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Software Science

Traffic Sim Predicts Jams Before They Happen 218

Posted by simoniker 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."
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Traffic Sim Predicts Jams Before They Happen More

Traffic Sim Predicts Jams Before They Happen

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  • What if people start using it? (Score:5, Interesting)

    by Zebidiah ( 573736 ) <zebidiah+newsletterNO@SPAMgmail.com> on Saturday July 03, 2004 @04:38AM (#9598630)
    What if people start using it? They avoid the traffic jams, thus no traffic jams. Wrong prediction!

    • Re:What if people start using it? (Score:5, Funny)

      by mphase ( 644838 ) on Saturday July 03, 2004 @04:45AM (#9598658) Homepage
      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.

      • Re:What if people start using it? (Score:2, Insightful)

        by Anonymous Coward
        you just described the problem of utilizing the intelligence gain from cracking WWII Nazi codes: if heard about a fleet of submarines and attack it, then they know you know the codes, so they change them...but if you do nothing, then what's the point of breaking the codes
      • It only applies if a large portion of the potential traffic was aware of the prediction

        Not necessarily. Depending on the situation, the threshold number of people whose behavior can change the situation will vary; could be large or small.

        Where I live (Seattle) the state DOT puts up a GREAT online traffic map [wa.gov], which I check religiously before hitting the road. I hope it someday incorporates technology like this.
    • "What if people start using it? They avoid the traffic jams, thus no traffic jams. Wrong prediction!"

      Oh the horror.
    • Blockquoth the poster:

      Wrong prediction!


      To steal a line from Minority Report, "The fact that you prevented it from happening doesnt change the fact that it was *going* to happen." (All hail the IMdb [imdb.com])
      • >>To steal a line from Minority Report, "The fact that you prevented it from happening doesnt change the fact that it was *going* to happen

        What I take away from that statement is that even though we learn how to avoid, or run from a problem. The problem is still there, just waiting to be solved.

        wbs.
    • Since this problem OBVIOUSLY reduces to the Halting Problem, it is easily proven that you cannot, in fact, predict traffic jams.
    • sounds like a stock analyst's prediction.

      "The price will go up", so people buy and the price goes up. "The price will do down", so people sell and the price goes down.

  • What is the cause? (Score:4, Insightful)

    by lachlan76 ( 770870 ) on Saturday July 03, 2004 @04:40AM (#9598637)
    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.

    • Re:What is the cause? (Score:5, Insightful)

      by skraps ( 650379 ) on Saturday July 03, 2004 @04:45AM (#9598660)
      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.

      • Re:What is the cause? (Score:3, Interesting)

        by Trent05 ( 70375 )
        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.

      • Re:What is the cause? (Score:5, Interesting)

        by Bozdune ( 68800 ) on Saturday July 03, 2004 @07:51AM (#9599136)
        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.
        • So to get this real time information, some idiot is going to put another screen or something in the dash of cars to display it and people will be watching it for traffic problems ahead of them instead of watching the road, causing even more traffic problems.

          There really is no good way predict and then relay the information.

          I am not sure what it is like up there in Boston, but in Texas the radio announcers give the same BS, but I am familiar enough with traffic flows to know what to expect. For example, p
        • Wow.. traffic reports must be infitely better here, then..

          In Toronto, you can watch the major local TV morning show, BreakfastTelevision on CityTV, and hear a traffic report based on, and with live video, since the Ministry of Transport has cameras set up all along the 400-series highways. (Tinfoil hat folks: The cameras are shit quality, frequently fogged up or out of focus, and way to far away to read plates..)

    • Re:What is the cause? (Score:4, Informative)

      by Wastl ( 809 ) on Saturday July 03, 2004 @06:02AM (#9598822) Homepage
      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

    • Just like the old "gridlock alert" days in NYC. They stopped doing them back in the 80's, because of that very effect. They announced a gridlock alert day for one of the games in the '86 world series, and my uncle said the traffic was so nonexistant that he didn't do under 55 until he got to Shea stadium.
    • Quote the article: "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. And soon it could get even worse when the website becomes available on 3G cellphones, he says."
    • In recent months, most of Atlanta's big traffic tie-ups (even worse traffic than usual) are caused by people threatening to jump [wgcltv.com] off of overpasses.

