US Patent 7271736 Emergency vehicle alert system

An alert transceiver in commuter vehicles in a line-of-site warning area receive line of sight (LOS) alert signals from another vehicle, such as an emergency vehicle. Upon detecting the LOS alert signal, the alert transceiver can relay the alert signals to other alert transceivers in commuter vehicles within a warning zone that are outside of LOS zone, thereby creating mobile tracking network (MTN). The alert signals can include any relevant information, such as information regarding a hazard that includes the type of hazard (emergency vehicle, fire, ambulance, etc.), the time stamped location, direction of travel, speed and planned route for the emergency vehicle; and/or the coordinates of warning zone as determined by alert transceivers.