NFPA Journal - July/August 2020 - 60

COWBOY UP Oklahoma State
University hoops fans surge onto
the court following a recent home
victory at Gallagher-IBA Arena.

TOO CLOSE FOR COMFORT

One phenomenon that our computer vision research project on
crowd management hopes to address is high-density crowds,
where people become packed together so tightly that the only
movement available to them is the collective motion of the crowd.
As they have demonstrated time and again, crowds of this density
can become deadly.
I experienced this phenomenon in 2014 when I was an undergraduate at Oklahoma State University in Stillwater, Oklahoma.
Early that spring, the OSU Cowboys faced the fifth-ranked Kansas
University Jayhawks in a basketball matchup at OSU's GallagherIBA Arena. I was there, in the middle of it all, part of the crowd
that packed the bleachers like sardines, eight rows behind the
home-end basket. The matchup was billed as the best home game
of the season, and noise and excitement rippled through the soldout arena for the entire game. In the final moments, the Cowboys
pulled away to win it, upsetting the favored Jayhawks. A rowdy celebration ensued, and fans prepared to storm the court as the final
buzzer sounded.
Packed in among the crowd, I had two options: rush the court or
be trampled. So I joined in, bounding down the bleachers, being
pushed and shoved from all directions, anxiously moving toward
center court. It seemed like I was trying to move through a sea of
feet, and I tripped; I could feel myself falling as the crowd continued
to move me forward. For a split second I was consumed by panic.
Fortunately, a friend was next to me and able to quickly lift me up,
and we kept moving in the giant scrum of bodies. We went until we
could no longer move forward, waiting for whatever happened next.
That's when the ordeal really began. We'd stopped, and all of the
people in front of us had stopped, but the crowd behind us continued to pour onto the court, pressing into every available inch. The
space around me shrank, then became none at all. I was in contact
with everyone around me, front-to-back and side-to-side. The
density of the crowd was immense, and I could feel the pressure
of all that contact increase. For a period of time, I felt as if I had no
individual physical control, that I was merely an involuntary part of
the mass. The only motion I experienced was from the pulses that
radiated through the crowd like shockwaves. I was overheated and
very anxious, and I kept telling myself to stay calm.

Eventually, the pressure began to subside. Space once again
appeared around me as the crowd dispersed and the celebration
died down. Although the excitement of the big win still consumed
us, I was relieved at actually being able to move again. We left the
arena unscathed and elated, but history has shown repeatedly that
the consequences of high-density crowds can be harsh, and sometimes lethal.
In these crowds, there is a vast array of psychological and
physiological pressures that can impact the human body. When
crowd density reaches approximately five to seven persons per
square meter, the group begins to behave as a single fluid mass.
If people in the rear are pushing forward, those in the front can
be crushed against one another or into physical barriers with as
much as 1,000 pounds of force. Such extreme pressure can result
in a condition known as compressive asphyxia, which can cause
erratic breathing, unconsciousness, and death. Most of the 96
people who died in a crush incident in 1989 at Hillsborough Stadium in Sheffield, England, during a soccer match succumbed to
asphyxia, the result of an agonizing buildup of pressure caused
by people crowding into viewing areas and trapping spectators
in front against chain link fences. In these situations, people
not overcome by the physical pressure can faint from the heat
emitted by the large mass of bodies, or be overtaken by extreme
psychological reactions such as anxiety and panic.
Looking back on that night at the basketball game, I realize
that the crowd management strategy had been successful. Barriers had been removed, and safety officials allowed portions of
the student section to storm the court while preventing others
from following. To the best of my knowledge, there were no
reported injuries. Even so, in venues like this, spectators often
take their safety for granted, and may not act until it's too late.
That's why crowd managers need relevant, timely, and accurate
information to inform their decisions during dynamic events,
which often must be made in just seconds. The data generated
by our crowd density tool, such as crowd counts and trends in
crowd density, aims to help safety officials make those decisions
in critical moments, preventing near-misses from turning into
tragedies. -VH

GETT Y IMAGES

THE AUTHOR RECOUNTS AN UNNERVING ENCOUNTER WITH A HIGH-DENSITY CROWD

60 | NFPA JOURNAL * J U L Y /A U G U S T 2 0 2 0

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NFPA Journal - July/August 2020

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