      So now for this traffic prediction to work, it basically has to predict bridge jumpers. Fortunately, as the government profiles us more and more and tracks us via RFID tags or whatever, it may be possible not only to predict when a person gets suicidal, but possibly also to predict the most likely date/time and even the correct overpass they will use.

      </Tong

  • Hooks law (Score:5, Interesting)

    by Anonymous Coward on Saturday July 03, 2004 @04:41AM (#9598643)
    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...

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

      Interesting. I think I'll make it into a bumper sticker.

      Check back in a few days and I'll let you know how effective it is calming down the idiot honking his horn behing me. ;-)

  • A note (Score:4, Insightful)

    by pyth ( 87680 ) on Saturday July 03, 2004 @04:42AM (#9598647)
    For those people concerned that releasing the predictions will interfere with the results, please remember that not many people will actually use this tool.

  • This is one of my pet peaves (Score:5, Interesting)

    by rsilvergun ( 571051 ) on Saturday July 03, 2004 @04:43AM (#9598651)
    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?

    • Re:This is one of my pet peaves (Score:5, Interesting)

      by willpall ( 632050 ) <pallwill-slashdot.yahoo@com> on Saturday July 03, 2004 @05:04AM (#9598701)
      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.

      • Re:This is one of my pet peaves (Score:4, Funny)

        by transient ( 232842 ) on Saturday July 03, 2004 @06:00AM (#9598816)
        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. ;-)

      • See, here in the fine State of Minnesota you have to be right behind the person in front of you at all times. You cannot even leave 1mm of space. If you do, some cheating asshole will try to move up the free flowing lane and cut over at the last possible moment to avoid the 35 minutes of backed up single lane traffic that you had to endure.

        Now, this may not seem that bad but... This cheating asshole fucks up the speed of those in the free flowing lane, causes people to mash on their breaks in the traffi
      • You're smoothening out the wave, but it does delay traffic flow. Your proposed method is fine for very long roads with few intersections, but not so good in places with lots of intersections, because it means fewer cars will make it through the intersection - which means slower average traffic speed and people taking longer to reach their destinations. For roads with lots of traffic lights, it's better if people accelerate at reasonable pace in lock-step but they must not overfill the road and block the int
    • Oh how I hate people with that attitude. :-)

      I'm not a driver (well, I've got a driving licence, but no car). I'm a cyclist. There is nothing more annoying than a slow moving car snailing along at 20mph when I'm in a training session - treading along at 30mph. It invariably causes me to be pissed of and just pass the slow driving sucker.

      Who far to often doesn't like being passed by a fast moving cyclist.

      Yeah, I know, I'm a dangerous asshole cyclist in the traffic, but eyh, it's my health - and I've nev
    • That only works when traffic lights are synchronized so that they turn green when you approach at the speed limit. There are far far more intersections where the lights are independent, and you have a reasonable chance of squeeking by on a green or yellow if you speed.

      -molo
  • 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. And soon it could get even worse when the website becomes available on 3G cellphones.

    ...and the system fails to take into account for drivers futzing with their cellphone instead of concentrating on the rear of the car in front of th

  • Measuring Theory Of Traffic (Score:5, Interesting)

    by uncreativ ( 793402 ) on Saturday July 03, 2004 @04:47AM (#9598668)
    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."
    • Blockquoth the poster:

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

      Yep, it's psychohistory all over again... *shaking fist* Curse you, Isaac Asimov!

    • They just need to take this into account... (Score:5, Insightful)

      by ebyrob ( 165903 ) on Saturday July 03, 2004 @05:46AM (#9598792)
      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.
    • Chaos Theory is more appriate here than quantum mechanics. Just measuring the flow of traffic doesn't change the flow of traffic. However, making predictions based on your measurements can create a feedback loop which can affet the system.

  • Isn't this a statistical problem? (Score:3, Insightful)

    by anubi ( 640541 ) on Saturday July 03, 2004 @04:51AM (#9598674) Journal
    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.

