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Wyoming Exhaust & Muffler Laws (2026)

Info: Your vehicle needs a muffler or other effective noise-suppressing system in good working order, and a cut-out, bypass or similar device (which routes exhaust around the muffler) is prohibited.

InfoVerified Jul 22, 2026

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Your vehicle needs a muffler or other effective noise-suppressing system in good working order, and a cut-out, bypass or similar device (which routes exhaust around the muffler) is prohibited. Wyoming sets no fixed decibel limit (Wyo. Stat. § 31-5-953).

Official source: wyoleg.gov →

General legal information, not legal advice — verify important decisions with a licensed attorney.

Exhaust & Muffler in states bordering Wyoming

The same rule in each neighboring state LawLert has verified, from that state’s own official source.

ColoradoInfo
Your vehicle needs an adequate muffler. A cutoff or bypass (which routes exhaust around the muffler) is prohibited, and so is any exhaust change that raises noise above the stock level. Colorado sets no fixed decibel limit for passenger cars (C.R.S. § 42-4-225).
Verified Jul 22, 2026 · Source: leg.colorado.gov · Full Colorado rule →
IdahoInfo
Your vehicle needs a muffler in good order, and cutouts and bypasses (which route exhaust around the muffler) are banned, along with changes that make the exhaust louder — in Idaho, "excessive noise" means more than 92 decibels measured at 20 feet (Idaho Code §§ 49-937, 49-106).
Verified Jun 19, 2026 · Source: legislature.idaho.gov · Full Idaho rule →
MontanaInfo
Your vehicle needs a muffler in good working order that prevents excessive noise and smoke, and muffler cutouts and bypasses (which route exhaust around the muffler) are prohibited. Montana sets no fixed decibel limit (Mont. Code Ann. § 61-9-403).
Verified Jun 19, 2026 · Source: mca.legmt.gov · Full Montana 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 →
South DakotaInfo
Your vehicle needs an exhaust system and muffler in good working order, the exhaust has to discharge to the rear or the side, and muffler cut-outs (which route exhaust around the muffler) are prohibited. South Dakota sets no fixed decibel limit (SDCL § 32-15-17).
Verified Jun 19, 2026 · Source: sdlegislature.gov · Full South Dakota rule →
UtahInfo
Your vehicle needs a muffler or other effective noise-suppressing system in good working order, and a cut-out, bypass or similar device (which routes exhaust around the muffler) is prohibited. Utah sets no fixed decibel limit (Utah Code § 41-6a-1626).
Verified Jun 19, 2026 · Source: le.utah.gov · Full Utah rule →

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