A removable vehicle directional light unit for use on a police or emergency vehicle which will be highly visible from a long distance for directing traffic to one or more specified lanes to reduce congestion and avoid accidents, particularly accidents involving police and emergency vehicles parked in the vicinity. The device is removably installed onto the rear window, mounted on the rear deck, or mounted on the trunk or top of the vehicle when in use and has a plurality of highly visible flashing lights configured in the shape of an arrow pointing in the direction leading away from a traffic blockage. The vehicle directional light unit includes a control box with a selector switch and flasher units to cause light groupings to flash in a selected pattern indicating the intended lane or lanes which approaching traffic should use.