California Code, Vehicle Code - VEH § 21760

(a) This section shall be known and may be cited as the Three Feet for Safety Act.

(b) The driver of a motor vehicle overtaking and passing a bicycle that is proceeding in the same direction on a highway shall pass in compliance with the requirements of this article applicable to overtaking and passing a vehicle, and shall do so at a safe distance that does not interfere with the safe operation of the overtaken bicycle, having due regard for the size and speed of the motor vehicle and the bicycle, traffic conditions, weather, visibility, and the surface and width of the highway.

(c) A driver of a motor vehicle shall not overtake or pass a bicycle proceeding in the same direction on a highway at a distance of less than three feet between any part of the motor vehicle and any part of the bicycle or its operator.The driver of a motor vehicle overtaking or passing a bicycle that is proceeding in the same direction and in the same lane of travel shall, if another lane of traffic proceeding in the same direction is available, make a lane change into another available lane with due regard for safety and traffic conditions, if practicable and not prohibited by law, before overtaking or passing the bicycle.

(d) If the driver of a motor vehicle is unable to comply with subdivision (c), due to traffic or roadway conditions, the driver shall slow to a speed that is reasonable and prudent, and may pass only when doing so would not endanger the safety of the operator of the bicycle, taking into account the size and speed of the motor vehicle and bicycle, traffic conditions, weather, visibility, and surface and width of the highway.