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Traffic Sim Predicts Jams Before They Happen

Posted by simoniker on from the driving-in-your-jam-jar dept.

Via_Patrino writes "The New Scientist reports that: A traffic simulation system is helping drivers by predicting jams up to an hour before they happen. Traffic flow can be divided into three categories: freely flowing, jammed, and an intermediate state called synchronised flow in which dense traffic moves in unison. Physicists at University of Duisburg-Essen have developed 'the first model to reproduce all known traffic states.' Predicted conditions are displayed on the official website, and more than 90 per cent of the time, traffic density is predicted correctly."

29 of 218 comments (clear)

  1. What if people start using it? by Zebidiah · · Score: 5, Interesting

    What if people start using it? They avoid the traffic jams, thus no traffic jams. Wrong prediction!

    1. Re:What if people start using it? by mphase · · Score: 4, Funny

      Good point. It only applies if a large portion of the potential traffic was aware of the prediction but still a good point. It's not a matter of being a right or wrong prediciton though, it's a matter or decreasing traffic. If it makes it so people get stuck in traffic less than it is a success. The statistic of being "right" or "wrong" in its prediciton is pointless. Though obviously if every damn person was aware of it the predicted traffic would become the perfect driving conditions because everyone would avoid that area. So then people would start to purposefuly drive in the areas the system said would have heavy traffic, knowing that everyone else would avoid it. But then because so many people did that there would be traffic and so people would learn to avoid the areas...repeat until you come to the topic of a land war in China.

      --
      vampirical
  2. What is the cause? by lachlan76 · · Score: 3, Insightful

    But the system still wouldn't be able to predict traffic jams caused by accidents and cars breaking down, so it wouldn't be perfect. And if everyone reads when there will be a jam, no-one will drive then, and the traffic jam will be at a different time.

    1. Re:What is the cause? by skraps · · Score: 5, Insightful
      And if everyone reads when there will be a jam, no-one will drive then, and the traffic jam will be at a different time.
      Presumably, this is a closed-loop system, with a short loop. The predictions are based on very recent, near real-time data. If the traffic is affected by people reading the predictions, then the predictions would adjust to compensate very quickly.
      --
      Karma: -2147483648 (Mostly affected by integer overflow)
    2. Re:What is the cause? by Wastl · · Score: 3, Informative
      Accidents can (probably) be predicted with probabilities. Assuming that you have "synchronized traffic" of a certain length, it is (probably) very likely that an accident happens.

      Besides, as far as I understand, the system currently only considers highways, which (at least in Germany) have at least dual carriage ways. If the traffic is not dense, most accidents or break downs do not cause jams, as the traffic simply passes by.

      Sebastian

    3. Re:What is the cause? by Trent05 · · Score: 3, Interesting

      Good call.

      I'm sure only a small pecentage of people would be checking the website. Heck, in my town they publish where the sobriety checkpoints are going to be set up for the weekends and holidays, and the cops STILL have a bumper crop of DUI/OMVI arrests.

      Oh well, I guess it pays to pay attention...and drink at home.

      --


      --
      The Marines: The few, the proud, the not very bright. - Slashdot tagline 04/21/05
    4. Re:What is the cause? by s.fontinalis · · Score: 3, Funny

      On American Motorways the probability of a vehicle breaking down in the traffic lanes is directly proportional to the nearness of a major holiday, as is the ability of the driver to shift the vehicle from the travel lanes.

    5. Re:What is the cause? by Bozdune · · Score: 4, Interesting

      Right.

      Note that this system is infinitely better than the radio "traffic reports," like those in Boston on 1030 WBZ. The announcers already know from experience where all the slowdowns are likely to be, so they just repeat the same B.S. every morning, true or false, until they get lucky and their helicopter spots something, or the State Police radio in an accident.

      I used to commute the Mass Pike eastbound from 495 into 128/95, and I can count on the fingers of one hand the times that the "traffic report" was actually accurate.

      As far as people paying attention to the web site and changing their route based on 30 minute or 60 minute advanced prediction, thus screwing up the "prediction," that's only an issue if you need advance warning before you leave the house. What's really needed is a real-time decision when you come up against a junction point. Which way? Tell me now. Should be easy enough to do with a real-time feed from your car to the model.

      Not that there's that many obvious alternate route choices around Boston anyway, but it sure would be helpful to have precise information on the jam-ups for those of us who know the back roads.

