Honolulu County, HI Noise Ordinances: Vehicle Noise (2026)
Key Facts
- Muffler required
- At all times, in operation
- Banned devices
- Dummy muffler, cut-out, by-pass
- Banned mods
- Exhaust that amplifies noise
- Baffles
- Must be fixed, not loose
Summary
Honolulu requires every motor vehicle and moped on public streets to run a working muffler that prevents excessive noise, and bans dummy mufflers, cut-outs and modified exhausts that amplify sound.
(a) A person may not operate a motor vehicle or moped on a public highway or street, unless the motor vehicle or moped is equipped, at all times, with a muffler or mufflers in constant operation and of such length and size or of sufficient capacity for the motor or exhaust system, or both, to prevent the escape of excessive or annoying fumes or smoke, and excessive or unusual noise. ... (c) ...equipped with a dummy muffler, cut-out, by-pass, or other similar device.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-10: Supplement 10, 12-2025 Ordinance No. 25-40 through Ordinance No. 25-56).
Full Breakdown
Every motor vehicle and moped driven on an Oahu public street or highway must run a muffler at all times, sized and maintained to keep exhaust and engine noise down to the level a properly working muffler produces. The code separately bans dummy mufflers, cut-outs, by-passes, exhaust systems modified to increase noise, add-on devices that amplify sound beyond the factory setup, and mufflers with loose or non-fixed baffles, covering the full range of straight-pipe and loud-exhaust modifications.
Violations & Fines
Driving with a straight-pipe, cut-out, dummy muffler, or noise-amplifying exhaust modification is a citable equipment violation under ROH § 15-19.28, enforceable by police on any public street.
Frequently Asked Questions
Is a loud aftermarket exhaust legal in Honolulu?
Can I drive with a cut-out or straight-pipe exhaust in Honolulu?
Sources & Official References
Other rules in Honolulu County
Compare Honolulu County to another location·View the Hawaii noise ordinances overview
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