Oregon Revised Statutes Oregon Vehicle Code § 816.270

(a) Mail delivery lights shall include two lights.

(b) Mail delivery lights shall be simultaneously flashing lights.

(c) Mail delivery lights may be constructed so that the lights flash continuously or are actuated by application of the service brake.

(d) Mail delivery lights shall have at least 12 square inches of effective illuminated surface.

(e) Mail delivery lights shall be of double face or two-way type.

(f) Mail delivery lights shall project an amber color to the front and a red color to the rear.

(g) Mail delivery lights shall be visible from a distance of not less than 100 feet to the front and rear in normal sunlight.

(h) Mail delivery lights shall be mounted on the highest part of the top of the vehicle in such a position that the illumination from the lights is visible both to the front and rear for the required distance and shall be spaced laterally as far apart as body construction will permit.

(i) Between mail delivery lights there shall be mounted a 22-inch by 7-inch sign with the wording “U.S. Mail” in four-inch letters in black on a white background.

(j) Mail delivery lights and the required sign shall be installed so that the sign can be easily lowered and the lights turned off when the vehicle is not actually engaged in United States Mail service.

(k) Mail delivery lights, the required sign, wiring, switches and mounting devices shall all be of a type that meets standards adopted by the Department of Transportation.