  3. Hooks law by Anonymous Coward · · Score: 5, Interesting

    I remember a few years ago being told by a teacher that traffic flowing under 28mph on Motorways obeys hooks laws for compression waves travelling through a spring almost perfectly...

    The compression waves travelling through the traffic are the reason that everything goes stop/start once traffic slows below a certain speed...

  4. A note by pyth · · Score: 4, Insightful

    For those people concerned that releasing the predictions will interfere with the results, please remember that not many people will actually use this tool.

  5. This is one of my pet peaves by rsilvergun · · Score: 4, Interesting

    I hate seeing people speeding to red lights, when if they'd just follow the flow of traffic and the lights they'd get where they're going just as fast, and without causing traffic jams. I'm a terrible driver, but I figured this simple thing out pretty early on. Why can't the rest of drivers?

    --
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    1. Re:This is one of my pet peaves by willpall · · Score: 5, Interesting
      Or a corollary to that:

      I drive a stickshift and consequently cannot stand stop n' go traffic on a freeway. So I even it out and am able to maintain a consistent speed regardles of the sporadic flow ahead of me. This of course pisses off the person behind me because I have "too much space" in front of me. They usually don't realize that I'm doing them, their car, and their gas mileage a favor. I wish people would just think about these things. The easiest lane to be in in this type of traffic is usually the lane with all the trucks, as they too cannot stand the constant shifting and braking of stop n' go traffic.

      --
      Libertarian: label used by embarrassed Republicans, longing to be open about their greed, drug use and porn collections.
    2. Re:This is one of my pet peaves by transient · · Score: 3, Funny
      I do this in my stick-shift too, though not on the freeway (I live in a small town). There's a leg on my drive home that's always backed up at a stop sign -- stop n' go like nothing else. If I shift into first and let the engine idle, I catch up to the car in front of me right as it starts accelerating. It makes people behind me crazy and I can't understand why.

      I guess it's just more evidence of the superiority of stick-shift drivers. ;-)

      --

      irb(main):001:0>
  6. Measuring Theory Of Traffic by uncreativ · · Score: 5, Interesting

    An idea borrowed from quantum mechanics...
    Measuring the system changes the system.

    What if everyone takes the same alternate route to avoid the "busy" route?

    As the story points out:

    "But the website has already become a victim of its own success, admits Schreckenberg. Some of the 300,000 people a day who are visiting the site are replanning their journeys on the basis of its forecasts, and this is beginning to make the forecasts themselves less accurate."

  7. Re:Pre-emptive analysis? by mocm · · Score: 5, Interesting

    There were and are several projects in Germany that develope traffic models in conjunction with models simulating the route choices of people depending on their lifestyles. The problem is that there are people that do not believe that people can be simulated by cellular automata and reject those simulation. But there are also city planers who use those models when planning new structures like stadiums, airports and others that need road connections.

    There is a sourceforge project thatsimulates multimodal traffic with cellular automata. Also have a look at this link for more information about traffic simulation.

    --
    ***Quis custodiet ipsos custodes***
  8. Isn't this a statistical problem? by anubi · · Score: 3, Insightful
    It seems to me its nearly as impossible to predict a traffic jam as it is to predict stock prices.

    Both are fundamentally chaotic.

    Sure, you can calculate expected probability based on past performances and expected flow... but we've all seen freeways humming right along at 70MPH and no problems until just ONE driver makes an error... then all hell breaks loose.

    I don't think even predicting the weather is as tricky as predicting traffic flow, as at least the weather patterns follow known laws of physics for at least near-term before losing out to the chaotic nature of weather patterns. People are just flat out unpredictable.

    --
    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]

    1. Re:Isn't this a statistical problem? by ratsnapple+tea · · Score: 3, Insightful

      While you might not be able to predict which driver makes an error, you can say with near certainty that somebody is going to munge up the traffic flow. That's what you base your predictions on. Remember that chaos theory indicates that although the underlying systems may be chaotic, the emerging patterns can be predicted with a fair degree of accuracy.

  9. so what your telling me is by Anonymous Coward · · Score: 3, Funny

    So what your telling me is, the traffic jam sim is a jedi? And he can see jams before they happen.

    And I guess he has an evil father right? "Luke, I can feel the road rage in you, you must let is out"

    And I guess news stories about traffic jams have to use lucas/powerpoint diagonal slides instead of hard cuts?

