Cal. Veh. Code § 21809

(a) A person driving a vehicle on a highway approaching a stationary authorized emergency vehicle that is displaying emergency lights, a stationary tow truck that is displaying flashing amber warning lights, a stationary marked highway maintenance vehicle that is displaying flashing amber warning lights, or any other stationary vehicle displaying flashing hazard lights or another warning device, including, but not limited to, cones, flares, or retroreflective devices, shall approach with due caution and, before passing in a lane immediately adjacent to the authorized emergency vehicle, tow truck, highway maintenance vehicle, or any other vehicle, absent other direction by a peace officer, proceed to do one of the following:
1. (1) Make a lane change into an available lane not immediately adjacent to the authorized emergency vehicle that is displaying emergency lights, a stationary tow truck that is displaying flashing amber warning lights, a stationary marked highway maintenance vehicle that is displaying flashing amber warning lights, or any other stationary vehicle displaying flashing hazard lights or another warning device, including, but not limited to, cones, flares, or retroreflective devices, with due regard for safety and traffic conditions, if practicable and not prohibited by law.
2. (2) If the maneuver described in paragraph (1) would be unsafe or impracticable, slow to a reasonable and prudent speed that is safe for existing weather, road, and vehicular or pedestrian traffic conditions.
(b) A violation of subdivision (a) is an infraction, punishable by a fine of not more than fifty dollars ($50).
(c) The requirements of subdivision (a) do not apply if the stationary authorized emergency vehicle that is displaying emergency lights, the stationary tow truck that is displaying flashing amber warning lights, the stationary marked highway maintenance vehicle that is displaying flashing amber warning lights, or any other stationary vehicle displaying flashing hazard lights or another warning device, including, but not limited to, cones, flares, or retroreflective devices, is not adjacent to the highway or is separated from the highway by a protective physical barrier.
(d) For the purposes of this section, “highway maintenance vehicle” means a vehicle used for the maintenance of highways and roadways in this state and is either of the following:
1. (1) Owned or operated by the Department of Transportation, a county, or a municipality or other political subdivision of this state.
2. (2) Owned or operated by a contractor under contract with the Department of Transportation, a county, a municipality, or other political subdivision of this state to maintain highways, roadways, or both.