Written and reviewed by Josh Kohanim, Esq., California Bar No. 328609 · Reviewed
In this guide
A rider who was not wearing a helmet, was wearing one an insurer now calls a novelty, or found the words no helmet in a Los Angeles collision report faces an argument with a statute behind it, a burden of proof, and a limit on what it reaches. Nothing here is a defense of riding without one. For the rest of the claim, see our Los Angeles motorcycle accident lawyer page.
The helmet rule for riders and passengers
Section 27803 says a driver and any passenger shall wear a safety helmet meeting the requirements established under section 27802 when operating or riding on a motorcycle, motor-driven cycle or motorized bicycle. It then defines wearing one, and the definition does real work: the helmet must be 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. An unbuckled helmet is not a worn helmet under this statute.
The section carries one narrow exemption, for a fully enclosed three-wheeled motor vehicle that is at least seven feet long and four feet wide, weighs at least 900 pounds unladen, and complies with the applicable federal safety standards. California is a universal helmet state, which is why national helmet-use statistics describe other states. The Insurance Institute for Highway Safety reports that in 2024, 89 percent of fatally injured motorcyclists were helmeted in states with laws covering all riders against 40 percent in states with no helmet law (IIHS Fatality Facts 2024). Those are United States figures, not California ones.
Why the label on your helmet matters
Section 27802 lets the department adopt helmet regulations and requires that they include compliance with Federal Motor Vehicle Safety Standard No. 218, codified at 49 C.F.R. section 571.218, and that a helmet be conspicuously labeled in accordance with the federal standard, which constitutes the manufacturer's certification that it conforms. The same section makes it unlawful to sell or offer for sale a helmet that does not meet the department's requirements.
What the helmet defense has to prove
Mentioning the helmet is not enough for the other side. Comparative fault is an affirmative defense, which means it has to appear in the answer, the defendant's formal response to the lawsuit, and be proved with evidence at trial. The jury hears jury instruction CACI No. 405, which reduces your damages by the percentage of responsibility the defense establishes. Civil Code section 1431.2 then makes each defendant liable for non-economic damages only in direct proportion to that defendant's own percentage of fault. It is the section that draws the line between economic damages, meaning objectively verifiable monetary losses, and non-economic damages, meaning pain, suffering and the rest.
California has no helmet instruction of its own. The closest structural model is CACI No. 712, the seat belt defense, which is written for cars and requires the defendant to prove that a reasonably careful person in the plaintiff's situation would have used the restraint, that the plaintiff did not, and that the injuries would have been avoided or less severe with it. That third element is where these arguments fail. It is a causation question, and answering it takes a physician or a biomechanical engineer willing to say that this helmet, at this impact speed and angle, would have changed this diagnosis.
| What the defense must establish | How it tries | What answers it |
|---|---|---|
| You were not wearing a conforming helmet | The collision report, the paramedic run sheet, scene photographs | Produce the helmet. An unphotographed shell in a hospital bag has ended this argument before |
| A reasonably careful rider would have worn one | The statute itself, read to the jury | Rarely contested. Concede it and move to causation |
| The injuries would have been avoided or less severe | A retained biomechanical engineer and a records review | Impact location, helmet standard test limits, and your treating neurosurgeon on the actual mechanism |
| A percentage the jury should assign | Argument at closing | CACI No. 405 requires proof, not an estimate, and the reduction applies only to the affected harm |
What the helmet argument never touches
Apportionment is the step where a jury divides responsibility for a specific harm. It is done harm by harm rather than as a single reduction across the verdict, which is why the helmet argument stops at the neck in almost every file. A rider with a femur fracture, a shattered wrist and a mild concussion has most of the claim sitting outside the defense entirely.
| Injury | Reached? | Why |
|---|---|---|
| Skull fracture or brain injury | Yes, if proved | The defense still needs a causation opinion tied to this impact |
| Facial fractures below the helmet line | Sometimes | Depends on helmet type. A half helmet covers less than a full face |
| Cervical spine injury | Disputed | Helmet mass and neck loading are argued both ways by engineers |
| Femur, tibia, wrist and pelvis fractures | No | A helmet would not have prevented any of it |
| Road rash, degloving and scarring below the head | No | Outside the protected area entirely |
| Lost wages and future earning capacity | Only through the head injury | Economic loss follows the injury it flows from |
When the helmet argument breaks down
- You were wearing one and it worked. A cracked shell is proof of the forces involved and answers the low-impact argument better than any description of it. Keep it, in the condition it is in.
- The helmet is gone. Emergency departments cut gear off and discard it. Without the physical helmet the defense is arguing from a report line, and so is everyone else.
- The strap was undone. Section 27803 requires it fastened, so expect the argument. It is still a causation question, and an unbuckled helmet that stayed on through the impact did its job.
- A passenger claim. The statute covers passengers, and CACI No. 711 puts a duty of ordinary care on a passenger for her own safety. A passenger who was handed a helmet and declined it is in a different position from one who was never offered one.
- The head injury is the whole case. Here the argument is worth real money to the defense, and it is the one file where retaining a neurosurgeon and a biomechanical engineer early is not optional.
- You were cited under 27803. A citation establishes only that you were cited. It says nothing about whether a helmet would have changed the diagnosis, which is the only question that reduces anything.
When the report says no helmet
- Find the helmet before anyone throws it away. Ask the hospital, the tow yard and whoever collected your property, in that order, and photograph it from every side including the label inside the shell.
- Give no recorded statement about it. The insurer's first call is designed to get you describing gear rather than describing the driver's turn.
- Separate your injuries on paper. List what is above the neck and what is not. The second list is untouched by the argument, and it is usually the longer one.
- Get the mechanism from the treating physicians. A surgeon's note on how the injury happened is worth more than a retained opinion produced two years later.
- Correct the report if it is wrong. Officers record what they saw at a chaotic scene. A supplemental report and a witness who saw the helmet come off on impact both go in the file.
Two neighboring arguments arrive with this one. If the insurer is also blaming your lane position, our lane splitting accidents page shows why no statute supports that. If the helmet argument is aimed at a head injury, the valuation question moves to future care and lost capacity, which our motorcycle accident settlements page maps by jury instruction, and our Los Angeles brain injury attorney page covers the medicine and the proof.
No fee unless we recover.