    • 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.
    • "in which dense traffic moves in unison, like marchers moving in step"
      Some important facts, which the system designers seem to have forgotten: Real systems veer towards chaos and orderly behavior is anathema to all nationals except Germans. That apart, any traffic simulation design could be considered a success if it can be put to use in all conditions. I am quite sure that this system will come a cropper on Indian roads where cars have to jostle for space with cattle, cycles, pedestrians, three wheelers,
    • just ONE driver makes an error... then all hell breaks loose.

      That's just one butterfly though. It's the jam spreading out from there that causes the problems.

      Both are fundamentally chaotic.

      Yes, but the principle of chaos is that small changes to the initial conditions lead to an exponentially divergent change to the result.

      So, the earlier you are able to detect a single car crash, or the traffic jam around it, the quicker you will be able predict a city-wide gridlock- and perhaps arrange for your own

    • Here in St. Louis, it's my observation that with relatively few exceptions, the big traffic jams always happen around the same times and places. Predicting a traffic jam with good reliability is possible primarily because inadequate roads/freeways for traffic flow during rush hour means really good odds of a problem in those key areas.

      Basically, we have a situation where a large number of people need to travel from suburbs in the west to their workplaces in the city itself (east). On the ride home, you g

    • Strange Attractor (Score:3, Informative)

      by Randym ( 25779 )
      It seems to me its nearly as impossible to predict a traffic jam as it is to predict stock prices. Both are fundamentally chaotic.

      As I read your comment, it struck me that the flow of cars past a given point resembles the flow of water from a drippy faucet, and that both can be modeled as a 2D strange attractor. Just as you can map the time differences between Drips [ D1, D2, D3, etc. are absolute time of drips; T1=D2-D1; T2=D3-D2; etc.], you can map the space differences between cars. Then map it on

  • so what your telling me is (Score:3, Funny)

    by Anonymous Coward on Saturday July 03, 2004 @04:58AM (#9598684)
    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.

  • Predicting the traffic is easy doing something (Score:4, Insightful)

    by Bob Bitchen ( 147646 ) on Saturday July 03, 2004 @05:00AM (#9598689) Homepage
    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.

    • 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.

      It's quite easy, actually. Give people an accurate prediction of a traffic jam on their route, and they will detour or postpone the journey. And most people already have an accurate prediction... that nasty jam on the way to work has been there every day for the la

      • The best change in lifestyle would be to telecommute, or move closer to work... but it also means that there should be suitable housing near your office.

        Alas, there are only two cities in the USA that could fit that mold: New York City and Chicago. Most other cities in the USA are so "spread out" that mass transit is not as viable as people think.

        Interestingly enough, London in the UK grew by following the Underground (subway) lines as they spread out from the center of London. But then, that growth happ
    • Car pooling and busing are not "a little bit of inconvenience" in most parts of America. Public transportation is all but non existant, and employers have come to expect employees to own cars and as such can locate their businesses pretty much where they damn well please. It doesn't help matters that in any community car retailers are bound to be among the most wealthy and influential; and they're not gonna take kindly to public transport. Seriously, what sane person would want the hassle, expense, and extr
    • "If people staggered the time they leave work"

      Hey if bosses are flexible about the time you arrive to work that'll help to. Then we'll only have probs if _everyone_ held a 9am meeting on the same day.

      It's not the inconvenience of car pooling etc that stops people from driving their cars. It's more like the "insurance" problem - you drive your own car "just in case" stuff happens and you need independent transport you can rely on. Taxis can help, but where I live they're not that reliable - they often refu

  • Here's the algorithm they use: (Score:5, Funny)

    by phandel ( 178702 ) on Saturday July 03, 2004 @05:01AM (#9598693) Journal
    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;
  • to this [amasci.com] page which was linked on slashdot a while back.
  • I see why they did that in Duisburg and Essen, two of the five or six larger cities in the Ruhrgebiet.

    The Autobahn A40 that connects the Ruhrgebiet cities from Dortmund via Bochum, Essen and Mülheim to Duisburg has the reputation of being the worst motorway in Germany, at least wrt/traffic jams. Guaranteed traffic jam 8-11am and 3-7pm.

    It was probably just a professor's idea how to get to work more quickly in the morning.

