If you’re in a crowd and people are close enough to bump into you, it may be too crowded.
That’s according to G. Keith Still, visiting professor of crowd science at Suffolk University and head of GKStill Internationala consulting firm that trains event organizers in hazard detection.
Such events, like the apparent increase in crowds during crowded Halloween festivities in South Korea’s capital of Seoul and the the tragedy at the Astroworld Festival in Houston in November 2021, caused numerous deaths and injuries.
Yet, who has studied the dynamics of crowd behavior and safety for more than 30 years, said organizers can help prevent crowd crushing incidents by monitoring a crowd’s density in real time and regulating the flow of people in a place.
Crowd density can be calculated in number of people per square meter, about one square meter. Younger, shorter people take up less space than older, taller people, but generally speaking things get uncomfortable once you hit five people per square yard, Still said — and all that is. more crowded can become dangerous.
“When bodies touch, that high energy and density can lead to these surges and crowd meltdowns,” Still said.
A sign that a crowd has become too dense is what Still called a “wheatfield effect”, where people sway uncontrollably. He said an example is visible online videos from a 2005 Oasis concert in Manchester, England, just before a large wave swept through the crowd towards the stage.
The key to preventing a disaster, Still said, is for organizers to monitor density and, if it starts to get high, slow or stop the flow of people entering the area. He said it is much more difficult to reduce crowds once the situation has become too dense.
If a room becomes too crowded, Still said, performers should stop and ask everyone to step back. Over the years, several artists, including A$AP Rocky and Linkin Park, did exactly that.
If you’re in a crowd, Still said you can help keep yourself safe by watching areas that are likely to become most crowded and pushing your way out of the crowd if you don’t have enough personal space. .
You can learn more by viewing an interactive chart here.