Certainly, there's a libertarian argument made against requiring seat belt use, including mathematical economics models that can prove it... provided a few unst

Certainly, there's a libertarian argument made against requiring seat belt use, including mathematical economics models that can prove it... provided a few unstated assumptions are met--like rational agents, complete information, perfect competition, etc... Of course, the problem is that those assumptions aren't met. If someone is more seriously injured in a car crash because they weren't wearing a seat belt, the cost of that is going to be borne by society at large in a variety of ways. A more serious accident is going to consume more Police and EMS resources. The increased hospital and resulting medical costs will be shared by millions of people through (even private) insurance companies. If the person dies, the investment the public made in the person's education is lost, etc... The response to these points from libertarians is typically to propose a system where someone can chose not to be bound by this rule, and pay the price in increased health care/disability premiums or something. But these systems ignore significant information and transaction cost problems. The person makes a statement about whether or not they want to be bound by a seat belt rule, but how is that information verified? (People lie...) If it's just a contract term, not a law, if someone is pulled over for speeding and wasn't wearing a seat belt, do the police ticket the driver for violating the contract? If someone who says they want to follow the seat belt rule is unlucky enough to just forget it the day they got into an accident, do we just let them die? If a crash victim comes into the hospital unconscious, do they verify seat belt contract compliance with the insurance company before spending money on life-saving treatment? Or do they treat the person only if they'll be able to pay out of pocket? The whole system is full of costs, complexities, and moral hazard--it's a mess. It's SO much simpler and less costly just to have a seat belt law that applies to everyone. Sure, a few people will find it a little paternalistic and annoying, but the other way is a lot worse. We might be willing to deal with a more complex and expensive system if the rule is very intrusive or highly restrictive of personal liberty. Being able to drive without seat belts isn't worth it.