  • Synchronized flow isn't stable (Score:4, Interesting)

    by KjetilK ( 186133 ) <kjetil@@@kjernsmo...net> on Saturday July 03, 2004 @05:42AM (#9598784) Homepage Journal
    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...

    • Your ideas about keeping more space on the road are sound, but if everyone were to do that (which, in my estimating and own experience is about twice as much space as most people give) the density of traffic would be much lower so fewer cars could fit on the roadway at a time.

      • Re:Synchronized flow isn't stable (Score:5, Insightful)

        by jrumney ( 197329 ) on Saturday July 03, 2004 @07:26AM (#9599052)
        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.
        • Actually, a two second following distance is just fine. In good weather and conditions. More is nice, but people tend to move in... (granted, I have seen people move from wide open outside lanes into congested center lanes for no apparent reason, other than basic stupidity I guess...)

          Now, back to reality. In periods of high traffic, it is NOT possible to keep such distances (at least without the liberal use of a grenade launcher). There are TOO MANY CARS. To keep a three second or greater following dis

  • Wonder if they will predict... (Score:3, Funny)

    by SalsaDot ( 772010 ) on Saturday July 03, 2004 @05:57AM (#9598811) Homepage
    ...the slashdot effect on their site

    oops, different flavour of jam

  • Other anti-jam techniques (Score:3, Interesting)

    by Bushcat ( 615449 ) on Saturday July 03, 2004 @06:04AM (#9598825)
    Some of the anti-jam techniques I've seen around the world tend to be based on getting information to the driver as quickly as possible.

    The ring road around Eindhoven has recommended speed indicators that show what speed you should be travelling at to hit the next light on green. It seems to work quite well.

    The Hanshin Expressway network around Osaka has video processing equipment that can automatically recognise traffic congestion, including the characteristics of traffic accidents. It then alters roadside information boards to route drivers around the congestion. Other areas do the same thing.

    adio bReacons update vehicle navigation systems in real time to show time to destination, congested roads, and if you're following a planned route, will re-route you as traffic conditions change.

    Unfortunately most signals in Japan aren't load-sensitive, but set to 1 minute green in each direction irrespective of time of day, day of the week or class of road. So circular routes around Tokyo, for example, become major barriers to traffic entering in the morning and leaving in the evening.

    On Japanese freeways, the major cause of congestion is the humble tollbooth.

    • It's funny that you should mention the tollbooth. Here in Orlando, Florida, the local Expressway Authority teamed up with the University of Central Florida and had this tool called TPSim (that's Toll Plaza Simulator) made for them. The tool allows them to simulate traffic through the plaza to determine the optimal number of attendant/cash lanes, change lanes and electronic-only lanes to best serve both directions of traffic. It really has helped the congestion around the Holland East (which was really ba

  • A traffic simulation system is helping drivers by predicting jams up to an hour before they happen.

    Let me guess- it predicts that traffic jams will happen on weekdays, around 5pm.

  • Comment removed (Score:3, Interesting)

    by account_deleted ( 4530225 ) on Saturday July 03, 2004 @06:57AM (#9598974)
    Comment removed based on user account deletion
    • 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

      I agree with #4, but #5? You'd never get on the highway around here. Not only that, but we have these things called "hills", and some trucks can only do 35 or 40 up them. Imagine if the right lane were solid with trucks moving along at 35mph! If you could get on, you'd still have to deal with the blue-hairs driving along at 45
    • Heck just 3)6)10) will get rid of 90% of traffic, you and me included ;). Voila - no traffic jams. Be careful what you wish/ask for.

      Seriously. I dunno about you, but in my experience nearly every driver is an idiot at least once in a few months. It only takes 1 idiotic action to screw up traffic for 20 to 10000 cars (depending on the idiocy of the act).

      If everyone were highly skilled and knowledgeable drivers, concentrating 100% on driving, and equiped with top notch well maintained vehicles, I bet the tr
    • 11) No stop lights within 1/4 mile of a high traffic exit. The spill over from lights such as these on loops cause much of the traffic congestion.

  • Rubbernecker screen (Score:2, Interesting)

    by abrinton ( 590891 )
    Why has nobody made a "Rubbernecker screen"? After an accident or incident, clear the roadway and put a screen up. Nobody can see the accident, and therefore they start moving again once the road is clear.

