Lane-splitting is legal in California, and research shows it can be relatively safe for motorcyclists when done at moderate speeds and with care. California is the only state that expressly permits the practice under Vehicle Code Section 21658.1, and the California Highway Patrol has published safety guidelines to help riders and drivers share the road.
At Fiore Legal, our motorcycle accident attorneys have spent 25 years helping injured riders throughout California, and understanding how lane-splitting law and safety research intersect matters when a crash happens.
Is Lane-Splitting Legal in California?
Lane-splitting has been legally permitted in California since January 1, 2017, when the state legislature added Vehicle Code Section 21658.1, which defines the practice as riding a motorcycle between rows of stopped or moving vehicles in the same lane. The statute authorizes the California Highway Patrol to publish educational safety guidelines for the practice, though the guidelines themselves are not enforceable traffic laws.
According to the CHP, riders and drivers should keep the following in mind:
- Danger increases as speed and speed differential between the motorcycle and surrounding traffic increase
- It is generally safer to split between the far left lanes than between other lanes of traffic
- Riders should avoid lane-splitting next to large vehicles such as big rigs, buses, and motorhomes
- Riding on the shoulder is illegal and is not considered lane-splitting
- Motorcyclists should stay visible and avoid lingering in other drivers' blind spots
- Intentionally blocking or impeding a motorcyclist, including opening a vehicle door to obstruct one, is illegal for other drivers
What Does the Research Say About Lane-Splitting Safety?
The most detailed research on lane-splitting safety comes from a UC Berkeley study conducted by the university's Safe Transportation Research and Education Center, which reviewed nearly 6,000 motorcycle collisions in California, including almost 1,000 in which the rider was lane-splitting at the time of the crash.
Among the study's key findings:
- Lane-splitting motorcyclists were markedly less likely to suffer head injuries, torso injuries, or fatal injuries than riders who were not lane-splitting
- Lane-splitting riders were significantly less likely to be rear-ended by other vehicles
- Lane-splitting appeared relatively safe when done in traffic moving at 50 miles per hour or less
- Injury rates did not increase when the motorcyclist's speed exceeded surrounding traffic by 15 miles per hour or less
These figures came from the study's data rather than from any fixed legal speed limit set by statute.
How to Lane-Split Safely
Riders who lane-split most safely tend to keep their speed close to the flow of surrounding traffic rather than significantly exceeding it. According to CHP safety guidance, several factors affect how safely a rider can split lanes:
- Speed differential, since danger increases the more a motorcycle's speed exceeds surrounding traffic
- Lane position, since splitting between the far left lanes generally gives a rider more room to maneuver than splitting between center lanes
- Vehicle size, since avoiding large vehicles reduces the risk posed by their wider blind spots and turbulence
- Weather, lane width, and visibility, all of which affect how much margin for error a rider has
The CHP recommends riders weigh the entire environment before splitting rather than relying on a single rule of thumb.
Common Causes of Lane-Splitting Accidents
Most lane-splitting collisions occur when a car driver fails to see the motorcyclist before changing lanes or opening a door.
According to CHP guidance and the UC Berkeley study on lane-splitting safety, the most frequent causes include:
- Sudden lane changes without checking mirrors or blind spots
- Drivers who are distracted or unaware that lane-splitting is a normal, legal practice in California
- Vehicle doors opened into a motorcyclist's path
- High speed differentials between the motorcycle and surrounding traffic, which increase the severity of injuries when a collision does occur
Who Is Liable in a Lane-Splitting Accident?
Liability in a lane-splitting accident depends on which driver's negligence caused the crash, not on the fact that the motorcyclist was lane-splitting.
California follows a pure comparative fault rule established in Li v. Yellow Cab Co. and applied through CACI No. 405 and No. 406, which means:
- A driver who changes lanes without checking for a motorcyclist can be held liable even though the rider was lane-splitting at the time
- Fault is apportioned by percentage among everyone whose negligence contributed to the crash, rather than assigned all-or-nothing to one party
- A rider found partially at fault can still recover damages, reduced by their share of responsibility
Insurance companies sometimes attempt to blame the motorcyclist simply because lane-splitting was involved, which makes a thorough investigation of the actual cause of the crash essential to a fair outcome.
What to Do After a Motorcycle Accident While Lane-Splitting
Riders involved in a lane-splitting accident should take the same careful steps as any other motorcycle accident victim to protect their claim:
- Call 911 and request a police report documenting the accident
- Seek medical attention immediately, since some motorcycle injuries are not apparent right away
- Photograph the scene, both vehicles, and any visible injuries
- Avoid admitting fault or discussing the details of the crash with the other driver's insurance company
- Speak with a motorcycle accident attorney before accepting any settlement offer
Why California Riders Choose Fiore Legal
Fiore Legal has represented injured motorcyclists throughout California for 25 years, and our attorneys understand how insurance companies try to shift blame onto riders simply because a crash involved lane-splitting. Our team has secured significant results for motorcycle accident clients across Los Angeles and communities statewide, and we handle every motorcycle accident case on a contingency basis so injured riders never pay out of pocket. If you were hurt while lane-splitting, our team is ready to investigate your case and fight for the compensation you deserve. Contact us today.
Disclaimer: The information on this page is provided for general educational purposes only and does not constitute legal advice. Every case is different. Past results do not guarantee future outcomes.
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