Wednesday 31 December 2014

Leaving the London Eye New Years Eve Celebrations area in double-time

Everyone is getting ready for New Years celebrations, I for one go to see the London Eye Fireworks almost every year. However, as the Mayor has decided to charge £10 to see the fireworks and the requirement of buying it in advance has put me off this year. No doubt I will still be watching it, albeit from a distance. However, if you're one of those lucky ones that have managed to purchase a ticket, and are looking forward to the fireworks, trust me, it's quite a view, and if you go in early enough, you'll get a good spot, when I say early, it's about 8pm. Especially the embankment area, it gets cordoned off after that (well, used to until they started charging), so the number of people is just about right.

The atmosphere is great with everyone in a celebratory mood, London turns into this extremely friendly place, where one feels part of this huge family that has come together to celebrate bringing in the New Year. You get to meet all sorts of people from around the World. When the countdown begins, there's a massive display on the Shell Tower block counting down the seconds until Big Ben strikes midnight, the lights around the London Eye start flashing, and off with a bang go the fireworks timed with music blurring through the speakers along the embankment. The pictures show last year's theme.

Sweet Flavoured theme in 2014
London Eye Fireworks 2014
However, once the fireworks and celebrations are over, you need to head back home or to another party, this is when it becomes a little difficult. The crowd, oh my, the crowd, if you've had a good spot on the embankment, it can take an hour or more to get to the exit at Trafalgar Square along Whitehall due to the number of people trying to get to the stations and back to wherever they want to go. The police generally use a pedestrian traffic management system allowing a certain number of people along Whitehall at a time with a number of break spots. There is also a final barrier at the end of WhiteHall into Trafalgar Square, where people can only exit from the middle of the barrier. The typical route one would take through the crowd to exit from a spot on the embankment is shown in the top map illustration. What happens here though is that you want to get out the quickest way possible, and instinct dictates that you take the shortest route through the crowd, which is through the middle of the crowd flow, where everyone is walking through and you follow the person in front, due to the herding effect, as I explained in my previous post. This is shown in the first picture. However, we don't want to use instincts here, we want to use a better approach to getting through and exiting as quickly as possible. How do we do that?

Typical exit route from the embankment
Exit route skirting the crowd flow (map via Open Street Maps)
We go against our instinct of getting through the dense crowd in the quickest possible way, that is, walking through the middle. Now that most people will be walking through the middle, what we want to do is look at the crowd flow, as long as it's a homogeneous flow, the density of the crowd is the greatest at the middle, so we want to avoid that area, and walk in the areas of least density that is moving in the direction of our exit. The area of least density in our case is the edge of the crowd flow, so as long you skirt the edge of the crowd flow, you will get through to the exit in the quickest possible way. It's only a small change from your typical way of walking in a crowd, just stick to it, and don't let your instincts take over, especially at the end point when you see the barriers, walk around it as shown in the figure. From personal experience, I got through the crowd with my friends to the exit in a little less than half an hour last year. Although I'm aware of this solution as part of my research, I still couldn't help my instincts telling me to go through the middle as well, especially when we were so close to the exit barriers, so it's an innate human trait I suppose, but I had to fight it off. There you go, a simple and effective way that not only works on New Years Day, but in other situations of dense crowds flowing in a homogeneous manner.

Now, hope you all have a really great New Year Celebrations, and hope the New Year is filled with joy and happiness.

Saturday 27 December 2014

Getting through Boxing Day Shopping: A form of self organisation

Boxing Day is a great day to go shopping, you can grab yourself bargains that you could not grab throughout the year, navigating your way through the thousands of bargain shoppers. A few years ago, I decided to brave Boxing Day shopping and became one of those bargain shoppers on a mission, on the most crowded shopping street in Europe, Oxford Street is what I'm talking about. The street that all Londoners try to avoid until hell freezes over, well, not quite, but you know what I mean, if you want to avoid crowds even on a normal day, you avoid Oxford Street.

Boxing Day 2011, Oxford Street
Boxing Day is a whole other occasion. It's an interesting place on Boxing Day, especially if you go in with a determined focus, you can get out of it unscathed by the evening, with bags full of things that you don't really need, but you just end up buying (I'll let other experts explain that behaviour: here and here).

