Motorcycle helmet and lane-splitting laws in Arizona

Arizona lets most adult riders go without a helmet, and since 2022 it lets them filter past stopped cars under a short list of conditions. Both rules surprise people, and both can shape what happens after a crash. If a car just hit you, what you were doing and what the law actually required of you can change the value of your claim. Here is what Arizona's statutes say, with the exact numbers and dates.

Who has to wear a helmet in Arizona

Arizona has a partial helmet law. Under A.R.S. § 28-964, a protective helmet is required only for a motorcycle operator or passenger who is under 18 years old.¹ Everyone 18 and over can legally ride without one. Officers can cite a 16- or 17-year-old rider who holds a license or permit, and an adult operator can be cited when an underage passenger rides unhelmeted.¹

Eye protection is a separate rule that reaches more riders. The operator has to wear approved glasses, goggles, or a transparent face shield, and that requirement drops only when the motorcycle has a protective windshield.¹ An adult can skip the helmet, but not the eye protection, unless the bike carries a windshield.

That freedom has a cost the statute doesn't mention. In 2024, ADOT recorded 219 motorcyclist deaths in Arizona out of 1,228 traffic deaths statewide.²³ The Insurance Institute for Highway Safety puts helmet effectiveness at roughly 37% to 42% for preventing death, and reports that riders without helmets are about three times as likely to suffer a traumatic brain injury.⁴ Riding without one is legal for adults. It is not the safer choice.

How a missing helmet can affect your injury claim

Arizona follows pure comparative negligence under A.R.S. § 12-2505. If you share some blame for a crash or your injuries, your damages are reduced by your percentage of fault, but your claim is not barred, even when your share is large.⁵ The narrow carve-out is that a person who intentionally, wilfully, or wantonly caused the harm gets no comparative-fault reduction in their favor.⁵

This is where the helmet question comes back. Because adults are not required to wear one, riding without a helmet is not a violation of Arizona law. An at-fault driver's insurer may still argue that a helmet would have lessened a head or facial injury and try to assign you a share of fault for that specific harm. Whether the argument gains any traction turns on the facts and your injuries, but expect it to come up, and expect it to target head-injury damages rather than the whole claim.

Lane filtering and lane splitting, which is which

People use "lane splitting" loosely, but Arizona law draws a hard line. Riding between lanes of traffic that is moving is still illegal here. What became legal is narrower: lane filtering past traffic that has already stopped.

Senate Bill 1273 added subsection (F) to A.R.S. § 28-903 and took effect on September 24, 2022.⁶ Under that subsection, the operator of a two-wheeled motorcycle may pass a vehicle stopped in the same lane and ride between lanes, but only when the move can be made safely and all of these are true:⁷

The road is divided into at least two lanes going the same direction.
The posted speed limit is 45 mph or less.
The motorcycle is traveling 15 mph or less.

The traffic being passed has to be stopped, not just slow.⁷ The rule covers two-wheeled motorcycles only, so a bike with a sidecar does not qualify.⁷ Ride outside any one of those limits, say filtering at 30 mph or slipping between cars that are still rolling, and you are back to an illegal maneuver.

What the filtering rules mean if a car hit you

Arizona is an at-fault state, so the driver who caused the crash and their insurer pay for the harm. If you were filtering within § 28-903(F) when a driver turned across you or opened a door, that legal maneuver helps your case.

If you were outside those conditions, the other side will use it. Under the pure comparative negligence rule in § 12-2505, the insurer will argue you were partly at fault for splitting moving traffic or filtering too fast and push to cut your recovery by that percentage.⁵ It rarely erases a claim on its own, because a driver who hit you usually carries most of the fault, but it can shrink the payout. Nailing down the speed, the lane, and the police narrative early matters, and Arizona crash reports are where those details live.

Deadlines and coverage to know after a motorcycle crash

You generally have two years from the date of the crash to file a personal injury lawsuit in Arizona under A.R.S. § 12-542, and the same two-year clock covers damage to the motorcycle itself.⁸ Miss it and the claim is usually gone, so this is the deadline to protect first. If your bike lost resale value even after a clean repair, that is a separate diminished value claim inside the same window.

The driver who hit you only has to carry minimum liability limits of $25,000 per person and $50,000 per crash for injuries, plus $15,000 for property damage, for policies issued or renewed on or after July 1, 2020.⁹ Motorcycle injuries routinely run past $25,000, which is why your own uninsured and underinsured motorist coverage matters. Arizona insurers must offer you UM and UIM coverage in writing at limits matching your liability limits, and you can reject it only in writing, so check your own declarations page to see what you actually bought.¹⁰

Distracted drivers are a steady threat to riders. Since January 1, 2021, A.R.S. § 28-914, the state's hands-free law, has banned holding or manually using a phone while driving, texting included, with civil penalties of $75 to $149 for a first violation and $150 to $250 for a later one.¹¹ If the driver who hit you was on a phone, that violation is evidence of negligence worth locking down.

If you were hurt in an Arizona motorcycle crash

Protect the two-year deadline, get the crash report, photograph the scene and your gear, and have your injuries documented. When the other driver blames your helmet choice or your filtering, that becomes a fight over percentages of fault, and it helps to have someone who handles Arizona motorcycle claims read the file. You can start with the legal directory to find an attorney.

This is general information about Arizona law, not legal advice.

Sources

Arizona State Legislature, A.R.S. § 28-964 (motorcycle helmet and eye protection). https://www.azleg.gov/ars/28/00964.htm
Arizona Department of Transportation, "Traffic fatalities in Arizona dip for second year in a row" (2024 Crash Facts release). https://azdot.gov/news/traffic-fatalities-arizona-dip-second-year-row
Arizona Department of Transportation, 2024 Motor Vehicle Crash Facts. https://azdot.gov/sites/default/files/2025-07/2024-Crash-Facts.pdf
Insurance Institute for Highway Safety, motorcycles topic overview. https://www.iihs.org/topics/motorcycles
Arizona State Legislature, A.R.S. § 12-2505 (comparative negligence). https://www.azleg.gov/ars/12/02505.htm
Arizona State Legislature, Senate Bill 1273, 55th Legislature, 2nd Regular Session (2022), effective September 24, 2022. https://www.azleg.gov/legtext/55leg/2R/bills/sb1273p.pdf
Arizona State Legislature, A.R.S. § 28-903(F) (lane filtering conditions). https://www.azleg.gov/ars/28/00903.htm
Arizona State Legislature, A.R.S. § 12-542 (two-year limitation for injury to person and property). https://www.azleg.gov/ars/12/00542.htm
Arizona State Legislature, A.R.S. § 28-4009 (minimum motor vehicle liability limits). https://www.azleg.gov/ars/28/04009.htm
Arizona State Legislature, A.R.S. § 20-259.01 (uninsured and underinsured motorist coverage). https://www.azleg.gov/ars/20/00259-01.htm
Arizona State Legislature, A.R.S. § 28-914 (hands-free and text-messaging ban). https://www.azleg.gov/ars/28/00914.htm

Motorcycle Helmet & Lane-Splitting Laws in Arizona