Is Lane Splitting Legal in California? What Motorcyclists Should Know

Lane splitting — riding a motorcycle between rows of stopped or slow-moving cars — is one of the most misunderstood topics in California traffic law, including by the drivers and insurers involved in motorcycle crashes. The short answer: it is legal in California. Here is what the law actually says and why it matters after an accident. This is general information, not advice about a specific case.

Yes — and California is the only state that expressly allows it

California Vehicle Code section 21658.1, added by Assembly Bill 51 and effective January 1, 2017, formally recognizes lane splitting. It defines the practice as driving a motorcycle between rows of stopped or moving vehicles in the same lane, on any divided or undivided road. California is the only U.S. state that expressly permits riding between lanes of traffic — everywhere else it is either prohibited or simply not addressed.

There is no set speed limit for lane splitting

A common myth is that the law caps lane-splitting speed at a specific number or a fixed differential over surrounding traffic. It does not. The statute itself sets no speed limit or speed-differential limit. Some earlier figures came from a California Highway Patrol document that was later withdrawn, and they are not part of California law. That said, a motorcyclist still must ride safely and can be found at fault for riding in a way that is unsafe for the conditions.

What the CHP guidelines are — and aren't

Vehicle Code 21658.1 directs the CHP to publish lane-splitting safety guidelines. Those guidelines are educational, not regulatory — they encourage riders to consider traffic and lane widths, watch for large vehicles that may not see them, avoid splitting in bad weather or poor road conditions, and generally split between the far-left lanes. Violating a guideline is not itself a traffic offense, but riding unsafely can still be used as evidence of fault in a crash.

Why this matters after a motorcycle accident

Because lane splitting is widely misunderstood, drivers and insurers often wrongly assume a lane-splitting motorcyclist was automatically at fault. They were not — lane splitting is legal, and fault depends on how each party actually behaved. Under California's pure comparative negligence rule, fault can be shared, so even a rider found partly responsible can still recover a reduced amount. The key is evidence: how the split was performed, the driver's conduct (such as an unsafe lane change), and the road conditions.