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Self-Adapting Traffic Lights
Roland Piquepaille writes "If you're like me, I bet you hate moments when you're in a hurry and all the traffic lights seem to intentionally switch to red just in front of your car. Now, according to Nature, a Belgian traffic researcher thinks that traffic lights that respond to local conditions could ease congestion and reduce your frustration. His method would not give you the individual power to switch the light to green. But if you were part of a group of cars approaching a red light, inexpensive traffic-flow sensors would detect your group in advance and turn the light to green. His simulations show that such adaptive traffic control is 30% more efficient than traditional ways of regulating traffic. However, his system has not been adopted by any large city. So you'll continue to be frustrated by these ?%&$! traffic lights for a while. You'll find more details and references in this overview."
My city has weight sensors laid under the tarmacs, so it knows if there are cars waiting/approaching and switches lights accordingly, or if it shall let the other direction keep going.
The real problem only arises when there are too many cards coming from all directions, and the lights will switch to the "traditional method" that is based on a predefined interval.
It's a catch-22 - Gershenson admits that the benefits wouldn't be as large in a big city where the situation is much more complex than in his simulations, however only bigger city needs to/will consider such traffic control.
Rock that crushes, Paper & Scissors that don't matter.
... when you can walk?
Don't need to deal with traffic lights then!
Don't lights like these exist already? We have lights that change for you in southern Wisconsin. They do force you to slow down a little as you approach the light.
Visit BobtheKing.com it's perhaps the best thing I've ever made to waste your time with.
When I was in San Jose, CA a couple of years back, they had a system up where sensors in the road would pick up cars at intersections. They then used microwave antennae to broadcast the information to lights further down the road. So if you were driving along at night with nobody else on the road, you would get long strings of green lights going your way.
His simulations show that such adaptive traffic control is 30% more efficient than traditional ways of regulating traffic. However, his system has not been adopted by any large city
I'll guess that the reason why is because a simulation shows this, not a real test. Traffic simulation has been a topic of much research, but as far as I'm aware, little convincing results have emerged... Simulations based on liquid flow do not work (they do not give anything like an average traffic), and those based on drivers modelization (ie, x % of 'aggressive drivers', y % of 'sloppy drivers', z % of 'careful drivers' etc) become incresingly complex and demanding with the scale of the simulation... I'm not aware of anything practical ever done with these (feel free to correct me).
In any case, if his adaptive system does work, it's a breakthrough. I've worked a few years back with people in charge of traffic and roads around Paris, and from what I've been told, nothing like this has ever worked better than static programming (with the exception of multiple programmings for different time of the day). From what I remember, even getting such programming right demands extremely experienced people. Of course, this might be specific to Europe where intersections are rarely perpendicular and often involve "creative" solutions.
Seattle has had self-adapting traffic lights at most major intersections for the last 5-10 years...
...the weather's hot, hot, hot with a chance of passion? do they flash to the rhythm of the music?
This is such a straightforward invention. I hope that similar inventions like this will see the daylight. It's all so straight forward.
people won't try to speed ahead anymore instead, they'll stick with a pack
I'm from a city in New Zealand (Hamilton) where we have a self monitoring system tied back to the City Council. Unfortunately it seems to be a little too smart, holding patterns that don't reflect the traffic. As a result, traffic changes its flow each day (drivers choose new routes) which further changes the trending and thus cancels the advantages you'd hope to gain. When the system is out or loops are cut (roadworks) the system reverts to timers/loops which seem to work better. Perhaps it's just when we add users the perfect system suddenly becomes imperfect...
I thought a majority of traffic lights were already predictive, I thought it was common sense to have this built into the technology when it was first created. If not as mentioned here but at least timed anyway to reflect busy and quiet periods in any given day.
On a side note, It annoys me as a pedestrian when you press the walk button, the green man comes on only when there is no traffic. Not of course when there is traffic and you need to cross the road in safety, thereby stopping the traffic.
Jonathanjk.com
Here in PA we have a system like that for emergency vehicles, late at night if you flash your high beams fast enough you can trigger a green light. Also i've noticed on the so equipped lights, if you stop before the light, and inch forward bit by bit, you can trip a green light. So dont we already have this?
get those cars off the road. Commuters are idiots. You should be living close to where you work.
It's nice to see a traffic signal enhancement that will actually make driving more efficient and direct rather than the opposite.
I do not deploy Linux. Ever.
I also understand that traffic routing is a complex undertaking, so I do understand any trepidation that traffic engineers or city hall would have in setting this up. It also costs money too, though I bet a lot less than widening the road would.
I hope something like this does work as well as advertised and that it gets deployed. Simulations are one thing, I'd like to see a real world application.
This is really, really old news!!
:)
There have been adaptive traffic lights for years (decades?). Most of them nowadays use cameras but some of the early ones using coils embedded in the road are still around.
(And no I'm not referring to the coils that are right at the light to detect waiting vehicles. You'll find the ones for adaptive systems between intersections at the midpoint of the block...).
So WTF, anyway? Is this guy related to Rip Van Winkle? He's got a hell of a lot more tech than that to discover out there!!!
It looks like this system favors large volumes of traffic that flow through a city - the city dweller that is actually living in the city would get blocked by the lave volume of traffic that isn't stopping, and is instead just passing though on a direct route.
So the end result, is that the person who pays for the traffic-signals via taxes gets shafted - and a bunch of out-of-towners begin to use the city as a shortcut.
Great for people who live in the suburbs, but bad for the actual city dweller.
If I should miffed, it's because our small city has wonderfull routes for the yuppies to get to the local Wal-Mart - but those same yuppies won't stop in the core of our city to buy things from the mom-and-pop business that are paying for the nice routes.
Moneyed corporations, non-working 'poor' and criminal prisoners are turning productive citizens into tax-slaves.
I for one welcome our new intelligent traffic directing overlords.
"frustrated by these ?%&$! traffic lights"
What country is that? Mine only has Green, Amber and Red lights!
First of all, there are sensors under the cars that are standing right before the intersection. These types of sensors are installed just about everywhere there are stoplights. But if you pay attention, you'll notice that on this street, there are also sensors about 200 to 300 feet back from the intersection. There is a sensor under each lane. By the way, this is a major city street, with three lanes of traffic for each direction.
When driving during the day, there is a lot of traffic, and so you might wonder why in the heck it seems that the cross streets have much longer "green" times than you do.
When driving at night, you'll easily see why. There are usually only a few cars on this street at night. You drive, and you can see that all the stoplights ahead of you as far as the eye can see are GREEN. You drive, and immediately as you pass over the sensor that is 200 to 300 feet back from the stoplight, the light in front of you changes to yellow, and then to red. This happens at a rate that makes it impossible to remain at a constant speed and go through the intersection before it turns red. You'll either have to floor it (and even then it is doubtful whether you'll make it--the yellows are very short), or stop, which is what you'll end up doing.
Now that you're standing at this red light, and the cross street has a green, you'll wonder why you have a red and the cross street has a green, WHEN THERE ARE NO CARS DRIVING ON THE CROSS STREET! Now here is the interesting part. The light could be red for a minute or two, or you might stand there for a long time. As a matter of fact, I noticed that at all of the stoplights on this major street, they will remain red until a vehicle approaches on the cross street. As soon as a vehicle approaches there, his light will change to red and yours will change to green. At 3:00 am, it might take a long time before a vehicle approaches on the cross street. One time, I actually waited ten whole minutes before such a vehicle approached, and only then did his light change to red and mine changed to green.
Now I have been living here for four years, and I have driven down this street enough times at night to tell you that this isn't a casual observation and that I'm not just jumping to conclusions. Others who have driven down this road at night have mentioned the same thing, and I noticed that it never, ever fails. The sensors are all wired such that you will have to wait at EVERY intersection, until a vehicle on the cross street approaches, at which time he will have to wait, and then you get a green light. It's almost as if city workers wanted to play a practical joke and taunt drivers with green lights that remain green for any amount of distance, but only until you actually get near the stoplight. During the day, you don't notice it so much because there is so much traffic that everybody is stuck anyway.
This is generally how your traffic lights work; underneath the tarmac is a series of coils designed to detect cars. If anything his technique is to expand the sensors past the few yards they currently detect, a fairly obvious idea but generally not worth the gain over the status quo and intelligent consideration. Generally speaking traffic at night is just daytime traffic but lighter. You pretty much don't see roving gangs of traffic encountering a series of red lights.
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Open Source Sysadmin
This isn't like normal weight-sensing or magnetic traffic lights. This system is designed to break the traffic down into chunks in such a way that no two chunks will approach the same light at the same time. This way, it can accomodate large amounts of traffic.
If you want to visualize how this might work, watch the episode of Futurama where they go to the planet of human-hating robots, where Fry and Leela are trampled by the robots going to and fro. The "chunks" of traffic would go past each other the same way the robots do in that scene, but regulated by stoplights.
Has anyone ever noticed that traffic signals appear to simply impede the smooth flow of traffic? I think you could achieve the same "adaptive" traffic control capability by doing away with the lights and installing simple stop signs. Let the traffic control itself. I've been at innumberable intersections where the signals or human traffic directors have merely managed to create obstructions to flow, in both directions, tha wouldn't have happened without the attempt to "control" traffic.
In our haste to exercise control over everything, most stuff just slips through our fingers the tighter we squeeze (thanks, Leia Organa).
