California Code, Public Utilities Code - PUC § 120269

(a) If the board licenses or regulates any for-hire vehicle services, pursuant to Section 120266, or any passenger jitney service, pursuant to Section 120267, and the licensed or regulated service employs, or contracts with, any driver who (1) is not required to be tested for controlled substances and alcohol pursuant to Part 382 (commencing with Section 382.101) of Title 49 of the Code of Federal Regulations, paragraph (3) of subdivision (b) of Section 53075.5 of the Government Code, Section 1032.1 of this code, or Section 34520 of the Vehicle Code, and (2) is not exempted under Section 34520 of the Vehicle Code, the board shall adopt, by ordinance or resolution, a mandatory controlled substance and alcohol testing certification program for those drivers.

(b) The program adopted pursuant to subdivision (a) shall meet substantially the requirements set forth in paragraph (3) of subdivision (b) of Section 53075.5 of the Government Code.

(c) Evidence derived from a positive test result collected pursuant to the program adopted under subdivision (a) shall not be admissible in a criminal prosecution concerning unlawful possession, sale, or distribution of controlled substances.