Marching orders

Issue 20 | Spring/Summer 2007

Report: John Watts
Photography: Greg Ford

Associate Professor Martin Burd from the School of Biological Sciences

Ant colonies might seem to have little in common with terrorist attacks and emergency evacuations of sports stadiums. But research underway at Monash University is showing how the behaviour of tiny Argentine ants might help humans engineer crowd control and traffic behaviour in panic situations.

Associate Professor Martin Burd, from the School of Biological Sciences, has been studying ants for almost two decades, but it was a sudden realisation in South America five years ago that set him on a new path.

"I was looking at the ant trails when I suddenly felt like I was in a helicopter looking on a highway down below giving the morning traffic report," he recalled.

"I was looking down and thinking, 'those ants look like people', and it was then that the correspondence between the crowd movements of ants and the crowd movement of people hit me."

Since then he has been collaborating with Monash transport specialists Professor Graham Currie and Dr Marjid Sarvi from Monash University's Department of Civil Engineering.

Their research has focused on natural engineering, studying how ant societies like the Argentine ants, classified Linepithema humile, engineer their crowd behaviour and traffic movements.

While the research is still ongoing, there have been a number of preliminary findings with some interesting counterintuitive discoveries.

"We've found that for a given width of pathway, the volume of traffic that can flow through it is actually higher when you have opposing flows of traffic mixing with each other," Associate Professor Burd said.

"We think the reason that works is because having these counterflows come up against each other breaks up clusters of ants that would otherwise be blocking those behind."

This finding might have relevance for human pedestrian crowd control in airports or other situations where people are burdened in some way that slows them down.

"We've also been studying the panic behaviour of ants and particularly how they escape through doorways," he said.

"And we've found something very interesting in ants - they never seem to form what we call 'arch-clogging'.

"You can imagine people rushing for a door and if you were sitting on the ceiling looking down above that doorway, you would see semicircular arch-like jamming formations occur.

"These might only last two or three seconds, then they'll break apart and a pulse of people will exit the doorway, but if 10 or 20 seconds later another jam forms for a few seconds, you're loosing a substantial fraction of the evacuation time from these clogging formations," he said.

"At least part of the reason seems to be that individual ants do not rush for the doorway to save themselves the way humans naturally would in a panic situation."

Associate Professor Burd wants to investigate how to apply these learnings to real-life situations.

"One suggestion is something as simple as putting a pillar in front of a doorway -- which would normally seem to block the exit -- could actually improve the escape by preventing the formation of these arch-jams," he said.

Other suggestions include building corridors that zig-zag slightly to improve pedestrian flows. "The changing of direction in a zig-zag should restrict the 'pushing pressure' that builds up within a panicked crowd, and thereby improve the orderly flow of pedestrians toward an exit."

While there are no practical applications of the research, which is still in its early stages, Associate Professor Burd says his group is "confirming general principles" that could have significant implications for the future.

"Anytime you have a situation where people might panic and need to escape -- whether it's a bombing, a bomb threat, a fire inside a building that needs to be evacuated -- could possibly be improved by our research," he said.

"The practical application would be in changing building designs, by us providing the evidence that a change would actually be efficacious and improve safety -- that is the long-term goal of our research."

For more information please visit Associate Professor Burd's web page.