All this presupposes that the govt. is interested in your time or convenience - ha. What would work is if drivers could place electronic bids indicating how many cents they would pay to receive preferential treatment at intersections. The traffic control software would compute which set of cars will pay the most and turn the lights green in that direction...
They can be used for evil just as easily.
Now I just need one that will recognize my motorcycle at 2am when no cars are around to tigger the lights for me.
I ride a supersport Yamaha YZF-R6. Weighs about 410 wet and I have problems triggering many stop lights, so much so that I have areas I don't ride when traffic is light because they never turn green for me.
People stop behind the senser, and then wait for the lights to change. Thermal camaras and magnetic sensors can't see cyclists. These systems are in use, and need a lot more work before they are really useful.
Lets just hope this new system comes before we get flying cars. Seriously, sitting at red lights is one of the most boring things you can do. One light after another.
What I hate is when you have a good speed going and you can see the green light, then it turns red and you have to waste all the gas getting back to speed again. This new system maybe able to solve our gas problem. Less stop and go = less gas.
Mark
In Korea only the elderly worry about traffic lights ...
Traffic is a huge problem here in Toronto. I think that such traffic management systems would improve not only the efficiency of traffic flow, but the quality of life in general. People will be in better moods if they have to spend less time in the car.
the sensors are nice coming off highways and such and we have them out here in nowhere texas actually but when going in to the cities I prefer timed lights. in austin there are streets where the lights are timed nicely to allow you go get all the way down to the end of the street with nothing but green lights if you are going the right speed.
Maybe, just maybe
..
Thet aren't out to get you, but in fact they screwed up the installation.
I've done a lot of construction and can see how this might happen, they screw things up all the time when they build things
You should contact whoever is responsible for the road a mention this.
US is currently preparing for a completely different thing - a more or less massive roll-out of red-light cameras (the thing where you get you car's photograph in the mail and a red-light ticket). As a preparation for this measure, stop lights are adjusted (most of the time the duration of yellow is simply reduced) in order to increase you chances of running red light, thus increasing the profit generated by red-light tickets. (This will also increase the fatality rate, of course, but this doesn't seem to be a reason for concern.) I'm amazed how much more often these days in California I see cars crossing intersection right under my nose even when I have green. A couple of years ago I'd see something like this about once in a month. These days I see it virtually every day. In this evironment it is highly unlikely (read - impossible) that US authorities will implement anything tha will to decrease your chances of running red light. Today they prefer to make money by decresing public safety, not by increasing it. So you can forget about anything like "driver friendly" stop light for a while.
Ok, putting the sensors in the cars might be a new approach. But "traffic lights that respond ot local conditions" have been around for a least a decade. Even my back-of-beyond home town of 35,000 has them throughout the city. If you drive between 45kph and 55kph, you stop at two out of about 20 lights at most--no matter where you are driving. Heck, there were even classes about this at my university back in '88. For the connesseurs of long German words, the name of the class was "Verkehrslastabhängige Signalsteuerungssyteme."
... .
But maybe the sumitterlives in a town with a large engineering and CS school and no #&*@ clue how to manage traffic flow--like I do nowadays. Yes, I am talking about University Park, PA or Champaign-Urbana, IL or Cambridge, MA, or
Once again: Just because something doesn't exist in the good old US of A doesn't mean that it's not common in other parts of the world.
If a group of cars is travelling in one direction, this system will give them green lights ahead of them. When the group passes, the lights will eventually turn red in the same sequence. This is fine ... unless you're travelling in the opposite direction. You see, lights are coupled. If you have a green light to go straight, the guy opposite you also has a green light to go straight. So when the light behind you turns red, the light in front of the guy travelling in the opposite direction also turns red. If you turn lights green in favour of one direction, you're turning lights red to the detriment of the other.
What does the system do if there is enough traffic load to trigger this system in both directions? And if the system is only effective when there are no cars on the road, is it worth it instead of just using common pressure pads at intersections?
*blinking cursor*
Looks like it would be handy during rush hour...
It's very unusual for Australian lights to operate on strict timing intervals when traffic flow data is available. It happens late at night ... when there is no traffic whatsoever, some lights will cycle through a defined sequence at the same rate ... but other lights will stay green continually on the more major road until some traffic arrives at the less major road.
Philadelphia I can guarantee does not have this thing, but they have done some things to help. Chestnut and Walnut Streets are each three lane one-way streets that span the city from Front St (aka 1st) all the way to 63rd. They're big throughways for rush hour traffic into and out of Center City.
The traffic lights in the city are just plain old and the vast majority still run off mechanical timers and switches. If you're standing near one (ie, about to cross on foot) you'll hear the clunk inside the box. Very few lights (if any) operate off sensory equipment.
Anyways, along Walnut and Chestnut, from about 38th to 63rd for Walnut, 63rd inbound to 29th for Chestnut, the lights are "timed" such that you can quickly go from one end to the other without hitting red more than once or twice. There's no central controller, each individual light is calibrated. It works great, except of course when power goes out or one of those mechanical switchs get jammed, thowing a timer out of whack.
The One Rule Of Chess You'll Ever Need: Don't play someone who carries a kit in their bookbag.
We have this, really. We drive up to to the light and it self-adapts to red......
-- TheMadRedHatter
while(1)
{
}
Ah, the story of life.
They detect if you're late for an appointment or hurrying to reach somewhere and then change to block your path
Slashdot: News for Nerds, Stuff that matters only to them
Being a pizza delivery boy....(umm...I mean Unix sysadminrootrootlife 666), I've noticed that these type of lights are already in place where I live and work, but not so much in cities, where they are obviously needed the most. The way the lights I've experienced seem to work, the lights prior to the heavily trafffic'd intersections also regulate the flow of traffic. It's madd fun flying through traffic just to catch up with the group of cars in front of you to just squeeze through the light. And make sure you tip well. A lot of thought goes into getting a pizza to it's destination in a timely fashion.
We already have something similar here in Phoenix, though it is implemented in individual vehicles. If a single car is approaching a given red light at sufficient speed, the red light may be unsafely disregarded.
[I believe Phoenix is still number 1 in collisions or fatalities or something bad, as a result of red-light-running. If not, we will be again.]
Roland Piquepaille is Jon Katz. Game. Set. Match.
Can someone explain why we're calling these "self-adapting" traffic lights? Aren't they just "adapting"? Self-adapting makes it sound like the traffic lights are adapting to something inside itself.
.. or the next thing that will happen is they get bored..
If your city is like most local governments, your local roads are paid for by property taxes paid mainly by residents, not businesses, unless you have a local sales tax, which is rare precisely because cities don't want to drive sales to the next town over.
As for Wal-Mart, it has just as much right to exist as stores downtown, more so if people wouldrather pay less for things sold in an EFFICIENT RETAIL ENVIRONMENT than pay more for things sold in an inefficient retail environment.
To get back on-topic, your whle premise is incredibly flawed - are you seriously suggesting that everyone from out of town will have green lights and everyone from in-town will have red lights?
News for nerds, comments by morons.
paintball
Somewhere around Stratford... It was funny to see how they broke down generating a traffic jam for a couple of miles :)))
Academics love simulations and models. They're great for proving theories. Problem though is that when the real world does not match the simulation model, then the theories don't work in the real world.
Independent traffic lights sound very unlikely to succeed since flowing traffic requires synchronisation of multiple lights to keep the flow going.
Engineering is the art of compromise.
So, if I understand the article, if I got a mobile home, and towed my XXL SUV, and behind that was a boat, I could become my own group and get all the green lights.
Or maybe I can buy a half-dozen of these and tie them at 15-foot intervals on a long rope I drag behind my car.
HIV Crosses Species Barrier... into Muppets
In my area traffic lights respond to a number of different input.
First off Lights are geared by the time of day. There many high traffic situations where traffic is high on certain streets so the lights regulate traffic accordingly.
The rest of the day the lights rely on a combination of pressure censors and lamination levels to determine how many cars are waiting at a particular intersection. In some instances pressure sensors are installed several yards before the intersection to being cycling the lights early.
Finally our city vehicles (with the exception of police, as we are county.) have triggers to over ride the lights at any given time. So ambulances and fire trucks always have the lights working in there favor.
The sensors can be either inductance or capacitance. Detecting changes in an electrical field. Bikes, alas, do not have enough metal in then to grossly affect either sensor, they are set to a higher threshold. I would go into the theory, but that is for another post, I suspect will be comming soon.
"This is not new. It has existed in [town name] for the last [5/10/50] years. These guys are way behind [my country]"
Clearly the article is not about the same kind of inductive sensors that is available in almost EVERY COUNTRY IN THE WORLD. Just because your country has vehicle sensors at traffic lights doesn't make you special - everyone hs it. Ditto for traffic light schedules for different times of day. Ditto for remote controlling traffic flow from a traffic operations center.
Even Belgium, the place this research is from.
So clearly this is NOT what the research is talking about.
http://www.themirt.com/
We have secretly replaced these Slashdot mods' sense of humor with a rusty nail. Let's see if they notice!!
In order for induction to work, you would have to have a large quantity of metal in your finger.
So unless you're Wolverine, you're probably out of luck.
so there.
This issue is a bit more complicated than you think.
Since I'm a lot more likely to be crossing the road on foot than driving along it, it's amazing just how long that 30 seconds seems when you're waiting for the fucking thing to change!
It doesn't appear sensitive enough to spot cyclists, but since cyclists invariably ignore the lights and just cruise right on through even if people are crossing, that seems to be moot...