    And Han Solo is the guy in the riced up car that speeds? Chewie likes "phat bass beats" in his WQRX p27983tyXX extreme ear-bleed SUB WOOFER SYSTEM.

    And I guess there will be massive traffic jam merchandising? Possibly even a prequel traffic jam series with JAR JAR BINKS who is the pedestrian who always presses the walk button even when he has no intention of crossing the street?

    And all the people who were caught in the traffic jams ages ago are like "this traffic jam sucks compared to the originals".

    Anyway, enough of this, may the green lights be with you.

  10. Predicting the traffic is easy doing something by Bob+Bitchen · · Score: 3, Insightful

    about it is the hard part. Changing behaviors is the most difficult thing to do. If people staggered the time they leave work and if they could tolerate a little bit of inconvenience of car pooling or riding a bus or train or subway then we might see the traffic ease up. Building more freeways and adding more lanes to existing freeways doesn't provide a lasting solution. Most people would reap the benefits of walking more to get mass-transportation and getting out of their cars more often. Of course there are the lucky ones that don't even need a car and can commute soley on public transit. Or just on foot.
    I predict that traffic will get so bad and car ownership will become so expensive that people will figure out ways to get around without a car and possibly even change their lifestyle in the process. But it will happen gradually, I think it is already.

    --
    http://tinyurl.com/3t236
  11. Here's the algorithm they use: by phandel · · Score: 5, Funny

    I believe the algorithm was leaked a few days ago:

    if ((time == 8am-ish) || (time == 5pm-ish))
    double jam =1; // double jam sandwich

    if (city == LA)
    long long jam = 2^64;

  12. Re:Pre-emptive analysis? by ratsnapple+tea · · Score: 3, Interesting

    Yeah, it's pretty common practice nowadays to use computer models to assist in urban planning, not just for designing new roads, but also to see where best to widen lanes, where to add additional lanes, and even how to time traffic lights. One problem with prediction, over the long term, is that it turns out no matter how much road you build, it isn't enough. So building in 5% additional capacity staves off traffic problems in the short term, but within a decade or two you've got 10% more drivers, the additional traffic coming from the fact that your original (planned) increase in capacity made it that much easier to drive. Of course, this is why governments are more and more turning to congestion tolls as a way to thwart this cycle. More here.

  13. Synchronized flow isn't stable by KjetilK · · Score: 3, Interesting
    Hm, I suspect that the synchronized flow state isn't stable: The main reason: People are driving too close to each other.

    If there is just a small change in velocity of one driver, the next guy is going to respond to it by hitting the breaks. The next guy is going to panic and hit it harder, and so it goes. I've seen this happen in real life many times: Just a small riple can make a jam, three or four cars involved is sufficient.

    I fact, I think I saw an article about this too, it could have been long ago in Europhysics News or something. They like publishing stuff like that.

    I'm trying to keep a lot of distance when I'm driving: Three seconds in normal situations (just count), and up to five seconds if I'm in synchronized flow. That way, I can absorb many ripples if the three or fours cars in front of me is slowing down. I think it helps, but surely it doesn't help a lot if it happens further ahead.

    It is of course important not to lag too much when the cars starts moving again, so I generally speed up to follow in the start, but then try to build up some good distance, when the flow gets going.

    But then, I'm just speculating...

    --
    Employee of Inrupt, Project Release Manager and Community Manager for Solid
    1. Re:Synchronized flow isn't stable by jrumney · · Score: 4, Insightful

      The density of traffic would be lower because the traffic is flowing more smoothly, not because less cars are using the road. This is a good thing.

  14. They just need to take this into account... by ebyrob · · Score: 5, Insightful

    Use the "effects" of the prediction to get the desired results. For example, if you want clear sailing on Route 9 going north at 4:00pm, predict bad traffic ahead of time.

    If you want more predictable traffic patterns, fudge prediction differences downwards so that less people will take action based on the predictions.

    It's all one big feedback loop, dampen accordingly.

  15. Wonder if they will predict... by SalsaDot · · Score: 3, Funny

    ...the slashdot effect on their site

    oops, different flavour of jam

  16. Traffic jam solution by reboot246 · · Score: 3, Interesting

    Just some ideas.

