Complete Guide to Vehicle Modification Laws in South Dakota
South Dakota gives vehicle enthusiasts more freedom than many states in certain areas — like ride height — while maintaining specific restrictions in others, like window tint and lighting. This guide breaks down the most common modifications, their legal status, and the exact statutory limits you need to know. All figures below were verified against primary statute text as of September 2026.
Underglow
Status: Conditional
Underglow lighting is legal in South Dakota, including while driving, but it comes with specific color and usage restrictions. Red visible from the front and blue anywhere are both classified as Class 2 misdemeanors, so those colors should be avoided entirely. Additionally, no more than three auxiliary lamps may be used on your vehicle. As long as you stay within these color and quantity limits, underglow while driving is allowed.
This is governed under SDCL §§ 32-17-9, 32-17-42, 32-17-17, 32-17-20. See the full underglow laws for details.
Window Banners
Status: Conditional
South Dakota doesn't regulate window banners based on transparency — instead, the law focuses on obstruction. Any sunscreening material that obstructs or reduces the driver's clear view is prohibited, and sunscreening film may not extend below the AS-1 line or the lowest point of the sun visor. A printed banner is only illegal if it actually obstructs the driver's view. Windshield strips are permitted.
This falls under SDCL §§ 32-15-2.9, 32-15-5. Check the window banners laws page for the complete rule.
Exhaust Noise
Status: Conditional
South Dakota sets no statewide decibel limit for passenger cars, giving owners some flexibility on sound output. That said, a muffler in good working order is required, exhaust systems may not produce excessive or unusual noise, and cutouts or bypasses are prohibited.
This is codified under SDCL § 32-15-17. More detail is available on the exhaust noise laws page.
Aftermarket Exhaust
Status: Conditional
Swapping out your exhaust system is perfectly legal in South Dakota. However, the replacement system must include a muffler in good working order, and cutouts or bypasses remain prohibited. There's no explicit "no louder than stock" requirement in South Dakota statute — instead, the standard is simply that the exhaust must not produce excessive or unusual noise. Note that removing a catalytic converter is prohibited under federal law, regardless of state statute. No specific South Dakota statute was found addressing aftermarket exhaust modifications directly beyond this general standard.
This is covered under SDCL § 32-15-17. Learn more at the aftermarket exhaust laws page.
License Plate Frames
Status: Conditional
License plate frames are permitted in South Dakota as long as they don't obscure any part of the plate. Plates must be conspicuously displayed and kept clear of mud, ice, and snow so they remain clearly visible. There's no express ban on plate covers, but any cover that obscures the plate would violate the visibility rule — the assigned number must stay visible at all times.
This is addressed in SDCL 32-5-98. See the license plate frames laws page for specifics.
Light Bars & LED Lighting
Status: Conditional
South Dakota permits three auxiliary driving lamps, but only if they're mounted 12 to 24 inches above the surface — a narrow window that rules out most roof-mounted or upper-bumper light bars. No cover is required for these lamps. Keep in mind the use rule: no auxiliary driving lamp other than a fog lamp may be lit while headlamps are on low beam.
This is governed under SDCL § 32-17-17. Full details are on the light bars laws page.
Window Tint
Status: Conditional
South Dakota's window tint law sets different minimum visible light transmission (VLT) requirements depending on window location. Front side windows require a minimum of 35% VLT, while rear side windows and the back window both require a minimum of 20% VLT.
This is set out in SDCL 32-15-2.4 & 32-15-2.5. Visit the window tint laws page for the complete breakdown.
Lift Kits
Status: Legal
Good news for truck and off-road enthusiasts: South Dakota sets no statewide lift, frame-height, or bumper-height limit. The only restriction that applies is the general overall-height cap on vehicles, and general equipment rules — such as headlamp height and working lighting — still apply regardless of how high you lift your vehicle.
There's no dedicated height section in SDCL ch. 32-15 covering this. See the lift kits laws page for more.
Lowering
Status: Legal
South Dakota has no statute limiting how low a vehicle may be. Enthusiasts who want to lower their ride have legal flexibility here — but remember that general equipment rules still apply, including proper headlamp height, working lighting, and ensuring nothing drags on the road.
Check out the lowering laws page for further reading.
Headlight & Taillight Tint
Status: Illegal
Smoked or tinted film on headlights and taillights is not permitted in South Dakota. Headlights must emit white light, and taillights must show red at the required visibility distance. Film that dims or discolors either light violates these color and visibility requirements — no film is permitted on these components.
This is enforced under SDCL 32-17-5, 32-17-8. Learn more on the headlight tint laws page.
Wheel & Tire Protrusion
Status: Legal
South Dakota has no fender, mudguard, or splash-guard requirement on the books, and there is no limit on tire protrusion. This gives owners running wider wheels and tires considerable freedom without a specific statutory protrusion restriction to worry about.
See the wheel & tire protrusion laws page for more.
Every modification above links to its full law page with exact limits, statute citations, and exceptions — or browse every South Dakota mod law in one place, free.
Disclaimer: This guide is for informational purposes only. Data is AI-extracted from public statutes and may contain errors. Always verify with local authorities.