Fears remain over crowd control

Artist's impression of the redesigned Jamarat Bridge, which may pose a safety risk to pilgrims.

Experts in crowd control are warning the haj pilgrimage could be marred by another disaster, the sort that has claimed hundreds of lives in previous years. Prof Keith Still, the founder of the UK-based consultancy Crowd Dynamics, believes recent safety improvements designed to ease the flow of pilgrims through the Jamarat Bridge portion of the ritual could backfire, creating a dangerous build-up of people at the Holy Mosque in Mecca, Saudi Arabia, where the haj culminates. Prof Still has become concerned that although the bridge itself has been improved to increased capacity, allowing half a million people to pass through each hour, the changes could shift the problem further down, to the Holy Mosque. "If you widen one part of a high-pressure system, you've just created a very big blockage somewhere else," he says. "You can't change one part of the system without affecting the rest." During haj more than two million Muslims converge for a week of holy rituals. In the past the resulting masses have resulted in crushes and stampedes, where pilgrims have been literally trampled to death. In Jan 2006, 362 people died during one portion of the journey, referred to as the stoning of the devil ritual, where pilgrims gather on the Jamarat Bridge at the city of Mina five kilometres east of Mecca. Crowds of more than a million people can gather in this spot, casting pebbles at three pillars on the bridge to mark the site where Abraham faced the devil during his own pilgrimage. The deaths happened after a surge in the crowd at a ramp leading on to the bridge knocked pilgrims to the ground and under the feet of the stampeding horde behind. The Jamarat Bridge was built in 1963 to allow more pilgrims to approach the pillars, with stoning taking place from either ground level or the bridge's deck. But the 2006 tragedy, and fatal incidents in earlier years, convinced Saudi authorities it needed to be redesigned. When Prof Still drew up plans for the bridge, he made the pillars oval in the cross section rather than circular. The wider shape allowed more pilgrims to get near them, streamlining their motion as they moved past. He also advised organisers on crowd flow through the bridge, resulting in a new design with five storeys and a variety of entrance and exit points. Another team, led by Prof Dirk Helbing, the chairman of sociology, in particular of modelling and simulation, at the Swiss Federal Institute of Technology in Zurich, studied video footage of the fateful events in 2006. They found that the speed of the crowd dropped dramatically up to half an hour before the trouble started. Armed with this knowledge they developed software that can monitor a video feed in real time for signs of pending trouble. The total cost of the redesigned bridge was Dh4.4 billion (US$1.2bn), money that appeared to be well spent. The first tier was finished in time for the Dec 2006 haj, and the second for last year's pilgrimage. On both occasions the ritual proceeded without incident. Even though incomplete, the new bridge, with its extra ramps and tunnels, seemed to be working as advertised. With the third tier in place this year, up to 500,000 pilgrims an hour will be able to pass through. And Prof Still is not the only person to predict the increased capacity could cause problems further on in the process. Prof Ed Galea, director of the fire safety and engineering group at London's University of Greenwich, said the old bottleneck could have served a valuable purpose. "In some circumstances, self-regulating flow conditions brought on by congestion in one location may in fact be necessary in order to prevent even worse and potentially dangerous conditions developing elsewhere," said Prof Galea. Prof Still has voiced his concerns about the situation in a report to the Saudi authorities. In response, they are limiting the flow of pilgrims across the Jamarat Bridge and have expanded a section of the ritual area at the Holy Mosque. But he is not convinced these measures will be enough to avert another disaster. "They've increased the size of one area but that doesn't necessarily increase its throughput of people," he said. "There's now concern over the tolerance of the Holy Mosque and its levels of throughput. It's very late to be asking these kinds of questions." * The National