Cal. VEH § 22358.7

(a) If the Department of Transportation or a local authority, after completing an engineering and traffic survey, finds that the speed limit is still more than is reasonable or safe, the Department of Transportation may or the local authority may, by ordinance, determine and declare a prima facie speed limit that has been reduced an additional five miles per hour for either or both of the following reasons:

(1) The portion of highway has been designated as a safety corridor. The Department of Transportation or a local authority shall not deem more than one-fifth of their streets as safety corridors.

(2) The portion of highway is adjacent to any land or facility that generates high concentrations of bicyclists or pedestrians, especially those from vulnerable groups such as children, seniors, persons with disabilities, and the unhoused.

(b) (1) As used in this section, “safety corridor” shall be defined by the Department of Transportation in the next revision of the California Manual on Uniform Traffic Control Devices. In making this determination, the Department of Transportation shall consider highways that have the highest number of serious injuries and fatalities based on collision data that may be derived from, but not limited to, the Statewide Integrated Traffic Records System.

(2) The Department of Transportation shall, in the next revision of the California Manual on Uniform Traffic Control Devices, determine what constitutes land or facilities that generate high concentrations of bicyclists and pedestrians, as used in paragraph (2) of subdivision (a). In making this determination, the Department of Transportation shall consider density, road use type, and bicycle and pedestrian infrastructure present on a section of highway.

(c) A peace officer shall issue only warning citations for violations of exceeding the speed limit by 10 miles per hour or less for the first 30 days that a lower speed limit is in effect as authorized by this section.