How to Control a Crowd

Writing by Sam Denby and Tristan Purdy
Editing by Alexander Williard
Animation led by Josh Sherrington
Sound by Graham Haerther
Thumbnail by Simon Buckmaster

[Sumanitu]

When the Wii came out in 2006, someone camped in a tent on the side of the Best Buy for 5 days. I showed up at 5am for the 9am opening. The camper had a notebook and took names of people that showed up. Surprisingly everyone respected that person's list 100%. They announced at 8am that they had 84 consoles and people that showed up after the limit left peacefully. Everyone else formed an orderly line when it was near opening time, by asking others the number they were given by this random camper. People also shared water and sodas with their neighbors in line

[michaelmayhem]

The key to good crowd control is partying with a strong tank that knows when to taunt or use his other abilities while as a dps you're focusing your fire correctly.

[Rothryn]

As a German, when I hear crowd crushes I'll always be reminded of the 2010 Loveparade desaster with 650 people injured (some quite severely) and 21 people dying from being crushed in a narrow tunnel that was the sole entry AND exit to the festival, because the venue was full and people wanted to get in.

[yeckiLP]

I feel that a simplified (even further) variant of this should be taught at schools, so that in a generation or two, enough people know about the problem to mitigate it. If everyone were patient/understanding enough, that pushing makes things worse, rather than better, even for themselves no pressure would build up..

[Kaiasky]

One of the things I love about concerts is a crowd that's aware of these risks. You often hear people shout "BACK THE F*** UP" at punk shows, or coordinate to shove backwards to ensure there's space to breathe at the front. It's a weird kind of self-knowledge that I'm sure has saved lives, though of course it only does so much without good crowd planning and security.

[drushkeye]

Hey, a Wendover video about exactly my job! I'm an engineer specialized in designing/planning busy spaces like these, and a in fact a few I worked on were in the video :). Really good overall, I just want to add a couple points:

- You said that in a crush scenario the crowd starts to be ruled "by something similar to fluid dynamics" - it's not "like" that's exactly what's happening, the crowd is basically a bunch of water balloons squished together.
- The main sign to look out for: if it feels or looks like everyone is moving as one (imagine a crowded wave pool at the waterpark) then it's becoming dangerous.
- If you're inside a crush and can't escape, the safest thing to do is to brace your hands against yourself and stick out your elbows.

Finally, to quickly summarize how planning solves this kind of thing: it's a lot like designing a car to keep you safe in a crash. You're not going to predict where or why the crush will occur. All you can do is design crumple zones to give the energy somewhere to go, by building doors/walls/fences that will break when pushed enough and not letting people completely surround the thing they want (which is what makes the Hajj so dangerous).

[johnbatsch]

My dad was at that concert in Cincinnati. He told me it was cold that day but because of the crowd it felt like summer from the body heat of everyone there. He also said he was in the back and everyone was shoulder to shoulder, people would sway back and forth like a wave and you couldn't do anything except move with it, the animation does a great job of showing this. Apparently the rush happened because The Who started their stage testing, and everyone assumed that the concert had started which led to everyone trying to make it inside.

[Ahiddenworldofmusic]

This was incredibly fascinating to learn about. I was in a crowd crush scenario a couple years ago at a concert. It got to "shock wave" density but I've always looked back on that memory fondly. I remember feeling weightless as we all swayed collectively to the music. Looking back at it now, that situation was way more dangerous then I knew and I wouldn’t be surprised if some people had gotten hurt or at the very least suffocated a bit.

[jaredwilliams]

I'm glad that you pointed out that it isn't necessarily any one individual's fault, but a design issue. I am a programmer, and I see design issues passed off all the time as "user error", including events like the false nuclear launch alert in Hawaii. The test and real alert options were poorly labeled, and there was no "are you sure" message. All it took was a single, simple mis-click to trigger a real alert instead of a test.

It seem like one of the main problems with crush events comes from the people in the back not realizing that their small push is being compounded and hurting someone in the front of the crowd. A concept that we try to use at work is "put the pain on the people causing the problem". We try to design our software so that if someone does their job poorly, that the problems come back to them, rather than be passed downstream to someone else. It almost seems like crowd control needs security officers near the back of the crowd that can work on preventing those in the back from pushing if the crowd density gets high enough at the front.

