Motorcycle claims in California turn on two rules that do not apply to any other kind of collision: the state’s lane splitting statute, which is unique in the country, and its universal helmet requirement. Both get raised by insurers, both are frequently described inaccurately online, and both are questions of evidence rather than assumptions about riders.
This page explains what those statutes actually say, how they bear on a claim, the deadlines that may apply, and what categories of compensation California recognizes. Our California personal injury attorneys handle these claims from our San Mateo office. For a free consultation, call 650-250-0705.
Robert B. Vaksman, Esq.
Founding Partner
“Some cases are easier than others, but this doesn’t matter at Vaksman Khalfin, because we have the resources to help our clients no matter what is at stake, especially if it’s hard."
ALAN D. KHALFIN, ESQ.
Partner & Managing Attorney
"People call me when they need to plan, but also when something terrible has happened and they need help. It is personal to my clients, so it is personal to me. We have to help: no matter what."
Is Lane Splitting Legal in California?
Yes. Vehicle Code section 21658.1, effective January 1, 2017, defines lane splitting as driving a motorcycle with two wheels in contact with the ground between rows of stopped or moving vehicles in the same lane, on both divided and undivided streets, roads, and highways. California is the only state that expressly permits it. The statute sets no speed limit and no speed-differential cap — it authorizes the CHP to publish educational guidelines, which are not themselves enforceable rules.
Key Takeaways
- Lane splitting is lawful in California under Vehicle Code § 21658.1, and a rider who was splitting lanes is not automatically at fault.
- The statute contains no numeric speed limits. Guidance circulating online citing a 10 mph differential or a 30 mph ceiling reflects CHP material that was withdrawn before the statute existed.
- Under Vehicle Code § 27803, a driver and any passenger must wear a helmet meeting the state’s standard, fastened by the straps and correctly sized.
- Most California injury lawsuits must be filed within two years, with a much shorter timeline where a public entity may be involved.
- California uses pure comparative fault, so a rider found partly responsible has a recovery reduced rather than barred.
What California's Lane Splitting Statute Actually Says
Before 2017, lane splitting occupied a grey area — neither authorized nor prohibited. The California Highway Patrol publishes the statutory text, which reads:
| Subdivision | What it provides |
|---|---|
| § 21658.1(a) | Defines lane splitting as driving a motorcycle, as defined in section 400, with two wheels in contact with the ground, between rows of stopped or moving vehicles in the same lane, including on both divided and undivided streets, roads, or highways |
| § 21658.1(b) | Permits the CHP to develop educational guidelines relating to lane splitting, in a manner ensuring the safety of the motorcyclist and of the drivers and passengers around them |
Two things follow that matter to a claim. The statute contains no numbers. The frequently repeated figures — splitting no more than 10 mph faster than surrounding traffic, never above 30 mph — come from CHP guidance published in 2013 and withdrawn in 2014, before section 21658.1 existed. They are not law, and treating them as a legal standard misstates the position.
Guidelines are educational, not regulatory. CHP guidance can inform how an officer describes a collision and how an insurer or a jury assesses whether a rider was riding reasonably, but departing from it is not itself a violation.
The CHP also notes that intentionally blocking or impeding a motorcyclist in a way that could cause harm is illegal, as is opening a vehicle door to impede one, and that drivers in the far left lane should move to the left of their lane to give a passing motorcyclist room.
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How Lane Splitting Is Argued in a Claim
Because lane splitting is lawful, the fact that a rider was doing it does not establish fault. What matters is how each party was operating in the circumstances — speed, spacing, visibility, whether a driver signalled or checked before changing lanes, and what the road and traffic conditions were.
Insurers regularly argue that a splitting rider bears responsibility as a matter of course. That is an argument, not a legal conclusion, and it is answered with evidence: vehicle data, dashcam or traffic camera footage, witness accounts, and where appropriate reconstruction analysis. Whether any party was negligent depends on what that evidence shows.
California’s Helmet Requirement
California requires helmets for all riders regardless of age. Vehicle Code § 27803 provides that a driver and any passenger must wear a safety helmet meeting the requirements established under section 27802 when riding on a motorcycle, motor-driven cycle, or motorized bicycle, and makes it unlawful both to operate and to ride as a passenger otherwise.
