Complete Guide to Vehicle Modification Laws in Kentucky
Kentucky offers vehicle enthusiasts a fair amount of freedom when it comes to modifying their rides, but several categories come with specific conditions attached to them. The figures, statutes, and rules in this guide were verified against primary statute text (September 2026), so you can plan your build with confidence. Below is a breakdown of the most common modifications and where Kentucky law stands on each one.
Lowering
Status: Legal
If you're looking to drop your ride, you're in luck. Kentucky has no suspension, frame-height, or bumper-height restrictions, meaning there's no statewide minimum ground clearance or maximum drop you need to worry about for a lowered stance. Check out lowering laws for more details.
Window Banners
Status: Conditional
Kentucky allows transparent sunscreening along a strip at the top of the windshield, as long as it doesn't encroach on the AS-1 portion. The key word is transparent — because the material must let light through, a printed or opaque banner is not legal in Kentucky. Only a clear tint band at the top of the windshield is permitted, not a decorative or advertising banner. This falls under KRS 189.110(2). See the full window banner laws for specifics.
Aftermarket Exhaust
Status: Conditional
Swapping out your factory exhaust is legal in Kentucky, but there are strings attached. A muffler in good working order is required, and cutouts or bypasses are prohibited. Your new setup also can't be louder than the exhaust your car originally came with. Catalytic converter removal is prohibited by federal law on vehicles originally equipped with one, and your exhaust can't exceed noise levels that disturb the peace. This is governed by KRS 189.140. Learn more at aftermarket exhaust laws.
License Plate Frames
Status: Conditional
Decorative license plate frames are fine in Kentucky, but they can't hide anything the state requires to be visible. No rim, frame, or other covering may in any way obscure or cover any lettering or decal on the plate — that means all lettering, numbers, and registration decals/stickers must remain fully visible. This is codified under KRS 186.170. Full details at license plate frame laws.
Underglow
Status: Conditional
Underglow lighting is legal in Kentucky, and you're even allowed to run it while driving — but color and behavior are restricted. Any light visible from the front of the vehicle must be white or amber, no red may show to the front, blue is prohibited entirely, and flashing is limited to turn signals and hazards. These rules come from KRS 189.040 and KRS 189.950. Check the underglow laws page for the complete rundown.
Wheel & Tire Protrusion
Status: Legal
Running wider wheels and tires? Kentucky has no fender, mudguard, or splash-guard section and no wheel-protrusion limit in its statutes, so there's no specific law dictating how far your wheels or tires can stick out beyond standard vehicle width requirements. More info at wheel & tire protrusion laws.
Light Bars & LED Lighting
Status: Conditional
Kentucky doesn't cap the number of lamps you can run or set a candlepower limit, and it doesn't require light bars to be covered. However, the state prohibits retrofit headlamp covers and films that change the color of emitted light — so a tinted cover on your lights is a violation on its own. Additionally, any front-visible light must be white or amber unless it's original equipment, and blue is prohibited. This falls under KRS 189.040(13)–(15). Read more at light bar & LED lighting laws.
Exhaust Noise
Status: Conditional
There's no statewide decibel limit for passenger cars in Kentucky, but that doesn't mean anything goes. You're still required to run a muffler in good working order, your exhaust cannot produce excessive or unusual noise, and cutouts or bypasses are prohibited. This falls under the same statute as aftermarket exhaust modifications, KRS 189.140. See exhaust noise laws for more.
Lift Kits
Status: Legal
Truck and off-road enthusiasts will be happy to know Kentucky sets no statewide lift, frame-height, or bumper-height limit. The only real ceiling is the overall vehicle height limit of 13 feet 6 inches that applies to all vehicles, and general equipment rules like headlamp height and working lighting still apply regardless of lift height. This is outlined in KRS 189.221. Full details at lift kit laws.
Window Tint
Status: Conditional
Kentucky's window tint law sets minimum visible light transmission (VLT) requirements: front side windows must allow a minimum of 35% VLT, while rear side windows and the back window require a minimum of 18% VLT. This is established under KRS 189.110.
Darker limits apply depending on vehicle type:
- SUVs: Front side windows still require a minimum of 35% VLT, but MPVs (multi-purpose vehicles) may use 8% on windows behind the driver.
- Trucks: Same rule — front side windows require 35% VLT minimum, with MPVs allowed 8% on windows behind the driver.
- Vans: Same rule applies as well — 35% VLT minimum up front, with MPVs permitted 8% on windows behind the driver.
For the complete breakdown by vehicle type, visit window tint laws.
Headlight & Taillight Tint
Status: Illegal
Unlike many of the other categories, tinting your headlights or taillights is a clear no-go in Kentucky. Film on headlights and taillights is not permitted at all. Headlights are required to emit white light, and taillights must show red at the required visibility distance — any tint that dims or discolors them violates these requirements. Kentucky law requires headlights to be clearly visible, and any tinting that reduces light output or changes color likely runs afoul of that standard. This is covered under KRS 189.040 and KRS 189.050. See headlight & taillight tint laws for the full picture.
Every modification above links to its full law page with exact limits, statute citations, and exceptions — or browse every Kentucky 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.