    1. Reduce the number of redlights needed and make the ones left more intelligent
    2. Use more public transportation, especially for commuting
    3. Get the idiots off the road
    4. All exits should be to the right, because exits to the left mix fast and slow traffic
    5. Restrict 18-wheelers to the right lane only and make them use by-passes when available
    6. Get the idiots off the road.
    7. Move wrecked vehicles off the highway as soon as possible, even if it means coming back to tow them later. Why shut down a whole interstate because of a vehicle in the median waiting for a tow truck?
    8. Make not using turn indicators a MAJOR fine, at least $500.
    9. Extend onramp and acceleration lanes
    10. Get the freaking idiots off the road!

    Idiots include - people talking on the phone, reading the paper, putting on makeup, sight-seeing, watching DVDs or TV, . . . you get the idea.

  17. Traffic Waves - research and animations by WRXFiles · · Score: 5, Interesting

    In 1998 William Beasley posted a paper on Traffic Waves in Seattle, subtitled "SOMETIMES ONE DRIVER CAN VASTLY IMPROVE TRAFFIC".

    The site has great animations and excellent explanations of the impact of different drivers actions on the overall flow.

    Worth a look: Traffic Waves

  18. Screw all the simulations!! by hlygrail · · Score: 3, Interesting

    In a former job many years ago, I did a lot of highway driving (deliveries and field service) and spent a good deal of that time thinking about traffic patterns, both as a mathematical system as well as a design process. My final conclusion after 2 years was that there are too many cases of poor road/intersection design and WAY too many cases of pathetic traffic light design, and even more cases where traffic lights hinder traffic flow in a very severe way, while not providing any of the originally-intended safety of said traffic light. The prevailing "wisdom" seems to be: if there's a traffic problem, put up a stoplight to control it. Not.

    Traffic dynamics is fascinating, and certainly deserving of some studious focus, but none of this means a single, blessed thing to me unless people will:

    at least drive at or near the speed limit, conditions permitting -- if you can't, get out of the way learn how to *accelerate* on an on-ramp so they merge at or near highway speeds -- when you don't, you cause massive traffic problems; stop tailgating so badly that traffic becomes a wave of stop/go -- backing off just a little bit means no more brake-light domino effect; stop driving 20MPH (that's 32.18KM/H for you Euro-geeks) below the speed limit in the left lane (or the right lane for your Euro-geeks) when the prevailing traffic is clearly ALL having to go around you -- you are a huge HAZARD if you're driving too slow in the left (Euros and Bahamians: right) lane;
    -or-
    get out of my way and let me do the above.

    I'd make the common observation that older folks tend to drive slower and tend to do so, totally oblivious, in the left lane. But then there is at least an equivalent problem in the soccer moms and high-strung business suits on cell phones driving SUVs and mega-SUVs who pay even less attention to what they're doing. Heck, I've seen people driving down the interstates here (I-40, I-95, I-85 -- pick one) during morning traffic, travelling at over 80MPH and reading the morning paper!

    That said, I think traffic problems tend to be less a mathematical/system problem than a brainless person problem, in many cases. Not all, but very many. Sadly, you can't "in-idiot" a driver, or a person for that matter.

    I've always wished for a traffic law that gave every driver a dart gun. When someone does something obscenely stupid or hazardous (e.g. driving in reverse on a 65MPH intersate because they missed their exit), you shoot them with the dart. Three darts means your vehicle is incapacitated for 30 days. (Hmmm... I think RFID tags would be perfect for this!! :) If your vehicle is tagged more than 6 times in 2 years, you lose your license for 1 year.

    Harsh? Definitely. But consider the *costs* of traffic in lost time, productivity loss, frustration/rage, increased fuel consumption, vehicle wear and tear, air pollution, etc. Pulling one person or one thousand people out of the traffic system to improve the flow for the masses sounds like good planning to me.

    Oh, and please direct any comments about my tendency to drive well above the speed limit to /dev/get_out_of_my_way...

  19. Traffic Waves by pipingguy · · Score: 4, Interesting


    See also this site.

    Have you ever been driving on an interstate highway when traffic suddenly slows to a crawl? You inch along for many minutes while waiting to see the accident which must have caused the jam. At the same time you also curse the "rubberneckers" who are causing the whole problem. But then all the cars ahead of you take off at high speed. The jam is over, but no accident, no police cars, nothing. WHAT THE HECK WAS THAT! A traffic jam with no cause? In the rear-view mirror you see all the poor saps behind you still stuck in the jam. But why? If all those people could just speed up at the same time, the whole traffic jam would evaporate. Why don't they ever do that? What caused the mysterious slowdown in the first place?