Black Hawk County, IA Noise Ordinances: Vehicle Noise (2026)

05, the Engine Noise Reduction Ordinance, makes it unlawful for any driver to use, operate or cause to be used or operated within Black Hawk County an engine brake, compression brake, or mechanical exhaust or assist device that aids braking or deceleration and results in excessive, loud, unusual or explosive noise from the vehicle. 010(B) sets the enforcement standard: simply using an engine brake, compression brake or mechanical exhaust device in a manner that emits loud, unusual, explosive or otherwise disturbing noise is itself prima facie evidence of a violation, meaning officers do not need a decibel reading to write a citation, only the character of the noise produced.

The ordinance was most recently amended in 2022 (traced through Ord. 141, 4/12/2022) after earlier versions in 2018 and 2002, and its text was originally codified at Code 2009 Section 3-6-1. The rule applies countywide, including on county roads that run through or near Waterloo, Cedar Falls and the county's smaller cities, since it targets the vehicle's operation on any road within the county rather than being limited to unincorporated territory the way the zoning and land-use titles are. Drivers of semi-trucks and other heavy vehicles equipped with 'Jake brakes' are the ordinance's primary target, since compression-release engine brakes on diesel trucks are the most common source of the loud, sharp exhaust noise the chapter is written to control on county highways.