Section 21658 Of Article 1. Driving On Right Side From California Vehicle Code >> Division 11. >> Chapter 3. >> Article 1.
21658
. Whenever any roadway has been divided into two or more
clearly marked lanes for traffic in one direction, the following
rules apply:
(a) A vehicle shall be driven as nearly as practical entirely
within a single lane and shall not be moved from the lane until such
movement can be made with reasonable safety.
(b) Official signs may be erected directing slow-moving traffic to
use a designated lane or allocating specified lanes to traffic
moving in the same direction, and drivers of vehicles shall obey the
directions of the traffic device.