The Law on Modulating Headlights on Motorcycles In Arizona

by Ricardo de la Moto

       Bob Thompson, his wife Karen, my wife Cheryl and I (Ricardo de la Moto) did a ride to Naco and Douglas on Valentines Day. We were getting the necessary documents to do some riding in Mexico.  We went to Douglas to get Mexican Motorcycle Insurance for Bob and to have lunch.  Bob was riding his R1150GS and I my R1100RT.  I put a modulator that I bought at Iron Horse on the headlamp. As we entered Douglas I was pulled over by a Douglas cop for my modulating headlamp. After a heated discussion he wrote me a ticket for having a modulating headlamp stating that they were illegal in Arizona. I had a lot of energy at this point to say the least. I immediately went to the court house to set a date to fight this. 

     After the court house, I went to the police station to complain about this miserable ticket.  The police sergeant there took me to his office and pulled out the traffic codes. Right there in the Arizona traffic code (28-947, Para E.) it states a motorcycle may have a modulating headlamp.  It's very important that you read paragraph E. Paragraph E is the exception for motorcycles.  I hope this helps someone. Modulating headlamps in Arizona are LEGAL!!!!     

Ricardo de la Moto

Here is the Arizona Law

28-947. Special restrictions on lamps

 A. A person shall direct a lighted lamp or illuminating device on a motor vehicle, other than a head lamp, spot lamp, auxiliary lamp or flashing front direction signal, that projects a beam of light of an intensity greater than three hundred candlepower so that no part of the beam strikes the level of the roadway on which the vehicle stands at a distance of more than seventy-five feet from the vehicle.

 B. A person shall not drive or move a vehicle or equipment on a highway with a lamp or device on the vehicle that is capable of displaying a red or red and blue light or lens visible from directly in front of the center of the vehicle. Lights visible from the front of a vehicle shall be amber or white. This section does not apply to an authorized emergency vehicle or a vehicle on which a red or red and blue light or lens visible from the front is expressly authorized or required by this chapter.

 C. Except as provided in subsection D or E of this section, flashing lights on motor vehicles are prohibited except either:

1. On authorized emergency vehicles, school buses or snow removal equipment.
2. As warning lights on disabled or parked vehicles.
3. On a vehicle as a means for indicating a right or left turn.

D. A vehicle may have lamps that may be used to warn the operators of other vehicles of the presence of a vehicular traffic hazard requiring the exercise of unusual care in approaching, overtaking or passing. The vehicle may display these lamps as a warning in addition to any other warning signals required by this article. The lamps used to display the warning to the front shall be mounted at the same level and as widely spaced laterally as practicable and shall display simultaneously flashing white or amber lights or any shade of color between white and amber. The lamps used to display the warning to the rear shall be mounted at the same level and as widely spaced laterally as practicable and shall show simultaneously flashing amber or red lights or any shade of color between amber and red. These warning lights shall be visible from a distance of at least one thousand five hundred feet under normal atmospheric conditions at night.

E. A person may equip a motorcycle with a means of modulating the intensity of a head lamp beam between the higher and lower brightness at a rate of two hundred to two hundred eighty cycles per minute. A person shall not modulate the head lamp beam during the hours of darkness as prescribed in section 28-922. 


A further note: According to Kriss in Tucson, a police motorcycle may not be operated in the city of Tucson unless the headlamp modulation circuit is working properly.
To further this legality, the federal government under section 7.9.3 from DOT says the same thing. Its on page 29 of a 46 page rule about lights on moving vehicles.