I'd like to see actual data for #2. For #3, it's not that cycling is dangerous. It's that roads and car culture are dangerous. No activity exists in a vacuum.

I'd like to see actual data for #2. For #3, it's not that cycling is dangerous. It's that roads and car culture are dangerous. No activity exists in a vacuum. And as for #1, the reason you wear a helmet is because the one time that you do fall headfirst onto concrete, the damage is life-long. It's not the frequency that you're protecting against, it's the inevitability of a fall and the potential lasting consequences. And finally, I'd like to add that I'm speaking from a San Francisco point of view.