Whenever any roadway has been divided into two 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 entirely 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 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 official traffic-control devices.

(3) Official traffic-control devices may be erected directing slow moving or other specified traffic to use a designated lane or designating those lanes to be used by traffic moving in a particular direction regardless of the center of the roadway and drivers of vehicles shall obey the directions of every such device.

(4) Official traffic-control devices may be installed prohibiting the changing of lanes on sections of roadway and drivers of vehicles shall obey the directions of every such device.

(5) Pursuant to subsection (1) of this section, the operator of a commercial motor vehicle as defined in RCW 46.25.010 may, with due regard for all other traffic, deviate from the lane in which the operator is driving to the extent necessary to approach and drive through a circular intersection.

Rules of court: Monetary penalty schedule—IRLJ 6.2.