Cass County, MO Noise Ordinances: Vehicle Noise (2026)
Key Facts
- Governing section
- Cass County Code § 380.140(B)
- Muffler cutouts
- Banned outright, cannot be reopened while moving
- Noise standard
- Exhaust quieted to modern passenger-car standard
- Horn rule
- Warning use only, no extra sound devices
- Maximum penalty
- $1,000 civil penalty per Section 100.210
- Enforcing agency
- Cass County Sheriff's Office
Summary
Cass County Code Section 380.140(B) bans muffler cutouts and requires every motor vehicle to run a properly attached muffler that quiets exhaust noise to the standard of a modern passenger car. Drivers cannot operate a vehicle so that its machinery, motor, signaling device or cargo makes excessive or unnecessary noise on unincorporated county roads.
Muffler Cutouts. Muffler cutouts shall not be used and no vehicle shall be driven in such manner or condition that excessive and unnecessary noises shall be made by its machinery, motor, signaling device, or other parts, or by any improperly loaded cargo. The motors of all motor vehicles shall be fitted with properly attached mufflers of such capacity or construction as to quiet the maximum possible exhaust noise as completely as is done in modern gas engine passenger motor vehicles. Any cutout or opening in the exhaust pipe between the motor and the muffler on any motor vehicle shall be completely closed and disconnected from its operating lever and shall be so arranged that it cannot automatically open, or be opened or operated, while such vehicle is in motion.
Full Breakdown
140 sits in Chapter 380's Article II, 'Other Vehicle Equipment,' and Subsection (B), captioned 'Muffler Cutouts,' is the county's core noise-equipment rule for motor vehicles. It flatly bans muffler cutouts, an exhaust bypass that routes gases around the muffler for a louder sound, and it separately bars driving in such manner or condition that excessive and unnecessary noises are made by its machinery, motor, signaling device, or other parts, or by any improperly loaded cargo, language broad enough to cover a straight-piped exhaust, a failing engine, or a rattling, improperly secured load.
Every motor vehicle must carry a properly attached muffler built to quiet exhaust noise as completely as is done in a modern gas-engine passenger car, and any cutout or opening in the exhaust pipe between the motor and the muffler must be permanently closed off and disconnected from its operating lever so a driver cannot reopen it while the vehicle is moving. Subsection (A) of the same section adds a related rule for horns: a signaling device must be used only for warning, never to make unnecessary noise, and no other sound-producing signaling device is allowed on the vehicle at all. 010.
Violations & Fines
Operating a vehicle with a muffler cutout, an exhaust that has been modified to bypass the muffler, or any other equipment that produces excessive and unnecessary noise is punishable under the general penalty, Section 100.210: up to $1,000 per offense, with each day the condition continues counted as a separate offense. Sheriff's Office deputies enforce Section 380.140 countywide.
Frequently Asked Questions
Are aftermarket exhaust cutouts legal in Cass County?
What noise standard applies to a car's exhaust system?
Can I use extra horns or noisemakers on my vehicle?
What's the penalty for a loud exhaust in unincorporated Cass County?
Sources & Official References
Other rules in Cass County
Compare Cass County to another location·View the Missouri noise ordinances overview
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