computer system; wherein the traffic management computer system is configured to: receive estimated locations of vehicles requiring intersection preemption from the fleet management computer system; and forward preemption requests to intersection controllers via a second network.