Abstract: An audible warning system which reduces the number of land vehicle traffic accidents where there are already traffic control devices installed such as at stop signs, intersection control lights and on vehicles in conjunction with side lights, tail lights and brake lights. The accident reduction results from the monitoring of approaching traffic with a radar-type range sensing system. Sound generators, based on parametric-array technology, permit the focusing of sound into waves of a few degrees width and aiming them at a particular vehicle or pedestrian located at a particular range from the sound projector.