Vehicle Mod Laws in Michigan

Replacing the exhaust system is legal in Michigan, 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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Michigan sets real numeric limits: 76 dBA at 35 mph or less and 82 dBA above that, measured at 50 feet, plus a stationary run-up limit of 95 dBA measured 20 inches from the tailpipe.

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Smoked or tinted film on headlights and taillights is illegal in Michigan. 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 Michigan as long as nothing required stays hidden. The plate must be maintained free from foreign materials that obscure registration information and must stay clearly legible.

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Michigan caps bumper height at 22 inches for cars and 26–30 inches for trucks by weight class, with related frame-height and lift-block limits.

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Michigan is one of the few states that genuinely requires covers: any lamp not expressly required or permitted, and not meeting the federal lighting standard, must be both covered and unlit while on the highway.

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Michigan applies a suspension rim-line rule: no part of the suspension may extend below the lowest point of a wheel rim, and the body or chassis may never contact the ground.

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Underglow may not be lit on Michigan public roads — non-permitted lamps must be unlit and covered; private property is the only place to run it.

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Michigan has no statute requiring fenders, mud flaps, or splash guards, and none limiting how far a tire may extend beyond the fender line. Only the general 8-foot-6-inch width cap applies.

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Tinted film is allowed along the top edge, no more than 4 inches from the top or below the factory shade band, whichever is closer to the top. Because the material must be transparent, a printed or opaque banner is not legal in Michigan — only a clear tint band.

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Front side windows may be tinted on the top 4 inches only. Rear side and back windows: any darkness.

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