Intelligent Traffic Management?

jcwren asks: "I was driving to work one morning, cursing the so-called 'traffic engineers' who configured our glorious network of traffic lights, when a few questions occurred to me. Do cities actually have a traffic management system that's either learning or adaptive (fuzzy logic, pseudo-AI, whatever)? I seem to remember that years ago that Phoenix had a far better traffic control system than Atlanta has ever had. What are peoples' thoughts (logically, not emotionally) on how traffic is managed in their cities?"

Comments

In Irivine, CA we have sensors

[Rebirth]

In Irvine, CA(Orange county) we have sensors at the pedestrian wlakways. You can see the cement clearly cut out ina rectangle. When a car goes over it, it signals for the light to turn green. Otherwose all the major streets are green and the smaller ones are red. THe smaller streets that intersect smaller streets are ona time-sharing mechanicism. IT also matter on the time of day, during night(10+ PM) it takes longer for the lights to change.

Re:In Irivine, CA we have sensors

[DeadSea]

Also called another way to make your city as unfriendly as possible to bicyclists.

Re:In Irivine, CA we have sensors

[bluGill]

If not, how hard is it for the cyclist to push the button?

Psycologist have studied those buttons and concluded that they are often not connected to anything. Well at least nothing useful, sometimes they turn on the walk light, IF a car is detected wanting to cross there.

In other words, the button doesn't make the light turn green, you need a car to come along as triggure the sensor so that you can cross!

Just arouther reason to hate traffic lights.

Portland traffic

[Baloo Ursidae]

Downtown Portland uses a somewhat adaptive timed signal system. When there are no events in the grid (ie, normal traffic flow, no transit trains or bridge lifts), the signals change at a rate that you can hit every green if you make the first one, maintaining a speed of 17-20 MPH.

If a light rail train enters the grid, the grid retimes itself by a couple of seconds as the train asks for its signal to be changed on demand (the operators have buttons to request signal changes and gates to go down by stations on the line).

If a bridge lift occurs, traffic parallelling the Williamette River gets longer green lights, allowing traffic to cross the traffic waiting for the bridge to go down.

My ride to work

[FascDot Killed My Pr]

My ride to work is nearly a straight shot on a four lane (not including two-way left-hand turn lane). There are many lights (probably 10-15 lights, during the 20 minute drive). Due (apparently) to some zoning oddity the speed limit is artificially low: 40 MPH most of the way, 35 in some spots. The road could easily handle 50-60.

A few years ago, a lot of money was spent "synchronizing" the traffic lights due to complaints from drivers. Some say it didn't work, but I have found that during times of high use (i.e. during my commutes) they ARE synchronized--if you drive 50-55. That's right, if you drive 10-15 MPH OVER the speed limit you can sail through every light while it's green (assuming no one is in your way).

So my conclusion: Sane traffic management is not what is being optimized. My question is: Why would it be? Sure, driver's want quick rides. But shop owners would like people to drive slowly (if not stop) to read their signs. City Hall likes people to speed because it brings in revenue. Etc. There are many different factors to optimize for, don't be surprise that YOUR goal isn't met as well as you'd like.
--

Re:People are sometimes better than computers

[anticypher]

The same thing in Paris. I know one of the computer people working on the paris traffic system. The french have thousands of sensors planted all over the place, as well as hundreds of surveillance cameras.

There have been a number of projects to examine knowledge based "AI style" traffic management. Many small companies offer controller systems which claim to have "fuzzy logic" and are able to learn about traffic patterns. Every single one of them fails when presented with a few basic external factors such as "weekend", "snow", "construction" or "accident". But given a perfect grid system (which Paris is NOT!), and perfect drivers, and the AI systems had no problem finding a perfect solution. But the slightest change threw the whole system into chaos, and quite often killed the system. None of the marketing claims survived even a small real world test.

So Paris has gone to its own system. The computers are doing what they do best, calculating. The humans do what they do best, adding intelligence to the chaos. Together, Paris traffic is only a mess, rather than a permanent gridlock :-)

the AC

Traffic lights are terribal.

[bluGill]

I did a search on this once. The most dangerious form of intersection is the one controlled by a traffic light. (The least has no controll at all) Second least is the round-about, which can handle as much traffic as the lights. (Except in a few extreem cases)

The above is all according to the US goverment, and if you search their web sites enough you can find it too. (I'm too lazy today - I already lost the battle with local traffic planners who have the old Not invented here syndrom and thus ruined traffic in myk town)

Good luck making use of the above knowlege though.

Timed Traffic Lights

[Jim Buzbee]

Remember, a series of lights timed for 30 mph is also conveniently timed for 60 mph! :-) ( I read that somewhere... )

Simple...

[The Iconoclast]

Traffic management is a brezee under *BSD! Check out BPF (Berkeley Packet Filter)!! It does policy and connection based routing!!

...

Oh, wait, you mean meat-space traffic with cars. Well, then just port the BPF to automobiles and OpenSource it!!! YAY!!!!

A wealthy eccentric who marches to the beat of a different drum. But you may call me "Noodle Noggin."

Re:Traffic lights are terrible.

[bluGill]

Err, this is direct from the goverment. Accidents per 100 cars or some such.

Now on face value you are right, a uncontrolled intersection cannot get as many cars through as a normal one. However a round-about (Not a traffic circle) can handle almost as many cars and is safer.