How the dangers of a crowd can be analysed with technology

When there is a collection or mass of people that are in transit, this creates a crowd. Whether they are within a stadium concert, a football match or any other type of celebration, crowds can be dangerous — and technology is leading the way to help battle the causes of crowd catastrophes and accidents. Crowds can cause suffocation and trampling, but calmer crowds can also be a persistent problem. When a group of people becomes a crowd, it becomes a fluid-like movement that suffocates individuals by crushing their lungs or throwing them into the air.

Regarding the safety of a crowd, many firms are investing in technologies that help to analyse and evaluate situations that may present a danger to a crowd. By law, event organisers are obligated to keeping crowds safe — so these technologies can be utilised efficiently within this endeavour. Dangers that are listed by the government are as follows:

· 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.

Examples

There are countless examples of crowd movement causing catastrophes, with many displaying signs of the factors we’ve covered above. Here’s just a few:

Lack of communication: In 1981, Greek football fans were killed when they tried to leave a match in Athens stadium, finding the gates locked. The rear of the crowd had no way of knowing this was the case and 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 fanbase 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: A riot by English and Italian fans in 1985 at a European Cup Final in Brussels led to a fight by spectators trying to escape the violence, which led to 38 deaths by asphyxia. Over 437 people were injured.

What are the dangers posed within a crowd?

The movement of people can resort in a force of over 4,500 Newtons or 1,000lbs within a crowd, which means that it is not usually the case that trampling is the main cause of death when it comes to crowd disasters. Objects that are supposed to protect a crowd can also become a potential hazard, as steel railing can be bent and cause injury to passers-by. These types of pressures can cause compressive asphyxia, a leading cause of suffocation within a crowd and the most common cause of death.

Surprisingly, it is rarely the case that ‘stampedes’ are the most common form of crowd catastrophe. A single trip or fall by one member of the crowd can be the deciding factor within a crowd catastrophe. This occurs within a crowd that has 6 or more people per square meter. Technologies that analyse motion on mass are therefore used in these situations where crowd footfall can be analysed to minimise the risk to those within the crowd.

A tragic example of a crowd surge that resulted in many casualties was the Ibrox Disaster in 1971; 66 people were crushed and killed during this accident, which was more than likely caused by someone simply tripping down the stairway. This caused a chain reaction of pushing and a pile up from the back to the front — resulting in compressive asphyxia for many.

Being able to pre-empt threats before they happen, while perceiving the extent to which there is a threat in a crowd, is crucial when alleviating the dangers that a crowd could potentially be faced with. Pre-emptive technologies that spot dangers before they happen, are therefore crucial to avoid future disasters.

Oasys software, a technology firm in the UK which invests in crowd simulation software, is using software that allows architects to design buildings that are safe for their users. For instance, in 2003 70 people were crushed while trying to escape from pepper spray that was being used to break up a fight. This may not have happened if technology could have established that this wasn’t enough space per square meter for people to leave the building safely.

How to prevent crowd disasters from happening

The factors that contribute towards a crowd disaster are noticeably complex, which means that attempting to prevent these disasters is exceptionally difficult, and often lacks proven results. The density of a crowd is the first immediate problem to tackle. Setting a specific limit of guests can help alleviate the dangers associated with crowd density, but this can often be an unrealistic method at larger events such as religious gatherings.

Another important factor when attempting to prevent a crowd disaster is communication. Placing barriers to try and create movement paths can cause their own problems, as barriers may actually lead to accidents rather than prevent them. Simple barriers like rope or posts may be less dangerous. The use of stewards to help promote communication is a recommended measure as they can prevent the issue that comes from a communication breakdown between the head and body of a crowd.

It’s important that a building contains clearly marked exits during a crowd surge. A timed exit in a large event, where people from different levels exit during different slots of time, is another popular prevention method.

Crowd technologies are what will help battle against disaster situations in the future, ensuring that people remain safe at all time within a large crowd. Using tools like MassMotion, those in charge of buildings or crowd control should first 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.

Sources:

http://www.bbc.co.uk/programmes/b00x53wd

http://www.gkstill.com/ExpertWitness/CrowdDisasters.html

http://www.crowdsafe.com/fruincauses.pdf

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