Iowa Code Title VIII. Transportation [Chs. 306-330B] § 321.393. Color and mounting

1. A lighting device or reflector, when mounted on or near the front of a motor truck or trailer, except a school bus, shall not display any other color than white, yellow, or amber.

2. No lighting device or reflector, when mounted on or near the rear of any motor truck or trailer, shall display any other color than red, except that the stop light may be red, yellow, or amber.

3. Clearance lamps shall be mounted on the permanent structure of the vehicle in such manner as to indicate the extreme width of the vehicle or its load.

4. The provisions of this section shall not prohibit the use of a lighting device or reflector displaying an amber light when such lighting device or reflector is mounted on a motor truck, trailer, tractor, or motor grader owned by the state, or any political subdivision of the state, including any local authority, while such equipment is being used for snow removal, sanding, maintenance, or repair of the public streets or highways.

5. The provisions of this section shall not prohibit the use of a lighting device or reflector displaying an amber, white, or blue light when the lighting device or reflector is rear-facing and mounted on a motor truck, trailer, tractor, truck-mounted snow blower, or motor grader owned by the state or any political subdivision of the state, including any local authority, while the equipment is being used for snow and ice treatment or removal on the public streets or highways.