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The Guide to Legal Car Modifications in Arizona

The Guide to Legal Car Modifications in Arizona ARENA Creative /

From purchasing a vehicle to drive in, or if you are relocating to Arizona, you need to know the ways in which you can modify your vehicle to ensure that it meets the street legal requirements in the state. Knowing these requirements will help you avoid fines and penalties of up to $100 or more.

Sounds and noise

Arizona does place some restrictions on modifications to your vehicle that can affect the sounds that it produces, such as the stereo system and muffler. While the state does not put any restrictions on the decibel levels of the sounds, there are requirements that may be subjective on the part of any officer called or who hears the sounds.

Sound system

  • Radios can’t be played at a volume that disturbs the quiet, disturbs sleep or annoys those who hear it, especially between the hours of 11 PM and 7 AM


Arizona muffler laws include:

  • Vehicle mufflers must be equipped and in good repair so as not to produce “unusual or excessive” noise levels.

  • Bypasses, cutouts, and similar devices are not allowed on vehicles driven on the highways

  • Exhaust systems must not permit excessive smoke or fumes to be released into the air

Tip: Also check with local county laws in Arizona to make sure you are following any municipal noise ordinances that may be more stringent than state-level laws.

Frame and suspension

Arizona does not limit suspension lifts or frame heights, providing that individuals use fenders and mud flaps. However, vehicles can’t be more than 13 feet, 6 inches in height.


Arizona laws do require that your vehicle pass emissions testing if driving into the Tucson and Phoenix areas. There are no other engine modification limitations.

Lighting and windows

Arizona also has restrictions on the lights that can be added to modify a vehicle and the levels of window tint that are permissible.


  • Lights higher than 300 candlepower can’t illuminate more than 75 feet in front of the vehicle

  • Passenger vehicles can’t display red, blue or flashing red and blue lights on the front center of the vehicle

Window tinting

  • Non-reflective tint is allowed on the front windshield as long as it is 29 inches above the driver’s seat when in its lowest position and as far back as it will go.

  • Amber or red tint is not permitted

  • Front driver and passenger windows must allow more than 33% of light to pass through

  • Rear side windows and rear window can be any darkness

  • Mirrored or metallic/reflective tints on the front and back side windows can’t be over 35% reflective

Antique/classic car modifications

Arizona requires that antique and classic cars be registered just as you would a recent model vehicle. Additionally, they will provide street rod plates for vehicles manufactured in 1948 or before that have:

  • Modifications to the brake, drive train, and suspension for safe use on the roads

  • Modifications including fiberglass or steel in the body that allows the vehicle to retain a basic body design of its model year while providing safe road use (not specified)

  • Modifications that include comfort or other safety features (not specified)

If you’re considering modifying your car to align with the restrictions set forth by the laws in Arizona, YourMechanic can provide the mobile mechanics to help you install the new parts. You can also ask our mechanics what modifications may be best suited to your car using our free online Q&A system, Ask a Mechanic.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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