Physics of 'green waves' could make city traffic flow more smoothly

[Sam Wormley]

Physics of 'green waves' could make city traffic flow more smoothly

> Many large cities around the world, especially in Europe and the US,
> synchronize traffic lights on the busiest streets to create green
> waves. When a green wave works as intended, all vehicles within the
> wave can drive through a sequence of green traffic lights at a
> certain speed without having to stop at the signals. The timing of
> the lights can be controlled either by sensors or timers, and can be
> set up for traffic in one direction or both directions. Green waves
> have several benefits, such as allowing for higher traffic loads,
> reducing traffic jams, controlling traffic speed, reducing fuel
> consumption and emissions, and facilitating bicycle and pedestrian
> traffic.

> The biggest disadvantage of green waves is that, when the wave is
> disturbed, the disturbance can cause traffic problems that can be
> exacerbated by the synchronization. In such cases, the queue of
> vehicles in a green wave grows in size until it becomes too large and
> some of the vehicles cannot reach the green lights in time and must
> stop. This is called over-saturation. As more and more vehicles stop,
> the traffic can cause a gridlock where vehicles can't move forward
> even when the light turns green because vehicles are backed up at the
> light ahead, which may still be red or turning green at the same
> time.
>
>
> Read more at:
> http://phys.org/news/2013-05-physics-green-city-traffic-smoothly.html#jCp

[ji...@specsol.spam.sux.com]

How traffic works has very little to do with physics and almost everthing
to do with human engineering.

The effects of attempting to synchronize traffic lights has been studied
to death over the last couple of decades. And this includes "smart"
systems where all the traffic is monitored and the lights are controlled
by adaptive algorithms.

The bottom line is it barely works and only for small areas and a system
that really works is one of the Holy Grails of traffic engineering.

If you really want to know something about how traffic works, forget
physics and look at the work at the University of California, Irvine
Institute of Transportation Studies or the University of Minnesota
Center for Transportation Studies.



--
Jim Pennino

[Sam Wormley]

On 5/22/13 5:04 PM, ji...@specsol.spam.sux.com wrote:
> If you really want to know something about how traffic works, forget
> physics and look at the work at the University of California, Irvine
> Institute of Transportation Studies or the University of Minnesota
> Center for Transportation Studies.

Thank you for the resources.

[benj]

Yeah, Thanks jimp! But, um, would you have any references that are
cartoons so that the rest of us here can understand them?

[ji...@specsol.spam.sux.com]

Sorry, no cartoons; papers with graphs and equations, but no cartoons.



--
Jim Pennino

[Chris Richardson]

On Thu, 23 May 2013 01:54:42 +0000, benj wrote:

>
> But, um, would you have any references that are
> cartoons so that the rest of us here can understand them?
>

This response, characteristically, is infused with sarcasm.

But cartoons would be, or could be, a much better medium of
expression.

The human brain naturally recoils when confronted with the
formalized locutions and hyperelegant verbiage that are spewed
by official publications and professional dissertations.

The undissembling mind craves only insightful and penetrating
*imagery*.

So c'mon, stupids. Shut your overrefined and pretentious
mouths and give us the profound cartoon.

[benj]

What you say is probably true, but the first step would be to create some
cartoons that actually contain correct information. Such as:

Cartoon
http://www.mrk-inc.com/users/bspam/AGWCartoon.htm