Lehi, UT Noise Ordinances: Vehicle Noise (2026)

City Code section 7-1-4, adopted by Ordinance 8-10-10.6 in 2010, bans operating or permitting the operation of 'any motor vehicle with a dynamic braking device engaged within the boundaries of Lehi City, except to avert imminent danger.' The section defines a 'dynamic braking device,' commonly called a jake brake, as one 'used primarily on trucks for the conversion of the engine from an internal combustion engine to an air compressor for the purpose of braking without the use of wheel brakes,' the loud compression sound heavy trucks make when slowing down.

Proof is built into the ordinance: 'the emitting of any compression noise shall be prima facie evidence of the use of engine compression,' so an officer who hears the distinctive braking sound has enough to cite a driver without needing separate proof the brake was engaged. The only defense written into the section is necessity, using the device to avert imminent danger, which covers a genuine emergency stop rather than routine hill-descent braking.

A violation is a class C misdemeanor, punishable under section 1-4-1, which caps a class C misdemeanor fine at $750 and allows up to ninety days in jail. Each day the violation continues is charged as a separate offense under the section's own continuing-violation language.