Hawaii Exhaust & Muffler Laws (2026)

Info: For cars, the muffler can't be noticeably louder than the factory one.

InfoVerified Jun 19, 2026

For cars, the muffler can't be noticeably louder than the factory one. Motorcycles and mopeds need a muffler, and a cutout or bypass (which routes exhaust around the muffler) isn't allowed. Hawaii sets no fixed decibel limit (HRS §§ 291-24.5, 291-24).

Official source: capitol.hawaii.gov →

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