* * * * *
                                        
                            Traffic jams just happen
                                        
I've been aware of “traffic waves [1]” for several years now and the animated
graphics on the site do illustrate the issue, but now it seems that Japanese
researches have actually created “traffic waves” on a closed course:

> Researchers from several Japanese universities managed the feat by putting
> 22 vehicles on a 230-metre single-lane circuit (see video).
> 
> They asked drivers to cruise steadily at 30 kilometres per hour, and at
> first the traffic moved freely. But small fluctuations soon appeared in
> distances between cars, breaking down the free flow, until finally a
> cluster of several vehicles was forced to stop completely for a moment.
> 
> That cluster spread backwards through the traffic like a shockwave. Every
> time a vehicle at the front of the cluster was able to escape at up to 40
> km/h, another vehicle joined the back of the jam.
> 
> The shockwave jam travelled backwards through the ring of vehicles at
> roughly 20 km/h, which is the same as the speed of the shockwave jams
> observed on roads in real life, says lead researcher Yuki Sugiyama [2], a
> physicist in the department of complex systems at Nagoya University.
> 

Via Hacker News [3], “Shockwave traffic jam recreated for first time - tech -
04 March 2008 - New Scientist [4]”

The video of the “traffic waves” [5] (called “shockwave traffice jams” in the
video) is fascinating to watch as the “traffic wave” just kind of happens.

[1] http://trafficwaves.org/
[2] http://traffic.phys.cs.is.nagoya-/
[3] http://news.ycombinator.com/item?id=785259
[4] http://www.newscientist.com/article/dn13402
[5] http://www.youtube.com/watch?v=Suugn-

Email Sean Conner at sean@conman.org

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