Twin Falls, ID Noise Ordinances: Vehicle Noise (2026)

Two sections of Title 9 of the Twin Falls City Code, adopted by the Twin Falls City Council, address vehicle noise. Section 9-9-10, Preventing Smoke And Noise, says no motor vehicle shall be driven on the street unless it is equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise, annoying smoke and escape of excessive gas. All exhaust pipes from the motor must be directed so as to prevent excessive or unusual noise. The section ends with a flat prohibition: a muffler cutout shall not be used on any motor vehicle on a street. The standard is equipment-based, since it requires a working muffler running all the time, and a cutout is banned outright rather than judged by how loud it is.

Section 9-9-20 deals with engine compression brakes. No person shall operate a vehicle while the vehicle or its operator is utilizing an engine compression brake without an exhaust muffler sufficient to prevent the creation of excessively loud noises, except when use of the brake is necessary in an emergency. The section states that it is not intended to prohibit the passage of vehicles equipped with engine compression brakes, but rather to limit the use of such equipment to emergencies. A truck with a compression brake can drive through the city; using the brake outside an emergency without an adequate muffler is the violation.

Section 9-9-11 adds a related limit: a gong, siren or exhaust whistle cannot be used on any vehicle other than those operated by the Police and Fire Departments, the sheriff or other peace officer, or an ambulance, and then only when responding to emergency calls.

The text read for this page contains no decibel limit and no separate rule on car stereos, so this page does not state one.