
Taking Traffic Control Lessons - From Ants - robg
http://blog.wired.com/wiredscience/2009/02/anttraffic.html
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electromagnetic
This reminds me of an experiment I once read about. It was a comparison
between 'angry' and 'calm' driving, during the angry days the driver was
supposed to avoid letting people in front of them and on the calm days they
were supposed to slow down and let people turn into their lane from side
roads. This wasn't about fuel efficiency, it was about how much time it would
cost you and quite counter-intuitively the 'calm' drivers who let multiple
vehicles go in front of them actually ended up getting to work faster.

They also mention the ants collecting behind an ant that's carrying something.
It's probably for a different reason (IE not losing the food) but it reminds
me of the fleet-style of driving where they want to get vehicles to drive
behind each other, sharing the same air pocket, which IIRC Mythbusters showed
that tailing a big rig could reduce drag by up to 80%, however that was
equivalent to being like 5 feet behind the big rig and they couldn't drive
'calm' enough at that distance and reduced efficiency, but at around 10 feet
they got like a 60% drag reduction. Fleet driving (by computer) would allow
vehicles to drive at 5 feet behind a big rig and get that drag reduction.
However, I don't know how you'd pay for fleet-style driving because vehicles
like a big rig would be improving efficiency for dozens of vehicles, which
would assume nationalized transportation control so big rig drivers don't get
ripped off on gas.

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anamax
> However, I don't know how you'd pay for fleet-style driving because vehicles
> like a big rig would be improving efficiency for dozens of vehicles, which
> would assume nationalized transportation control so big rig drivers don't
> get ripped off on gas.

You're assuming that the "drafters" cost the big rig gas (actually diesel),
presumably by increasing air-resistance. They don't. Drafting reduces air-
resistence for the lead vehicle too.

You can see this in car races. Two (or more) cars running close together,
front-to-back, are faster than any of the cars are when running by themselves.

I don't know how much fuel drafting would save big-rigs (there's a somewhat an
odd relationship between fuel used and work done in diesels) but at the very
least, it doesn't cost them fuel.

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electromagnetic
I know it doesn't _cost_ the big rig, but it doesn't _save_ them much either
(only a nominal amount from reduced tail drag as they don't form a complete
air bubble), so why should they allow someone to basically metal-hump their
vehicle for marginal to no benefit? For example: If it saves you $0.50 for
every 5 minutes you tail a big rig, should the drafter be paying $0.25 to the
truck driver?

I'm also talking about the electronic fleet, where it's controlled by
computers in each vehicle. However there's also the mechanical fleet, where
two (or more) vehicles actually latch on to each other, this would be great
for electric cars and would also allow them to power-share. For example, 5
vehicles join together but only 2 keep their engines running but the power
comes from all 5 vehicles' batteries equally.

~~~
anamax
> For example, 5 vehicles join together but only 2 keep their engines running
> but the power comes from all 5 vehicles' batteries equally.

Why is power-sharing interesting for electrical vehicles?

Yes, you want to avoid free-riders, but IIRC the efficiency of electrical
motors isn't that dependent on load, at least for partial loads.

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jacquesm
more fascinating reading on this subject:

<http://www.itu.dk/~mikkelbu/projects/ars.html>

and this classic:

[http://www.cs.nott.ac.uk/~gxk/courses/g5baim/papers/ants-002...](http://www.cs.nott.ac.uk/~gxk/courses/g5baim/papers/ants-002.pdf)
(pdf)

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boredguy8
Hofstadter has an article about traffic and the benefit of defection. A
Universally Optimal (UO) path isn't necessarily Individually Optimal (IO) if
everyone else is obeying the laws of UO. So if I know that everyone is going
to obey UO laws, there's an increased incentive to defect to an IO route and
save substantial time off my travel. However, if everyone follows the IO
route, travel is slower for me than the UO route is for me.

The underlying theme of cooperation v. defection reappears through time, from
the Ring of Gyges to the Prisoner's Dilemma to experiments with splitting
money _. I'd be all for a computerized traffic system if everyone had to
follow it.

_ Experiments where n units are divided between two people where one person
can split the money, and the other person can approve/disapprove of the split.
If the second person approves, both walk away with the money, if they
disapprove, nobody gets anything. I'm sure someone has links to experimental
results, but if the divide is too large ($9 / $1), even though it's a gain for
the second person, they reject the offer.

