Wausau, WI Noise Ordinances: Vehicle Noise (2026)

030(c) bars discharging the exhaust of any steam engine, stationary internal combustion engine or motorboat engine into the open air except through a muffler or other device that effectively prevents loud or explosive noise. Subsection (d), the compression-brake rule, goes further: no one may use motor vehicle brakes in the City of Wausau that are activated or operated by engine compression, in whole or in part, on any unit or component of the vehicle, with a single carve-out for City employees operating City-owned vehicles. Both subsections sit in the same 'Loud and unnecessary noise prohibited' section that also covers loudspeakers and railroad whistles, and were carried forward from a 2001 ordinance, Ord.

02(3). In practice this reaches straight-piped or modified exhausts on cars and trucks as well as unmuffled compression 'Jake brakes' on trucks passing through the city on state highways, since the ban applies to any motor vehicle brake activated by engine compression rather than only to a listed class of heavy trucks. There is no separate decibel meter test in the text: the violation turns on whether the exhaust lacks an effective muffler or whether the brake is compression-activated at all.