[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.