Veh. Code, § 22507.6

Local authorities may, by ordinance or resolution, prohibit or restrict the parking or standing of vehicles on designated streets or highways, or portions thereof, for the purpose of street sweeping. No ordinance or resolution relating to the parking or standing of commercial vehicles in a residential district shall be effective with respect to any commercial vehicle making pickups or deliveries of goods, wares, or merchandise from or to any building or structure located on the restricted street or highway, or for the purpose of delivering materials to be used in the repair, alteration, remodeling, or reconstruction of any building or structure for which a building permit has previously been obtained. No such ordinance or resolution shall be effective until the street or highway, or portion thereof, has been sign-posted in accordance with the uniform standards and specifications of the Department of Transportation, or local authorities have caused to be posted in a conspicuous place at each entrance to the street a notice not less than 17 inches by 22 inches in size, with lettering not less than one inch in height, setting forth the day or days and hours parking is prohibited. As used in this section, “entrance” means the intersection of any street or streets comprising an area of restricted parking for street-sweeping purposes on the same day or days and hours with another street or highway not subject to such a parking restriction, or subject to parking restrictions on different days and hours.