    You could even pay for it by selling ad space!! (I can't beleive I suggested that!!)
    • So your idea is to put something designed to get people to look at it on something designed to stop people looking. I'd patent that one real quick!

    • Wrong answer: when something like an accident happens you need to slow down. In fact anytime you see flashing lights (cop car, tow truck whatever) you better slow down until you know what is going on and have figured out how/if it affects you.

      Granted most people look at the wrong thing, but at least they are slowing down. You shouldn't be watching the emergency itself. You need to have a broader focus of how the operations might affect you!

  • ..and other 300,000 users in the "prediction" system at the same time: "hmm I-95 is gonna be jammed in one hour from now.I better go home a little bit earlier today." tada!! =D we have succesfully jammed the road with one hour in advance!! What an improvement! Thanks again modern physics!

  • I think the problem is too many cars on the road (Score:3, Interesting)

    by Stevyn ( 691306 ) on Saturday July 03, 2004 @07:32AM (#9599074)
    Well, yeah, call me captain obvious. I saw this show on the history channel a little while ago that did a computer simulation of traffic on a highway. It actually showed that up to a certain point, a lot of cars on the road is fine. However, once it hits a certain point, the flow dramatically drops.

    Living in New Jersey, traffic is a part of my daily life. I've noticed that even when there are a lot of cars on the road, the traffic can still move along above the speed limit in rush hour. But there is still that point when all the traffic just seems to stop and you're crawling along at 10 miles an hour.

    The show also mentioned a study the government funded. They spend several million dollars to try and figure this problem out. Their conclusions: "there are too many cars on the road." Now, for the low low price of $20,000, I could have told them that.
    • Once you have a certain density it just takes an "event", and then traffic will slow. An "event" could be someone just braking a bit too much, or doing something that causes someone else to slow down dramatically. Once that happens you get a wave of slowed down vehicles propagating down the highway. Without a high enough density, the "event" can be avoided or may not even affect other vehicles significantly.

      The worst are events that cause chokepoints. Then you end up with the "hourglass" effect. Lots of ne

  • Traffic Waves - research and animations (Score:5, Interesting)

    by WRXFiles ( 758044 ) on Saturday July 03, 2004 @07:48AM (#9599119)

    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 [amasci.com]

  • i87 Between 8:15-8:45 High Traffic south bound from Exit 8-6
    i87 Between 4:45-5:15 High Traffic North Bound between Exit 4 and 5 and exits 7-8

    It is easy to predict in Albany NY because all the state workers work outside of albany and many of them live up north. In Saratoga County. So when they go to work they tend to go south towards Troy, Latham and Albany Plus there is a big bridge between exit 7 and 8 and people become stupid on the bridge (There are no tools and the same amount of lanes) and slow down.

  • Not news (Score:3, Interesting)

    by Jugalator ( 259273 ) on Saturday July 03, 2004 @08:17AM (#9599221) Journal
    SimCity did this ages ago!

    The view can be seen here [wuphonsreach.org] in the most recent version.

  • M25 (Score:2, Interesting)

    by bobblebob ( 758047 )
    On the M25, the road that circles London, grid lock is avoided with variable speed limits and discouraging drivers from excessive changing of lanes. The road is constantly monitored by CCT and the speed limit set accordingly. The speed limit is enforced by speed cameras. In the rush hour the speed limit is reduced to 50 mph as apposed to the usual speed limit of 70mph and this, some how, reduces the risk of grid lock. Also if there's congestion at say junction 15 the speed limit will be reduced prier to the

  • Screw all the simulations!! (Score:3, Interesting)

    by hlygrail ( 700685 ) on Saturday July 03, 2004 @08:52AM (#9599376)

    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...

    • Your traffic tips and hints seem mostly correct, bad driving is something that definitively causes many problems such as traffic jams. However, bad driving can be modelled to a certain extent so it does not make all models useless per se. About the left/right lane and Europe: ALL european countries on the mainland drive on the right (as opposed to left) side of the road, just as Americans do. The left lane is therefore the fast lane in Europe as well. On highways, nearly all off-ramps are on the right side
    • The problem with this are the people who are for the 55mph speed limit. They think that "slower is safer" for some reason. I don't understand how that works, since when NJ raised the speed limit fatal accidents went down.

