California Code, Vehicle Code - VEH § 22512

Except as otherwise indicated in subdivision (b), none of the following provisions shall apply to the driver or owner of any service vehicle owned or operated by or for or operated under contract with a utility or public utility, whether privately, municipally, or publicly owned, used in the construction, operation, removal, or repair of utility or public utility property or facilities, if warning devices are displayed and when the vehicle is stopped, standing, or parked at the site of work involving the construction, operation, removal, or repair of the utility or public utility property or facilities upon, in, over, under, or adjacent to a highway, bicycle lane, bikeway, or bicycle path or trail, or of a vehicle, whether privately, municipally, or publicly owned, if warning devices are displayed and when the vehicle is engaged in authorized work on the highway, bicycle lane, bikeway, or bicycle path or trail: