5 ms·

The Mathematics of Crowds: How Pedestrians Inadvertently Self-Organize

63 points by webmaven 4y ago

moving_sofa 4y ago
Cycling is similar. No need to use traffic lights for cycle-only crossings. Relevant: https://www.youtube.com/shorts/jgacSmLBSIQ https://www.youtube.com/shorts/jgacSmLBSIQ
_nalply 4y ago
It's emergent behaviour: From simple rules interesting patterns appear. Like the Game of Life. After short thinking I see these rules (without having read the article carefully): 1. When other people stand in your way, you slow down. 2. When someone in front of you walks in the same direction, you follow them. 3. Driving influences behaviour, for example you tend to go around people at the right side (in UK, Ireland, Australia, NZ, Thailand, Japan and so on: on the left side). No wonder you get interesting patterns (curved lanes). I wonder whether the direction of the curve is pointing the opposite for left- and right-driving countries. And I also wonder if you mix people from different countries whether the curves disappear.
- rrobukef 4y ago
  The dominant hand is also important. As a lefty I have a tendency to evade left resulting in a will-they-won't-they when the other evades in the same direction.
  - melagonster 4y ago
    I remember a lot of people prone to choose left side. so supermarket put things they want to sold a left side of entrance. although this book is old: [1]The Secret Family: 24 Hours Inside the Mysterious World of Our Minds
- 8fingerlouie 4y ago
  > When someone in front of you walks in the same direction, you follow them. I had the exact same thought. It's logical. If you're moving across a crowded place and the person(s) in front of you are acting as "ice breakers", you naturally follow them in that direction as it is the easiest choice. If you're moving on your own (you're the ice breaker), you will tend to avoid other people according to normal "traffic rules", and assuming everybody else also does that you effectively have lines going each direction. Also unsurprisingly, if you ask people to "evade" to the opposite side this messes up the system.
therockspush 4y ago
Brits know a thing or two about queuing up. I wanna know why people will drive around the parking lot hunting for that sweet spot, spending who knows how much time, instead of grabbing the wide open spot a lane over that adds about 4-5 seconds of walking.
- KineticLensman 4y ago
  > I wanna know why people will drive around the parking lot hunting for that sweet spot I wanna know why at my local supermarket a lot of people try to park as soon as they enter the car pack, in effect blocking the entrance lane while they do so (so that in busy times the queue backs up onto local roads). I.e. the entrance lane itself has parking spaces and is adjacent to the store's pedestrian entrance. A different local supermarket has an entrance lane that forces you to the far side of the car pack before making spaces available. Overall traffic flow is superior because the people who still want to park near the store entrance aren't blocking incoming traffic while they do so.
youngNed 4y ago
I have been thinking about this more than can be healthy recently. In my kids school there is an open yard, through an open gateway, into another open yard in front of the school ┌─────────┐ │ │ │ │ │ │ │ │ │ │ ┌──────┴───xx────┴──────────┐ │ │ │ │ │ │ │ │ │ │ └───────────────────────────┘ Lets say xx is the gateway. At pick-up time this is where parents will stop to talk. This used to drive me mad as it was literally a bottleneck and i wondered why people could be so inconsiderate, but I started to observe, and people would meet, greet each other, and then walk together to that point to stop and talk - and everyone would do it, it is like they are drawn to that gateway to talk - and it has baffled me, i really think we are hardwired to do it, despite the impracticality of it for other people - why??
- ethanbond 4y ago
  If you like thinking about this sort of stuff, you’d get a kick out of flipping through Christopher Alexander’s A Pattern Language. Full of observations and examples like this from city scale down to room scale.
- therockspush 4y ago
  I understand completely, and there's probably a good part of it explained by peoples space awareness turning off when they're around their kids. If I had a haypenny for every time someone walked their doublewide stroller into me, forget about it. But people do it everywhere. Elevators, stairs, bars. Ants do it for a reason. https://www.youtube.com/watch?v=aiNEORy0Krc https://www.youtube.com/watch?v=aiNEORy0Krc People do too but if they aren't aware enough to move out of the way, it might tell you what part of the brain those people are operating with.
mcdonje 4y ago
There's a good pop-sci book on this subject called The Perfect Swarm by Len Fisher. I highly recommend it.

