IS MY MOD LEGAL?

Exhaust Noise in Hawaii

Conditional

Hawaii sets no statewide decibel limit for passenger cars. A muffler in good working order is required, exhaust may not produce excessive or unusual noise, and cutouts or bypasses are prohibited.

Verified against primary sources · August 2026

What the law says

Hawaii law is qualitative rather than numeric: A muffler in good working order is required, exhaust may not produce excessive or unusual noise, and cutouts or bypasses are prohibited. Hawaii's test is comparative: no muffler, cutout, or bypass that noticeably increases noise above the factory level, with fines from $25 to $250. Note that § 291-24 covers motorcycles and mopeds only, and Hawaii's old vehicular-noise rule chapter has been repealed, so no numeric limit applies.

Specific Limits

Statewide decibel limit
none

Statute

Haw. Rev. Stat. § 291-24.5

Read the statute →

Frequently Asked Questions

Are exhaust noise legal in Hawaii?
Hawaii sets no statewide decibel limit for passenger cars. A muffler in good working order is required, exhaust may not produce excessive or unusual noise, and cutouts or bypasses are prohibited.
What are the exact exhaust noise limits in Hawaii?
Statewide decibel limit: none. Source: Haw. Rev. Stat. § 291-24.5.

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