The Guide to Legal Car Modifications in Idaho

ARENA Creative / Shutterstock.com

Whether you live in the state or are planning to move there, Idaho has regulations that cover vehicle modifications that you must follow to ensure that your vehicle is considered street legal when you drive on the roads. The following information will help make sure you know what you can do with your modifications.

Sounds and noise

Idaho limits the noise levels that vehicles can emit from the engine/exhaust systems and the sound systems.

Sound system

Idaho does not have specific laws in place concerning sound systems in vehicles, other than that they cannot cause a nuisance or annoyance to those in a particular area, which is by its nature subjective.

Mufflers

  • Mufflers are required and must be in good working condition.

  • Mufflers can’t be altered to produce sounds louder than the original manufacturer equipment.

  • Mufflers can’t emit sound that registers more than 96 decibels when measured at a distance of 20 inches and 45 degrees from the exhaust.

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

Frame and suspension

Idaho has the following regulations in place for the vehicle frame and suspension systems:

  • Vehicles can’t exceed 14 feet in height.

  • There are no body lift kit limits providing the vehicle is within the maximum bumper height for its Gross Vehicle Weight Rating (GVWR).

  • Vehicles 4,500 pounds and under have a max front bumper height of 24 inches and rear bumper height of 26 inches.

  • Vehicles between 4,501 and 7,500 pounds have a max front bumper height of 27 inches and rear bumper height of 29 inches.

  • Vehicles between 7,501 and over 10,000 pounds have a max front bumper height of 28 inches and rear bumper height of 30 inches.

  • 4x4 vehicles with a GVWR under 10,000 pounds have a max front bumper height of 30 inches and rear bumper of 31 inches.

  • Bumper height must be a minimum of 4.5 inches.

Engine

Those living in Canyon County and in the city of Kuna, Idaho are required to pass emissions testing. These are the only engine requirements throughout the state.

Lighting and windows

Lights

  • Blue lights are not permitted on passenger vehicles.
  • Two fog lights are allowed.
  • Two spotlights are allowed.

Window tinting

  • Non-reflective tint can be applied above the manufacturer AS-1 line.
  • Front side windows and rear window must allow more than 35% of light to pass through.
  • Back side windows must allow over 20% of light through.
  • Reflective and mirrored tints can’t reflect more than 35%.

Antique/classic car modifications

Idaho requires vehicles older than 30 years to have an Idaho Classics plate. These cars can’t be used for daily commuting or driving, but use in parades, tours, club activities and exhibits is permitted.

If you want to make sure your vehicle modifications are in compliance with Idaho laws, 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

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

Related articles

Disabled Driver Laws and Permits in Idaho
Disabled Disabled driver laws vary from state to state. It is important that you understand the rules in your state, whether you are a disabled driver or not. How do I know if I am eligible for a disabled parking...
Windshield Laws in Idaho
If If you drive a vehicle in Idaho, there are many different rules of the road that you have to follow to stay legal and safe. However, you are also required to make sure that your windshield is in compliance...
What are the Car Pool Rules in Idaho?
Idaho Idaho is a beautiful and rural state, and as a result its scenic drives (https://www.yourmechanic.com/article/top-10-scenic-drives-in-idaho) are much better known than its freeways. However, as with all states, freeways are responsible for getting a large number of Idaho citizens to...

Related questions

Engine modification
Sounds like a nice build. Assuming you used the 305 crank, the engine will still be called a 5.0 or 305, since that is the cubic inch displacement of the engine.
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...
What kind of modification/performance can I do to my car?
Hello - the best way to keep your Altima running like new is "attentive maintenance (https://www.yourmechanic.com/scheduled-maintenance/nissan-altima/?year=2009&mileage=150000)". Keep fluids (oil, transmission fluid, coolant) topped off and changed at recommended intervals. If your timing chain and associated components (tensioner, idler, chain guides,...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com