California lane splitting: what riders should know after a crash

Know what California calls lane splitting.

Vehicle Code section 21658.1 defines lane splitting as operating a motorcycle with two wheels in contact with the ground between rows of stopped or moving vehicles in the same lane. The definition applies on divided and undivided streets, roads, and highways.

Legal does not mean risk-free.

The California Highway Patrol states that lane splitting is legal, while warning that danger increases as the speed difference and overall traffic speed increase. CHP guidance also says splitting is typically safer between the far-left lanes, advises riders to avoid splitting next to large vehicles, and distinguishes illegal shoulder riding from lane splitting.

Document how each vehicle moved.

After a collision, preserve helmet-camera or dashcam footage in its original form. Photograph the motorcycle, other vehicles, lane markings, debris, and sight lines. Record traffic speed, the lanes involved, any turn signal, where contact occurred, and what each witness observed. Avoid editing video or relying only on social-media copies.

Fault requires a fact-specific review.

The fact that a rider was lane splitting does not by itself answer who caused the crash. A review may consider whether a driver changed position, whether the rider could be seen, relative speeds, available space, road conditions, and whether either person had time to react. The collision report is one source of evidence, not a guaranteed fault determination.

Common questions