The law today
Unchanged. RCW 46.61.608 prohibits operating a motorcycle between lanes of traffic or between adjacent lines or rows of vehicles. That covers filtering through stopped traffic as well as splitting moving traffic.
Nothing on this page changes that. Until a bill passes and takes effect, filtering is an infraction. See the full lane splitting rules.
What the proposals have looked like
Washington bills have generally proposed something much narrower than California-style splitting. The recent shape has been shoulder use on limited-access roadways rather than riding between lanes, and heavily conditioned:
- Only when adjacent traffic is at or below a low threshold, in the region of 25 mph.
- A strict speed cap for the filtering rider, around 10 mph above the adjacent lane speed.
- One motorcycle at a time, not a column.
The intent is rear-end protection in stop-and-go traffic, not faster commuting. Whether that distinction survives contact with actual riders is part of what legislators debate.
Where it has stalled
Earlier bills in the 2023-24 sessions died in committee. The most recent proposal was reintroduced and retained in committee in January 2026 and received a House Transportation public hearing in February 2026, without advancing further at the time of writing.
That is a common pattern for this subject nationally: a hearing, sympathetic testimony from riders, concerns raised about enforcement and driver expectation, and no floor vote.
Because this changes session by session, check the Washington State Legislature bill information site for current status rather than relying on any article, this one included.
What other states did
Useful context for why riders keep asking. California has permitted splitting for years. Arizona, Montana and Utah adopted limited filtering under specific low-speed conditions, and Colorado followed in 2024 and Minnesota in 2025. The Washington proposals resemble that second group rather than California.
The safety argument is genuine on both sides. Filtering removes the rear-end exposure of a stationary rider at the back of a queue. It also introduces a motorcycle into a space drivers do not expect one, which is its own hazard.
What to do in the meantime
Ride the law as it is. The practical substitute for filtering is the habit we teach: when you stop in traffic, leave an escape path, stay in gear, keep watching your mirror until a vehicle has stopped behind you, and position yourself where you are visible rather than tucked into a blind spot.
If you want the law changed, the productive route is contacting your legislators during session, not testing it on I-405.