Complete Guide to Vehicle Modification Laws in Indiana
Indiana has specific rules governing everything from lighting and exhaust to tint and ride height. This guide breaks down what's allowed, what's restricted, and what will get you a ticket. The figures cited below were verified against primary statute text (September 2026), so you can rely on them when planning your next build.
Light Bars & LED Lighting
Status: Conditional
Indiana permits two fog lamps, one auxiliary passing lamp, and one auxiliary driving lamp, and there is no requirement that these lamps be covered. However, no more than 4 front lamps over 300 candlepower may be lit at one time on a highway. The specific size allowances are: fog lamps must be 12-30 inches off the ground, the auxiliary passing lamp must be 24-42 inches, and the auxiliary driving lamp must be 16-42 inches. Before adding a light bar or auxiliary lighting setup, check light bars & LED lighting laws to make sure your combination doesn't exceed the lit-lamp cap. This is governed under Ind. Code §§ 9-19-6-14, 9-19-6-15, 9-19-6-16, 9-21-7-3.
Lift Kits
Status: Conditional
If your car was originally equipped with bumpers, Indiana requires you to keep them, and bumper height cannot vary more than 3 inches from the original manufactured height. For trucks up to 11,000 lb declared gross weight, the maximum bumper height is 30 inches. This effectively caps how far you can lift a passenger vehicle before running afoul of the bumper-height rule. Review lift kit laws before making major suspension changes. Statutory basis: Ind. Code §§ 9-19-4-1, 9-19-4-2.
Underglow
Status: Conditional
Underglow lighting is legal in Indiana, including while driving, but it comes with color and behavior restrictions. No red or blue lighting is allowed, flashing is prohibited, and any light visible from the front of the vehicle is limited to white or amber. Green lighting is reserved for EMS use. Specifically, any lamp visible from directly in front of the vehicle's center must show white or amber — every other color is barred from the front. Flashing or revolving lights are prohibited except for turn signals, rear-mounted lamps may show red, and flashing or revolving green is reserved for permitted EMS personnel. Full details are available on the underglow laws page. This falls under Ind. Code §§ 9-21-7-10, 9-21-7-11, 9-19-14.5.
Aftermarket Exhaust
Status: Conditional
Swapping your exhaust system is legal in Indiana, but a muffler in good working order is required, and cutouts or bypasses are prohibited. Modifications that make your exhaust louder than the originally installed muffler are not allowed. Catalytic converter removal is prohibited by federal law, so you must maintain your original equipment converter or an EPA-approved replacement. The muffler requirement exists specifically to prevent excessive noise, and sound levels must not exceed reasonable limits that could disturb the peace. Check aftermarket exhaust laws before installing a new system. Governed under Ind. Code §§ 9-19-8-3, 9-19-8-4.
License Plate Frames
Status: Conditional
License plate frames are legal in Indiana as long as nothing required stays hidden. Your plate must remain clearly legible, free from foreign materials, and unobstructed by any accessory or opaque object. Transparent covers are not expressly banned. Frames and covers are permitted as long as they don't obstruct or obscure any portion of the plate — including numbers, letters, or state identification markings. See license plate frame laws for the full rule. This is addressed under Ind. Code § 9-18.1-4-4.
Wheel & Tire Protrusion
Status: Legal
Indiana has no fender, mud-flap, or wheel-protrusion provision on the books. The only relevant restriction is the general 8-foot-6-inch overall width limit that applies to vehicles on the road. If you're planning a wide wheel-and-tire setup, this gives you more flexibility than many other states — check wheel & tire protrusion laws for confirmation.
Lowering
Status: Conditional
Lowering your vehicle is subject to the same bumper-height rule that governs lift kits: passenger-car bumper height may not vary more than 3 inches from the original manufactured height. This single rule constrains both lowering and raising a vehicle, so slammed builds need to stay within that 3-inch window. Full specifics are on the lowering laws page. Statutory reference: Ind. Code § 9-19-4-1.
Window Banners
Status: Conditional
Indiana allows a strip on the uppermost part of the windshield, as long as it extends no further down than the AS-1 line. Because this strip must be transparent, a printed or opaque banner is not legal — only a clear tint band qualifies. If you're considering a windshield banner or sun strip, review window banner laws first. This is governed under Ind. Code § 9-19-19-4.
Exhaust Noise
Status: Conditional
Indiana sets no statewide decibel limit for passenger cars, but a muffler in good working order is still required, exhaust cannot produce excessive or unusual noise, and cutouts or bypasses are prohibited. Even without a hard decibel number, this means you can still be cited for an unreasonably loud setup. See exhaust noise laws for more. Statutory basis: Ind. Code §§ 9-19-8-3, 9-19-8-4.
Window Tint
Status: Conditional
Indiana's tint law sets a consistent minimum across the vehicle: front side windows require a minimum of 30% VLT, rear side windows require a minimum of 30% VLT, and the back window also requires a minimum of 30% VLT. Since all three areas share the same 30% threshold, there's no differing standard between front, rear, and back glass in Indiana. Check window tint laws for the complete rule. This falls under Ind. Code § 9-19-19-4.
Headlight & Taillight Tint
Status: Illegal
Smoked or tinted film on headlights and taillights is illegal in Indiana. Headlights must emit white light and taillights must show red at the required visibility distance — tinted film that dims or discolors either violates this requirement. Headlights must emit white or amber light and cannot be covered with tinted material that reduces light output or changes color. If you're considering smoked lens covers, check headlight & taillight tint laws first, since this is one of the few outright prohibitions in this guide. Statutory basis: Ind. Code § 9-19-6-4.
Every modification above links to its full law page with exact limits, statute citations, and exceptions — or browse every Indiana 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.