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Modern Crowd Control Lessons (from Ancient Pompeii)

What computer models are telling us about how to manage a crowd, the ancient Romans already seemed to know

Crowd behavior can be so distinct from individual behavior that the crowd is thought of as one thing, a kind of superorganism with its own psychology. Back when Pompeii’s amphitheater still hosted gladiatorial spectacles, Titus Livius (Livy) complained that crowds are “either humble and servile or arrogant and dominating…incapable of making moderate use of freedom.” Gustave le Bon, who wrote about group psychology in the early 20th century, said we must either figure out the psychology of crowds or “resign ourselves to being devoured by them.”

No security phenomenon is as volatile, none can flip from managed to chaotic as quickly as a crowd. That’s why professionals such as Still are concerned by poor design in modern stadiums. (Still says he’s also concerned about a marketing trend where companies harness crowds to generate buzz, a phenomenon called “crowd crazing.” The tightly hyped launch of a video game system, for example, has spurred violence, as have discount bridal gown shopping events, the grand opening of Ikea furniture stores and the lead-up to a sporting event between rivals.)

For a long time, the crowd itself, the mob mentality, mass panic, was inevitably blamed for disasters. But in the past decade, the science of crowd dynamics has undergone a broad philosophical shift, led by experts like Still who suggest that the mob mentality is a myth. Using computer modeling that combines a wide breadth of knowledge, from architecture and design to human physiology and psychology, Still has upended the assumption that the crowd causes disaster, and underneath that assumption he has found that it’s possible to manage the risk inherent in crowd dynamics and reduce the possibility of disaster.

“It’s not a stampede, it’s a design and management problem,” says Still. “The stampede is the effect, not the cause. It’s an entirely predictable crowd dynamic. We can tell you what factors give rise to that behavior and how to engineer a system to limit it.

“And, lo and behold,” he says, explaining the paradox he sensed in Pompeii’s amphitheater that day, “if you look at Pompeii stadium, 2,000 years ago, they did this incredibly well.” When he compares the Pompeii stadium’s design to what computer models tell him is good crowd management design, “the geometry, the ratios and spaces at Pompeii, they are all optimal.”

Turn the page for a tour of Pompeii’s Anfiteatro, and what makes its design, from a crowd dynamics standpoint, optimal.

Build a Big Bathroom. Pompeii amphitheater’s bathroom is the design element most distinct from modern stadiums. In fact, there was only one public toilet, and it wasn’t in the stadium, it was next to it. The toilets were part of a larger structure, called a palaestra. Originally in ancient Greece, a palaestra was a gymnasium complex, but here its function was broader. People gathered here during events. Likely they conducted business and got food and drink here too. The palaestra was effective because it was huge, the size of four and a half football fields; its footprint roughly matches the stadium’s. The public pool at its center, with a 3-foot shallow end and 8-foot deep end, was 75 feet wide by 115 feet long. “Not only were there plenty of toilets,” says Still, “but the route to and from them allowed for a wide dispersal of people.” In modern facilities, there are many small bathrooms that endure rushes during intermissions, and the path usually narrows at the bathroom’s entrance. Still says modern stadiums should build more and bigger bathrooms, give patrons large areas to line up outside of them and, as much as possible, separate their location from the stadium’s main traffic. At Pompeii, he says, “they clearly planned for the rush that would occur at the end of a spectacle. You had the same human needs”—to visit rest rooms—“but the layout and design made the whole dynamic of moving to and from much better.”