The Guide to Legal Car Modifications in Massachusetts

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Whether you live Massachusetts or are moving to the area, you need to know about the vehicle modification laws to make sure your car or truck is street legal. From sounds to classic cars, the following information will make sure you know what to expect from the Massachusetts car modification laws.

Sounds and noise

Massachusetts regulations on sound are a bit vague in some areas. However, the following are what you need to know when modifying your vehicle.

Sound system

The sound emanating from your vehicle cannot cause the ambient sound levels at the nearest property line to increase by more than 10 decibels from normal sound levels. These regulations and subsequent enforcement defines noise as that which is of a duration and/or intensity that contributes to noise pollution in the air.

Mufflers

  • Mufflers are required on all vehicles and must prevent unusual or excessive noise and be in good working condition.

  • Muffler cutouts, bypasses or other modifications that are designed to amplify the sound are not permitted.

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

Frame and suspension

Massachusetts regulates lift and suspension systems on vehicles.

  • Vehicles cannot be taller than 13 feet 6 inches.

  • Vehicles with a GVWR under 10,000 have a 2-inch suspension lift limit.

  • 4x4 vehicles must follow (wheelbase inches X wheel track inches) divided by 2200 to determine lift limit.

Engine

Massachusetts does not have engine swap or modification guidelines. However, all vehicles must pass emissions testing and general inspections.

Lighting and windows

Lights

  • Red and blue flashing or rotating lights are only permitted on emergency and police vehicles.

  • Fire department members can have red flashing or rotating lights on personal vehicles with permit that can only be used when responding to an emergency situation.

  • Failing to comply with the above regulations could result in a fine between $100 and $300.

  • Spotlights cannot shine more than two feet above the ground at 30 feet from the vehicle.

Window tinting

  • Non-reflective tint can be applied to the top six inches of the windshield.
  • Front side, back side and rear windows must permit 35% of light to pass through.
  • Side mirrors are required if back window is tinted.
  • Front side and back side window reflective tint cannot reflect more than 35%.

Antique/classic car modifications

Massachusetts allows vehicles that are older than 25 years old and used only for club activities, exhibitions, and parades to be plated as antique motor cars with the required Certificate and Affidavit of Vehicle Owner.

If you want to make sure your vehicle modifications follow Maryland 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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