      What people don't realize, is that if every stupid speed limit were obeyed, no lights jumped/ran, all stops made completely, traffic would be many times worse than it is.

      • What people don't realize, is that if every stupid speed limit were obeyed, no lights jumped/ran, all stops made completely, traffic would be many times worse than it is.

        Yeah traffic lights are stupid, I never pay attention to them, I just go whenever. It helps traffic flow.

        Now, anyone who agrees with me, we can just take your license away right now, because you're obviously too immature to be on the road. And if any of you seriously want to reply to argue the merits of running red lights, just kill y
    • I saw a fellow in Dallas a while back who had in huge red letters on the back of his car, "COURTESY SAVES LIVES". He always had a big space in front of him, where anybody could merge, and a smile on his face if you passed him. And, I still try to emulate his attitude. He made a difference in the traffic each day he drove, and in the attitudes of many people who saw and followed his advice.

  • Traffic Waves (Score:5, Interesting)

    by pipingguy ( 566974 ) on Saturday July 03, 2004 @09:51AM (#9599592)

    See also this site [amasci.com].

    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?
    • Wow! That's exactly the same observations I have done! I have too noticed that I can actually clear up a jam by keeping like five seconds up to the next car, slowing down slowly.

      There's a funny Traffic Wave Generator in Drammen, Norway. Unintended of course, but nonetheless. It's a longish bridge going from northeast to south in this picture [map.finn.no], and at the northwestern end, there's a lot of traffic coming in, and at a relatively high pace. The speed limit is something like 90 km/h, which means the average sp


      • Ugh. Norway, like Canada, Sweden, the Netherlands, and France just do not count in this forum. NIH.

        I'll bet that most Americans don't even know what Norsk Hydro is or what it does.

        Ignorance is bliss.

  • Avoiding Traffic Jams (Score:2, Informative)

    by aismail3 ( 735831 )

    Bill Beaty investigated how to avoid traffic jams by recognizing the intermediate state of synchronized flow and undoing the damage six years ago. Apparently, a traffic jam can be stopped, even once started, by a single car.

    Traffic Waves [amasci.com]

  • Color-blind mode!! (Score:3, Informative)

    by beej ( 82035 ) * on Saturday July 03, 2004 @11:59AM (#9600145) Homepage Journal
    Their applet has a color-blind button on it! This absolutely rocks!! I mean, when I can't see the difference between "light" and "vicious" traffic, I'm pretty much screwed. This simple addition made the applet useful to me again!

    When building software like this, you do a great service to take us R/G colorblind people into account. We're not as rare as you think! BWHAHAHA! ;)

    • Re:Color-blind mode!! (Score:3, Insightful)

      by TheLink ( 130905 )
      Am I wrong or would carrying a piece of green or red transparent film help? That way red or green could look black/darker to you whilst letting the other colours through.

  • It's easy to predict traffic correctly 90% of the time. Traffic jams tend to occur at rush hour on certain roads. You can predict the traffic 90% of the time just using a clock.

    The other 10%, when traffic jams occur unexpectedly, is the hard part. But it's what people need to know.
  • I did similar work in college in the mid to late seventies. I did not use "live data" but had I access to it at the time, it would have worked well. One of the very interesting items is that a single car on a two lane Interstate (four lane if you are in a region that counts both sides, kind of like deer antler points being regionally different too), and if that car moves 5 miles an hour slower than the ambient traffic, and if the road is at over 50 percent capacity, the slowdown will cascade and the result

  • I know exactly how to predict traffic jams... (Score:3, Informative)

    by LamerX ( 164968 ) on Saturday July 03, 2004 @04:34PM (#9601598) Journal
    Look at the clock. I predict that every weekday at 7:00am-8:00am and 5:00pm-6:00pm traffic will be at its heaviest. Avoid driving at these times and you will be set. Also, I predict that road construction will cause traffic congestion as well. In the foreseeable future, I also predict unknown random traffic accidents to cause congestion. Use your radio tuner device in your car to listen for reports of these strange incidents and avoid those routes!

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