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Obstacles Near Emergency Exits Speed Evacuation 199

Posted by Soulskill
from the george-carlin-would-agree dept.
BuzzSkyline writes "Despite fire codes that require emergency exits be clear of obstacles, some types of obstacles actually speed evacuation. The counterintuitive conclusion resulted from a series of experiments performed at a TV studio in Japan. Researchers from the University of Tokyo asked 50 volunteers to exit the studio through a narrow door. Video tapes of the experiments show that people made it out quickest when a pole was placed about 30 degrees to one side of the exit. The lead researcher believes an obstacle reduces jamming and friction among people in crowds by decreasing conflicts as the crowd presses toward the exit. A paper describing the research is scheduled to appear in the journal Physical Review E in September, but a preprint is available on the Physics Arxiv."
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Obstacles Near Emergency Exits Speed Evacuation

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  • Old news (Score:2, Insightful)

    by Anonymous Coward

    Keep your eyes open and you'll see plenty of real world applications of this principle already in place.

    • Re:Old news (Score:5, Insightful)

      by Heed00 (1473203) on Saturday August 22, 2009 @11:41AM (#29156037)
      That doesn't make it old news. Can you provide evidence the principle has previously been articulated?

      Perhaps next time you could provide some actual examples/citations/references rather than just effectively saying, "I knew that".

      I've seen plenty of obstacles in place to route/control footfall traffic, but none that I can think of to speed up egress. You have examples of those?
      • by chrisbtoo (41029)
        I certainly remember seeing a TV programme in the UK about the phenomenon, and I haven't lived there for over 5 years.
        • Yes, the OP's correct this is well known. The programme I saw (again, in the UK) showed the effect of having a building's column designed near a fire exit. Everyone's first thought was "criminally stupid", until it was explained that this reduces the occupants' ability to crowd the exit, thus reducing the pressure from weight of bodies (live ones) thereby allowing more people out - rather than jammed in the exit.
          • Re: (Score:2, Insightful)

            by dmartine40 (1571035)
            While this looks like the result of such a design, I wonder if the effect it has on crowds isn't distraction? I would guess that a wide-open exit route, while giving people all the room necessary to evacuate, may also (inadvertently) give them the "freedom" to guage their movement and personal space relative to each other. In a big enough group, it wouldn't take much, or long, to turn an evacuation like this into chaos. Could that be where excessive crowding would occur?

            But place a big enough obstacle

            • by pjt33 (739471)

              I've seen reports (3+ years ago) on simulations using a pretty simple model - people want to move away from the fire but still have some concept of personal space due to crushing being painful - which gave very similar results. Doesn't necessarily mean your hypothesis is wrong, but it certainly makes me wary of complex psychological theories.

            • I believe the wall is already a big enough static object.
          • by cas2000 (148703)

            i remember seeing a docco about that a few years ago too. IIRC, the idea was borrowed from observations of exits in ant nests, or something like that.

      • Re: (Score:2, Informative)

        by Anonymous Coward

        That doesn't make it old news. Can you provide evidence the principle has previously been articulated?

        I'm not the original AC, but here is a link to a set of slides from the Technical University of Aachen (Germany), dated June 10th, 2002:

        http://www.or.rwth-aachen.de/~fora/Veranstaltungen/Symposium/2002/VortragHermanns02.pdf [rwth-aachen.de]

        It's in German, but look at page 5. The pictures speak for themselves. Above the right picture is written:

        "Improvement: place a column in front of the exit."

        The talk was given apparently by a guy from this company:
        http://www.gts-systems.de/index.php?lang=english [gts-systems.de]

        • Re: (Score:3, Interesting)

          by speedtux (1307149)

          That's a simulation; the work from Tokyo is tests with real people.

          So, the principle has been articulated, but this work is still a new contribution.

      • by Larryish (1215510)

        I've seen plenty of obstacles in place to route/control footfall traffic, but none that I can think of to speed up egress. You have examples of those?

        Pitbulls. Lots and lots of pitbulls.

  • by Anonymous Coward on Saturday August 22, 2009 @11:33AM (#29155977)

    It's the woman on the pole that's causing the premature evacuation

  • by VMaN (164134) on Saturday August 22, 2009 @11:35AM (#29155995) Homepage

    I wonder if those volunteers were realistic enough.. They should have set the place on fire to see some face stomping, and in the long run maybe save lots of lives..

    People act very irrationally when they are afraid of being burnt alive for some reason.

    • Re: (Score:3, Insightful)

      by evanbd (210358)
      You don't have to set the place on fire. It suffices to offer a monetary reward for getting out soon enough. Of course, you still have the problem of people hurting themselves / each other in the experiment, but that does show it's realistic enough for most purposes.
    • by 0100010001010011 (652467) on Saturday August 22, 2009 @12:40PM (#29156421)

      Just do it for Money or Prizes. Heck set up these studies on Black Friday in Anytown USA.

      1 Entrance to Walmart at 10 different locations. 5 with poles, 5 without. 2-50" Plasma TV's for $100 at each location...

    • by TubeSteak (669689)

      I wonder if those volunteers were realistic enough.. They should have set the place on fire to see some face stomping, and in the long run maybe save lots of lives..

      On the one hand, this research is useful for crowd control.
      Think stadiums, concerts, fairs, festivals, hotels etc.
      (Though I can't imagine a hotel or concert hall would ruin their layout just for crowd control)

      On the other hand...
      "During the experiment, the team also found that people exiting in a single-file line were by far the most efficient. Yanagisawa said that the next step is to program models of people intelligent enough to self-organize into a line."

      Which in the light of your "set the place on fire"

    • by X0563511 (793323)

      Well, it's one thing to die. It's another to burn to death. That's an awfully painful way to go!

  • by Angst Badger (8636) on Saturday August 22, 2009 @11:37AM (#29156011)

    It's shocking that anyone in this day and age still finds it surprising when scientific experiments produce counterintuitive results. So-called intuition and common sense are usually nothing more than widely held but unquestioned assumptions. That people involved in software as much as Slashdot readers and contributors should be surprised is even more absurd. We ought to know well that intuitive interfaces are really familiar interfaces; the only really intuitive interface, as some wit once remarked, is the nipple.

    In any case, knowledge unverified by scientific experimentation is not knowledge at all. If there is anything surprising here, it is that we made it all the way to 2009 before someone thought to conduct experiments on a matter as important to public safety as emergency exits.

    • by d3ac0n (715594) on Saturday August 22, 2009 @11:58AM (#29156137)

      Actually though, if you give it a bit of thought, the result is not as counter-intuitive as you might think.

      Basically, rather than having a flat wall with an exit that everyone bottlenecks up at, the pole acts as a "funnel wall" forcing people to line up earlier and more quickly. The same principle has been in use for hundreds of years with cattle and sheep. The "cattle gate" as we now call it, acts to slowly funnel stock animals into a single file line where they can be sheared, branded, loaded onto trucks, etc.

      It just goes to show you that mammalian group behaviors are more universal than we might like to think.

      • by Miksa (300587) on Saturday August 22, 2009 @12:24PM (#29156327)

        I think the bus drivers in local traffic seem to have come up with the same solution. They usually drive a few meters past the bus stop, so most of the people have to walk beside the bus forming a line naturally before stepping in. Always makes you wonder why more people don't stand after the stop at the point where the bus door will be. Guess that's people for you.

        • Then the driver would simply stop at an earlier point rather than a later point forcing everyone to walk backwards.

