It’s been quite a few years since I drove to work, but I certainly recall the frustration of unexexpected and seemingly cause-less jams… seems we just suck at driving and that our cars will eventually handle the load for us through an adaptive cruise control.
A little more than a decade ago, scientists realized that vehicles behave like molecules in a gas. In the most notorious similarity, cars ahead of you that stop or merely slow down can cause a compression wave — a patch where the cars are jam-packed — to propagate backward until it reaches you. The wave can persist for hours after the initial bunch of cars hit their brakes, with the result that drivers who never saw that deceleration are totally clueless about why they aren’t moving. An estimated 75% of traffic jams are like this, having no visible cause. [WSJ.com (sub required)]