California motorcycle rules — lane splitting & helmet law

Q: Is lane splitting legal in California?

Yes. Vehicle Code §21658.1 — added by AB 51 and effective January 1, 2017 — expressly permits it, making California the only U.S. state to do so. The statute defines lane splitting as riding a two-wheeled motorcycle between rows of stopped or moving vehicles in the same lane, and it sets no speed limit ; the CHP publishes separate safety guidance.

Q: Is there a speed limit for lane splitting?

Not in the law. §21658.1 sets no speed cap and no speed-differential limit . The commonly cited figures — about 30 mph, and no more than 10–15 mph faster than surrounding traffic — are CHP safety guidance , not statutory limits. Ordinary posted speed limits and reckless- or unsafe-driving laws still apply.

Q: Does California require a motorcycle helmet?

Yes. Vehicle Code §27803 requires every rider and passenger, of any age, to wear a properly fastened helmet meeting the U.S. DOT (FMVSS 218) standard. There is no adult exemption , and it is a primary offense — an officer can stop and cite a rider for it alone.

Quick facts TL;DR · 5 bullets

✓ California is the only U.S. state that expressly permits lane splitting — legal since January 1, 2017 under Vehicle Code §21658.1 (added by AB 51).

✓ The statute sets no speed limit and no speed-differential cap. The often-quoted "about 30 mph" and "10–15 mph faster than traffic" figures are CHP safety guidance, not law.

✓ California's helmet law (§27803) requires every rider and passenger, of any age, to wear a properly fastened DOT-compliant helmet — with no adult exemption, and it's a primary offense.

✓ Riding on the shoulder is not lane splitting and is not permitted.

✓ This page describes the riding rules; being licensed to ride — the permit, CMSP, and tests — is the motorcycle license guide.

Lane splitting Legal (CVC §21658.1)

Speed limit in the law None — CHP figures are guidance

Legal since Jan 1, 2017 (AB 51)

Helmet Required — all riders & passengers

Helmet standard DOT-compliant (§27803)

This page covers the rules of riding a motorcycle in California — lane splitting, the helmet law, and the basic equipment the Vehicle Code requires. It describes what the law says and what the CHP recommends; it doesn’t tell you how to ride. Getting licensed to ride — the permit, the CMSP course, and the tests — is a separate topic, covered in the motorcycle license guide (which also has the instruction-permit limits: no passengers, no freeway, no night riding).

Lane splitting is legal in California

California is the only U.S. state that expressly authorizes lane splitting. Vehicle Code §21658.1, added by AB 51 and effective January 1, 2017, both defines it and permits it.

The statute defines lane splitting as riding a two-wheeled motorcycle between rows of stopped or moving vehicles in the same lane, on any divided or undivided road or highway. The same law directs the CHP to develop lane-splitting safety guidance — an educational role, not a rule-making one.

Before 2017, lane splitting sat in a legal gray area: not prohibited, not expressly allowed. AB 51 removed the ambiguity by writing it into the Vehicle Code.

The law versus CHP safety guidance

This is the distinction most write-ups get wrong. The law (§21658.1) permits lane splitting but sets no speed limit and no cap on how much faster a rider may travel than the vehicles around them.

The figures that circulate — riding at no more than about 30 mph while splitting, and no more than 10–15 mph faster than surrounding traffic — come from CHP safety guidance, not the Vehicle Code. They are recommendations the CHP has published to reduce risk. They are not legal speed limits for lane splitting, and this page presents them as guidance rather than law. Ordinary posted speed limits, and the laws against reckless or unsafe driving, apply to a rider the same as anyone else.

Helmet law

Vehicle Code §27803 requires every motorcycle rider and passenger to wear a safety helmet that meets the U.S. Department of Transportation standard (FMVSS 218), properly fastened with the chin strap. It applies to all ages — there is no adult exemption — and it covers motorcycles, motor-driven cycles, and motorized bicycles.

It is a primary offense, meaning an officer can stop and cite a rider for a helmet violation on its own, without any other reason for the stop. A non-compliant “novelty” helmet that doesn’t meet the DOT standard does not satisfy the law.

Required equipment

California law also sets baseline equipment for a street-legal motorcycle. In brief:

At least one rear-view mirror (§26709).
A passenger seat and footrests if a passenger is carried, with the passenger seated behind or beside the driver (§27800–§27801).
Turn signals on motorcycles manufactured in 1973 or later.
A muffler kept within the noise limits (§27202); a modified exhaust that exceeds them is not street-legal.
Handlebars no higher than the rider’s shoulder height.

The full equipment list, along with the CHP’s lane-splitting safety tips, is in the California Motorcycle Handbook (DL 665).

Special cases

Lane splitting vs. lane filtering

Lane splitting means riding between rows of stopped or moving vehicles — what §21658.1 authorizes. "Lane filtering" usually describes moving between stopped or slow traffic and is the term some other states use; California's statute uses the broader lane-splitting definition.

The shoulder is not a lane

Riding on the shoulder, or between traffic and the edge of the road, is not lane splitting and is not permitted. Lane splitting happens between rows of vehicles within the roadway.

The speed figures are guidance, not law

The "about 30 mph" and "10–15 mph faster than traffic" numbers are CHP safety recommendations. The Vehicle Code sets no numeric limit, so those figures are not enforceable speed thresholds for lane splitting itself — though ordinary speed limits and reckless-driving laws still apply.

Frequently asked questions

Is lane splitting legal in California?

Yes. Vehicle Code §21658.1 — added by AB 51 and effective January 1, 2017 — expressly permits it, making California the only U.S. state to do so. The statute defines lane splitting as riding a two-wheeled motorcycle between rows of stopped or moving vehicles in the same lane, and it sets no speed limit; the CHP publishes separate safety guidance.

Is there a speed limit for lane splitting?

Not in the law. §21658.1 sets no speed cap and no speed-differential limit. The commonly cited figures — about 30 mph, and no more than 10–15 mph faster than surrounding traffic — are CHP safety guidance, not statutory limits. Ordinary posted speed limits and reckless- or unsafe-driving laws still apply.

Does California require a motorcycle helmet?

Yes. Vehicle Code §27803 requires every rider and passenger, of any age, to wear a properly fastened helmet meeting the U.S. DOT (FMVSS 218) standard. There is no adult exemption, and it is a primary offense — an officer can stop and cite a rider for it alone.

Can I lane split on the shoulder or between traffic and the curb?

No. That is not lane splitting and is not permitted. Lane splitting is riding between rows of vehicles within the roadway; the shoulder is not a traffic lane.

Is lane splitting the same as lane filtering?

They're related but not identical. "Filtering" usually refers to moving through stopped or slow traffic, while California's §21658.1 uses the broader lane-splitting definition — between stopped or moving vehicles.

Related guides

Other guides readers of this page also use.

How to get a motorcycle license Permit, CMSP, skills test — the licensing side Class M motorcycle license M1 vs M2 defined Road signs & signals The rules-of-the-road study guide Registration by vehicle type The motorcycle-as-vehicle side

About this guide

Published by

DMVCA· an independent California DMV information publisher

Fact-checking

Fact-checked against primary sources — the California Vehicle Code, DMV publications, and government sources — and cited on the page.

Update cadence

Reviewed quarterly and after any federal or state policy change.

Sources. California Vehicle Code §21658.1 (lane splitting) · California Vehicle Code §27803 (helmet requirement) · California Vehicle Code §26709 (mirrors) · California Highway Patrol — California Motorcyclist Safety Program (lane-splitting guidance) · California Motorcycle Handbook (DL 665)

Last verified July 16, 2026 · reviewed quarterly and after any policy change.