This happened to me the second day I rode using clipless pedals/cleated shoes. I thought I heard something drop from my bike, and came to a quick stop, before releasing a foot. Duh!! I slowly toppled over toward the right, landing on a very gravelly road. My right leg and knee were pretty scraped up, with rivulets of blood running down into my nice new bike socks. I had fun picking the pebbles out of my skin....

I don't know any way to prevent this other than just being more careful and getting more mileage. I'm just very conscious now about my surroundings, and when in doubt, I release a foot. It's easy enough to slip it back in when conditions warrant.

That was a month ago, and the scabs are just now truly gone. The skin is still pink and raw-looking. I think I had permanently scabby knees as a kid, so maybe this is just my second childhood.