Ark. Code Ann. § 27-51-302: Driving on roadways laned for traffic

Whenever any roadway has been divided into two (2) or more clearly marked lanes for traffic, the following rules in addition to all others consistent with this subchapter shall apply:

(1) A vehicle shall be driven as nearly as practical entirely within a single lane and shall not be moved from the lane until the driver has first ascertained that movement can be made with safety; and

(2) Official signs may be erected directing slower-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 every such sign.