Remember kids... always wear a helmet. (The almighty bikeradar helmet thread)

The way I see it, youre going up a road, suddenly a car pulls out infront of you without looking, you break, but the momentum plunges your front wheel into the side of the car and you flip over the bonnet.

If you weren't wearing a helmet the driver might have seen a fellow human being approaching and waited
You could learn a lesson from the disaster that was motorcycle helmet compulsion, that has caused more deaths than it ever saved