          • by apenzott (821513)

            Where I am from, if the bus driver stops short of the bus stop the indication is as follows:

            • End of the line
            • I am on break
            • Don't bother me (until I come back to move the bus, then you can board.)
        • Re: (Score:2, Informative)

          by Anonymous Coward

          I'm sure policy varies by city / state, but in the city I drove for, there's footprints where you're supposed to put the door and people are supposed to wait. It's far enough back so they don't get whacked by the mirror as the bus pulls up (seen it happen!) and it helps elderly and children know where to go. Good drivers will usually hit it every time if they want to, but laziness, traffic conditions, and situation on the bus (someone standing unsteadily/in a bad spot such as down in the stairwell waiting t

        • by roman_mir (125474)

          What's a bus?

      • by instarx (615765)

        This isn't mammalian group behavior - it's physics. Reduced crowding as a result of an obstacle inserted into a pathway isn't human behavior any more than gumballs funneled from a vending machine is gumball behavior.

    • by causality (777677) on Saturday August 22, 2009 @12:01PM (#29156157)

      It's shocking that anyone in this day and age still finds it surprising when scientific experiments produce counterintuitive results.

      Why is it shocking? Is it ... counter-intuitive for you?

    • It's shocking that anyone in this day and age still finds it surprising when scientific experiments produce counterintuitive results.

      I bet your intuition was different.

    • by Culture20 (968837) on Saturday August 22, 2009 @12:19PM (#29156281)

      the only really intuitive interface, as some wit once remarked, is the nipple.

      And yet I've never seen one person try to suckle a laptop pointer-nub.

    • by Deadstick (535032) on Saturday August 22, 2009 @12:25PM (#29156331)

      If there is anything surprising here, it is that we made it all the way to 2009 before someone thought to conduct experiments on a matter as important to public safety as emergency exits.

      We made it to 1942 before we even required emergency exits to open outward. Google "Cocoanut Grove Fire".

      rj

    • by RepelHistory (1082491) on Saturday August 22, 2009 @12:35PM (#29156385)

      In any case, knowledge unverified by scientific experimentation is not knowledge at all.

      I'm for science as much as anyone on this site, but don't you think that's a bit of an exaggeration? You can't learn ANYTHING except through the scientific method?

      So-called intuition and common sense are usually nothing more than widely held but unquestioned assumptions.

      We DID actually evolve intuition for a reason. It's obviously not right all the time, but there's a reason why we're told to "go with our gut." Intuition is the means by which we pick up all those hundreds of subconscious signals that would otherwise slip by. It's kind of important.

      Oh and one more thing while I'm on this tangent: the scientific method uses intuition as part of its process. All scientific experimentation begins with a hypothesis, and without intuition, scientists would be totally unable to come up with a hypothesis to test. Try it: using ONLY deduction, try to think of a hypothesis to test for an experiment. Sorry for the off-topic post, I juar felt like this needed addressing.

      • Intuition is just the scientific method with a small sample size.

      • Well, the thing is, our intuition is often, but not always right. Scientific reasoning is the only means I know of to distinguish the cases when our intuition is right form the cases where it's wrong. I would say that ideas unverified by scientific reasoning are really only opinion, not knowledge. You can't learn anything conclusively without sound reasoning and observation, and while intuition is immensely valuable for guiding reason, treating what your intuition or common sense tells you as knowledge i

      • This is called the philosophy of science [wikipedia.org], which is a branch of epistemology [wikipedia.org]. As with all philosophy, it's very contingent on exactly how many things are defined, so I'm adding a lot of links to explain the terminology. This has been beat to death long before we got here, so I'm just summarizing one side of things here.

        In any case, knowledge unverified by scientific experimentation is not knowledge at all.

        I'm for science as much as anyone on this site, but don't you think that's a bit of an exaggeration? You can't learn ANYTHING except through the scientific method?

