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