If you just take a step back, and look around at what is happening, people start flocking to shops to spot bargains. In order to get to these shops, they navigate the thousands and thousands of people on the street. You have a shop (or many shops) in mind, and you want to get to each shop as quickly as possible so that you don't miss out on those bargains of the year. In order to get to the next shop in the quickest possible way in a crowd, you start mimicking behavour, humans are indeed great social creatures that navigate the social world through mimicry. We like to copy others, in order to be socially accepted, and at the same time, we like forming our own unique identity, and we work by balancing these conflicting interests.

In this context, we find ourselves mimicking each other whilst navigating crowds. Due to the sheer number of people in our path, we can't normally see our destination clearly, but we know the direction we want to go. For example, I want to walk to Selfridges  through the Boxing Day crowds to grab that sought after bargain (yes, that's where we all want to go on Boxing Day, considering they had an estimated turnover of £2 million in one hour yesterday). How do I get there?

First of all, I can't see my way due to the amount of people present, so I observe the person walking in front of me going in the direction of Selfridges, and I start following them. What I'm actually doing here is I'm passing my decision making power to the person in front as I can't see the path, and I'm trusting that person to take me in the direction I want as quickly as possible through the crowd. There is a term for this kind of following behaviour, known as herding. This is the first step I take in order to get me to my bargain. The transfer of power itself is known as social contagion.

Now, if I take a step back (not literally), and look around, I start to see every one of us is following a person in front of us in order to help us get through the crowd. The herding behaviour leads to multiple layers of people flow forming travelling in the same direction, especially due to the number of people on the street. We can look at this from  an analogy of car traffic on a motorway. On a motorway junction, before entering the motorway, at the slip road, two roads merge into one. Similar merging happens when I'm walking through the crowd, the merging of people travelling in the same direction. This gives rise to our second phenomenon, known as the zipper effect . It's pretty much like zipping your jacket, where each zipper tooth is layered over the other, similarly you're the zipper tooth, and you start zipping against other pedestrians travelling in the same direction.


There's a lot of trust we put in the person in front to get us to our destination. This trust we put in each other leads to our third phenomenon, the emergence of lanes formed of the 'zipped' multiple layers through the crowd. These lanes can be in both directions, and there may be more than two lanes at the same time. Due to the herding behaviour, these lanes generally become homogeneous, and we are unconsciously giving up a part of our identity to become part of this homogeneous flow. This may or may not seem obvious, but the observance, and dissection of these individual steps that lead to these phenomena help us explain the way crowds behave. How we transfer our own identity to the identity of the crowd, leading to the emergence and disappearance of flows and lanes, gives us an understanding of our own identity within a crowd. There is also a term for these types of flows, not a creative name, but one that makes the meaning clear, it's known as lane formation. These lanes are ever changing, and they adapt to people in the crowd just standing, the existence of bus stops, street lamps, etc. along the street. It's interesting to see how we as people are adaptable, and this adaptability also works really well at a macro-scale, the flow lanes adapting to the environment present to us.

Being a part of these lanes, and flowing amongst it then gets me close to my destination, that is Selfridges. This gives me the flexibility to again take control of my decision making and I walk towards it and enter this multi-million pound department store in order to grab that well sought after bargain. Before I know it though, I've again passed part of my decision making to the marketers that get me to buy items that I don't really need. Again, I leave that to the other experts I've linked to, to explain how that's done.

Boxing Day 2011, Oxford Street (showing the emergence of Lanes)
Why am I talking about this? Well, in addition to the fact that this is a blog on crowd simulation and to understand how crowds form and behave, it was one of those things, where I was walking along Oxford Street on Boxing Day a few years ago, I decided to take a picture of the crowd at the time and post it on one of our current social media platforms. However, observing the photo closer, you start to distinguish the lanes that have formed through the crowds, which I thought was quite interesting to observe in my natural environment outside my normal research realm. As you can see with the photo overlaid with the lanes. Also, the current timing seemed quite fitting, as I decided I didn't want to brave it again this year.

Other than that, hope you've all had a great Christmas, have a better understanding of what you do when you go out shopping on Boxing Day, but most importantly, found yourselves some good bargains that you actually do need.

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