3) When reasonably necessary to avoid conditions (including, but not limited to, fixed or moving objects, vehicles, bicycles, pedestrians, animals, surface hazards, or substandard width lanes) that make it unsafe to continue along the right-hand curb or edge, subject to the provisions of Section 21656. For purposes of this section, a “substandard width lane” is a lane that is too narrow for a bicycle and a vehicle to travel safely side by side within the lane.
Which means that a bicycle can use the entire lane anytime they feel that they need to. With the exception of the “bicycle rights advocates” that want to ride in the middle of the street just to piss motorists off, most cyclists will stay to the right as long as it is safe for them to do so.
