

Ants show that emergency exits can work better when they’re obstructed - dnetesn
http://nautil.us/issue/23/dominoes/want-to-get-out-alive-follow-the-ants-rp

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nostromo
I read the book about The Station nightclub fire tragedy on a long flight
once. The book had a different reason for people clustering at a single exit.
It wasn't because of a heard instinct, it's because in an emergency people
rush to the exit they used to enter. In the short amount of time to think in
an emergency, people do not look around for new emergency exits. They go with
what they know: the way they came in. (I believe this is why flight attendants
remind people that their closest emergency exit may be behind them.)

In a situation of panic this leads to overuse of the main entrance and
underuse of emergency exits. In extreme cases, it can lead to a crush and
cause the exit to become inoperable.

Another issue is that emergency exit signs are posted high, but those are the
first areas to be obscured by smoke in a fire.

My take away was to keep egress in the back of your mind when in crowds and to
make a mental note of emergency exits.

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callahad
Planning for unreliable alternative exits is one of the fun aspects of cave
diving: you virtually always exit by returning to your point of entrance, even
if you're nominally closer to another means of egress, since you can't be
certain that the "closer" exit is genuinely navigable. When diving a traverse
between two points, the best practice involves diving as far as you can one
way, leaving a marker, then entering from the other side on a second dive,
evaluating your gas situation at the marker, and then either continuing or
aborting the dive.

~~~
eeZi
"Fun"

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rmxt
Anybody able to find a video of the corner exit with no obstruction? Wish they
posted that one, being that they claimed it was the fastest.

~~~
jameshart
Seems logical that the two walls act to funnel people down towards the opening
- a 90 degree-wide corner exit is halfway between a 180 degree-wide funnel
towards a single door in a wall, and a 0 degree wide corridor that leads to a
door.

Likewise the 'obstructed' wall entrance just turns into two corner exits,
side-by side (I imagine the scenario doesn't work out well for the individuals
caught directly behind the pillar, as the flow past each side of the pillar
into each exit zone prevents them from getting into either flow effectively).

~~~
aout
I'd bet that if you put another pillar behind each side of the pillar
obstructing the exit you'll double the throughput.

~~~
PhasmaFelis
And thus it follows that, by repeatedly adding pillars and doubling the number
and halving the size/spacing at each step, you can approach infinite
throughput!

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4rt
no link, but there was a good article or documentary about 10 years ago about
how you can improve throughput of an automatic-opening double door by putting
a bollard in the centre. iirc it was over 2x increase.

basically people aim for the centre and people cluster up waiting for them to
pass instead of having 2 way travel all the time.

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weitzj
If you are interested in this stuff you should read
[http://www.elsevier.com/books/stochastic-transport-in-
comple...](http://www.elsevier.com/books/stochastic-transport-in-complex-
systems/schadschneider/978-0-444-52853-7)

Also: [http://www.thp.uni-koeln.de/~as/](http://www.thp.uni-koeln.de/~as/)
[https://www.uni-due.de/zlv/portrait/schreckenberg.php](https://www.uni-
due.de/zlv/portrait/schreckenberg.php)

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prof_hobart
The TV show Crowd Control did something about this last year
([http://channel.nationalgeographic.com/crowd-
control/videos/e...](http://channel.nationalgeographic.com/crowd-
control/videos/emergency-exit-experiment/))

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swamp40
This is very interesting, but the title is misleading.

The ants don't _do_ anything better than humans.

They just _act_ like panicked humans do, so you can easily test different
theories about the best way to build exits.

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dang
We switched to the subtitle.

~~~
ars
The new title is still misleading (although I'm not asking you to change it,
it's the fault of the article).

They don't do better with it obstructed, they do better when there are
channels leading to the exit.

~~~
dang
I don't doubt you, but in cases like this it is helpful if someone can suggest
an accurate, neutral title. We don't have the capacity to absorb all the
content well enough to do that in every case.

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ewindisch
I don't know why they're republishing this. This same source published the
same article last year: [http://nautil.us/issue/13/symmetry/want-to-get-out-
alive-fol...](http://nautil.us/issue/13/symmetry/want-to-get-out-alive-follow-
the-ants)

Interesting, but old news.

