When I got hit by a guy's trailer last Sunday while riding at 40 mph, my helmet took most of the impact when I hit the road.

Thankfully, the helmet did its job and dispersed the energy that would have been transmitted to my skull. I didn't get knocked out, nor did my pretty bald head end up with a bunch of nasty road rash.



What's not shown is the cracked and buckled styrofoam pieces on the inside of the helmet.

FWIW, this is the second helmet I've wrecked (the previous was about 10 years ago in a mountain bike accident).

Based on my personal experience, helmets work. They may not be perfect (nothing is), but they're cheap insurance, and they do their job in most accident scenarios.