You must think in Russian.
...or if they are bribed.
In China the traffic lights start out as a full circle and get smaller and smaller until a change occurs. In this way, you know before you even reach the light just when it is going to change so there is no suprise.
I think this sort of thing needs to be adopted here in the U.S. as well.
from the article:
...resulting in that frustrating middle-of-the-night situation where you wait at a red light on empty streets.
Yes... I wait at that red light... yes.
I hate the Late Night traffic syndrome, where you are parked at a red light and no one is coming the other way.
It's 2005 (almost), in these obvious situations the lights/sensor array should just let you through.
"Sig free in '03!"
A shocking exposé about /. editors conspiring to drive traffic to Roland Piquepaille's pointless blog.
Are they getting kickbacks? Did Roland save them from a bear attack in the woods?
Seriously, this is two Roland Piquepaille posts in LESS THAN 24 HOURS. Why don't you guys just drop that pretense that he's a regular submitter like the rest of us.
The truth shall set you free.
Weight sensors under the tarmac ?
I dont know about those, but that seems expensive and complicated.
Here in NJ, in the middle of no where, many lights have radar sensors.
You can see them, they are like little comeras pointing at you, but with no lens.
How do I know they are radar? Cause they mess up with radar detectors.
Actually, you can correlate the stop of the beeping whit the light turning green.
There are many all over, and they have been there for the last three years at least. ( age of my detector
I thought that it would be a great idea to put an entire city's traffic lights on a private LAN system which monitored for traffic sitting waiting to go through the intersection. (Using whatever method to detect this which is cheapest.)
So instead of having all of those individual boxes out there that cost money to take care of on an individual basis - you just have a simple control box which sends and receives information. Think of it - each light detects if it is working or not and automatically calls for a human to come out and fix it. Lights become more coordinated than before because entire series of lights can all be set to green at one time. Emergency vehicles can carry wireless boxes with an encrypted password on it that tells the lights they are coming up to that they need to get through. And for those who misuse such things, the system could be rigged to monitor where each vehicle is located and if a vehicle is in two places at the same time the fake vehicle could be flagged and stopped by police officers.
How is the signal transmitted? Does the city have to lay hundreds of miles of new cable/DSL/Fiber Optic lines? NO WAY! All they have to do is to do the IP over the electrical lines and suddenly the entire set of traffic lights in any city is connected. You would have to install the proper boxes to listen for and accept the commands from the central server. But it is a lot less in cost than having to lay new communication lines. This might even be possible with wireless communications soon.
So you say: "What about large cities with several small cities within it or nearby? Won't they affect each other?" The answer is: NO - They won't. Remember that with TCP/IP v6.0 you have billions and billions of IP addresses to choose from. I think we can dole out a few thousand from this group for this purpose. Also, the power to the lights are (I believe) on a dedicated circuit which would effectively make all of the lights reside on a private LAN line not available to the public. (So someone would actually have to try to sabotage the lights rather than there being an accidental sabotage by a private individual on the same electrical line.) Filters can keep the two separate (ie: Public and Private IP over the electrical grid.).
Would it be bogged down? Not really. You don't have to be connected all of the time to the light. Only for the few milliseconds it takes to connect, tell the light to change orientation, and then disconnect. Let's say there are 100,000 traffic lights in your city. What do you do? You break it down into lots of 5,000 (so 20 servers). The average web server can handle 5,000 people per second while dealing out static web pages. This should be a snap because the information is a lot less than the average web page. The twenty servers are attached also to a single system which monitors all of the twenty servers by simply flipping between them like a TV monitor camera does. Or you could hire twenty people (one per server) to watch what was going on.
Similar to how monorail systems are monitored presently (only we throw out the static LED display and just use a monitor to display the light's status'), this system only has to keep track of if a light is working or out and can be programmed for different algorithms depending upon what part of the day it is. So rush hour traffic coming into the city is given preferential treatment over cross town traffic. At the evening rush hour the flow is reversed. Otherwise, lights respond according to the sensors. Keeping lights green for on coming traffic and red for empty streets.
Think of it - no more traffic lights that stay red for five minutes or more for no reason. Traffic lights that help you reach your destination. Block crooks from escaping areas by always turning their lights red and blocking their escape by always having the cross traffic moving through the intersection.
Someone put a black hole in my pocket and now I'm broke.
they'll manage to make things only worse here in Austria. For years we have had a typical thumb traffic light here at the crossing Simmeringer Hauptstrasse/Kaiserebersdorfer Strasse/Hasenleitengasse and wait times were at most 1 minute. Some years ago they have replaced this with a sensor controlled system and now you have to wait about 3 minutes, because the sensor for the second traffic light check for traffic before you can reach it after the first light turn green. Anyone remembering "Schilda"?
Most major cities have this somewhere, somehow in effect. Weight sensors, radar, etc.
Around here (Cincinnati, OH) a lot of lights use a type of radar to "look" for cars. You can easily find them by turning on your radar detector.
The down side is that the radar only looks for stopped cars waiting at a light. Someone should have told those people about the doppler effect...
Get your Unix fortune now!
if(cars.dir(1) > cars.dir(2)) { // LIMIT is defined
if(green.dir(1)) {
if(time.dir(1) < LIMIT) {
light.green(1);
light.red(2);
}
else if(green.dir(1) != true) {
if(time.dir(2) < LIMIT - (cars.dir(1) - cars.dir(2)) {
light.green(1);
light.red(2);
}
}
Yeah, I know, it's incomplete and ugly but I just wanted to show a general picture. Yeah, this would work for small traffic situations, but, honestly, this could cause a lot of problems (bugs, etc.). Perhaps very limited "learning" traffic lights would be good, but totally self-adapting could cause lots of problems.
- dshaw
Note About the Code: Yeah, i did that in the little Slashdot comment box. It's ugly, unindented, and probably has nonsensical if/then cycles. Please let it be, since it's hypothetical anyway.
... would be to factor in time-of-day controls. I think they have those in Toronto, but I have yet to see that is any US city I've lived in.
TOD would do things like switch off those aggravating left-turn red arrows which plague many suburbs, which force you to wait 3/4's of the cycle to make your turn. That helps when traffic is heavy and left turns are risky and need the additional cover... but when it's 10PM and I can see clearly that there is no one coming, these things are just ridiculous. I end up driving past the light and then doing a U-turn to get into the street.
Just leave a few minutes earlier... People want to buy these 10 ton SUVs and watch DVDs and play video games in them, listen to satellite radio, drink their Starbucks and eat McDonalds. If you create a vehicle that is nearly as comfortable as your living room, why are you in such a hurry to get out of it? I drive a small Honda Civic, and people will gladly risk my life to whip across 3 lanes of traffic and make a U-turn into WalMart. Trust me, my time IS as valuable as yours, and I am not in that much of a hurry.
word.
Honestly, if people would all show enough common sense and courtesy on busy roads, we wouldn't need at least half the sets of lights in existence.
Having said that, there are some very useful mechanisms for controlling traffic flow. Like the green arrow to turn across what could otherwise be the oncoming flow of traffic from the other direction - if vehicles stop passing the sensor, or a certain amount of time passes, the arrow changes and oncoming traffic is given the green signal. It gets people out of the turning lane that would otherwise just get in the way.
Now if only we could make people stay in the slow lane unless overtaking, and learn how to merge (You know who you are)!
In a junction outside an university there is a newly implemented traffic light control. The mechanism is so simple: if a button is not pressed, the traffic light wouldn't stop the cars for people crossing. There is a fucking big instruction above it.
Everyday I'd encounter a group of at least 20(mostly in suits suggesting their discipline of study), obviously having already been stuck there for at least 15 minutes, swearing at the damn traffic light, and about how the Government only do things in flavors of drivers blah blah blah.
I'd then proundly walk into the crowd, use most explicit motion to press the magic button, and enjoy watching the puzzling crowd in awe.
This is the first ever traffic light control I've ever seen adaptive to GEEKS!
What this guy seems to be talking about is a greedy algorithm to optimizing traffic flow. That is, each local intersection does what is in its best interest, and hopefully this will lead to optimization in the whole system. It's called 'greedy' because each local case doesn't cooperate with others to find an optimal solution for the whole network of intersections, just its own. Greedy algorithms definitely have some merit, as many computer scientists will tell you. However, I'd place my money on a centralized system that's running a non-greedy optimization algorithm for the whole network of traffic, even if it is more expensive, for large cities with extreme volumes of traffic.
There is at least one set of lights in my city that are timed rather than radar/rollover sensor triggered. The reason is that they are on the main road out of the city to the capital, where ideally there should be no lights/junctions. So the lights are deliberately timed to only allow traffic from the side junctions for a few seconds every few minutes.
But for all out madness, one cannot beat signal-controlled roundabouts. I don't know is anywhere else but Ireland insane enough to use these, possibly the UK, but it's rather run having to randomly stop at red lights while going round a roundabout.
The two main such roundabouts in Ireland are the Red Cow Roundabout in Dublin (the "Mad Cow Roundabout") and the Kinsale Road Roundabout in Cork (the "Magic Roundabout"). Best avoided - but usually unavoidable. Oh yes, I nearly forgot, the former now has a tram system travelling across it too. Fun fun fun.
-- *~()____) This message will self-destruct in 5 seconds...
