Good luck with that...................... Indeed, and this is where the issue becomes more nuanced than simply asking who caused the collision. Consider two otherwise identical accidents. In the first, a motorcyclist pulls out in front of a car, is struck, falls, and suffers catastrophic brain injuries because he was not wearing a helmet. In the second, the same collision occurs, but the rider is wearing a properly rated helmet. He walks away with little more than bruises and a headache. The mechanism of the accident is identical. The difference in outcome is not. The question then becomes: who is responsible for the additional injury? The collision may have caused the rider to fall, but it was the decision to ride without adequate head protection that transformed a survivable accident into a life-changing one. The same principle applies even where the motorist is deemed at fault. If a driver makes a mistake and clips a motorcycle, are they responsible for the collision itself, or are they also responsible for every additional injury that results from the rider choosing to ignore basic safety laws? At some point, personal responsibility has to enter the equation. A rider who chooses not to wear a helmet or wear an non-conforming helmet is not merely accepting a risk to himself. He is increasing the potential consequences of any accident, regardless of who causes it. That is why helmet laws exist in the first place. They do not prevent collisions; they reduce the severity of the outcome. Without a helmet, the rider is operating illegally and knowingly exposing himself to a substantially greater risk of serious injury. Even where another party contributes to an accident, it is difficult to argue that they should bear full responsibility for injuries that would likely have been prevented, or significantly reduced, had the rider complied with the law. The same argument extends, albeit less clearly, to novelty helmets, poor-quality helmets, or helmets that fail to meet recognised safety standards. The principle remains the same: if an individual voluntarily removes a layer of protection designed specifically to prevent catastrophic injury, they must bear some responsibility for the consequences when that protection is needed. In many Western countries this debate rarely arises because helmet compliance is largely taken for granted. The assumption is that road users are complying with basic safety requirements, and liability is assessed within that framework. Where widespread non-compliance exists, however, it becomes harder to ignore the distinction between responsibility for causing an accident and responsibility for the severity of the injuries that follow. So - where you say good luck with that - I'd agree..... But I'd be wishing the guy with a 350 baht helmet far more luck, not to end up smashing his head in the first place.