National City, CA Noise Ordinances: Vehicle Noise (2026)

Title 12 of the National City Municipal Code does not print a muffler standard, a car stereo rule or an engine-brake rule of its own. The vehicle-specific noise provision is Section 12.10.260, which covers motorized off-road vehicles operating off a public right-of-way or on private property. It is unlawful to operate or cause to be operated such a vehicle in a way that the sound levels emitted violate Section 12.06.020. The section applies to all motorized vehicles, whether or not duly licensed and registered or identified, and lists commercial and noncommercial racing vehicles, motorcycles, go-carts, three-wheelers, amphibious craft, campers, snowmobiles and dune buggies. Motorboats are not included.

The Section 12.06.020 limits come from Table III. Measured at or beyond the boundary of the property where the sound is produced, a vehicle running on a lot next to homes with fewer than 9 dwelling units is held to 45 dB(A) from 10 p.m. to 7 a.m. and 55 dB(A) from 7 a.m. to 10 p.m. Commercial land is limited to 60 and 65, light industry east of I-5 to 70, and heavy industry west of I-5 to 80. Section 12.06.040 takes five dB off the limit for a steady whine, screech or hum, or a repetitive impulsive noise.

Road noise is handled differently. Section 12.12.060(E) exempts automotive noise generated by vehicles properly equipped and operating on public rights of way in accordance with the California Vehicle Code from the Section 12.06.020 limits, and Section 12.12.080 exempts noise regulation preempted by state or federal law. A muffler or exhaust complaint about a street-driven car therefore falls outside this chapter, while an oversized-speaker complaint can fall under the loudspeaker rules of Section 12.10.080, since Section 12.04.620 defines sound amplifying equipment to include loudspeakers attached to or operated from a vehicle.

The chief of police enforces nuisance noise. Officers issue an abatement order first, and equipment exceeding the limits is declared a public nuisance under Section 12.18.100.