

Flocking for Road Traffic Efficiency Improvement - bhrgunatha
https://highwayflocking.github.io/

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lucb1e
This is meant for self-driving cars, right? Because I can not see this happen
with human traffic.

I was also waiting in the video to see busier traffic simulations, but didn't
see any. I suspect the model of keeping distance then breaks down completely
and creates lots of congestion, ifnot collisions (if the road is full and you
need to evade an oncoming vehicle...). On the upside, you use the whole road
dynamically instead of only a fixed few lanes, that is a nice improvement.

~~~
sindre
Yes, this is for self-driving cars.

I think you under-estimate the numbers of cars on the road.

I don't remember the exact throughput used for the video, but I think it was
around 5500. On a equivalent road the minimum distance between two cars is
about 2 seconds. That gives a throughput of 1800 cars per road per lane
(3600/2). For two lanes (resembling the one used in the video) this would give
a absolute maximum throughput of 3600 roads per hour.

Which means that our system, with about 5000 cars per hour, give a much higher
throughput than the maximal on a standard highway.

All the details is in the thesis (link in the url, or
[https://highwayflocking.github.io/Flocking_for_Road_Traffic_...](https://highwayflocking.github.io/Flocking_for_Road_Traffic_Efficiency_Improvement.pdf)).

~~~
penguat
could you easily simulate human speed control, with gentle variance and
effective repulsion between vehicles? or overload the road and see how it
breaks down.

~~~
sindre
Yep, in our thesis we have tried with throughputs from 2000 to about 15000,
and with different types of load. We assume that all vehicles are automatic,
so no human speed control.

~~~
yellowapple
How feasible would it be to simulate non-automatic vehicles with the models
you've provided? My hypothesis is that humans, too, could implement the
proposed steering behaviors (albeit likely with some degree of imperfection)
and thus could feasibly implement some or all of the proposed flocking
strategy, but I wouldn't know where to begin with testing things like blind
spots and slower reaction times.

At the very least, I reckon the "yield to higher-priority traffic", "maintain
distance from other vehicles", "maintain distance from road boundaries", and
"drive forward" behaviors to be (relatively) easy for human drivers to
implement, seeing as they do these things already (albeit with lanes as visual
reference points), and do so even better with modern driving assistance
technologies like blind spot indicators. Dynamic adjustment to asymmetric load
would be harder, but I suspect even this could be feasible.

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darkmighty
Currently all vehicles fit in the space of a lane. Unless your road is really
large, the most efficient packing of cars really should be neatly aligning
them alongside. Vehicles are also very stable in the direction across the
road, so stimulating separation in the perpendicular direction seems
unnecessary.

I mean, if we are using AI to drive cars might as well use the most efficient
configuration (and not one that only interacts with local neighbors as is
required for fish).

Dynamic lanes seem useful though (if a bit scary).

~~~
goodcanadian
Separation in the perpendicular direction is required to allow room to
maneuver left or right in the event of unexpected events (or even expected
ones like oncoming traffic or emergency vehicles). This applies for both self-
driving vehicles and human controlled ones.

~~~
darkmighty
Autonomous vehicles could coordinate to allow manuevering. I mean, if there is
enough space, surely you can keep cars at whatever separation, but in heavy
traffic the most efficient would be leaving a lane on the right or left
exclusive for emergency (or maybe coordinating vehicles for clearance).

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joosters
Imagine a road without lanes? No need to imagine, visit Cairo!

~~~
sindre
One of the original authors here. In our thesis we actually have cited a paper
that used an analysis of the traffic from India for something resembeling what
we have done.

~~~
spenczar5
Fascinating! Could you provide a link, either to your thesis or that paper you
cited? I'd love to read more.

~~~
sindre
I have uploaded the thesis to
[https://highwayflocking.github.io/](https://highwayflocking.github.io/)

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phkahler
400 meters of road with no driveways, no intersections, no traffic lights, is
just a waste of time. These results do not apply to the real world.

~~~
rayiner
The interstates are hundreds of miles without driveways, intersections, or
traffic lights.

~~~
judemelancon
[http://en.wikipedia.org/wiki/List_of_gaps_in_Interstate_High...](http://en.wikipedia.org/wiki/List_of_gaps_in_Interstate_Highways#At-
grade_intersections_and_traffic_lights)

In any case, typical interstate highways certainly have numerous interchanges,
which are the other kind of junction.

~~~
toomuchtodo
Looks like a perfect list of shovel-ready infrastructure projects (TODO fixes
to the interstate system).

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sls
This reminds me of the description of traffic on the Motie home world Mote
Prime in "A Mote in God's Eye"

I found this quote from it at the following link:
[http://aramink.com/blog/2012/08/31/the-mote-in-gods-
eye-35-y...](http://aramink.com/blog/2012/08/31/the-mote-in-gods-eye-35-years-
later/)

"Tall, ugly buildings loomed above them to shoulder out the sky. The black
streets were wide but very crowded, and the Moties drove like maniacs. Tiny
vehicles passed each other in intricate curved paths with centimeters of
clearance. The traffic was not quite silent. There was a steady low hum that
might have been all the hundreds of motors sounding together, and sometimes a
stream of high-pitched gibberish that might have been cursing. Once the humans
were able to stop wincing away from each potential collision…"

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Retra
Not to be a naysayer, but birds and fish can move in three dimensions, which
naturally makes collisions much rarer. There are more than two directions to
turn to avoid a collision.

~~~
sindre
The ideas still applies in two dimensions, we just have one fewer dimension.
(Actually, looking at Particle Swarm Optimization, ideas from flocking is used
from 1 dimension, to many more than 3).

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onion2k
* The 72% increase in throughput was achieved with diverse asymmetric traffic.*

Does that mean "If you have most of the cars going one way it's more efficient
to use more of the road for traffic moving in that direction"? It sounds like
it does. And, well, duh.

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mrbonner
hah, I already saw this happening in Vietnam. People don;t give a damn about
lanes.

