The Mysteries of Friction

While on the way to a Scholars' Bowl tournament in Riley, KS, yesterday, the suburban I was driving hit a patch of black ice and slid off of I-70 and into the median. Praise God, no one was hurt, and the only damage to the suburban was a flat tire. The odd part about the whole situation was that I was not driving that fast, certainly not as fast as people who were passing me moments before I slid off. While we were stuck in the median waiting on a tow truck, innumerable vehicles passed along the same spot on the road, and none of them slid off the road. It's as if the black ice that we hit was no longer even there. For whatever reason, a combination of factors caused us to lose traction and slide off of the road. Friction, thou art a fickle naive.