Let riders filter past stopped traffic
In 6 states a motorcyclist can legally ride between lanes of stopped or slow cars. Everywhere else the law says to wait in line with the cars, with nowhere to go if the driver behind doesn’t stop. This site explains the practice, shows the law in each state and sums up the research, including the parts that argue against it.
Splitting and filtering are different
People use the two words loosely. The laws don’t, so it helps to keep them apart.
Lane splitting
Riding between lanes of moving traffic, usually a little faster than the cars on either side. It is common in California, where it was legal long before a statute named it.
- Traffic
- Moving
- Legal in
- California and Minnesota
Lane filtering
Moving slowly between lanes of stopped or crawling traffic, usually only up to a speed limit set in the law, often to get to the front at a light.
- Traffic
- Stopped or slow
- Legal in
- Arizona, Colorado, Montana and Utah
Why riders ask for it
-
Getting hit from behind
Stopped in a lane, a motorcycle sits between two cars with no crumple zone and no room to move if the driver behind is looking at a phone. In California crash data from 2012 and 2013, riders who were lane splitting were rear-ended less often than other riders who crashed (2.6% against 4.6%).
Source: UC Berkeley SafeTREC, 2015. The study only covered riders who crashed, so it can’t say whether splitting changes the chance of a crash in the first place.
-
Heat
An idling engine sits between the rider’s knees, and the rider sits in protective gear in the exhaust of the car ahead. Riders in Western Australia’s review of its filtering law listed less exposure to heat and exhaust fumes among the benefits.
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Congestion
A motorcycle that moves up through a queue isn’t taking up a car-length of it. Advocates also point to fuel and emissions savings. The California researchers list both among the benefits riders commonly cite, but nobody has measured them well, so we treat them as a likely bonus and not the main argument.
Source: SafeTREC, 2015, introduction.
Where it’s legal today
2 states allow splitting in moving traffic and 4 allow filtering when traffic is stopped or slow. The rest don’t allow either.
- Lane splitting legal, in moving traffic, within limits2
- Lane filtering legal, in stopped or slow traffic only4
- Not legal: a statute prohibits riding between lanes29
- Not legal: no statute authorizes it, and general lane rules apply16
Pick a state
Hover over a square, or tab to it, to see its law here. Select it for the details and the official source.
Each state was checked against its statute or legislature site on October 26, 2026. Squares are arranged by rough location, not drawn to scale. The outlined square is Ohio, where this site is written.
What the research shows, and what it doesn’t
The best-known study, from UC Berkeley in 2015, found that California riders who crashed while lane splitting were hurt less often than riders who crashed otherwise, as long as traffic was under about 50 mph and the rider was no more than 15 mph faster than the cars.
France’s official trial of lane splitting, on the other hand, saw motorcycle crashes rise on the roads it covered, and police and AAA have told legislators that drivers don’t expect a bike between lanes. We summarize each study and each objection, with links, so you can judge them yourself.
Ask for it in your state
State law decides this, so state legislators are the people to ask. A short, polite message from a rider who lives in their district is worth sending. We’ve written a sample you can adapt.