These destroyed helmets did exactly what they were designed to do. They were ruined, and my head was not.
I was riding with a group approximately in the middle of nowhere, and made a bad downhill turn ... I thought I must have hit gravel, but my fellow riders didn't see any, so it was probably just poor bike handling skills in my second year of recreational riding. In any case the front wheel slid out and I went down, receiving a broken collar bone, bruised ribs, and no damage at all to head. Road rash was confined to my legs. The helmet surface lost some skin, but my scalp didn't. The helmet cracked, but my skull didn't. That's the way it's supposed to work.
So I bought a new helmet, which lasted until ...
Commuting to work, my front tire suddenly lost pressure just as I entered a downhill curve at about 30. I remember the whoosh of air escaping, and then trying to slow ... and then laying on the ground, thinking that moving out of the street would probably be a good idea, and how did that work again?
I don't think I was out cold, but the back, left part of my head slammed the pavement pretty hard. I was disoriented for at least a few moments, and seem not to have formed a long-term memory of the last seconds before the crash. The back of the helmet is completely smashed. I noticed a small bruise on my head today, but most of the pain is from extensive road rash, another broken collar bone, and a bruised rib. If I were not wearing a helmet (cinched up properly so that the back of my head was protected) this might well have been a life-threatening accident. At the very least I would be hospitalized for some time, because there is no way my skull would be intact.
At the very end of September, on my commute to work, I stopped at the light on Alder at 18th. Bicycle traffic at this intersection is two way, but car traffic is one way only, which can confuse drivers. A car waited at the light to enter from the North, and I waited at the light to cross from South to North. When the light turned, we both entered ... the driver looked right, turned left, and popped me. My bike was totaled, my collarbone was broken again, and I got some really colorful bruises on my upper body. The main impact was with the car, followed by a drop to the pavement. My helmet smacked the ground and protected my head perfectly, earning retirement after only a couple months of use. My bicycle took early retirement too.
The helmet I bought after my September 2006 crash is now more than three years old, and ready for replacement. (Helmets should be replaced before their materials degenerate from age.) I am pleased to once more be retiring a helmet without an accident, and I hope I am able to retire the next one in the same manner.