Florissant, MO Noise from Specific Sources: Car Alarm Limits (2026)

750 of the Florissant Code of Ordinances makes it unlawful to willfully make or continue any loud, unnecessary or unusual noise that disturbs the peace, comfort or repose of the neighborhood, and Subsection A lists twelve factors officers weigh in deciding whether a sound crosses that line, including its volume, duration, whether it is recurrent or constant, the time of day, and the density of the surrounding area. 1 then targets vehicle horns and signaling devices specifically: it is unlawful to sound any horn or signaling device on an automobile, motorcycle or other vehicle on any City street or public place except as a genuine danger warning or during an approved parade.

The Section separately bars creating any unreasonably loud or harsh sound with such a device and sounding it for an unreasonable period of time, language that reaches a car alarm that blares on and on after being triggered. It further restricts signaling devices to a Police whistle or one operated by hand or electricity, and bars using a horn, whistle or other device operated by engine exhaust, or sounding a signaling device simply because traffic is held up. 080: a fine of up to one thousand dollars, imprisonment in the City or County Jail for up to three months, or both, with each day a violation continues charged as a separate offense.