Mathematically Designed to Move People

01 July 2012

Interview with

Professor Steven Bishop, University College London

With tens of thousands of people visiting the Olympic park during the games and with them all attending at the same time, venues inside the grounds need to be able to handle large crowds safely and efficiently.  The risk of congestion is quite high and this can cause both distress and discomfort for the individuals who have to queue.

But now, scientists are using mathematical models to visualise how large crowds move in certain spaces in order to predict where problems might arise, and this means, architects can overcome these issues before the designs have even left the drawing board.  This new technology is now being used in a wide range of public spaces including the recently refurbished King's Cross station in London. 

Meera Senthilingham went along to the station to meet Steven Bishop, the Professor of Dynamics at University College London to find out how these models can keep crowds on the move.

Meera -   We're here at King's Cross Station in London where a new concourse opened back in March earlier this year.  This station serves over 14 million people passing through every year,  nearly 110,000 people every day.  So when designing such a station, the movements and mentalities of crowds and how they move needs to be accounted for.  So Steve, this is what you look in to, the mathematical modelling of people as they move through a space such as this...

Steve -   Yes, modelling crowd movements in major structures is an important Kings Cross Station crowd controlaspect of all design nowadays for large structures.  This one is pretty magnificent actually.  It looks very stadiumlike on the inside and certainly, a lot of modelling would have had to have been done in the design process.

Meera -   So, how do you actually model people and the movement of people mathematically?  What's taken into account?

Steve -   Well, there are three factors really:  There's the individual person themselves, the second is the crowd movement as an object, but there's also the environment within which they're moving.  So, those three aspects all need to come into play.

Meera -   What do you actually do to see how those factors would come together to get hundreds of thousands of people moving through a station like this every day?

Steve -   Well firstly, an understanding of flows, like fluid flows, are very useful to give an overview of what's happening, to understand how those flows move through an object, through a space.  But it's also important then to think about how individuals behave, because we're not robots and we don't always act as flows.  We often go against the flow, so we have to understand how individuals behave, which is sometimes irrational.

Meera -   What would you say are the main ways that models can be combined with design in order to make a space "crowd friendly"?

Steve -   The important thing is, with mathematics, you can actually do modelling on the computer so you can do experiments on a computer in silico, saving you the hassle of having to build a structure and find out there's a problem later on.  The idea is that you can run through different scenarios very quickly on a computer so that we can really understand how the form and the function interrelate.

Meera -   Let's take King's Cross Station here for example.  What kinds of things are around us that you can see have been thought about to model people moving through?  Just below us here, there are at least hundreds of people passing every minute, and there's no congestion, it's all very free-flowing...

Steve -   It's a fascinating thing to watch actually, especially if you watch it and speed it up.  But of course, where the columns are to support the roof are really important parts of what's going on, and in particular, where are they positioned in relation to exits and entrances.

Meera -   But it's also got very high ceilings and it's very light in here, and generally quite a pleasant environment.  Is this quite important for crowds?

Steve -   Of course, it's aesthetically pleasing but also, makes people feel a bit happier if they can see lights and have space above them as well as around them.  So they've learned quite a lot of lessons.  Don't forget there was a fire not 100 yards from here, the King's Cross underground fire that there was a major disaster in 1987, so we have learned something from that.

Meera -   That's touching on the fact that there have been various failures in the past where large crowds have been involved.  What do we need to know about what happens in a case of an emergency where large numbers of people are involved?

Steve -   So when we look at past failures, we often find there are many contributing factors.  There's not just a single entity.  So firstly, when large groups of people get together, there's often a stop/go in their flow.  So that when they stop, they begin to panic and worry about what's going on.  Then if you get inflows and outflows coming together or cross flows that becomes really problematic.  More importantly, in new buildings where you don't know where you are, you're not sure where the exits are.  So this is a critical factor in getting people to know really what the alternative ways out are.  And that's where training new staff comes in helpful.

Meera -   Is that the kind of thing that's accommodated now, the extra level of information for people to know where to go?

Steve -   The information and monitoring.  So firstly, King's Cross here is monitored probably more than any station in the world, but secondly, information can be given back to the people via announcements that we can hear almost every few minutes.  So, information to be gained and information given out is really critical in the time of stress.

Meera -   Does this tap in to human psychology and human behaviour in the fact that people like to know what's going on?

Steve -   It does, absolutely, and that's where mathematicians like myself would have to work with psychologists.  Everybody is different, so it's quite important to understand how people behave.  We can learn a lot from studying other animals too, but people that have this particular thing that they have real choice.  They can make decisions much, much quicker and so, we really need to understand those to get the right results.

Meera -   What about the actual design of the structure?  What else can you see here that perhaps would've been thought about to keep crowds moving?  For example, there is a one-way system in place here.  Does that make quite a huge difference?

Steve -   That's a huge difference here.  The arrivals and departures being separated makes a lot of difference particularly if, for the arrivals, you have lots of people waiting to meet other people, so these are very stationary objects, and this can create problems.

Meera -   And how do you account for the different types of disaster that could happen?  There could be a fire or there could be a bomb scare in a station like this.  Do these all need to be thought about differently?

Steve -   Yes, those and more actually.  Even somebody fainting or a fight occurring.  People have to sit down and think outside of the box about what could possibly go wrong and then we try and then prevent that failure.  Once we know what they possibly are, we can design against it.

Meera -   And what about the context of the actual building and its purpose?  This is a large station with people moving through it each day but for something like the Olympics, a stadium, people will be stationery, only moving at very specific times.

Steve -   Yes, it's quite critical in a stadium because although people may arrive slightly staggered, they all pretty much leave at the same time.  The important thing to remember there is that if everybody is leaving all at once at the final whistle, the exits need to be large enough to account for that.  You also have to have signage and make sure that people don't stop immediately outside the door, another critical thing.  We often see that in fire evacuations; people will stand immediately outside the door and just block the exit for everybody else.

Meera -   So it's keeping people moving again.

Steve -   It's always the case.  If people are moving, they're generally happy.  When they're stationery, they tend to get a bit edgy.

Meera -   In summary, what position would you say we're in today using these models and designing buildings for large numbers of people?

Steve -   We're certainly in a much better position, Meera, because we have the experience of what's gone before and the technology to actually predict what might happen in certain scenario events.  So, we have an understanding of people's behaviour together with information technology as well as bright area designs.  On top of that, we can add scenario setting from mathematical modelling to actually help us really understand the whole picture.  So we're understanding how it all comes together.

Louise -   And that was Steven Bishop from University College London talking to Meera Senthilingham on how modelling the movement of people can help keep crowds moving at the Olympic games this summer.

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