Most traffic laws (light times, speed limits, etc.) are made arbitrarily or based on generating revenue (shorter yellows to get you to run a light with a camera, unreasonably low speed limits). Designing roads and regulations based on what people actually do with them would help greatly.
I actually went on a tour of the traffic management facility back in 1992, they were doing adaptive remote control of traffic signals back then. There is some more information about the Sydney system in the following URL: http://www.esri.com/news/arcnews/spring02articles/ gettingthere.html
A small part of the article:
Operating in real time, SCATS constantly adjusts signal timings in response to variations in demand and capacity. A tiered system enables it to automatically adapt itself to changing traffic conditions. Controllers located at each intersection measure traffic density through sensors embedded in the road surface. Regional computers analyze information from up to 128 local controllers and set optimal signal phasing times for an area based on the current traffic conditions. A central computer located at the TMC monitors the operation of each region.
Semaphore timings, delay and magnetic responsiveness control more than traffic, congestion and crosswalks. Government uses many devices to control the population, its streets and traffic. Semaphores are just another tool. Red light cameras too affect driving behavior with side-effects reducing traffic counts on heavily used intersections and commercial trucks routing around them. ...its not about you.
Now he and his Traf-O-Data company will get into software and take over the world.
Open source red light runners, unite!
It must be just you. It doesn't happen to me, EVER.
In my city, the streets are in a 1-mile grid. The streets every 1 mile are major streets, and there are 1/2 mile streets that are collector roads. I'm not sure I'd want these at major intersections, but where a major street meets a collector road, it would work well. Set it up so that a large group of cars coming on the major road would turn the light green regardless, and then when there arent cars coming, the light would be able to cycle to the collector road and let everyone out.
The Doormat
If you're not outraged, then you're not paying attention.
This seems like a classic problem for chaos science, does anybody know of any models?
Some colleagues of mine from Europe were in the states working for a few months. It wasn't prudent for them to purchase a car since they were here for such a short period of time. Since they also lived in the city, public transportation was fine, and walking got them to most places they needed. One night, after some late night partying got them hungry, they wanted to get something to eat. The only place that was open was the late night Wendy's, but it was just a drive-thru. One friend went up to the speaker/automated ordering booth, and stood there waiting...and waiting...before realizing as he stepped aside for a car to go through, that the sensor below allowed the attendant inside to know that there was a car waiting for ordering. He did what any person, half-drunk, hungry from partying would do...he stepped on the sensor and jumped with all his might -- to no avail. Eventually, he sobered up enough to actually walked by the window to talk to a real human. Ahhh...if it wasn't weight sensors, then the mere presence of a human standing on the pad should have activated it, no?
Linux at home
Maybe this is different, but we have these things called smart streets which apparently also predict loads.
This sig no verb.
The article mentioned each junction being independent from each other, with no centralization. This strike anyone else as a possible emergent system? It doesn't appear to have the local communication that emergent systems do but it seems to me that you could get some interesting behavior out of this. Nothing terribly complex or anything but not necessarily predicted. The traffic flow could end up absolutly perfect for the situations, adapting to rush hours and eliminating traffic jams. Or, you could just get some directions having essentially no lights and others being always red. This would be no uber intelligent neural net of course but I would like to see the simulations and real-life trials.
/. a while back that had no lights and all the cars reserved a time to go through.
It would be really cool if each junction could remember traffic patterns (don't know exactly why but I'm sure there is a reason) as well as warn nodes around it about the situation. Maybe if it there is a lot of traffic and all the cars have to slow it could tell the node next to it to stop letting cars through for a little bit until the traffic at that junction cleared up. Or in the case of an accident, have other junctions not allow any traffic to pass to the scene. This would require some kind of communication system but it wouldn't have to be long range. You could even have a system of reporting patterns for statistics and research that jumps across the junction nodes until it reaches a collection point.
The whole system seems better than that automated traffic control mentioned on
Particularly near Central Washington University, the lights change to flashing red in one direction and flashing yellow the other direction between 11PM and 7AM. No detection needed, though it doesn't do anything during the day.
Calling atheism and agnosticism a religion is like calling bald a hair color.
Problem though is that when the real world does not match the simulation model, then the theories don't work in the real world.
:
. html .
Indeed. Just for kicks, here's a description of the simulation they use (from the paper here, emphasis mine)
The Simulation
We implemented the methods described in the next section in NetLogo [12],
a multi-agent modelling environment. We extended the "Gridlock" model [13]
which is included in the NetLogo distribution. It consists of an abstract trac
grid with intersections between cyclic single-lane arteries of two types: vertical
or horizontal. In the first series of experiments, cars only flow in a straight
line, either eastbound or southbound. Each crossroad has trac lights which
allow trac flow in only one of the arteries which intersect it with a green light.
Yellow or red lights stop the trac. The light sequence for a given artery is
green-yellow-red-green. Cars simply try to go at a maximum speed of 1 "patch"
per timestep, but stop when a car or a red or yellow light is in front of them.
Time is discrete, but not space. A "patch" is the size of a car. A screenshot of the
environment can be seen in Figure 1. The reader is invired to test the simulation
(source code included), with the aid of a Java-enabled Internet browser, at the
URL http://homepages.vub.ac.be/cgershen/sos/SOTL/SOTL
The user can change dierent parameters, such as the number of arteries or
number of cars. Dierent statistics are presented: the number of stopped cars,
the average speed of cars, and the average waiting times of cars.
Traffic signals that are controlled by loop detectors are a real pain for bicycles, in particular those made of aluminum, titanium or carbon fibre.
I hope that that since this is a Belgian idea, consideration of alternate forms of transportation will be considered.
By the generally agreed upon definition of the word, Yuppies would be the ones that live in the city itself. And as a professional city dweller myself, I find it amazingly irritating that the traffic lights here in Cleveland never seem to agree. Especially since much of the East side is devoid of freeways, so you're required to take local roads to get anywhere. People who come in on a direct route generally live much farther out and take the freeways, at least around here.
Why is this being treated as some sort of new technology? I had always assumed this was standard everywhere. In Oklahoma City where I live, EVERY traffic light has this; there is only one in the entire city that I know does not. (I'm sure there are more, but they ARE rare.) I've seen them standard in every major city in Oklahoma I've been to, also.
In low traffic situations (e.g., night) usually the "bigger" road stays on green, and will only switch if a car is detected on the crossroad. Sometimes you won't even have to stop since they put additional sensors maybe a couple hundred feet before the light, so it knows you're approaching, and will switch to green before you even are close enough to start braking.
When the light is busy, it still helps because there are never any unnecessary lights (or lights that stay on too long.) If there is no one turning left in a left-turn lane, the light won't turn on, and instead straight traffic from the opposite direction will get the light immediately. If you get to a left turn lane after straight traffic has already been given a green light, but there are no more cars coming from the opposite direction, that side will turn red, and you'll get to turn left. Lights know to turn red after it doesn't recognize any more traffic, or if it's been on for a certain period of time.
During rush hour, the busy lights will usually favor the traffic (e.g., waiting longer before giving cross-traffic a green light, even if it detects them) which I'm sure is programmed in based on time of day.
Is this any different from what is bring "proposed"? Is there something I'm missing?
BTW, the sensors here are the inductive loops that they explain here.
Assume (for this post) that these devices actually work and improve the efficiency of city streets. This is why you can't find them on your block:
(1) Safety. A lot of effort is spent proving that a traffic control device is safe. When traffic lights screw up and allow opposing green lights, people die. It is entirely unacceptable for a traffic control device to screw up.
So when a city is faced with buying a proven design or a new advanced design that improves efficiency but may be a liability concern, the city will go with the proven design.
I concede that the new system would be tested endlessly, but I claim that any complex system will have flaws that don't show up until deployed in the field. I've seen unbreakable unix systems crash. It happens.
I think that provable safety in this application can (and will someday) be done. I just wouldn't want to be the first city adopting it.
So another option to ensure safety is redundancy such as that used in some airplanes. That is, multiple independant systems working on the traffic problem, and if any of them fail the others will notice. Doing this right costs money, which brings us to point 2.
(2) Cost. My city really doesn't even bother fixing road problems. I went to Berkeley CA the other day and they had enormous potholes that were "fixed" by painting bright colors around them so they could be avoided. If Berkeley doesn't want to spend a couple bucks to patch a hole, then why would your little town bother to consider removing existing systems that cost hundreds of thousands of dollars and replace them with ones that probably cost more?
Further, why would you want your city to spend this money for a marginal improvement in flow? The answer is because some intersections are so terrible that you always are caught up in traffic. These intersections are the bottlenecks that hold up everybody, ones where 30% improved efficiency would be a blessing, which brings us to the 3rd point.
(3) This doesn't help the worst intersections. This switching system would be nice for those pesky lights in your neighborhood that always seem to be red when you arrive, and that you are always first in line and usually the only one to go through in your direction.
I claim that the intersections which could use a 30% improvement the most are those that would not be helped by this system. That is because no matter which side is getting green, every precious second of green light is being used by traffic. This is 100% efficiency, as measured by throughput / theoretical maximum throughput. You can not improve this system by watching for groups of cars, since there are always groups of cars coming.
This would be a neat feature on some intersections, but these intersections aren't the ones that DOT really focuses on improving. The effort involved in making small intersections intelligently switch lights isn't generally worth the cost of doing so.
That said, I'd like to see this in use in my neighborhood, and I'm glad that people are looking into solving traffic congestion problems.
