Generally, motorcycles are entitled to full use of a lane on a highway; these vehicles are subject to certain operational benefits and limitations.  Motorcyclists may operate two abreast in a single lane.  An operator of a motorcycle may not pass a vehicle in the same lane as the vehicle being overtaken, unless the vehicle is a bicyclist.

A motorcycle may not be operated between lanes of traffic, a practice commonly referred to as lane-splitting, lane-sharing, or lane-filtering.  California is the only state in the U.S. that allows lane-splitting.

The operator of a motorcycle may overtake and pass in the same lane as the vehicle being overtaken, or operate between lanes of traffic.  The operator of a motorcycle may only pass in the same lane or between lanes of traffic when the motorcycle is traveling at a speed of 35 miles per hour or less and not more than 10 miles per hour over the speed of traffic flow. 

It is a traffic infraction for an operator of a motor vehicle to intentionally impede or attempt to prevent a motorcyclist from operating as permitted under the bill.

PRO:  Motorcyclists are vulnerable and have a higher sense of risk on congested highways.  If motorcyclists don't have to stop on congested highways, there's less chance of getting rear-ended.  This bill will help reduce motorcyclists fatalities.  Utah has a pilot going that is similar to this bill and it is working well.  The Health Impact Review was inconclusive, meaning there is no certainty of risk to motorists from this bill.  Motorcyclists lane-sharing is safe if done at speeds of less than 50mph.  A UC Berkeley study found that lane-sharing is not unsafe.  Motorcyclists being rear-ended is a huge problem.  Electric bikes go fast, yet they have the same privileges as bicyclists.  Motorcyclists are worried of being boxed in—this bill allows for safe maneuvers to avoid safety hazards.  The UC Berkeley study shows that with lane-sharing if injuries occur they are much less severe in an accident.  The bill helps promote more safety for motorcyclists.  It also help alleviate bottlenecks.  Getting motorcyclists out of the way helps all motorists travel more safely. 

CON: This bill makes all motorists less safe on the highways.  2021 was one of the most unsafe years on the highways and this bill will not help change that trend.  Drivers are not yet trained and ready for this bill.  A Washington Traffic Safety Commission study found that motorcyclists caused more rear-end accidents on the highways than vice versa.  This bill does not increase safety. 

OTHER:  WSDOT has serious concerns about this bill.  The bill is not clear as to which highways the bill applies, nor is it specific as to which side of traffic the motorcyclists can pass.  The bill is problematic for vulnerable users of the highways, and has the potential for causing more deaths on the highway.  The Health Impact Review shows that the evidence is not clear on the health impacts of the bill.  Studies show mixed findings regarding whether lane-sharing will lead to more collisions.  Lane-sharing laws in California, Utah, and Montana have not yet been well researched.