California Code, Vehicle Code - VEH § 22510

(a) Local authorities may, by ordinance or resolution, prohibit or restrict the parking or standing of vehicles on designated streets or highways within their jurisdiction, or portions thereof, for the purpose of snow removal. The ordinance or resolution shall not 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 until the local authorities have caused to be posted in a conspicuous place at each entrance to the street or highway, a notice not less than 17 inches by 22 inches in size, with lettering not less than one inch in height, setting forth the days parking is prohibited. The signs shall, at a minimum, be placed on each affected street or highway, at the boundary of the local authority, and at the beginning and end of each highway or highway segment included in that area. No person shall stop, park, or leave standing any vehicle, whether attended or unattended, within the area marked by signs, except when necessary to avoid conflict with other traffic or in compliance with the directions of a traffic or peace officer.

(b) No ordinance or resolution authorized by subdivision (a) which affects a state highway shall be effective until it is submitted to, and approved by, the Department of Transportation.

(c) The Department of Transportation, with respect to state highways, may restrict the parking or standing of vehicles for purposes of snow removal. The restrictions shall not be effective until the highway, or portion thereof, has been posted with signs in accordance with the uniform standards and specifications of the department. No person shall stop, park, or leave standing any vehicle, whether attended or unattended, within the area marked by parking restriction signs, except when necessary to avoid conflict with other traffic or in compliance with the directions of a traffic or peace officer.