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 herewith, shall apply:
(1) A vehicle shall be driven as nearly as practicable within a single lane and shall not be moved from such lane until the driver has first ascertained that such movement can be made with safety;
(2) Upon a roadway which is divided into three (3) lanes and provides for two-way movement of traffic, a vehicle shall not be driven in the center lane except when overtaking and passing another vehicle traveling in the same direction when such center lane is clear of traffic within a safe distance, or in preparation for making a left turn, or where such center lane is at the time allocated exclusively to traffic moving in the same direction that the vehicle is proceeding and such allocation is designated by traffic-control devices;
(3) Traffic-control devices erected to direct specified traffic to use a designated lane or to designate those lanes to be used by traffic moving in a particular direction regardless of the center of the roadway shall be obeyed by drivers of vehicles;
(4) Traffic-control devices installed to prohibit the changing of lanes on sections of roadway shall be obeyed by drivers of vehicles.
State law reference--Similar provisions, R.R.S. 1943, 60-6,139.