A flashing light system for mounting on the roof of a police car or other vehicle where special warning lights are desired. The system includes a plurality of lights preferably arranged side-by-side across the width of the vehicle roof, each of the lights having associated therewith a parabolic reflector or beam-shaping lens which rotates about a vertical axis approximately coaxial with the axis of the corresponding light source thereby creating a flashing effect. The several parabolic reflectors or beam-shaping lenses are driven conjointly from a common drive motor, and the plurality of rotatable reflectors or lenses may be arranged at predetermined angles relative to one another so as to vary the sequence of the light flashes and thus create an unlimited variety of different flashing effects. In accordance with a preferred embodiment, each light source is stationary while its associated reflector or lens rotates, the reflectors or lenses being oriented at different rotational positions relative to one another to achieve the foregoing desired variety of different flashing effects.