astro
June 13, 2009, 2:32pm
1
Math model may decrease phantom traffic jams
Some traffic jams have no apparent cause — no accident, no stalled vehicle, no lanes closed for construction. There is no easy way out of these maddening messes once you’re stuck in them, but a new study has figured out how to reduce the odds of them forming at all.
These phantom jams can form when there is a heavy volume of cars on the road. In that high density of traffic, small disturbances (a driver hitting the brake too hard, or getting too close to another car) can quickly become amplified into a full-blown, self-sustaining traffic jam.
A team of MIT mathematicians has developed a model that describes how and under what conditions such jams form, which could help road designers minimize the odds of their formation.
‘Jamitons’ — how they form and spread
The equations, similar to those used to describe fluid mechanics, model traffic jams as a self-sustaining wave. Variables such as traffic speed and traffic density are used to calculate the conditions under which a jamiton will form and how fast it will spread.
Oh man, I hate those. In Washington there’s a spot on southbound I-5 between Marysville and Everett where these “phantom” traffic jams are disturbingly common. There are no offramps or onramps on this stretch, no changes to the number of lanes, nothing that would explain the fact that nearly every time I drive through there, traffic slows to a crawl for about half a mile or so. The jam always disappears before actually hitting Everett, too - so it’s not like the pressure was relieved by any vehicles exiting the freeway.
Interesting article, anyhow.
Thudlow_Boink:
Aslan
I always knew it was actually infrastructure planning that Lewis was writing about.
That’s cool but I’m not sure what the solution would be other than on ramp stop and go signals, which we already have.