Hawaii County, HI Noise Ordinances: Vehicle Noise (2026)
Key Facts
- Governing sections
- HCC §§ 24-108 through 24-111
- Muffler required
- At all times, in constant operation
- Noise standard
- No more than stock muffler at minimum
- Cut-outs/dummy mufflers
- Prohibited outright
- Enforcing agency
- County of Hawai'i police, § 24-12
Summary
Hawaii County law requires every motor vehicle on a public highway or street to run a muffler in constant operation, sized to stop excessive or unusual noise. Modified exhausts, dummy mufflers and cut-out by-pass devices are all banned under HCC Chapter 24, enforced islandwide by county police.
No person shall operate a motor vehicle on a public highway or street unless the motor vehicle 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 and exhaust system to prevent the escape of excessive or annoying fumes or smoke, and excessive or unusual noise. Excessive or unusual noise as used in this division means noise in excess of the usual noise which would necessarily result from the operation of a motor when reduced to the minimum by a muffler.
Full Breakdown
Hawaii County Code Chapter 24, Article 6, Division 5 governs vehicle noise directly. Section 24-108 defines a muffler as a device with baffle plates, chambers or a perforated tube packed with spun glass, spun steel or similar sound-deadening material, built to receive exhaust gas and control exhaust noise from the motor. " Section 24-109(b) defines the standard: excessive or unusual noise means noise beyond what necessarily results when a motor's noise is reduced to the minimum by a working muffler, so the baseline is a properly functioning stock exhaust, not a driver's own judgment of what sounds acceptable.
Section 24-110 separately bars operating a vehicle whose motor and exhaust system are not properly equipped and adjusted to prevent excessive or annoying fumes, smoke, and unusual noise, covering wear and misadjustment as well as missing hardware. Section 24-111 closes the loop on aftermarket modification: no one may operate a vehicle on a public highway or street with a motor or exhaust system altered or modified to the point the emitted noise becomes excessive or unusual, or fitted with a dummy muffler, a cut-out, a by-pass, or a similar device that routes exhaust around the muffler.
Enforcement runs through Section 24-12, which puts the duty on county police officers and officers assigned by the chief of police to enforce all street traffic laws of the County, including this division, islandwide from Hilo to Kona and every rural stretch between.
Violations & Fines
A defective, missing, removed or bypassed muffler, or an altered exhaust that raises noise above the stock-muffler baseline, is a violation of Sections 24-109 through 24-111, enforced by County of Hawai'i police officers under Section 24-12. Citing officers stop the vehicle under the standard traffic-citation process; there is no separate muffler-specific fine schedule quoted in these sections.
Frequently Asked Questions
Is a loud aftermarket exhaust legal in Hawaii County?
Can I remove my muffler for off-road use only?
Who enforces the muffler and exhaust rules in Hilo and Kona?
Sources & Official References
Other rules in Hawaii County
Compare Hawaii County to another location·View the Hawaii noise ordinances overview
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