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Missouri Exhaust & Muffler Laws (2026)
Info: Your vehicle needs a properly attached muffler to quiet the exhaust, and muffler cutouts and excessive noise are barred — a violation is an infraction.
Your vehicle needs a properly attached muffler to quiet the exhaust, and muffler cutouts and excessive noise are barred — a violation is an infraction. Missouri sets no fixed decibel limit (Mo. Rev. Stat. § 307.170).
Official source: revisor.mo.gov →
General legal information, not legal advice — verify important decisions with a licensed attorney.
Exhaust & Muffler in states bordering Missouri
The same rule in each neighboring state LawLert has verified, from that state’s own official source.
- ArkansasInfo
Your vehicle needs a factory-spec muffler in good order, and cutouts and bypasses (which route exhaust around the muffler) are banned, along with any device that produces excessive noise or smoke. Arkansas sets no fixed decibel limit (Ark. Code § 27-37-601).
Verified Jul 30, 2026 · Source: ardot.gov · Full Arkansas rule →
- IllinoisInfo
Your vehicle needs an adequate muffler and exhaust so it doesn't make excessive or unusual noise, and cutouts and bypasses (which route exhaust around the muffler) are prohibited, as are changes that increase noise. Illinois sets no fixed decibel limit (625 ILCS 5/12-602).
Verified Jun 19, 2026 · Source: ilga.gov · Full Illinois rule →
- IowaInfo
Your vehicle needs a muffler in good working order so it doesn't make excessive or unusual noise, and muffler cutouts and bypasses (which route exhaust around the muffler) are prohibited. Iowa sets no fixed decibel limit (Iowa Code § 321.436).
Verified Jun 19, 2026 · Source: legis.iowa.gov · Full Iowa rule →
- KansasInfo
Your vehicle needs a muffler or other effective noise-suppressing system in good order, and cutouts and bypasses (which route exhaust around the muffler) are prohibited, while excessive noise is barred. Kansas sets no fixed decibel limit (K.S.A. § 8-1739).
Verified Jun 19, 2026 · Source: kslegislature.gov · Full Kansas rule →
- KentuckyInfo
Your vehicle needs a suitable, efficient muffler; running with the cutout removed is prohibited, and so is any change that makes the exhaust louder than the factory setup. Kentucky sets no fixed decibel limit (KRS § 189.140).
Verified Jun 19, 2026 · Source: apps.legislature.ky.gov · Full Kentucky rule →
- NebraskaInfo
Your vehicle needs a muffler or other noise-suppressing system in good working order, cutouts and bypasses (which route exhaust around the muffler) are unlawful, and changes that increase noise are banned. Nebraska sets no fixed decibel limit (Neb. Rev. Stat. § 60-6,286).
Verified Jun 19, 2026 · Source: nebraskalegislature.gov · Full Nebraska rule →
- OklahomaInfo
Your vehicle needs a muffler or other noise-suppressing system, a cutout or bypass (which routes exhaust around the muffler) is prohibited, and so is any exhaust change that's louder than the factory (OEM) setup. Oklahoma sets no fixed decibel limit (47 O.S. § 12-402).
Verified Jun 19, 2026 · Source: oscn.net · Full Oklahoma rule →
- TennesseeInfo
Your vehicle needs a muffler in good working order, running at all times, cutouts (which route exhaust around the muffler) are prohibited, and the excessive or unusual noise the law bars includes engine noise from a non-motorcycle that's noticeably louder than similar vehicles and over 95 decibels. …
Verified Jul 26, 2026 · Source: publications.tnsosfiles.com · Full Tennessee rule →
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