Complete Guide to Vehicle Modification Laws in Colorado
Colorado's vehicle modification laws strike a balance between enthusiast freedom and roadway safety, but several categories carry specific statutory limits that are easy to miss. The figures and rules in this guide were verified against primary statute text (September 2026), so you can treat them as an accurate snapshot of current Colorado law. Below, we break down the most common modifications — from lift kits to window tint — so you know exactly where you stand before you start wrenching.
Lift Kits
Status: Conditional
Colorado doesn't set a numeric lift height or bumper-height limit, but that doesn't mean anything goes. Under C.R.S. §§ 42-4-233, 42-4-504, you may not alter the front or rear suspension from the manufacturer's original design except in accordance with department specifications. Heavy-duty shocks and overload springs are expressly allowed. The overall vehicle height is capped at 14 feet 6 inches, and there is no statewide bumper-height limit. Before installing a lift kit, make sure the suspension work still complies with department specifications — see the lift kits laws page for the full text.
Lowering
Status: Conditional
Lowering your vehicle falls under the same suspension rule as lift kits: C.R.S. § 42-4-233 prohibits altering the front or rear suspension away from the manufacturer's original design except as the department specifies. There's no numeric drop allowance written into the statute — compliance is based on department specifications rather than a fixed measurement. Check the lowering laws page before making changes.
License Plate Frames
Status: Conditional
License plate frames are legal in Colorado as long as they don't obscure any required information. Clear covers are allowed, but tinted or distorting covers are banned. All plate characters and validation stickers must remain visible, and the plate must stay readable by automated plate readers (ALPR). Frames are permitted outright, provided they don't block any portion of the plate number, letters, or stickers. This is governed by C.R.S. § 42-3-202. Full details are on the license plate frames laws page.
Underglow
Status: Conditional
Colorado takes a notably strict approach to underglow and accent lighting. Under C.R.S. §§ 42-4-238, 42-4-213(4), and 42-4-215, green light use is limited to a stationary emergency command post. A non-emergency vehicle may not even be equipped with a lamp capable of showing red or blue from directly in front — doing so is a class 2 misdemeanor. Any extra front lamps must show white or amber. If you're set on adding underglow or accent lighting, steady white or amber is the configuration that keeps you compliant. See the underglow laws page for specifics.
Wheel & Tire Protrusion
Status: Legal
Good news for owners of wider wheels and tires: Colorado's splash-guard statute (C.R.S. § 42-4-1407.5) expressly exempts registered passenger vehicles and trucks up to 10,000 lb empty weight. That means there's no fender-coverage or protrusion limit for ordinary cars and light trucks in the state. More detail is available on the wheel & tire protrusion laws page.
Light Bars & LED Lighting
Status: Conditional
Colorado doesn't require light bars to be covered or wired to a switch-off when on public roads, but it does regulate them through lamp-specific rules under C.R.S. §§ 42-4-212, 42-4-219, and 42-4-220. You're limited to two lamps per auxiliary category — this includes spot lamps, fog lamps (12-30 in), auxiliary passing lamps (20-42 in), and auxiliary driving lamps (16-42 in) — and each category has a mounting-height band that a roof-mounted bar typically can't satisfy, meaning lighting one on the road can violate the lamp rules directly. No more than 4 front lamps over 300 candlepower may be lit at one time on a highway, and any lamp over 300 candlepower must be aimed within 75 ft and be of a department-approved type. Review the light bars laws page for the complete breakdown.
Exhaust Noise
Status: Conditional
There is no statewide decibel limit for passenger cars in Colorado. That said, C.R.S. § 42-4-225 requires a muffler in good working order, prohibits exhaust that produces excessive or unusual noise, and bans cutouts or bypasses. Even without a specific decibel number, these baseline requirements still apply to every vehicle on the road. See the exhaust noise laws page for more.
Headlight & Taillight Tint
Status: Illegal
Smoked or tinted film on headlights and taillights is illegal in Colorado under C.R.S. §§ 42-4-205 and 42-4-206. Film is not permitted on these lenses, headlights must emit white light, and taillights must show red at the required visibility distance. There is a narrow exception: headlight tinting is allowed only if it doesn't impair required visibility and illumination standards, and it must not reduce light output below state-mandated minimums for safe operation. In practice, this means most aftermarket tint films on headlights or taillights will violate the law. Full details are on the headlight & taillight tint laws page.
Window Tint
Status: Conditional
Colorado's window tint law (C.R.S. § 42-4-227) sets a minimum visible light transmission (VLT) requirement across the board. Front side windows require a minimum of 27% VLT, rear side windows require a minimum of 27% VLT, and the back window requires a minimum of 27% VLT. There's no distinction by window position in terms of the percentage — all three areas share the same 27% VLT floor. See the window tint laws page for the complete rule.
Aftermarket Exhaust
Status: Conditional
Swapping out your exhaust system is legal in Colorado, but C.R.S. § 42-4-225 requires a muffler in good working order and prohibits cutouts or bypasses. Modifications that make the exhaust louder than the originally installed muffler are also prohibited. Additionally, removing the catalytic converter is prohibited by federal law. If you're planning an aftermarket exhaust upgrade, keep these limits in mind — details are on the aftermarket exhaust laws page.
Window Banners
Status: Conditional
Printed window banners and windshield strips are allowed in Colorado under C.R.S. § 42-4-227, with specific placement rules. Non-transparent material is permitted as long as its bottom edge sits no more than 4 inches from the top of the windshield. The material may not be red or amber, and it must not create glare. Within those parameters, a printed banner in the windshield strip area is legal. Check the window banners laws page for the full rule text.
Every modification above links to its full law page with exact limits, statute citations, and exceptions — or browse every Colorado mod law in one place, free.
This guide is for informational purposes only. Data is AI-extracted from public statutes and may contain errors. Always verify with local authorities.