California Vehicle Code Section 21658.1 makes California the only U.S. state to explicitly legalize lane splitting — riding a motorcycle between lanes of traffic moving in the same direction. The law doesn't set a precise speed differential or define exactly how lane splitting must be done; it simply states that a motorcycle may be driven between lanes as long as it's done in a manner that doesn't endanger the safety of the vehicles or persons involved.
What CHP guidance recommends
The California Highway Patrol has published non-binding safety guidance (not law, but widely referenced) suggesting:
- Riders shouldn't split lanes at speeds more than 10 mph faster than surrounding traffic
- Lane splitting at speeds over 30 mph isn't advisable
- Splitting between the far left two lanes is generally safer than weaving between multiple lanes
- Riders should be visible and predictable, avoiding sudden lane changes within the gap
These guidelines aren't codified into law, which means there's no specific statutory speed limit for lane splitting — but they're frequently referenced by insurers, police, and courts when evaluating whether a rider's conduct was "safe" under the broader statute.
How this plays into accident claims
Because the statute uses a general "safety" standard rather than a bright-line rule, fault in a lane-splitting accident often comes down to specific facts: the speed differential, visibility, whether the other driver made an unsignaled lane change, and road conditions. Insurance adjusters and, if necessary, courts weigh these facts under California's comparative negligence framework.
This means lane splitting itself isn't evidence of fault — but how it was done can become a factual question in a disputed claim.
What to document if you're lane splitting when a crash happens
If you're involved in an accident while lane splitting:
- Note your approximate speed and the speed of surrounding traffic, if you can estimate it
- Identify whether the other vehicle changed lanes, opened a door, or otherwise created the hazard
- Look for witnesses in adjacent vehicles, who may have a clear view of what happened
- Check for traffic camera coverage at the location, if applicable
A note on insurance
Some riders assume lane splitting voids their insurance coverage. That's generally not accurate in California — lane splitting is legal, and insurers can't deny coverage simply because a legal activity was occurring. However, how fault is allocated for the specific accident is a separate question from whether coverage applies at all.
For an assessment of how these rules might apply to your situation, consult a licensed attorney familiar with California traffic law.