The detail that catches people out is in subdivision (e). “Wearing a safety helmet” is defined as having a compliant helmet on the person’s head, fastened with the helmet straps, and of a size that fits the head securely without excessive lateral or vertical movement. A helmet that is unfastened, too large, or novelty rather than compliant may not satisfy the statute even though the rider was wearing something.
The section applies to riding on the highways, and it contains a narrow exception for a person operating or riding in a fully enclosed three-wheeled motor vehicle meeting specified dimensions, weight, and federal safety standards.
How Helmet Use Bears on a Claim
Where a rider was not wearing a compliant helmet, an insurer may argue that this contributed to the harm and that any recovery should be reduced accordingly. Whether that argument succeeds, and to what extent, depends on the evidence about how the injuries occurred and what difference a helmet would have made in the specific circumstances — a factual question rather than a foregone conclusion.
Two points are worth keeping separate. Helmet compliance concerns the extent of the harm, not who caused the collision; a driver who turned across a rider’s path is no less responsible because of what the rider was wearing. And a rider who was wearing a compliant helmet can still sustain serious injuries, including traumatic brain injuries, which is a separate question from whether the statute was met.
Deadlines That May Apply
| Situation | General rule | Source |
|---|---|---|
| Most injury claims against a private party | Two years from the date of injury | Code Civ. Proc., § 335.1 |
| Claims involving a public entity, including road surface and design conditions | A written claim generally must be presented to the entity before any lawsuit, on a timeline much shorter than the general two-year period | California’s Government Claims Act |
| Uninsured or underinsured motorist claims | Governed by your own policy, which commonly imposes its own notice and filing requirements | Your policy |
The public entity row matters more for motorcycles than for cars. Pavement defects, gravel, uneven surfaces at lane joins, and poorly maintained roadway edges can destabilise a motorcycle in ways that would barely register in a car, so a claim against the agency responsible for the roadway is a realistic possibility — and it runs on the shortest clock of the three.
Insurance and Why Your Own Coverage Matters
California requires proof of financial responsibility, and the state’s minimum liability limits increased on January 1, 2025. Those minimums remain modest against the cost of a serious injury, and motorcycle collisions tend to produce more significant harm than comparable collisions between enclosed vehicles.
That makes uninsured and underinsured motorist coverage on your own policy frequently more important than the at-fault driver’s limits. Insurers must offer uninsured motorist coverage in California and declining it requires a written rejection, so it is worth checking your declarations page. Our car accident page sets out the current minimum limits in detail.
Who May Be Responsible
- Another driver, and in some cases their employer where they were acting within the scope of employment
- A commercial vehicle operator or motor carrier, as covered on our truck accident page
- A rideshare driver, and in some circumstances the platform, in an Uber or Lyft collision
- A public entity responsible for a roadway or its maintenance
- A motorcycle, component, or helmet manufacturer where a defective product may have failed
- A repair or maintenance business, where work performed may have contributed
Whether any of these parties is legally responsible is a question of evidence. Identifying them early affects which insurance may apply and which deadlines govern.
Shared Fault and Damages
California follows a pure comparative fault approach: a rider found partly responsible is not barred from recovering, and the recovery is reduced by that share. Because both lane splitting and helmet arguments are used to shift responsibility onto riders, how fault is investigated and documented can matter a great deal.
There is no preset value for a motorcycle accident claim, and no attorney can promise a figure. The categories California recognizes include:
- Past and future medical expenses, including rehabilitation and ongoing care
- Lost income and reduced future earning capacity
- Property damage and related costs
- Pain, suffering, and loss of enjoyment of life
- Loss of consortium, in claims brought by a spouse
Where a collision is fatal, certain surviving family members may be able to bring a wrongful death claim, which follows its own rules about who may sue.
