Dressed in a combination of sensors and an orange cap, strange festival-goers mingled with the dancing hordes of the Hellfest festival, devoted to metal rock. This one ends Sunday in Clisson (Loire-Atlantique) after an exceptionally extended version over two weekends. VSScientists are conducting an unprecedented study there on crowd movements in order to better prevent accidents and fatal jostling.
“We are here to try to understand the phenomena that take place in dense crowds and how to prevent the dangers associated with these crowds“, sums up Julien Pettré, researcher at Inria (National Institute for Research in Digital Science and Technology) in Rennes.
Julien Pettre directs a European program called CrowdDNA (the DNA of the crowd, literally), carried out since 2020 in partnership in particular with German, English and Spanish researchers. Why did you choose the Hellfest, which ends on Sunday in Clisson (Loire-Atlantique) after an exceptionally extended version over two weekends?
“We know that there are dances linked to the music listened to where physical interactions will occur between individuals“, explains the researcher, installed with his team in a prefab behind the main stage throughout the festival. “Circle pits” (participants quickly run in a circle), “walls of death” (walls of death, two rows of festival-goers separated by a clear space darken on it) and other pogos or slams (festival-goers carried by the crowd, lying down) have become essential rituals of the extreme music festival.
“We are a bit like astronomers who come to observe the stars“, underlines Mr. Pettré. “But the crowd telescope does not really exist so we mix different types of data“. To observe the moving constellations of Hellfest, the festival management agreed that Inria could recover the images filmed continuously by the cameras on the watchtowers of the “Warzone”, one of the six stages of the festival.
For their part, once or twice a day, two young volunteers from the small team put on a special suit equipped with sensors distributed all over their bodies, which record their movement. The cap allows the team to spot them on the videos. Even though their gear may go unnoticed at a festival known for its eccentric outfits, they wear a t-shirt meant to warn the general public: “Hellfest and Inria collaborate here to study crowds“. They then mingle with the crowd of the chosen concert, once or twice a day.
“We try to do everything,” explains Thomas Chatagnon, a 25-year-old Inria doctoral student. One of the volunteers is in charge of going to mingle with the “circle pits” or other “walls of death”, the second must let himself be carried by the flow or go up the crowd as if he wanted to leave the concert. The most dangerous ? “The times when we lose our balance“, judges the young researcher.
Compulsory figures, such as “walls of death” or “circle pits”, are not the riskiest. “It’s pretty controlled and only people who feel like going there go. Incidents happen when people have not decided to be there“, he says. The information collected in the field will then be “coupled” with videos, with a view to computer modeling the movements of “guinea pigs” in the middle of the crowd.
With an objective as simple as it is ambitious: to invent new computer tools to detect in time the warning signs of a possible accident, or even of a catastrophic stampede like the one which had caused nine deaths and hundreds of injuries during a rap concert at the Astroworld festival in Houston (Texas) in November 2021. “When we have detected these small signs of the spread of a movement in a crowd, we can alert the manager (of an event) who will decide whether or not to intervene to disperse the crowd“, explains for example the head of the project.
The study, also carried out in the laboratory, in stadiums or in public places in the partner countries, must continue until 2024. In the meantime, “we hope to come back to Hellfest next year!“, smiles the researcher.