A system for coupling a warning light to a rear of a vehicle. The system includes a coupling bar for connecting the unit to a conventional tow bar deployed on the rear of the vehicle. A beacon mount is pivotally connected to the coupling bar so that it may be pivoted away from the rear of the vehicle without removing the unit from the tow bar. A warning beacon is affixed to the top of the beacon mount such that when the system is deployed, the beacon is positioned at or above the height of the vehicle. A supplemental beacon guard may be deployed adjacent to the beacon so as to prevent direct viewing of the beacon by the vehicle driver. The coupling bar comes in two designs. The first includes a pair of extensions that terminate in rear-facing lights designed to enhance visibility behind the vehicle. Corner markers may also be employed on the ends of the extensions to provide the driver with a visual identifier of the rear corners of the vehicle. The other embodiment of the coupling bar includes on the beacon mount a pair of rear-facing lights. The system may alternatively be used deployed in a roadway as a warning light system for oncoming traffic.