Motorcycle Claims in San Mateo and on the Peninsula
Our office at 15 North Ellsworth Avenue, Suite 105, San Mateo, CA 94401 serves riders injured across the Peninsula. Collisions here happen in commute traffic on US-101 and I-280, where lane splitting is routine, and on El Camino Real and the surface streets feeding it, where left turns across a rider’s path and drivers pulling out from side streets are recurring patterns. Riders on Skyline Boulevard and the roads over the coastal ridge face a different set of conditions, including surface debris and maintenance issues on routes maintained by more than one agency.
Civil matters for this area are generally heard in the San Mateo County Superior Court. Where a city, the county, or a state agency may share responsibility for a road condition, the Government Claims Act timeline applies. Details about the office are on our San Mateo page, and related explanations are in our California personal injury guides.
How Our California Motorcycle Accident Attorneys Can Help
Vaksman Khalfin, PC can investigate how the collision happened, respond to lane splitting and helmet arguments with evidence rather than concession, identify every party who may be responsible and every policy that may apply including your own UM and UIM coverage, work with treating providers to document the injury and its effects, and handle the insurers directly. Where a roadway condition may have contributed, we can assess whether a public entity claim needs to be presented and act within that shorter window. If a fair resolution is not offered, we are prepared to litigate.
The firm’s personal injury practice is led by Alan D. Khalfin and Robert B. Vaksman. We handle motorcycle cases on a contingency-fee basis: there is no upfront cost, and attorney’s fees are owed only if we recover compensation for you. To talk with a California motorcycle accident attorney, call 650-250-0705 or schedule a free consultation.
This page provides general information about California law and is not legal advice; reading it does not create an attorney-client relationship. Every case is different, and prior results do not guarantee a similar outcome.
Reviewed by Alan D. Khalfin, Partner and Managing Attorney, Vaksman Khalfin, PC (admitted in California). Last reviewed: 08/13/2026
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California Motorcycle Accident Frequently Asked Questions Frequently Asked Questions
Yes. Vehicle Code section 21658.1, effective January 1, 2017, defines lane splitting as driving a motorcycle with two wheels in contact with the ground between rows of stopped or moving vehicles in the same lane, on both divided and undivided streets, roads, and highways. California is the only state that expressly permits it.
No. Section 21658.1 sets no speed limit and no speed-differential cap. The often-repeated figures of 10 mph above surrounding traffic and a 30 mph ceiling come from CHP guidance published in 2013 and withdrawn in 2014, before the statute existed. The statute authorizes the CHP to publish educational guidelines, which are not enforceable rules.
No. Because lane splitting is lawful, doing it does not establish fault. Insurers frequently argue otherwise, but responsibility depends on how each party was operating — speed, spacing, visibility, and whether a driver signalled or checked before changing lanes. That is resolved with evidence.
Yes, for all riders regardless of age. Vehicle Code section 27803 requires a driver and any passenger to wear a safety helmet meeting the requirements established under section 27802, and makes it unlawful both to operate and to ride as a passenger without one.
Under section 27803(e), it means having a compliant helmet on your head, fastened with the helmet straps, of a size that fits securely without excessive lateral or vertical movement. A helmet that is unfastened, oversized, or a novelty item rather than a compliant one may not satisfy the statute.
Possibly. An insurer may argue that the absence of a compliant helmet contributed to the harm and that any recovery should be reduced. Whether and to what extent that argument succeeds depends on the evidence about how the injuries occurred. It also concerns the extent of the harm rather than who caused the collision.
Most personal injury lawsuits must be filed within two years of the injury under Code of Civil Procedure section 335.1. If a public entity may share responsibility — for example where a road surface condition contributed — a written claim generally must be presented to that entity first, on a much shorter timeline.
A claim against the public agency responsible for the roadway runs through California's Government Claims Act, which requires a written claim to the entity before a lawsuit and operates on a much shorter timeline than the general two-year period. Because surface conditions get repaired, documenting the location and condition early matters.
Uninsured motorist coverage may apply where the other driver has none, and underinsured motorist coverage where they have insurance but not enough to cover the harm. Given the severity typical of motorcycle collisions, this coverage is often the more significant source of recovery.
Vaksman Khalfin, PC handles motorcycle cases on a contingency-fee basis: there is no upfront cost, and attorney's fees are owed only if we recover compensation for you. Initial consultations are free.
