Skip the auto shop - Our mechanics make house calls

The Guide to Legal Car Modifications in Colorado

The Guide to Legal Car Modifications in Colorado ARENA Creative / Shutterstock.com

Whether you currently live in Colorado and want to modify your car or you are moving to the area and want to ensure your vehicle is street legal, you need to know the laws and regulations throughout the state. Below you will find out what you need to know to make sure your vehicle is legal on Colorado roadways.

Sounds and noise

Your sound system and muffler must meet certain requirements in Colorado in order to avoid fines.

Sounds system

Colorado regulations limit the decibel levels in specific areas. These include:

  • Residential - 55 decibels between 7 AM and 7 PM, 50 decibels between 7 PM and 7 AM

  • Commercial - 60 decibels between 7 AM and 7 PM, 55 decibels between 7 PM and 7 AM

Mufflers

Colorado muffler modification laws include:

  • Vehicles with a gross vehicle weight over 6,000 pounds and produced prior to 1973 can’t produce noise that exceeds 88 decibels at 35 MPH or less or 90 decibels between 35 and 55 MPH.

  • Vehicles with a gross vehicle weight over 6,000 pounds and produced after January 1, 1973 can’t produce noise that exceeds 86 decibels at 35 MPH or less or 90 decibels between 35 and 55 MPH.

  • All vehicles must have a working muffler.

  • Bypasses and cutouts are not permitted.

Tip: Also check with local county laws in Colorado to make sure you are following any municipal noise ordinances that may be more stringent than state-level laws.

Frame and suspension

Colorado frame and suspension laws include:

  • Suspension modifications cannot alter the type that was originally used by the manufacturer.
  • Vehicles can’t exceed 13 feet in height.

Engine

Colorado has regulations regarding engine modifications as well:

  • Engine swaps must be done with engines that are the same year or newer.

  • Gasoline engines that are over three model years old are required to pass emissions tests.

Lighting and windows

Lights

  • Vehicles can have no more than two spot lamps.

  • Vehicles can have no more than two fog lamps.

  • One running board courtesy lamp is permitted per side in white or amber.

  • No more than four lamps greater than 300 candlepower can be lit at a single time on the highway.

Window tinting

  • Non-reflective tint is allowed on the top four inches of the front windshield.
  • Front side and back side windows must allow over 27% of the light through.
  • Rear window must allow over 27% of light through.
  • Mirrored or metallic tint is not permitted.
  • Amber or red tint is not permitted.
  • Two side mirrors are required if the back window is tinted.

Antique/classic car modifications

Colorado only requires that antique, classic and custom-built vehicles be registered at your local county DMV location.

If you’re considering modifying your car to be within the laws in Colorado, YourMechanic can provide the mobile mechanics to help you install the new parts. You can also ask our mechanics what modifications may be best suited to your car using our free online Q&A system, Ask a Mechanic.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem What the P0121 code means P0121 is a generic OBD-II code which indicates that the Engine Control...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed Related Trouble Codes: P2441: EVAP Vent Valve Stuck Open EVAP trouble...


Related questions

Q: Debating installation of a leveling kit

The biggest problem people run into with these types of kits is buying the cheapest kit they can find. Not saying that the cheapest may not be good, but it is much more important to find a kit that is...

Q: The car shut off, cannot be started

The crankshaft damper may have a loose bolt and is what's causing the lower timing chain gear to be loose. The gear pin may shear and cause the no start or loss of power. However, if this is not the...

Q: Packing power. Looking to add more off-road performance.

If you want to add some more power easily to your vehicle I would recommend an intake system or an exhaust system or both. The intake system and the exhaust system are two of the easiest ways to add power...