Vehicle Mod Laws in Oregon

Replacing the exhaust system is legal in Oregon, 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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Oregon caps passenger-car exhaust at 94 dBA for pre-1976 vehicles and 91 dBA for 1976 and newer, using a stationary test at 25 feet under DEQ procedures.

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Smoked or tinted film on headlights and taillights is illegal in Oregon. 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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It is unlawful to use any frame or plate holder that obscures the numbers, letters, or registration stickers so as to render them unreadable, and unlawful to place material altering the plate's color, configuration, numbers, letters, or material.

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Oregon sets no statewide lift, frame-height, or bumper-height limit. The only cap is overall vehicle height of 14 feet, and general equipment rules — headlamp height, working lighting — still apply.

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Oregon requires no cover. Auxiliary lights used on the highway must be mounted no more than 54 inches above the surface and show white light forward; anything mounted higher may not be lighted on a highway.

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Oregon applies a rim-line test: no portion of a passenger vehicle other than the wheels may have less clearance than the lowest point of any wheel rim in contact with the road.

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Underglow is legal in Oregon, including while driving, subject to color and flashing limits: No red visible from the front, blue reserved for police, and no flashing or strobe effects.

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Oregon requires Type III fenders or mudguards on each axle of a passenger car: they must extend the full width over the tire, from above and forward of the tire center down to within 27 inches of the highway.

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Tinting material may be applied to the top 6 inches of the windshield and to no other portion. Oregon uses inches, not an AS-1 line. Because the material must be transparent, a printed or opaque banner is not legal in Oregon — only a clear tint band.

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Front side windows: minimum 35% VLT. Rear side and back windows: minimum 35% VLT. Darker limits apply behind the driver on some larger vehicles.

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