Oh man, this has been bugging me for about ten years. It seems that we already have a system with a built-in method of measuring traffic load via the sensors and a way to control that traffic via red-amber-green lights.
What we currently do with this system is impose on it an artificial set of rules that makes the lights change in a way that is smarter than just alternating every X seconds. But no matter how sophisticated we get, the whole approach is flawed in the same way that a spam filter with a fixed, unchanging set of rules grows less and less effective over time.
The article talks about partially "adaptive" traffic lights, but why not go all the way? I say unleash a bunch of totally Darinistic code modules on traffic lights. Have them mutate, and each generation the ones that score well (by reducing the traffic load they can measure) survive while the rest die off.
Clearly in the beginning the code modules would suck, but then you get a traffic system that is genuinely inhumanly efficient, and adapts to changing conditions. Why can't we have that?
This is what I think about every time I sit at an intersection with nobody coming in the other direction. Am I crazy?
I should buy some cement.
Seriously, complain. Then get everyone else you know to do so as well. If things are not fixed within a month start a letter writing campaign. Include the newspapers and your congressmen.
Those sensors are adjustable. You just need to be annoying enough that they fix the problem.
The city could also adjust the light to switch to red right just as you are entering the intersection, and station a cop nearby to collect the revenue stream. I know a few small towns around where I live that would definitely not pass on an opportunity like this if it were available.
For a previous poster, no weight sensing is ever used. It is always induction loops.t .nsf/DOCINDEX/STREAMS
Queensland exports STREAMS http://www.mainroads.qld.gov.au/MRWEB/Prod/Conten
This allows both computer algorithms and humans to change each traffic light in the entire city. Thus if flow problems build up, humans can intevene to change flow patterns. In fact, it is faster to travel some of our main roads in peak hour than it is late at night when lights are generally switched to local control mode rather than coperative streaming. Note our city (Brisbane) is now also changing over to LED traffic lights (they look great!)
46137
And God I hate them. The cities that have properly timed lights and don't use these stupid sensors, have lower problems with speeding and "Orange Light" runners. Why? because if the lights are timed out to traffic flow staying at one constant speed guarantees you to always be green. In those areas that have the "smart" lights it's a constant traffic jam. Small side roads with a single car every minute, Short lights because backed up traffic is always over the jam detector (a loop device about 100 feet back from the light to signal backup.) Since in both directions there is always traffic over the top of them you get really short lights both ways and a blue ton of people pushing the light, drag racing to the next one to try and get 2 in a row etc. Then you add into the mix the "Left turn traffic" detectors .... ugh. Sometimes low tech is really higher quality and more intelligent.
No thanks. The problem here is that people drive on roads not on simulations. The benifit from these is not signifigant enough to justify the expense. In fact local studies I've seen done in California show that in most cases these lights actually increase polution not decrease it over the long haul.
I'm sorry, I'm to tired to be witty at the moment so this message will have to do.
Heh, that's funny, just yesterday I browsed around on arxiv.org (the famous repository of physics/math/cs papers) and saw the
original paper.
During high traffic times, they pretty much have to do the normal timed cycle to allow all traffic through.
But, many traffic lights don't need to be fully operational during non-peak times when traffic is low. Where I used to live, in Michigan, they had basic traffic lights, which they would switch to blinking mode in the evenings (the main road blinks yellow, to allow traffic through; the crossroad blinks read, and people proceed through when they can - after stopping).
In California, with an abundance of tax dollars, they use sensor based traffic lights. So, in the evening when I approach the intersection, it detects me, pauses for several seconds, then stops oncoming traffic to allow me through. I have to stop and wait, and oncoming traffic has to stop and wait. So, it's less efficient for all involved.
The net effect is that I seem to get stopped at EVERY traffic light I hit. Their expensive, over-engineered sensor lights don't seem to operate any better at peak times either.
Seems like using a Poisson Process (or other Renewal Process) to model the arrivals at a stoplight wouldn't be such a bad idea. Poisson Processes (and variations thereof) make great tools for mathematically modeling the arrivals of packets at router nodes, and this doesn't seem too different.
Just a random toss-out, but it seems like it'd be an ok starting point.
Heck with his system. I just want the computers that they use to monitor the sensors at the light to respond to you if you are there before the light changes. As it is, these systems currently seem to decide what will happen over 5 and sometimes as much as ten seconds in advance of their next step through a cycle. If you get to the red light for a left turn in that time window, the system will completely ignore you and make you sit there (often several minutes) while it goes through a complete traffic cycle and then finally acknowledges you and lets you make that left turn. There is simply no reason with the modern electronics in traffic control devices that this decision could not be made just a fraction of a second before the next step in the cycle. Such a system would be somewhat safer too, as it would be less frustrating to drivers and so would cause less people to cut through the intersections when the lights are against them.
I'm an American. I love this country and the freedoms that we used to have.
Nothing like watching an intersection in Manhattan from the 20th floor. In spite of all the horror NYC driving stories, the drivers, especially taxi drivers, have a natural driving instinct that seems to enforce Darwin's survival of the fittest theory. But unlike other metropolitan drivers (Chicago, Detroit, LA), the natural NYC drivers can drive in any other city. The only other natural instictual drivers that can compete with NYC drivers are the real Italians, and for a real challenging driving experience drive in Rome.
The moral of the story, if you are not Roman, do all New Yokers a favor and don't drive in NYC, take a cab, public transportation or walk.
From what I have seen in my travels throughout the country, I think that I have figured out how many of the newer traffic signals are programmed.
In fact, they are quite smart. And they are very integrated with the rest of the systems that we allow to control our lives.
I am talking about databases (credit, DMV, medical, payroll; whatever); POS; Criminal; and whatever else there may be (perhaps even Church membership records).
And don't forget those nasty little RFID tags on merchandise, hospital and nursing home patients, and everything else.
So, here is what is going on.
The system is aware that you have just finished shopping and on the way home with your groceries. It knows that you have some frozen food and ice cream.
It also knows that you have voted for Kerry and that you belong to the Church of the Universal Left Socialist republics. It knows that you have just bought your home which happens to be in a conservative Christian neighborhood. It also knows that you are a transexual flaming radical faeirie (such as myself).
You can be sure that it will do it's darndest to delay you as much as possible so that:
a. The ice cream will melt and and become liquid
b. The frozen food will melt and spoil
c. You will not get home in time enough in order
to go to the doctor's appointment to be checked
on your medication for HIV.
d. You will get frustrated enough to try to go
through a red light and trigger the photo
enforcement system (after further knowing
that your credit cards are maxed out and that
you cannot afford to pay the fine)
Now, if you are like me, and you don't even own
and drive a car, then the system is **REALY** going to hate you. You are not a conformist at all. Boy, when you rent a car for that once a year time you need one; better be prepared to stop for at least five minutes at each and every intersection you come across!
Luv
As you know, the products you buy in the stores have RFID sensors.
Cleara
presume I drive a car. I'm a cyclist cage boy.
Sources?
Hmmm, this is news?! or even a "new" "idea"?! There are several areas in the US that already have done this or are trying to do this, and for oh, ~ a decade now: Oakland County, MI USA.
*YAWN*
The City of Pleasant Hill has ensured that all traffic lights turn *red* as you're approaching them. I think that they do that to either taunt oncoming drivers, or so the city can collet revenue from the people that punch it and run through the light.
:P
Catching red light runners around here is *very* easy.
If you're like me, I bet you hate moments when you're in a hurry and all the traffic lights seem to intentionally switch to red just in front of your car.
Yes, I am like you - and I can't wait for traffic lights that will know the two of us are in a hurry.
Even if the bike was made of plastic and bubblegum you can always trigger the detector if you kill your ignition and then re-start the bike. The windings in the starter motor create a significant electromagnetic disturbance when cranking the engine.
Did any of the mods read the links the parent posted?
They are in no way insightful.
"Traffic Calming" is a term used (even in his links) for measures taken in residental neighborhoods.
The story we are discussing has nothing to do with residential streets. It's like comparing apples to oranges - there's quite a bit of difference in traffic needs and management goals between urban coridors and residental streets.
His second link is to a bit of opiniated hogwash saying that speedbumps "inconvenience and hinder the legitimate travel of responsible motorists" Sounds like they hired an ex-NRA spokesperson.
Goes on to say shit like "Deflection devices built to slow passenger vehicles, create even greater delays to emergency response vehicles. The longer wheel-base, stiff suspension, high vehicle weight, as well as the sensitive equipment and injured victims transported by these vehicles, requires drivers to slow almost to a stop to negotiate the devices safely." Which ignores the fact that "traffic calming" measures are used to discourage through-traffic on minor streets - routing traffic to the roads designed to handle it. Properly deployed - they are not ever used on every pathway through a neighborhood.
By the time Trafic-Net became self-aware it had spread into millions of Traffic grids across the planet. Highways, airports, local towns and cities. It was software; in cyberspace. There was no system core; it could not be shutdown. The attack began at 6:18 PM, just as he said it would. I should have realized it was never our destiny to stop judgment day - merely to survive it, together. He knew; he tried to tell us. But I didn't want to hear it. Maybe the future has been written. I don't know; all I know is never stop fighting. And I never will. The battle has just begun.
I made a telescoping probe(two broomsticks wrapped with coat hangers that i could extend to ~10') that I could use on most of the city streets as things were often very tight. Sometimes I would jump out of the car and go press the button. Other times I would yell at pedestrians to please punch the button. And never forget the pizza driver motto: 'No Cop No Stop'
I had those lights so down after several years of driving those streets that I could save several minutes per hour. May not seem like much these days, but I grabbed an extra 2$-4$/hour using these tactics.
