[direwolf20]

And there are countries where everyone rides a bike, and they are not usually the ones with mandatory helmets. When you hit someone with a bike you are less likely to kill them than when you hit them with a car, so more bike riding means less deaths, without even considering the effects of air pollution.

Helmets are fine for sport riding, but inconvenient if you want to ride 5 minutes to the shops on a whim. And that kind of riding is usually less intense and safer, I presume, anyway. Football has helmets, walking doesn't.

[bluGill]

Those countries also have a higher number of brain injury cases vs countries where people wear helmets.

If you are hit by a car a helmet will do approximately nothing. However there are a lot of accidents that happen where you are not hit by a car where a helmet will help. (and even more when knee and elbow pads are what you need)

[direwolf20]

What if you're hit by a bike instead of a car because someone took the bike instead of the car?

[bluGill]

A helmet can make a big difference in saving your brain if you are hit by a bike. Or if you hit a slippery spot and fall off your bike. Or - hundreds of other things that happen.

cars are too big and heavy for a helmet to make a difference - but they are not all that can go wrong. Even in car heavy US there is more than a car that can harm you.

[direwolf20]

Got it — helmets should be mandatory for pedestrians, in case they are hit by bikes.

[gtr]

Well unironically you would be safer if you did that! Although it's a trade off between looking ridiculous and being safe. I personally don't think bike helmets should be mandatory because it puts people off riding a bike (including me), but do acknowledge that they do make an individual safer.