CA Veh Code Section 26708.7

Notwithstanding any other law, a vehicle operated and owned or leased by a federal, state, or local agency, department, or district, that employs peace officers, as defined by Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2 of the Penal Code, for use by those peace officers in the performance of their duties, is exempt from California law, and regulations adopted pursuant thereto, prohibiting or limiting material that may be placed, displayed, installed, affixed, or applied to the side or rear windows, commonly referred to as window tinting or glazing.