Section 21657 Of Article 1. Driving On Right Side From California Vehicle Code >> Division 11. >> Chapter 3. >> Article 1.

. The authorities in charge of any highway may designate any highway, roadway, part of a roadway, or specific lanes upon which vehicular traffic shall proceed in one direction at all or such times as shall be indicated by official traffic control devices. When a roadway has been so designated, a vehicle shall be driven only in the direction designated at all or such times as shall be indicated by traffic control devices.