This model of allowing groups of cars through is the same as what naturally happens where there are no traffic lights, and cars and bicycles share the road. It is termed critical mass.
The term "critical mass" in this sense, was adopted from an observation made by American George Bliss while visiting China. He noted that traffic in China, both motorists and bicyclists, had an understood method of negotiating unsignalled intersections. Traffic would "bunch up" at these intersections until the back log reached a "critical mass" at which point that mass would move through the intersection. This description was related in the Ted White documentary Return of the Scorcher (1992) and subsequently adopted by the Critical Mass movement.
Perhaps the only difference with this traffic light system is it tries to preempt the "bunching up".
In State College, PA, every diamond highway interchange has these. If the light's been red for a while and you start coming up the off-ramp, it'll be green before you even get a chance to slow down. Not only that, but they use optical sensors instead of inductive sensors. I know the inductive ones are hard as hell to change with a motorcycle (you have to be right on the edge of the coil), I dunno how the optical ones are.
It just occured to me, I wonder if there are any self-learning algorythms that could be adapted to traffic lights. Imagine a light (or a group of lights) controlled by a central system that learns from traffic patterns over time and becomes better at managing lights due to experience.
Possible?
While you're at it, could you come up with adaptive drivers? Thanks.
It's 10 PM. Do you know if you're un-American?
some great NYC traffic footage in this wonderful film.
This has already been implemented in the trafficlights around my Uni four years ago or something. They measure the trafic around the lights and switch according to this. Funny walking up to the lights when there is no cars around. It will switch to green for pedestrians immediately. The same will happen if a lone car comes driving towards the corner.
You insensitive clod!
I got nothin'.
*leaves Slashdot*
Don't blame me -- I voted for Roslin.
One of these days, every vehicle will have an embedded RFID chip. Traffic Control systems will be designed to monitor these RFID tags. They will know if the vehicle is parked, or how fast it is moving. They may also know the source and destination for this particular tag.
Sound like a routing protocol yet???
They will know the capacity and interaction of the entire traffic system at the micro level (ie between intersections) and adjust signals in realtime to optimize this flow.
Combined with auto-guidance systems, the vehicles will move smoothly to any final destination as singular entities or massive, intelligent recombining groups.
You heard it here first.
Ride your bike more often. Unless you're in a real hurry, those mean ol' red lights are nice little breathers between the segments of your ride.
OK, this doesn't apply to those in a serious urban cityscape, or those with long comutes, but you get the idea. Red lights are just more oppertunities to show that a bike can accelerate from 0-10mph faster than just about anyone on the road.
Evan - needs to hit preview before submitting
Yep, you heard me. They don't time traffic lights to ease and speed the flow of traffic. They do it to slow down and (particularly in commercial areas) trap traffic in areas where you're more likely to shop.
There's a big huge (relatively new) mall a short distance from my house. Since it was a green-field site before they build anything, they had a chance to give it a nice, pleasant, open layout. But no. They gave the roads the most horrible, ass-backwards, retarded and unnavigable layout that I've ever seen. You often have to head in the opposite direction to the one you really want to go. And if you want to get back to the highway - good luck!
And the *very* worst are when traffic lights are places in residential areas. They put the lights in to slow down traffic - then people speed to beat the lights - or sit there, idling for 3 minutes, pumping carbon monoxide out into the atmosphere right next to the houses. They've slowed the average speed of the traffic, frustrated drivers who then use the area for drag racing, increasing the overall exhaust poison output in the area.
Local council road planners are bastards and deserve to be put up against the wall when the revolution comes. The very desire to have such power is the thing that makes them least suitable for it. Replace them with a shortest-route, minimal time computer algorithm and be done with it. Better yet - start building roundabouts instead of traffic lights.
I wish Japan would adopt traffic lights with sensors in the first place? All of them here seem to run on a timer. They're no end of frustration. From Tokyo to small country towns, it's all the same. Some lights display a bar graph of how long until the light turns green again, but they don't react to traffic conditions.
It's common to have to stop at a set of lights and have no cars come through on the adjoining road.
No wonder people here run red lights all the time.
we have these in Sao Paulo, Brazil for ages
Speeding ahead is part of the problem. As the submitter says:
I don't know about the US, but in major cities here in the UK, traffic lights along high volume traffic routes are synchronised (or at least as good as they can get them to be taking into account intersections with other large roads) such that if you drive at 30mph, you will go through one green light after another after another. By contrast, if you travel at 20mph you'll be too slow and get caught by red lights, and if you go at 40mph, it will seem like every set of lights is turning red in front of you and you have to stop and wait for the 'green wave' to catch you up.
Of course, this may just be a myth that I picked up, but it seems to a) be sensible, b) be possible, and c) fit circumstantial evidence - seems to work for me most of the time.
You know you've been IMing too long when you almost say 'lol' out loud to a non-geeky friend...
...is a network of monitoring buoys...like one at every street corner...that monitors traffic throughput and reports it to a central computer. Then, when you get in your car, you connect to said computer (wireless, obviously), and enter your destination. It in turn gives you the route that will get you there the fastest, based on the travel rates of the various paths available.
:)
This will effectively load-balance traffic across all the major streets during the busy hours, and will work well since it offers the maximum possible payoff to each individual participant.
I would happily pay for this system through vehicle taxation.
I suspect that some cities set their lights that way to drive ticket revenue. If everyone slows down to less than 20 miles under the speed limit, there goes the speeding ticket cash cow.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
In Amsterdam I find that often roads and traffic lights are designed to maximize driver frustration. There are too many cars in the city and it is a way to reduce the convenience of driving to get people out of their cars. So this could be used in reverse to maximize frustration for drivers.
That's fine if there isn't any congestion. Then you can send cars merrily along ASAP to their destinations.
But if there's congestion, there's no point sending tons of cars to queue up in piles causing even more congestion and making things worse.
It might actually be better to keep the cars back till things clear up a bit.
I believe that's done in some places - different modes of operation for peak and off peak hours. During off peak you get a "green wave". During peak hours you don't - traffic gets "trickled" into the system at whatever rate they think it should be trickled in (doesn't mean they get it right or not).
The city near where I live, when things get really congested - some intersections get blocked up coz drivers miscalculate and go when it's green and the road ahead is congested - they are guessing that the road ahead would clear up before it turns to red. Then the other lanes can't move across when it's their turn.
Trouble is, if they don't go, sometimes there won't be a gap - because any gaps will keep getting filled by another lane.
The ironic thing is - the city has to resort to using traffic policemen to direct traffic in order to improve the traffic situation.
Previously when the traffic cops were doing that the motorists complained that the cops were making things worse. So one day the cops all stopped directing traffic, left it to the lights and things were really bad!
I don't see easy solutions - when there's just too much traffic, you're going to have to wait.
The point of any traffic control system is to make sure traffic flows efficiently through the network, not through a particular intersection.
So taking the instance of a crossroads. If there was more traffic through the north south part of the intersection than the east west, then you would think it logical to allow more flow on the more congested arm.
But that only makes sense in a local context. If the north-south arm fed directly into a zone of even higher congestion, then it would make sense to hold the traffic longer to prevent gridlock further along.
Just like you would with any network.
Though I guess minimising road rage is important, and perhaps more people would get frustrated waiting at a red light for extended periods than crawling bumper-to-bumber at zero speed, even if the red-light hold would get them to their destination quicker in the long run...
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Sydney has had this for the over 20 years.
Around 2500 of the intersections in Sydney are linked together and they "marry" and "divorce" each other based on live statistical data as cars flow through the intersections.
It's a self-calibrating system. It has been exported to many countries.
The local intersection controllers measure traffic flows and adjust timings locally and also are linked to regional controllers that share statistics for an area and these regional controllers are all linked to the central monitoring facility in the city.
Google on the Sydney Co-ordinated Adaptive Traffic System (SCATS)
e.g. http://www.traffic-tech.com/pdf/scatsbrochure.pdf
fish and pipes
I've said it before (but i can't find out how to see all of my past history of comments) - the traffic lights [will] go *in* in the cars. They will be integrated into the cars comprehensive feedback system. It's all stuff waiting for the correct/sufficient level of security to make such things viable against the designs of the malicious. In this way, a central traffic system will post regulating suggestions to a users car, to encourage an overall more smooth traffic flow.
.
-shpoffo
So would a group of six mini coopers count the same as three ford explores? Length wise they would be about the same if they were tailgating?
I make my face look like this and concerned words come out.
Ann Arbor, MI has something like this in place. Late at night when there is no cross-traffic on the sensors, if you approach a red light and maintain constant speed at the speed limit (or below), it will turn green in time for your arrival at the intersection!
My old roommate was from there and told me about it, and I had a hard time believing him, but I went up there with him, and got to see them firsthand - they do work, but only at late night when there's no cross-traffic.
What traffic control signals need to do is a "greatest good for the needs of the many" calculation, so if a group of 5 cars approach from one direction and a group of 2 from the other, the group of 2 gets a redlight, and the 5 get a green.
-- You are in a maze of little, twisty passages, all different... --
there's this intersection near a secluded freeway entrance, controlled by lights. it seems that unless you're car is at a specific spot, the entrance to the freeway doesn't turn green.
