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The Guide to Legal Car Modifications in Hawaii

The Guide to Legal Car Modifications in Hawaii ARENA Creative /

If you live in, or are planning to move to, Hawaii, you need to know the requirements for modified vehicles to ensure your car or truck will be street legal. Here you will find out about the rules and requirements so you can ensure you are following the laws in your state.

Sounds and noise

Hawaii regulations cover both the sound systems and the mufflers of all vehicles on the roads.

Sound system

  • Sounds from a vehicle’s radio or stereo equipment can’t be audible from 30 feet away. In this case, plainly audible requires only that the sounds can be heard, not that words are clear.


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

  • Cutouts, bypasses and other equipment designed to amplify the sound of the engine or muffler are not permitted.

  • Replacement mufflers can’t allow sound levels beyond those created by the original manufacturer parts.

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

Frame and suspension

Vehicles in Hawaii must comply with the following regulations:

  • Vehicles can’t exceed 14 feet in height.

  • Body lift kits can’t exceed three inches.

  • Vehicles 4,500 pounds and under have a max front and rear bumper height of 29 inches.

  • Vehicles between 4,501 and 7,500 pounds have a max front and rear bumper height of 33 inches.

  • Vehicles between 7,501 and 10,000 pounds have a max front and rear bumper height of 35 inches.


Hawaii requires that all modified vehicles, which includes any that have parts that have been removed, added, altered or substituted by parts that were not used by the original manufacturer, undergo a Reconstruction Inspection and safety inspection and receive a sticker stating that the vehicle passed it.

Lighting and windows


  • Blue lights are not permitted on passenger vehicles.

  • All reflectors must have a D.O.T. stamp on them – in most cases aftermarket lens do not have this stamp, and the vehicle will not pass the Recon or safety inspections.

  • One spotlight is permitted.

Window tinting

  • Non-reflective tint can be applied to the top four inches on the windshield.

  • Front and back side windows and rear window must allow more than 35% of light to pass through.

  • Vans and SUVs can have any tint darkness on back side and rear windows with side mirrors.

  • Reflective and mirrored tints are not permitted.

Antique/classic car modifications

Hawaii requires that classic or antique cars also pass the Reconstruction Inspection and safety inspections.

If you want to modify your vehicle but want to make sure you are in compliance with the Hawaii 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

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