If you've ever encountered a "phantom traffic jam" or traffic slowdown that doesn't seem to have an apparent cause, it was probably some jackwagon tailgating somebody. Researchers at MIT found that not only does tailgating not get you anywhere faster, it actually creates traffic jams that shouldn't exist.
Photo by Leeann Cafferata.
Tailgating, or the act of driving so closely behind someone you could write "wash me" in the dirt on their rear window, has always been rude (not to mention unsafe). At best the car in front of you will speed up a little in fear of being road rage murdered, but more than likely you'll just look like an impatient jerk.
And what's worse is you're making things less convenient for yourself and every other driver in your lane, says MIT professor Berthold Horn and postdoctoral associate Liang Wang. In order for traffic to keep moving smoothly, Horn says cars need to be evenly spaced on the road:
"Our work shows that, if drivers all keep an equal distance between the cars on either side of them [front and back], such 'perturbations' would disappear as they travel down a line of traffic, rather than amplify to create a traffic jam..."
Here's a nifty animated graphic to explain what happens:
via CSAIL / MIT
Basically, when you tailgate, you remove your ability to slow down gradually in the event a car up ahead reduces its speed. Because you have less time to react and avoid rear-ending the car in front of you, you hit the brakes hard and take away all of your vehicle's momentum in an instant.
All the cars behind you then have to slow down quickly as well while you build up speed again. It causes a chain reaction that eventually brings traffic to a crawl -- or causes accidents -- for no good reason.
Of course, Horn and Wang are very aware people aren't going to stop tailgating or pay more attention to the space between themselves and other vehicles, so they hope adding features to future vehicles can fix the problem. By implementing what they call "bilateral control" into adaptive cruise-control systems, phantom traffic jams may become a thing of the past.
They estimate drivers may even be able to get somewhere nearly twice as fast. Until then, give yourself plenty of space between you and the car ahead as best you can. It benefits everybody on the road.