GOOD Q&A: Audrey Dussutour GOOD Q&A: Audrey Dussutour
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GOOD Q&A: Audrey Dussutour

by Patrick James

March 6, 2009

For ants, slow and steady wins the race

No matter how speedily our cars are able to go, we still find ourselves sitting in heaps of traffic-stopped, cranky, and cursing the slow truck in front of us. But according to Audrey Dussutour of Universite Paul Sabatier in Toulouse, France, we would do well to take a few cues from ants, who, in spite of Dussutour's best efforts, never get stuck in traffic. She offered an explanation of how moving cooperatively and embracing slowness could cure the traffic that ails us.GOOD: What do you mean when you say ants don't get stuck in traffic?AUDREY DUSSUTOUR: I've done lots of experiments trying to fool them or create traffic jams, but I've never really succeeded because they always find a solution to avoid it on the trail.  They just change the rules.G: That's nifty, but why look at ants in the first place?AD: When working with human traffic-like with pedestrians and cars-you can observe but you can't really do experiments because it causes problems.G: So you look for something similar nature?AD: Yes, but there is not a lot of redirectional flow in the environment. Animals are always unidirectional. For example, in migration, you never see a flow of inbound and outbound traffic, except in ants, termites, and humans.  They are the only ones. So the model we had was to study ants, because they form this big trail, which of course makes us think of our roads.G: So the inbound and outbound flow of the ants is like watching humans on a narrow two-lane street?AG: Yes, and in fact, ants give us more solutions than humans.G: How?AD: For my paper I was working with Isca ants, and they carry food, like big leaves. The ants that carry food are slower; the ants who are behind have to adjust their speed to the loading ants.  But it's funny-and quite unexpected-they never try to overtake the loading ants, even if the loading ants were very slow. Because the loading ants are always given the right of way on the trail, if the others just stay behind the loading ants, they took the benefit of that too.G: So by going more slowly, they actually collectively went faster?AD: Right. But, it doesn't work with cars. If you are on a highway behind a slow truck, you probably overtake them each time.G: Yes, the slow truck doesn't automatically get the right of way. Does that mean ants are just more co-operative than we are?AD: Yeah, they are co-operative, but I don't know if they know what they are doing. The intentions come from the group, so there is always priority rule. They always give the right of way to an ant carrying food.  They always give right of way to an ant who doesn't have the space to move.G: How else do they avoid traffic?AD: The ants always select the best way to go. Imagine the ants have two roads. One is very short but it is very narrow too-so it is going to be overcrowded very quickly-and one road is very wide but very long. When the flow is very low, they always take the short road, but as soon as it gets overcrowded, they move to the long branch, so they don't lose time. So ants are more flexible in a way. Because ants have no rules, there is no boss somewhere saying, "you go there, you go there."  It is more self organized.  And humans are exactly the opposite.  We have laws in traffic.G: How do we apply this knowledge to human traffic problems?AD: Just remove the rules and it would work. I'm kidding, but if you look at videos from the south of Asia, Thailand, or India, sometimes traffic doesn't seem to have any rules, but it works very well, and has a very nice flow. It is like bikes and trucks, and pedestrians. It looks scary from our point of view, because we are not used to that.  But if it looks like it works, why interfere? But, in fact, the ants can collide. They can really bump into each other with no harm to anybody. But with humans it would be more difficult.A version of this piece appeared on page 79 of GOOD 015: The Transportation Issue.
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GOOD Q&A: Audrey Dussutour