(1) Upon all roadways of sufficient width a vehicle shall be driven upon the right half of the roadway, except as follows:
(a) When overtaking and passing another vehicle proceeding in the same direction under the rules governing such movement;
(b) When an obstruction exists making it necessary to drive to the left of the center of the highway; provided, any person so doing shall yield the right-of-way to all vehicles traveling in the proper direction upon the unobstructed portion of the highway within such distance as to constitute an immediate hazard;
(c) Upon a roadway divided into three marked lanes and providing for two-way movement traffic under the rules applicable thereon;
(d) Upon a street or highway restricted to one-way traffic; or
(e) Upon a highway having three lanes or less, when approaching a stationary authorized emergency vehicle, tow truck or other vehicle providing roadside assistance while operating warning lights with three hundred sixty degree visibility, or police vehicle as described under *RCW 46.61.212(2).
(2) Upon all roadways having two or more lanes for traffic moving in the same direction, all vehicles shall be driven in the right-hand lane then available for traffic, except (a) when overtaking and passing another vehicle proceeding in the same direction, (b) when traveling at a speed greater than the traffic flow, (c) when moving left to allow traffic to merge, or (d) when preparing for a left turn at an intersection, exit, or into a private road or driveway when such left turn is legally permitted. On any such roadway, a vehicle or combination over ten thousand pounds shall be driven only in the right-hand lane except under the conditions enumerated in (a) through (d) of this subsection.
(3) No vehicle towing a trailer or no vehicle or combination over ten thousand pounds may be driven in the left-hand lane of a limited access roadway having three or more lanes for traffic moving in one direction except when preparing for a left turn at an intersection, exit, or into a private road or driveway when a left turn is legally permitted. This subsection does not apply to a vehicle using a high occupancy vehicle lane. A high occupancy vehicle lane is not considered the left-hand lane of a roadway. The department of transportation, in consultation with the Washington state patrol, shall adopt rules specifying (a) those circumstances where it is permissible for other vehicles to use the left lane in case of emergency or to facilitate the orderly flow of traffic, and (b) those segments of limited access roadway to be exempt from this subsection due to the operational characteristics of the roadway.
(4) It is a traffic infraction to drive continuously in the left lane of a multilane roadway when it impedes the flow of other traffic.
(5) Upon any roadway having four or more lanes for moving traffic and providing for two-way movement of traffic, a vehicle shall not be driven to the left of the center line of the roadway except when authorized by official traffic control devices designating certain lanes to the left side of the center of the roadway for use by traffic not otherwise permitted to use such lanes, or except as permitted under subsection (1)(b) of this section. However, this subsection shall not be construed as prohibiting the crossing of the center line in making a left turn into or from an alley, private road or driveway.
[2007 c 83 § 2; 1997 c 253 § 1; 1986 c 93 § 2; 1972 ex.s. c 33 § 1; 1969 ex.s. c 281 § 46; 1967 ex.s. c 145 § 58; 1965 ex.s. c 155 § 15.]
Rules of court: Monetary penalty schedule — IRLJ 6.2.
*Reviser’s note: RCW 46.61.212 was amended by 2010 c 252 § 1, changing subsection (2) to subsection (1)(d)(ii), effective January 1, 2011.
Legislative intent — 1986 c 93: “It is the intent of the legislature, in this 1985  amendment of RCW 46.61.100, that the left-hand lane on any state highway with two or more lanes in the same direction be used primarily as a passing lane.” [1986 c 93 § 1.]
Information on proper use of left-hand lane: RCW 28A.220.050, 46.20.095, 46.82.430, 47.36.260.
(1) Upon the immediate approach of an authorized emergency vehicle making use of audible and visual signals meeting the requirements of RCW 46.37.190, or of a police vehicle properly and lawfully making use of an audible signal only the driver of every other vehicle shall yield the right-of-way and shall immediately drive to a position parallel to, and as close as possible to, the right-hand edge or curb of the roadway clear of any intersection and shall stop and remain in such position until the authorized emergency vehicle has passed, except when otherwise directed by a police officer.
(2) This section shall not operate to relieve the driver of an authorized emergency vehicle from the duty to drive with due regard for the safety of all persons using the highway.
[1965 ex.s. c 155 § 32.]
Rules of court: Monetary penalty schedule — IRLJ 6.2.
(1) The driver of any motor vehicle, upon approaching an emergency zone, which is defined as the adjacent lanes of the roadway two hundred feet before and after (a) a stationary authorized emergency vehicle that is making use of audible and/or visual signals meeting the requirements of RCW 46.37.190, (b) a tow truck that is making use of visual red lights meeting the requirements of RCW 46.37.196, (c) other vehicles providing roadside assistance that are making use of warning lights with three hundred sixty degree visibility, or (d) a police vehicle properly and lawfully displaying a flashing, blinking, or alternating emergency light or lights, shall:
(i) On a highway having four or more lanes, at least two of which are intended for traffic proceeding in the same direction as the approaching vehicle, proceed with caution and, if reasonable, with due regard for safety and traffic conditions, yield the right-of-way by making a lane change or moving away from the lane or shoulder occupied by the stationary authorized emergency vehicle or police vehicle;
(ii) On a highway having less than four lanes, proceed with caution, reduce the speed of the vehicle, and, if reasonable, with due regard for safety and traffic conditions, and under the rules of this chapter, yield the right-of-way by passing to the left at a safe distance and simultaneously yield the right-of-way to all vehicles traveling in the proper direction upon the highway; or
(iii) If changing lanes or moving away would be unreasonable or unsafe, proceed with due caution and reduce the speed of the vehicle.
(2) A person may not drive a vehicle in an emergency zone at a speed greater than the posted speed limit.
(3) A person found to be in violation of this section, or any infraction relating to speed restrictions in an emergency zone, must be assessed a monetary penalty equal to twice the penalty assessed under RCW 46.63.110. This penalty may not be waived, reduced, or suspended.
(4) A person who drives a vehicle in an emergency zone in such a manner as to endanger or be likely to endanger any emergency zone worker or property is guilty of reckless endangerment of emergency zone workers. A violation of this subsection is a gross misdemeanor punishable under chapter 9A.20 RCW.
(5) The department shall suspend for sixty days the driver’s license, permit to drive, or nonresident driving privilege of a person convicted of reckless endangerment of emergency zone workers.
[2010 c 252 § 1; 2007 c 83 § 1; 2005 c 413 § 1.]
Effective date — 2010 c 252: “This act takes effect January 1, 2011.” [2010 c 252 § 6.]
On a two-lane highway where passing is unsafe because of traffic in the opposite direction or other conditions, a slow moving vehicle, behind which five or more vehicles are formed in a line, shall turn off the roadway wherever sufficient area for a safe turn-out exists, in order to permit the vehicles following to proceed. As used in this section a slow moving vehicle is one which is proceeding at a rate of speed less than the normal flow of traffic at the particular time and place.
[1973 c 88 § 1.]