This is what drives me nuts:
"The next time a traffic jam materializes in front of you for no apparent reason, think about Japan. That’s where scientists have, for the first time, recreated “shockwave” traffic jams, in which one driver’s slowing down creates a ripple effect that moves backwards through traffic, grinding everything to a halt for miles."
It especially happens when you have merge lanes and bridges. You're driving normally then suddenly it's a parking lot. You look ahead and you see people crawling along on the bridge, 5 car lengths behind the guy in front, for no apparent reason. Then you finally get to the bridge and it's clear sailing.