Wednesday, 17 March 2010

Ghost Jams

via Lester, a nice video showing ghost jams in action

See New Scientist for more.

The drivers were asked to drive around at a constant speed. For a while this works OK, eventually a ghost jam develops and propagates at the same speed that they're observed in real traffic. I don't know if they tried to apply any external stimulus to see if they could guide it better.


  1. It looks like something I've done. I'm not sure if you ever read this article:

    I believe this explains the origin of spontaneous symmetry breaking. :)

  2. No, haven't read it. Looks very interesting - will check it out as soon as I can get on the university VPN (bring on open access!).

    Need to learn more about these dynamic transitions in general. Seems really cool because you can't have 1d phase transitions at equilibrium.

  3. Yes it is. I had spent couple of years focusing on this type of system for my master thesis, they are fascinating! If you are intrested in these type of systems, except for the Bando's car following model, you can try to search hydrodynamical model and celllular automata model for traffic system; and it turns out to certain limit they are pretty much equivalent. :)

  4. Finally got around to reading the PRE - it's really good! Very simple model with all the assumptions laid out clearly. I'm interested to follow the story where there is a distribution of the drivers sensitivities (the a parameter), rather than say a perturbation in the positions of the cars. I guess this is a big complication from the neat simple picture though.

    Anyway, all good stuff. Maybe I'll pick through the 500 forward citations (!) to see about the sensitivity thing - might take a while...