Summary: You may pass on the right only if it is done safely and there is sufficient room to do so without driving off the main roadway. You may temporarily drive on the right shoulder if you are driving slow and impeding normal traffic flow.

21650: Upon all highways, a vehicle shall be driven upon the right half of the roadway, except as follows:

• (f) When the vehicle is necessarily traveling so slowly as to impede the normal movement of traffic, that portion of the highway adjacent to the right edge of the roadway may be utilized temporarily when in a condition permitting safe operation.

21754: The driver of a motor vehicle may overtake and pass to the right of another vehicle only under the following conditions:

• (a) When the vehicle overtaken is making or about to make a left turn.
• (b) Upon a highway within a business or residence district with unobstructed pavement of sufficient width for two or more lines of moving vehicles in the direction of travel.
• (c) Upon any highway outside of a business or residence district with unobstructed pavement of sufficient width and clearly marked for two or more lines of moving traffic in the direction of travel.
• (d) Upon a one-way street.
• (e) Upon a highway divided into two roadways where traffic is restricted to one direction upon each of such roadways.

21755: The driver of a motor vehicle may overtake and pass another vehicle upon the right only under conditions permitting such movement in safety. In no event shall such movement be made by driving off the paved or main-traveled portion of the roadway.