Everyday I have to stop for almost non-existent traffic which serves a university traffic flow here in Penang, Malaysia.
I've been wanting to hack into the microcontroller to balance out the flow but here we have cops patrolling for petty personal gains, which inadvertantly leads to cops who can't differentiate real crimes from good intentions.
...the lights do this on purpose, but it's not personal.
All those inductance loops, and in some other locations, video cameras hooked up to image analysis apps, do it to help all sorts of things. The ones that do it at 4am are doing it to slow you down. Approach the light below the speed limit, and the light probably won't change.
What gets me are the areas with well-heeled residents that have one entrance onto a busy road, and they have a light. No matter how heavy the traffic on the main road, their light always turns green to let them out when they approach the light, with little or no delay. But a couple of miles away, the place iwth the low-income apartments, a school, etc., well...no lights, just weak 20mph school zone signs.
Some cities want people to slow down. Unfortunately in cities like that they deliberately plan to slow down traffic to prevent things like.. oh.. racing maniacs, and in the process they end up creating huge traffic snarls when there's a busy stream of people.
In some cities also, they want to slow traffic down to prevent growth--this was the strategy of the city planners of Vancouver, for example (BC Canada) and they made such monumentally stupid decisions as make the Patello bridge only two lanes wide (instead of the ten (!) lanes Patello himself wanted.) They also deliberately snarled up the downtown core to prevent it from turning into a downtown New York. Unfortunately it's heading that way anyway, and now that they've fucked up the planning, they're paying much much more for it.
We've had these installed for at least 5 years all over Sweden.
It's kinda neat driving in the middle of the night getting the reds to switch to green over and over again as one approach them and noone is waiting on the sides.
Buy all your crazy japanese videogames from
The best intersection technology avaliable today is roundabouts. No traffic light can come close to the flow in one of those.
HTTP/1.1 400
Here (a small town in Poland), we have two sets of such "smart" traffic lights already.
And ironically, they were installed because there was not enough money in the town budget to afford synchronizing the old traffic lights (so that you get green light at about the time you get from one to the other), which actually required pulling maybe 600m of cable.
Interesting, how people "reinvent" things that are in use for a long time in other parts of the world, and interesting how nobody notices...
Anagram("United States of America") == "Dine out, taste a Mac, fries"
my city installs traffic lights and make them turn red right when you approach them on purpose, to piss off drivers, in an attempt to force people to use the stupid road level trams (that, of course, being on the same level as cars, get stuck in traffic).
the problem with that plan is that the idiotic trams stop working at 11pm. so, if you go to the movies with it, you have to walk back home (how practical)
.....I have never seen a queue of traffic at broken traffic lights that is as long as the queue of traffic at the same junction when the lights were working. They use less power too.
They whose government reduces their essential liberties for temporary security, receive neither liberty nor security.
under the theory that traffic accidents are fewer if there are more cars stopped more often. So, while motorists think that traffic should move more smoothly, their local bureaucrats are thinking exactly the opposite. Plus it boosts revenue from all the red lights frustrated drivers run.
No one ever had to evacuate a city because the solar panels broke!
Ok...what if or when they fail? What if the sensors fail? Changing them would be a pain and the road would become patchy from changing the sensors.
Of course this breaks down because [a] people do run lights, and [b] even the people who don't end up getting more and more frustrated - which I'm sure isn't going to inspire safe driving.
TiggsTiggs
"120 chars should be enough for everyone..."
or a pedestrian bridge....
Moo!
A friend of mine back in the day used to be a dealer for traffic light systems for Orange and Seminole Counties, FL (Orlando).
n t/index.html
There is a device on most intersections in the area that detect EMT and fire vehicles and turn all of the lights on that side of the intersection green as to clear traffic. These sensors hang in between the stop lights.
Another friend of mine claimed that he could flash his hi-beams at night and cause the sensors to think he was an ES vehicle. After speaking with the dealer I found out this guy was full of crap.
Apparently the system works like this:
Each vehicle has a strobe on top of the roof. When the siren/lights are activated, the strobe turns on automatically. The strobe flashes in a specific pattern and "activates" the sensor as it approaches the intersection. Behind the strobe however is an IR emmiter which sends a coded signal to the light which apparently identifies the vehicle and then gets logged in the system.
This allows them to track the time and number of the vehicle that went through the stop light turning everything green. It also lets them search for unauthorized uses in the system.
A somewhat unrelated point:
Seminole co is the second richest county in the state (other than Palm Beach). They have too much money. These peckerheads like to install traffic lights at intersections even if they are not needed...why? "to slow the traffic down" It pisses me off more than anything. The Central Florida area already has enough traffic problems and these waterheads are trying to slow things down... I guess they won't be happy until we are turned into the industrialized Star Wars planet of "Coruscant" and no one can move anywhere on the ground. http://www.starwars.com/databank/location/corusca
Its nukin futs!
Libertas in infinitum
i think this research simplifies the traffic control problem. this method might work for small intersections where the traffic distributions between two roads are highly asymmetric. but if we evaluate the city's traffic as a whole, it seems to me this is an optimization problem and i doubt this local optimization at SMALL intersections matters. the traffic problems exist at MAJOR intersections. i believe the real problem is how to simutanously adjust and schedule the lights at all MAJOR intersections such that the traffic (or any cost function) of the whole city is minimized.
It's no secret that our current government wants to force motorists off the road, either through excessive use of tax, or any other congestion 'saving' scheme that involves more money on our part. For this reason, I don't believe these devices will be used to turn our lights green on approach, but rather to red instead. It's a sad state of affairs, and unfortunately there's nothing that can be done about it.
It wouldn't be so bad to let individual drivers flip the switch to green - if they pay for it. You could tell a computer in your car how much your time is worth to you (say $10.80 per hour, which is 3 cents per second) and at a junction the cars queuing would bid in an auction for the right to go first. This sounds a rather extreme free-market solution but it's not really any different from congestion charging, which already exists in some cities.
-- Ed Avis ed@membled.com
here
This junction on Lochee road will go from green->amber->red->green straight away if there is no cars waiting on one of the other minor roads
All spelling mistakes are due to solar flares...honest
There are quite a few roundabouts near Boston, MA, but we call them "rotaries."
There's one a few blocks away from where I live that has lights, red flashing at each of the five entrances, and yellow flashing at each of the five exits and 5 crosswalks across the middle. Only the lights for the crosswalks activated turn red, while the rest remain flashing normally, thereby clogging up the whole thing everytime someone crosses anywhere.
What I don't understand are the two-lane rotaries, whereby one has to cut someone off to exit the rotary from the inside lane.
his homepage has papers on his current research.
Think about how it got to be that you live so far from work. The fact that American cities are built in such a way that car ownership and use is mandatory is just about the worst thing about an otherwise great country. As it stands you either have to pay huge amounts of money to own a stupid automobile, or pay huge amounts of money to live in one of the few places which is built to a reasonably decent scale and still has jobs.
Why not just build cities to a proper human scale?
____________________________________
-- I beleve you'll like this -->
Damn, so you mean I could have published my A-level statistics project in Nature 12 years ago? Bah!
A Roland Piquepaille submission with a link to the actual story? Granted, I expected everything to go to hell at the office when I was away for a few days, but at slashdot too?
Could he actually be listening to all the people bitching about his submissions at last? At least he got a link to his blog in there too, although it was a close run thing. Not that he made it clear that it was his blog, of course - that would be asking too much...
It's official. Most of you are morons.
Although it's a Belgian invention, these traffic systems are operational since 1993-1994 in Belgium... I'm not sure what the big fuzz is. In the town where I live, we've had several of these lights, detecting when cars get close to the light and either switching it to green or keeping it green. It has a priority for each street and each hour of the day.
Recently, they've also implemented anti-speeding sensors, which turn the light to red when you're driving faster than the speed limit. There's a sign at the traffic light saying "Red light ? You're probably drove too fast !". Can be annoying when the person behind you is speeding and you're not, but in general it does slow people down.
Again, I'm not sure what the fuzz is all about...
Will the system recognize high value vehicles like ambulances, police, and firefighters? If so, will elite politicians and corp execs have access to such? Would that be a bad thing? Either way, will there be a fee? (monthly? per use? High Value (see above)? Usable on Bridge and Pike tolls?)
During light traffic hours, a large group of cars will get the light over a single car, though the single car will get the light immediately after passing.
These can't be the only three rules. Take the above for example, and assume heavy traffic on the order of rush-hour, and you are that one car wiating to get onto the busy road. Unless many others start lining up as awell, you would be waiting a *loooonnngggg* time.
There must also be some maximum length for a light to remain red.
I'm in the UK and the traffic lights seem to wait till there isn't much traffic (using weight sensor s or whatever). I thought they did this in most countries and had for a while.
Joe Llywelyn Griffith Blakesley
[This post is in the public domain (copyright-free) unless otherwise stated]
City-wide coordination of traffic signals is quite common in Europe. Until a few years ago I was one of the programmers working on SCOOT. When I worked on it, it was possible to control an entire city of traffic signals with one small VAX (mmm...OpenVMS). It worked by collecting flow/occupancy data from sensors buried in the road (ususually inductive), putting them into a model (written in DEC C) running on the VAX, and then making a succession of small adjustments to the timings of the signals.