        Actually, yes. It is a perfectly valid theory of epistemology [wikipedia.org], common to empirical [wikipedia.org] naturalism [wikipedia.org]. If knowledge [wikipedia.org] is defined as "justified [wikipedia.org] true [wikipedia.org] belief [wikipedia.org]" (a classical definition), and you hold tha

    • by Keebler71 (520908) on Saturday August 22, 2009 @12:36PM (#29156397) Journal
      it's not counter-intuitive to anyone who has studied gas dynamics.... they've rediscovered the "nozzle" [wikipedia.org]
    • by value_added (719364) on Saturday August 22, 2009 @01:17PM (#29156635)

      So-called intuition and common sense are usually nothing more than widely held but unquestioned assumptions ... We ought to know well that intuitive interfaces are really familiar interfaces; the only really intuitive interface, as some wit once remarked, is the nipple.

      I'd suggest that anyone who is a pediatrician or has otherwise observed a new mother trying to teach her baby how to breast feed would classify the "nipple as intuitive interface" line as not only an unquestioned assumption, but also one that's wrong.

      Put simply, the nipple, to use your terminology, is a familiar interface. The familiarity happens very early, and there's a wealth of factors that motivate it, but still it's something that's learned.

      • My son was born 11 days ago so i have a recent anecdote on this. My son latched on to the nipple within 2 minutes of being born. Pretty much as soon as my girlfriend put his mouth next to it he chomped down.

    • In any case, knowledge unverified by scientific experimentation is not knowledge at all.

      Then I guess we don't really know that there infinite number of primes, or that that the one millionth digit of pi is 5, or that the American civil war happened, or that ... well you get the point.

      Knowledge comes in many forms. Experiment is only one way to obtain it. It is a very powerful way, but it does have its limits and it most certainly isn't the only way.

    • by epukinsk (120536)

      I continue to be shocked that people continue to be shocked by things that continue to happen!

  • by Joe The Dragon (967727) on Saturday August 22, 2009 @11:39AM (#29156017)

    but small exit ways can lead to death like what happened at the e2 nightclub.

    http://en.wikipedia.org/wiki/2003_E2_nightclub_stampede [wikipedia.org]

    http://www.cnn.com/2003/US/Midwest/02/18/btsc.flock/ [cnn.com]

    • by timeOday (582209)
      It would be ridiculous to see this research as an indictment of fire codes as the summary (and GP) imply. OK, by tuning the exhaust manifold you can decrease backpressure a bit. That's nice. Maybe even counterintuitive. But it's not what fire codes about, which is stopping people from piling junk in front of emergency exits that blocks people exiting, which is far more significant than this.
      • by aaarrrgggh (9205)

        Very good analogy on the back-pressure.

        The "blocking of exits" isn't what architects are curious about, it is the focus on funneling exits rather than just having a certain width offer a constant carrying capacity. Fire codes are tricky, in that they try to balance safety with general application practicality. For the most part (excluding A(ssembly) occupancies), distance separation of exits is focused more on ensuring that a problem in one area doesn't keep all occupants stranded. It works in many appl

    • by aaarrrgggh (9205) on Saturday August 22, 2009 @12:26PM (#29156343)

      The building codes try to increase exit width to handle higher traffic flow. The reality, at least as suggested by the research, is similar to what landscape architects have known for generations: people walk faster on a narrow sidewalk than a broad one.

      In an emergency, you hit the maximum carrying capacity of any pathway. The key to evacuating a densely occupied space is to convince people to spread out to multiple different exit points, which is confusing in an emergency situation.

      I don't think anything is perfect, but when people approach a single door from a number of different angles optimum traffic flow doesn't happen.

      • by Gorobei (127755) on Saturday August 22, 2009 @01:10PM (#29156595)

        The weird thing is that people who actually design stuff for crowd control have known this since at the least the 1980s. The goal is to get people ordered into efficient lines heading towards the goals and make sure people understand the process is fair and nothing is to be gained by jumping lines. For a real world example, see Heathrow's newer terminals versus its older ones, or any third world airport: if you make it easy to cheat by changing lines, and other people can see you do it, you get a mob in short order. So, keep lines narrow, and hard to switch from one to another, and people move faster. That means barriers - big ones. Just think Disneyworld, airports, good stadia.

