There's no doubt that the belt played a role in reducing your injuries.

But you'd then argue being able to keep your foot on the brake doesn't help your chances of avoiding causing injury/death to others?

If you're hit from the side, you were already traveling forward.

Er, so? If you're hit hard from the side with no seat belt, your whole body is likely to be thrown around and keeping your foot on the brake is going to be far more difficult. Sorry but this does seem like a pointless discussion - if you were somehow able to prove that seatbelts basically never helped drivers avoid causing injuries/deaths to others then I'd agree a $50 fine is probably sufficient. But given what I've seen in this thread and elsewhere (including direct personal experience), seatbelts most definitely do help with that, and a fine + license suspension seems quite justified if you're caught driving without one (in Australia the fine is $550 plus a loss of 4 "demerit points" - lose 12 and your license is suspended. Seems a bit soft to me - the penalty for driving at 60k/h in a 50 zone is about the same.)

> if you were somehow able to prove that seatbelts basically never helped drivers avoid causing injuries/deaths to others

I'm not arguing it never happened. I'm suggesting it doesn't happen often enough to be a major factor in seatbelt laws. Laws addressing highly unlikely events often don't take into account other effects.

For example, when seatbelt laws were proposed, many people reported that they were saved from certain death by being thrown from their car. For example, if the car caught fire. Or the car went off a steep embankment. I don't recall any anecdotes about thrown people causing other accidents.

"Laws addressing highly unlikely events often don't take into account other effects." Agree 100%, but I'm not convinced you could call such events "highly unlikely". I don't have enough data to say.

I don't have data, either. But I do recall the debates about making seatbelts the law. The talk was always about whether one was safer being thrown from a car than staying in the car. I never heard mention about being thrown from a car causing another accident.

After the law passed, I heard many people say they wouldn't wear the belt out of fear of being trapped in a burning car.

It's just that these discussions have been completely forgotten since, and the assumption is that seatbelts are always better.

I wear a seatbelt because the odds are better. I'm aware there are cases where it isn't.