An overview of California's bicycle laws, reviewed and cited to primary sources. Use the sections below to jump to a specific rule, or the Sources block at the end for the full citation list.
This guide is for general information only and is not legal advice. Laws change — verify current rules with your state DOT or a licensed attorney before relying on this for any legal matter. Read full disclaimer.
Helmet rules
Required under age
Required under age 18
Applies to passengers
Yes
Standard
CPSC
Penalty
Fine of up to $25 for a first offense; courts often waive or reduce the fine on proof of helmet purchase and completion of a bicycle-safety course.
No statewide rule. Cal. Veh. Code § 21206 expressly authorises cities and counties to regulate bicycle operation on sidewalks. San Francisco prohibits sidewalk riding by anyone aged 13 or older (S.F. Transp. Code § 7.2.12); Los Angeles permits it except where it endangers pedestrians; San Diego bans it in business districts. Always check the local municipal code.
California prosecutes cycling under the influence under a separate statute (CVC § 21200.5) rather than the standard auto DUI law (CVC § 23152). Maximum fine of $250 with no jail time. The offense is not a DUI conviction, so it does not trigger an automatic driver-licence suspension; courts may, however, refer riders under 21 to the DMV for a discretionary licence review.
White lamp on the front, visible from a distance of 300 feet to the front and from the sides of the bicycle.
Rear requirement
Rear reflector or light
Rear spec
Red reflector — or a solid or flashing red light with a built-in reflector — on the rear, visible from 500 feet when directly in front of lawful upper-beam headlamps. Side reflectors are required on each side: white or yellow forward of center, red or white rear of center. Pedal reflectors (white or yellow) are required on the front and back of each pedal, or equivalent reflective material on the rider's shoes or ankles.
California has no statutory two-abreast cap for bicycles. The general lane-position rule under Cal. Veh. Code § 21202 ('as close as practicable to the right-hand curb') applies; group rides commonly default to single file in narrow lanes and two abreast where the lane is wide enough to share.
Cal. Veh. Code § 21960 authorises Caltrans and local authorities to prohibit pedestrians, bicycles, and motor-driven cycles on any freeway or expressway by sign. In practice, every urban Interstate segment in California is signed prohibited; many rural Interstate shoulders (notably parts of I-5, I-8, I-10, I-15, I-40, and I-80) are signed open. Always check the Caltrans bicycle-on-freeways map for the specific corridor before riding.