        • Re: (Score:3, Interesting)

          by Gorobei (127755)

          Oh, and design the exit assembly areas so as to encourage dispersion from the final choke point at the exit: ideally, have the exit open to an amphitheater like shape so people will walk/run downhill/in various directions. Add attractors to get them away from the choke point fast: like, big sign advertising free beer 100 yards off to the side (seriously.)

          • You do NOT want people RUNNING DOWNHILL in any emergency situation. That leads to lots and lots of trampling. Someone running quickly hits someone running not so quickly and you have two bodies on the ground. People trip over the downed people and all of a sudden you have a very bad situation.
            • by Gorobei (127755)

              You're quite right, of course. The goal is big fanout + channelling to get the mob density down, plus gentle downhills to nudge the people in the right directions. A fire exit killer is often not the pure size of the exit, it is that that the first 100 people out form a crowd outside and slow the egress of the next 400 people. You can deal with the risks of people running downhill as long as the running reduces bottlenecks and trample risk - it's the difference between panic inside a burning nightclub an

    • by shma (863063) on Saturday August 22, 2009 @12:29PM (#29156363)
      They are not suggesting making the exit smaller, they are suggesting that an obstacle is placed further from the door to reduce the number of paths to the door and keep the number of people trying to push through the exit at any given time to a minimum. See Fig. 18 in the arXiv paper if you want to look at a diagram of this.

      Interestingly enough, these results seem to have been known for a while (probably based on anecdotal evidence). I distinctly remember my fluid mechanics teacher telling our class almost exactly the same thing in 2006, explaining that a crowd headed for the exit behaved in similar ways to a fluid trying to pass through a small opening.
  • Lofty goals (Score:5, Funny)

    by xZgf6xHx2uhoAj9D (1160707) on Saturday August 22, 2009 @11:43AM (#29156041)

    Yanagisawa said that the next step is to program models of people intelligent enough to self-organize into a line.

    Personally I think it would be most useful to model humans :\

  • by Kjella (173770) on Saturday August 22, 2009 @11:43AM (#29156047) Homepage

    The biggest issue with a real emergency situation is panic. People being squished against fences, walls and other obstacles because there's too many people behind squeezing, making it more dangerous and less efficient. Same is really for people being trampled, it's very dangerous and almost impossible to help someone being trampled back on their feet in such a crowd for the risk of not getting up yourself. I'd be very careful placing obstacles which might lead to more well-behaved behavior in scientific tests (left, right, left, right, that's so much better) but would be very danerous in a real panicking crowd.

    • The biggest issue with a real emergency situation is panic. People being squished against fences, walls and other obstacles because there's too many people behind squeezing, making it more dangerous and less efficient.

      So people act like a cornstarch solution?

      I'm not even sure where to begin in crafting a joke...

    • by dbcad7 (771464)

      I don't go to events with large groups of people.. I love live music, but even if I had free tickets I wouldn't go to a concert and be a speck in a sea of humanity. I just don't see it as enjoyable. I find it amazing that people will pay hundreds of dollars for the "privilege" of being inconvenienced in their movements. The chance of being trampled is really only a side thought in why I don't go, but it is a legitimate concern.

      Flying is perhaps the only situation that I allow myself to be in a crowd.. Board

      • I don't go to events with large groups of people.

        The only time I really got scared was on new years eve one year here in Melbourne. I was on a big road bridge which literally filled up with people. I couldn't move a limb. A panic in that situation would be deadly.

        The last time we had a fire drill at work our group got forgotten and "died". Thats okay because if we have a real fire nobody is going to wait to be told to go.

  • Already known (Score:5, Informative)

    by Dachannien (617929) on Saturday August 22, 2009 @11:50AM (#29156085)

    These guys [informs.org] already figured this out several years ago. (Sorry, I couldn't find a non-subscription link.)

