Loudoun County, VA Noise from Specific Sources: Car Alarm Limits (2026)

Loudoun County directly addresses car alarms and vehicle horns in Section 654.02(d)(6) of the Codified Ordinances. The sounding of any horn or signaling device/alarm on any motor vehicle, motorcycle, bicycle, or other vehicle on any street or public place of the county, continuously or intermittently for more than 20 consecutive seconds, is prohibited except as a danger warning or as permitted by state law. A key enforcement provision allows law enforcement to arrange for towing: if the alarm sounds continuously for 15 minutes after a law enforcement officer arrives and the owner cannot be located, the officer may arrange for the vehicle to be towed at the owner's expense. Section 654.02(d)(4) separately prohibits the spinning of tires, racing of engines, and similar vehicle noise, as well as noise from vehicles lacking mufflers or exhaust systems conforming to Virginia Code Sections 46.2-1047 and 46.2-1049. Warning devices such as back-up alarms on trucks and other equipment are exempt under Section 654.02(e)(10). Emergency vehicle sirens and alarms are also exempt under Section 654.02(e)(4).