If you drive good, then you get karma points. A scanner at the traffic lights picks up on your karma and weights the light sequence accordingly. At times where they have no choice but turn red, you get karma points at compensation. Might be a little bit tricky to implement, but would certainly remove the "Why do I always get caught on red?" frustrations, and encourage better driving. (This post originally started as a joke but now that I think of it, it's a pretty good idea)
I currently work as a Traffic Signal Designer in South Western Pennsylvania. I would like to clear up a few issues related to the comments being made in this post. First, in regards to the traffic detectors, the most common is a detection loop (appears as hexagonal cut in the pavement) which is an induction loop cut under the traffic stream to detect traffic. Another increasingly common detection system is a video camera which uses pattern matching to sense a vehicle sitting on the approach. This detection, particularly on the side roads, helps to provide the best efficiency of operations for the intersection by passing the most vehicles in the least time possible. Secondly, the concept refered to in this post of serving a group of approaching vehicles (a platoon) is currently employed in the US. It is however mainly used in locations where signals are closer than 1 mile apart. This is accomplished by offseting the times for the signals so the vehicles may pass through a series of signals after being stopped at one. Finaly in regards to the comment on SCOOT. There are several different systems which are used to monitor and optimize traffic signal systems. All the signals are linked together and communicate to one central location for instructions. By using the detectors at all the signals it is possible to determine the amount of traffic in the system and adjust according. Companies such as Naztec, Eagle, and Econolite all have systems to accomplish this and many large and medium size cities employ this technology.
I'm sure that the engineers have good simulation software for this. I would like to hear from someone knowledgable; what are the parameters? They'd have to vary from region to region as we all know that people drive differently in different parts of the country.
/* drives at least 20 MPH over, slams on brakes in heavy traffic when radar detector goes off */ /* will cause any amount of risk to others in order to gain 0.1 seconds - cuts off everyone regardless */ /* drives 10 MPH under limit */ /* drives RV at limit, changes lanes without looking */ /* Pct of roadway under construction - increases everyone's irritability and irrationality. */ /* self explanatory */
Anyone got guesses as to the parameters? Here are mine:
int PctManiac;
int PctAssholes;
int PctGranny;
int PctGrampa;
int PctConstruction;
int PctDrunk;
Obviously the values are going to be different in Florida, Chicago, Boston, Seattle, and at different times of the day.
Seriouly, I bet this is a pretty interesting simulation to work on. Anything that must try to predict human behavior, and which is readily researched in the field would be fun.
I go to school in North Bay Ontario and every intersection seems to have some sort of sensing system installed (weight or other). During peak traffic hours I think that the lights go on a timing schedule but anytime after that you wont find yourself wating at a red light too long. I find it really helpful at those left turn lanes. For example; you know when you get to a left turn lane a little late and the green arrow light turns red? Well here if you get to the light and there isn't traffic coming the other way the green arrow light will go on again without waiting for another cycle. I find this system really cool and I think the larger cities really have nothing to lose. Originally from Toronto, I wouldn't mind a system like this one.
Also a little off topic, we also have LED traffic lights which I'm sure are really cutting down on the city's power consumption. I'm curious to know how many people have these LED traffic lights in their city...
Cheers
News for Nerds, stuff that ages for the others
...you insensitive clod!
What we need is for Richmond to spend money on the roads here in NVa instead of pouring money into the vast road system in Richmond. NVa accounts for 60 to 70% of the tax base in VA and gets 20 to 30% back.
We are tired of financing roads for the rest of Virginia!
But these sensors sound cool anyhow!
Dan
Easy Home Improvements
researchers propose mounting a transport container (having seats and windows) onto four rotating disks, vertically mounted and aligned with the direction of travel. The assembly to be propelled by a horse or even an on-board heat engine.
Traffic lights (in UK anyway) have been controlled by such systems for as long as I can remember - which is back to when detection was by pneumatic rubber stips in the road, which I understand operated camshafts via a pneumatic cylinder. Rubber strips have long been replaced by magnetic induction loops, and the decision algorithm has long been more sophisticated, such as (in some cities) giving greater priority to buses (which have special transponders).
I read years ago that in London the lights along key routes were linked to a single computer that gathered traffic into bunched "convoys" which were then fast tracked through green lights for several miles. I have even experienced it working well (at off-peak times anyway) until it is fouled up by some pillock up front deciding he is going the wrong direction and stopping suddenly.
It's suprising and infuriating how many driver are oblivious of the magnetic loops (the trace of which can be seen in the road surface) - they stop just short of them, but if they moved forward another yard the lights would change green.
That is the real (perhaps only) question a municipality cares about. Those familiar with the red-light camera scheme already understand that the goal is to raise revenue, not improve efficiency (or safety).
There is not nearly enough love in the world, but there is far too much trust.
I can't believe that we can talk around the world on a wireless phone, worldwide internet communication, have a Tivo in our home to digitally record programs, and yet the stoplights on our streets are YEARS behind where technology is. Don't you hate being the only car around, and having to come to a stop, wait for the light to change (while no cars have come) then go?
A 286 computer can manage traffic better than those $60,000 stoplights.
What's the deal with news about stoplights?
Stoplights that show timers in Singapore?
Supposedly 'new' smart stoplights?
Here, in the midwest USA, for all of our many faults, for our political apathy, for our boring and endlessly flat terrain, one thing we do have is intelligent stoplights...
There are weight sensors in the road (and sometimes several distances of sensors) that determine when groups of cars approach an intersection.
It really does work fairly well, but there are limited gains in very high traffic situations.
This is both near and in Chicago, as well as in Iowa, and small towns all over the area.
AFAIK, its a very standard technology.
WhiteWolf666 an exBush supporter. All you new-school,compassionate,save the children Republicans can rot in hell
Actually, you just need to get timing of one of those strobes on an ambulance or fire truck that has the off sequence pattern. Mount that bad boy to your car and never wait for a red light again... Of course, don't be seen by a squad car, might prove detremental to your ticket budget.
what our current traffic management head did is to disable the traffic lights and close intersections on a streth of road. instead u turn slots were placed around every kilometer. traffic eased up because cars do not stop on intersections anymore. there is a continuous flow of traffic.
a very no-tech way of easing the traffic. i would hope that they actually increase the number of roads where they do that. (but i think the problem is space on the road for the u turn slots.)
Live your life each day as if it was your last.
Traffic circles are starting to catch on in maryland. Sometimes simplicity beats technology.
The other Catch-22 is some traffic sensors only detect you if you're slightly overlapped, at least here in Newark, OH. I have seen people (usually elderly people) stuck at a left-turn lane for close to a half hour before they finally pulled up enough to trigger the signal. (They usually get "subtly pressured" By the people behind them tailgating them)
This sig has absolutely no significance and serves only to take up screen space and waste the time of the reader.
As often as not, traffic control devices in the U.S. are in place to generate revenue, not necessarily for reasons of safety.
n al s.html
The National Motorist Association (here in the U.S.) is all over this kind of discussion. I've been a member since the early 1980's and in fact became a life member after a few years. The guy who started it is still at the helm and is zealous about protecting driver's rights. I like to describe their organization like this: The NMA is to drivers as the NRA is to firearms owners.
The NMA has a link on their website to some information about traffic lights:
http://www.geocities.com/jusjih/trafficlightsig
I found the above link on looking at the NMA's website (http://www.motorists.org). Their website isn't bleeding edge cool, but has a lot of good information for drivers.
And at the risk of turning this into a plug for them, I'd like to say that I highly recommend that anyone who is concerned about their rights as a driver, that you check ou their website. The NMA was the #1 driving force, if not the sole force in getting the ridiculous 55 MPH repealed a few years back. I know that most everyone in the U.S. is happy for that. Check out their website at http://www.motorists.org
In Switzerland we have this situation already. The sensors in the street switch the traffic light to red if some other cars are waiting and there is a too large gap in the line of cars going over the crossing. Drives me nuts! One idiot slow car driver is enough and the light flips red just when he crosses the white line. It's also very dangerous, because people adapted to it and try to keep to short distance.
This is one of the few places I have ever seen where the traffic signal was set up correctly. Doesn't make Marlee Way wait unnecessarily and gives enough time for most traffic using it to get through. I wish they would fix more traffic signals like this.
The lessons of history teach us - if they teach us anything - that nobody learns the lessons that history teaches us.
Sounds like my High School photo editor's car, a Yugo, stick shift. I would (alone) lift the BACK wheels off the ground to get past the parking brake. Then I would walk his car to a new parking spot while the engine was going pft...pft...
I'll admit to being on swimming/diving team and being able to leg press more than the car weighed at the time (I was leg pressing around 1200 lbs for reps.Shamefully my bench press was less than 10% that.)
It was lots of fun fun seeing him...(scratching head)"I know I parked here...Why is my car over there!" pointing behind a school bus 50 feet away!
The gag got old after quite quick. The second time I moved his car I was witnessed by some football players on the news staff. His car would be anywhere other than where he left it! At least they had the decency to not put it in the third floor stairwell as my Dad (and several of his friends) did to someone's Bug when HE was in high school!
Phil
Laugh, it's good for you!
I first conceived of this concept and the urgent need for it almost twenty years ago! Even back then the technology existed to do it, but now it can be done even more cheaply and reliably. There's really no excuse, except that the bureaucracy doesn't wanna spend the tax money to fund it: some of their funding comes from the traffic ticket fees collected from the desperate impatient exasperated people who run those traffic lights. If they make the system more efficient and tolerable, it hurts their municipal pocketbooks.
You've never watched one of the greatest classic geek films of all times? For shame.