    During the pilgrimages to Mecca, one of the things that people are supposed to do is go into a large stadium and cast rocks at three pillars. Zillions of people attend this event, and there have been numerous trampling deaths at the entrance to the stadium. These guys showed that having obstructions near the entrance improves traffic flow, and so they recommended to officials in Mecca to install such obstacles there, resulting in far fewer trampling deaths near the entrance. Other means of traffic calming [spiegel.de] were used to mitigate deaths elsewhere in the stadium.

  • and research the big shopping spree the day after thanksgiving when people trample each other trying to get in to the local Walmart when the doors just open
  • There's various places in fluid dynamics where 'obstacles' are put to improve flow aren't there? Those cone shaped things in jet engines for instance (and falcon's have similar cone shaped things in their nostrils.) Maybe this is like that.

  • It Makes Sense (Score:5, Insightful)

    by StormyMonday (163372) on Saturday August 22, 2009 @12:03PM (#29156187) Homepage

    Think of it as impedance matching.

    • by aaarrrgggh (9205)

      Kind of; the goal is to allow people to accelerate through the constrained opening; the pole moves restricts flow in advance of the opening so optimal flow can happen through the door.

      People panic to get to the door, so the pole helps to restore some order to traffic flow.

    • by naasking (94116)

      Excellent analogy. Reflected waves on mismatched transmission line is a beautiful analogy for the jostling that can happen as people try to squeeze past each other through a door.

  • During the experiment, the team also found that people exiting in a single-file line were by far the most efficient. Yanagisawa said that the next step is to program models of people intelligent enough to self-organize into a line.

    It would also been interesting to see if a few spoilers can break the flow. (As in the onset of turbulence in a fluid?)

  • but what about disabled people? I would think that the obstacle would cause big probles with wheelchairs and walkers.

    • but what about disabled people? I would think that the obstacle would cause big problems with wheelchairs and walkers.

      The article did not say the obstacle had to be in front of the ext. One example given was a pole 30 degrees to the right. By helping people to form lines in advance of the exit, this approach prevents a mash of bodies. This in turn may enable those with wheelchairs and walkers a chance of passing through instead of stopping up an exit.

      I think there are public venues where this should be considered.

  • This instantly reminded me of a roundabout, which also helps with congestion and crashes.

    Which makes it obvious where to place such poles.

    And where to put some girls on them. :P

    • Re: (Score:3, Funny)

      by Mr. Freeman (933986)
      Roundabouts help immensely with congestion and crashes. There were far too few before all these roundabouts were built. The accident investigators were getting quite bored.
  • Why a Pole? (Score:4, Funny)

    by consumer_whore (652448) on Saturday August 22, 2009 @12:36PM (#29156391)
    Would a Russian or Italian be as effective?
  • Isn't this well known? I've seen TV documentaries with computer animations showing the difference between a crowd at an exit and a crowd at a partially blocked exit. Against intuition, the partially blocked exit allows more people to escape in a given time.
  • My first thought was that Bernoulli (one of them :-)) is smiling in his grave.
  • They should test it out at a subway exit. Many times they have a single stair that leads from the platform out and there are a LARGE number of times each day that a lot of people try to exit it.

    It should be easy to put a camera up and time people for a week, then install a pole and time them again. Have an intern count the number of people each time as well as speed.

  • I'm reminded of one airplane evacuation study where everyone exited the plane in a nice orderly fashion. Then they repeated the same study but paid the people based on the order they exited the plane. Let's just say the results were different. People climbing over seats pushing each other out of the way... Gov study in PDF [dtic.mil]
  • "about 30 degrees to either the right or left side of an exit door" ??? Vertically, diagonally? That phrase makes zero sense...
  • What next? Bad drivers break up traffic jams? People lining up single file at a ticket booth? Zippers?

    I wish the people who built my high school had known this. After a pep rally, I was shocked at how kids were squeezing their way through the doorway in a huge clump. Unfortunately, someone got their foot under my leg and I fell over, and I was stampeded for, oh, a good 40 seconds before anyone realized they were stomping on the back of a person. Then, the principal yelled at me for the incident. Herd

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