[XiadaniLicarayen]

That plane anecdote is so spot on. One time a train I was on malfunctioned. We were waiting for a long period of time before the announcement to disembark was made. I was instantly able to find one other person who was going to the same place as me to split an uber. Another person overheard and asked to join, everyone was super friendly and I didn't even think about the fact that if the train hadn't malfunctioned we never would have spoken a word to each other.

[abaniahmadbani]

As an Indonesian, I really appreciate when you mentioned that the cause of death in Kanjuruhan tragedy is mainly because of the crowd fleeing from the tear gas, not by the riot itself. Because, although all of independent and international journalist & investigators said so, but those authorized institution always stated otherwise, even without any supporting evidence.

[mariosebastiani]

As my father taught me: "Avoid crowds. The bigger the worse. Crowd are not made by single persons, they're made by a lot of people, and thus can't be reasoned with".

[Kangaxx]

Realizing that crowds are fluids actually let me regain control once during a music festival. I was stuck in the crowd, impossible to move, waves running through the masses, but I kind of saw the dynamics at play. And by simply angling my body and shoulders I could let the waves push me through the masses, not being able to move out of my own power but directing the power the pressure waves excerted on my body. Once I figured that method out I reached the less dense parts of the crowd quite fast.

[jacobmacdonagh]

The identity point I think perfectly describes how British people act towards each other on vacation. At home surrounded by other Brits, we barely acknowledge strangers and keep to ourselves but as soon as we are on vacation, anyone British in your hotel you immediately strike up conversation with cus there’s this sense of camaraderie

[gavinjenkins]

I think there's a huge 3rd factor here you didn't specify: NOT KNOWING IT'S AN EMERGENCY. When there's a fire, everyone is "Oh damn! fire!" and is on high alert, mindful of people in pain, etc. When you're in the back of a crowd trying to move up to get game consoles, you have no idea you're causing harm or anything bad is happening, so there's no particular reason to even stop and think about it.

[wilberforce]

I was part of a human stampede one time. It was super scary. It really was like fluid dynamics; I felt like I was just part of a single consciousness made up of hundreds of people.

[phoenixmaemind]

I was at a P!ATD concert and it was impressive to me that they had several moments where they told EVERYONE to take some big steps back. They actually paid attention.

[mghtyboar]

Thanks for the explanation 👍I once encountered a situation at a small concert attended by around 7.000 people. When leaving the concert hall through a corridor and a very small exit, (the concert took place in a repurposed school gym) a pushing crowd developed behind me. This pushing back and forth happened several times. Eventually, I and a group of individuals nearby linked arms and created a makeshift barrier with our bodies. We managed to lessen the movement and as more people joined us and started shouting to those in the rear to wait, the crowd calmed down again and left organized afterwards. That was a scary experience, I can't imagine how forceful a larger crowd can become.

[stevenneiman]

I think two other reasons disasters don't trigger crowd crushes are that they push people away rather than towards, and trigger concern for the safety of oneself and others. Away rather than towards is fairly intuitive, since moving away from a concern will naturally spread the group out unless funneled through choke points. As for conern for safety, when you're at the back of a crowd trying to get into a desirable area you're just thinking about where you want to be, not about how the crowd might be dangerous to people further in who are compressed by the mass of bodies, but when you are in a burning building awareness of the fact that the situation is dangerous for everyone present is at the forefront of your mind so you will naturally tend to be more aware of how your actions might further endanger others.

[saadalqarni]

I have been working in organizing Hajj crowds since 2010 until now, and let me tell you the amount of work and organization is mind-blowing, and it is a science in itself.
The authorities are now working to include artificial intelligence technology to manage crowds, starting next year every pilgrim will wear an electronic bracelet that includes all his personal and health information. Also, through an electronic application, the pilgrim will receive instructions on which way to take, when, where and how to move!

This is important because we plan to receive more pilgrims in the coming years.