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The Guide to Legal Car Modifications in Iowa

The Guide to Legal Car Modifications in Iowa ARENA Creative /

Whether you currently live in Iowa or you are planning on moving to the state, you need to know the laws and regulations regarding vehicle modifications to ensure that your car or truck remains street legal throughout the state. The following are the vehicle modification laws applicable in Iowa.

Sounds and noise

Iowa has laws concerning both the sound systems and mufflers on vehicles. Additionally, they also require that horns can be heard from 200 feet, but are not harsh, unreasonably loud or produce a whistling sound.

Sound system

Iowa does not have any specific laws governing sound systems in vehicles, other than that they can’t produce noise levels that may harm, annoy or cause damage to any other reasonable person.


  • Mufflers are required on all vehicles and must be in proper working condition.

  • Bypasses, cutouts and other similar devices that amplify the sound are not permitted on mufflers.

  • Mufflers must prevent excessive or unusual smoke or noise when in constant operation.

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

Frame and suspension

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

  • Vehicles can’t exceed 13 feet 6 inches in height.
  • There are no frame height or suspension lift limits.
  • There are no bumper height restrictions.


Indiana does not have regulations regarding engine swaps or modifications affecting performance. Porter and Lake Counties require emissions testing on vehicles with a Gross Vehicle Weight Rating (GVWR) of 9,000 pounds or less and that were manufactured after 1976.

Lighting and windows


  • Blue lights are not permitted on passenger vehicles unless driven by emergency personnel. In these cases, a certificate of authorization must be carried in the vehicle at all times.

  • Flashing white lights are not permitted on passenger vehicles unless the vehicle is owned by emergency personnel and authorization is granted.

  • Blue stationary and flashing lights are not permitted on passenger vehicles.

  • One spotlight is permitted.

  • Three auxiliary driving lights are permitted if mounted no lower than 12 inches and no higher than 42 inches.

Window tinting

  • Non-reflective tint can be applied to the top of the windshield above the AS-1 line from the manufacturer.

  • Front side windows must allow over 70% of light through.

  • Back side and rear windows can have any darkness of tint with both side mirrors on the vehicle.

  • Iowa law is not specific on reflect window tint, requiring only that it is not excessively reflective. Iowa does not allow medical exemptions for darker tint on front windows.

Antique/classic car modifications

Iowa allows vehicles that are 25 or more years old to be registered as antique. If the vehicle is registered as such, it can only be used for exhibitions, education or entertainment purposes. It can only be driven on roadways to or from these types of events or when requiring maintenance.

If you want to make the modifications you make to your vehicle follow Iowa law, 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

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