Check your cleats and tighten them before leaving the house! I've never given it a thought and today one of them fell out unknowingly to myself, so when I went to step out at at the train crossing and my foot was viced to the pedal. Tipped over right in the middle of the road and couldn't get the cleat out or get up. A big dump truck came up behind me, but stopped well enough away. I ended up sort of crawling off the road as best I could with the bike on top off me. Dudes came out because they thought I was messed up after getting hit or something. Once they helped me get on my feet, I was able to pull my foot of the pedal. It was pretty dark, but I've got flashers or I think I would have been squashed. It happened at kind of a blind turn where most of the vehicle traffic is big dump trucks and big 18 wheeler dumpers. Anywho.. learn from my mistake. Check your cleats often.