63 points by webmaven 4y ago

Cycling is similar. No need to use traffic lights for cycle-only crossings. Relevant: https://www.youtube.com/shorts/jgacSmLBSIQ https://www.youtube.com/shorts/jgacSmLBSIQ

_nalply 4y ago

It's emergent behaviour: From simple rules interesting patterns appear. Like the Game of Life. After short thinking I see these rules (without having read the article carefully): 1. When other people stand in your way, you slow down. 2. When someone in front of you walks in the same direction, you follow them. 3. Driving influences behaviour, for example you tend to go around people at the right side (in UK, Ireland, Australia, NZ, Thailand, Japan and so on: on the left side). No wonder you get interesting patterns (curved lanes). I wonder whether the direction of the curve is pointing the opposite for left- and right-driving countries. And I also wonder if you mix people from different countries whether the curves disappear.

rrobukef 4y ago
The dominant hand is also important. As a lefty I have a tendency to evade left resulting in a will-they-won't-they when the other evades in the same direction.
- melagonster 4y ago
  I remember a lot of people prone to choose left side. so supermarket put things they want to sold a left side of entrance. although this book is old: [1]The Secret Family: 24 Hours Inside the Mysterious World of Our Minds
8fingerlouie 4y ago
> When someone in front of you walks in the same direction, you follow them. I had the exact same thought. It's logical. If you're moving across a crowded place and the person(s) in front of you are acting as "ice breakers", you naturally follow them in that direction as it is the easiest choice. If you're moving on your own (you're the ice breaker), you will tend to avoid other people according to normal "traffic rules", and assuming everybody else also does that you effectively have lines going each direction. Also unsurprisingly, if you ask people to "evade" to the opposite side this messes up the system.

therockspush 4y ago

Brits know a thing or two about queuing up. I wanna know why people will drive around the parking lot hunting for that sweet spot, spending who knows how much time, instead of grabbing the wide open spot a lane over that adds about 4-5 seconds of walking.

KineticLensman 4y ago
> I wanna know why people will drive around the parking lot hunting for that sweet spot I wanna know why at my local supermarket a lot of people try to park as soon as they enter the car pack, in effect blocking the entrance lane while they do so (so that in busy times the queue backs up onto local roads). I.e. the entrance lane itself has parking spaces and is adjacent to the store's pedestrian entrance. A different local supermarket has an entrance lane that forces you to the far side of the car pack before making spaces available. Overall traffic flow is superior because the people who still want to park near the store entrance aren't blocking incoming traffic while they do so.

youngNed 4y ago

I have been thinking about this more than can be healthy recently. In my kids school there is an open yard, through an open gateway, into another open yard in front of the school ┌─────────┐ │ │ │ │ │ │ │ │ │ │ ┌──────┴───xx────┴──────────┐ │ │ │ │ │ │ │ │ │ │ └───────────────────────────┘ Lets say xx is the gateway. At pick-up time this is where parents will stop to talk. This used to drive me mad as it was literally a bottleneck and i wondered why people could be so inconsiderate, but I started to observe, and people would meet, greet each other, and then walk together to that point to stop and talk - and everyone would do it, it is like they are drawn to that gateway to talk - and it has baffled me, i really think we are hardwired to do it, despite the impracticality of it for other people - why??

ethanbond 4y ago
If you like thinking about this sort of stuff, you’d get a kick out of flipping through Christopher Alexander’s A Pattern Language. Full of observations and examples like this from city scale down to room scale.
therockspush 4y ago
I understand completely, and there's probably a good part of it explained by peoples space awareness turning off when they're around their kids. If I had a haypenny for every time someone walked their doublewide stroller into me, forget about it. But people do it everywhere. Elevators, stairs, bars. Ants do it for a reason. https://www.youtube.com/watch?v=aiNEORy0Krc https://www.youtube.com/watch?v=aiNEORy0Krc People do too but if they aren't aware enough to move out of the way, it might tell you what part of the brain those people are operating with.

mcdonje 4y ago

There's a good pop-sci book on this subject called The Perfect Swarm by Len Fisher. I highly recommend it.