Vehicle Mod Laws in Arizona

Replacing the exhaust system is legal in Arizona, but a muffler in good working order is required and cutouts or bypasses are prohibited. There is no statutory 'no louder than stock' rule — the standard is that the exhaust must not produce excessive or unusual noise.

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Arizona sets no statewide decibel limit for passenger cars. A muffler in good working order is required, exhaust may not produce excessive or unusual noise, and cutouts or bypasses are prohibited.

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Smoked or tinted film on headlights and taillights is illegal in Arizona. Headlights must emit white light and taillights must show red at the required visibility distance, and tint that dims or discolors them violates those requirements.

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License plate frames are legal in Arizona as long as nothing required stays hidden. The plate must be clearly legible and the state name at the top must not be obscured — frames covering 'Arizona' are illegal.

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Arizona sets no statutory lift, frame-height, or bumper-height limit. Raising a pickup has one direct consequence: it loses the rear splash-guard exemption, so guards are required. Headlamps must stay between 22 and 54 inches.

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Arizona requires no cover for auxiliary lamps. The limit is four front lamps over 300 candlepower lit at any one time on a highway, aimed so no part of the beam strikes the roadway beyond 75 feet.

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Arizona has no statute limiting how low a vehicle may be. The practical floor is the 22-inch minimum headlamp height, plus general equipment rules.

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Underglow is legal in Arizona while driving if front-visible light is white or amber, nothing red shows from the front, nothing flashes, and lamps stay under 300 candlepower.

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Arizona sets no fender-coverage rule for passenger cars. Rear fender splash guards are required on trucks, trailers, and buses — and on pickups up to 10,000 lb GVWR only if they have been modified from the original bumper height.

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Transparent material is allowed on the topmost portion, with its bottom edge at least 29 inches above the undepressed driver's seat, and it may not be red or amber. Because the material must be transparent, a printed or opaque banner is not legal in Arizona — only a clear tint band.

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Front side windows: minimum 33% VLT. Rear side and back windows: any darkness.

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