Exhaust Noise in Montana
Montana caps exhaust noise at 95 dB for all motor vehicles except motorcycles and quadricycles, measured under SAE J1169. A muffler in good working order is separately required and cutouts are prohibited.
Verified against primary sources · August 2026
What the law says
Montana is one of the few states with a real statutory decibel number (MCA § 61-9-435), tested under SAE J1169 (May 1998). The muffler and cutout rules live in § 61-9-403.
Specific Limits
- Exempt
- motorcycles and quadricycles
- dB limit cars
- 95 dB
- Test standard
- SAE J1169 (May 1998)
Frequently Asked Questions
Are exhaust noise legal in Montana?
What are the exact exhaust noise limits in Montana?
Street-legal exhaust noise picks
Gear that helps you mod without a ticket in Montana.
Measure your exhaust at the test RPM before a fix-it ticket does.
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