I have seen a few collisions on my commutes, usually on the major roads. As a rule I don't tend to take main thoroughfares.
My commute was thwarted this morning when my freewheel suddenly and then intermittently not engaging. It happened the 3km mark. Fortunately I was able to get it engaged long enough to 'limp' home. I could have taken one of my other bikes, but with a light dusting of snow on the roads I didn't feel right about riding on slick tires. Oh well.
Stay safe out there.