The Dangers of a Crowd

As a mass of pedestrians in the same place at the same time, crowds can be easily created. Football matches, concerts, stadium gigs or festivals are just a few examples. While these occasions are often people gathering to have a good time and enjoy some entertainment, the mass of people in a crowd can be extremely dangerous. Suffocation and trampling are just some of the many dangerous problems that crowds cause.

Oasys Software, a UK technology business, provide crowd analysis software, MassMotion, to assist architects design safer environments for pedestrians, reducing the risk of crowding. With calmer crowds actually causing the most problems, event organisers have a legal duty to ensure the safety of the pedestrians in visiting crowds. They are legally required to do their best to prevent the following dangers outlined by the Government:

Crushing between people
Crushing against fixed structures such as barriers
Trampling
Surging, swaying or rushing
Aggressive behaviour
Dangerous behaviour such as climbing on equipment or throwing objects

The actual dangers in crowds
The leading cause of death in crowds is crushing and suffocation. Mass movement of large crowds can lead to forces of over 4,500 Newtons, or 1,000lbs, being exerted. This can cause steel railings to bend and those who are against these railings can suffer from extreme pressure to the chest causing suffocation.

Surprisingly, this is rarely caused by a stampede. You need to have room and movement for a stampede, so if there was enough room to stand on top of people, there would most likely be enough room to move out of the way. Instead, this type of crushing is caused in dense crowds by something as simple as one person falling or tripping, causing a delayed chain reaction through the crowd.

One of the main causes of this is a group reaction to a threat – pedestrians trying to avoid something. For instance, a 2003 crush in a Chicago nightclub was triggered by people attempting to avoid the pepper spray being used to break up a fight. Over 70 people were killed or injured. Unlike a panic, these situations usually involve cooperation and assistance.

Crowd crushing accidents can also be linked to the idea of ‘craze’ – where a mass amount of people rush to try and attain a valued object or goal. There is a lack of communication meaning these accidents can be hard to prevent once they have begun. The ‘head’ and ‘body’ of a crowd can’t properly communicate to warn each other and prevent the consequences. The lack of communication means that often the wrong signals are sent to those at the back or ‘body of the crowd. When those in front end up immobile and trapped, those at the rear are lead to believe there is movement so keep pushing resulting in further crushing and often disastrous consequences.

Examples
Unfortunately, there are countless incidents where crowd movement has cause catastrophes – many of which display signs that we have previously mentioned.

Lack of communication:
In 1981, Greek football fans were killed when they tried to leave a match in Athens stadium, finding the gates locked. Whilst those at the front of the crowds were aware of the situation, there was no way to communicate the message to the rear meaning they continued to press forward, causing 24 deaths.

‘Craze’ behaviour:
In 1989, 96 people were killed and more than 170 injured at Hillsborough Stadium in Sheffield, England. A larger than expected fan base was trying to enter the stadium, which caused police to open gates to relieve crowd pressure. Instead, the crowd surged into the stadium, crushing fans into enclosed terraces.

Reaction to perceived threat:
In 1985, there was a riot by English and Italian fans at a European Cup Final in Brussels which led to spectators trying to escape the violence. This led to 38 deaths by asphyxia (suffocation through pressure to the chest). Over 437 people were injured.

Preventative measures
The prevention of crowd disasters can be extremely difficult as the contributing factors can be very complex, and as mentioned before, there can be a huge lack of communication throughout the crowd. If you limit the amount of guests, you can tackle the crowd density – but this can be difficult at some open events such as religious gatherings.

The use of stewards can help improve the level of communication. They should be situated at different intervals between the head, body and rear of the crowd. Whilst barriers can be useful, sometimes they cause more problems than they prevent, so it is best to stick to rope for separating the crowds. They are a safer measure.

For crowd surges, it’s vital to ensure proper access and exits are in place. A timed exit in a large event, where people from different levels exit at different slots of time, is another popular prevention method.

Technology is helping fight against crowd crushing and other dangers. Using tools like MassMotion, not only helps architects design safer buildings for crowds, but also helps those in charge of buildings or crowd control run simulations to test the stresses of pedestrian flow and crowds. These tools can help in evacuation planning, giving an unparalleled insight into the unique spectacle of crowd movement.