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Power Transportation Technology

Traffic-Flow Algorithm Can Reduce Fuel Consumption 328

thecarchik writes "New projects from German automakers Audi and BMW promise to ease congestion simply by looking at traffic signals and driving style, in an effort to smooth the flow of traffic. Through a test course in Munich, vehicles were able to post phenomenal fuel efficiency gains simply by adjusting the timing of traffic lights depending on traffic volume — to whatever speed provides a so-called 'green wave' of four or more synchronized signals."
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Traffic-Flow Algorithm Can Reduce Fuel Consumption

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  • It astounds me (Score:5, Insightful)

    by skelterjohn ( 1389343 ) on Thursday June 03, 2010 @08:08PM (#32453356)

    That this isn't done everywhere. With all the red light cameras everywhere (for safety), you'd think they could put a few out there that would make it so I don't spend 3 minutes every morning staring at an empty intersection.

    • Re:It astounds me (Score:5, Informative)

      by Garble Snarky ( 715674 ) on Thursday June 03, 2010 @08:18PM (#32453436)
      Traffic timings don't even need to rely on cameras, they frequently take input from the inductive sensors (even more ubiquitous than cameras) in all four streets on the intersection.
      • Re:It astounds me (Score:5, Interesting)

        by Anonymous Coward on Thursday June 03, 2010 @09:31PM (#32453866)

        Which inductive sensors suck hard for cyclists. I frequently go grocery shopping early in the morning or late at night when there's practically no traffic -- wanna make a left turn? Your choice: sit there for upwards of 5 minutes waiting for a cager to come trip the light (and then they have to wait for you to get through the intersection, a delay I'm sure they appreciate), or disregard the signal (yep, that's an infraction -- being on a bicycle gives me no immunity to laws, just to sensord) and turn when it's safe, without causing grief for others. I always come to a full stop, then turn left when there's no traffic, just to demonstrate a level of caution should that light be under observation, but I'd almost invariably be clear blowing straight through.

        Fortunately, one light along the way has cameras, NOT to ticket unwary marks for racing a short yellow, but to control the intersection. Car pulls up? you get a green in a few seconds, just like the loop sensors. Bike pulls up? you ALSO get a green, although the same delay means it'll be green before you get there, and you get just enough time to make it through before yellow. I wish more lights were set up this way.

        Besides, for the purpose of maintaining a green wave at traffic speed, I suspect cameras are the better oiption, as you can use the camera of the intersection you're controlling, whereas the induction sensors are usually too close (won't show the wave until the lead vehicles are practically stopped), and you'd need to use the sensors from the previous intersection.

        • Turn right on red, do a U-turn, proceed at will. Totally legal. My favorite maneuver is similar: to turn left, go straight through the intersection, take the first U-turn, then turn right.
          • by yotto ( 590067 ) on Thursday June 03, 2010 @10:08PM (#32454098) Homepage

            U-Turns aren't legal here, but I frequently turn right, then turn around in a driveway or parking lot, and still get back to the intersection in plenty of time to beat the light change.

            However, this is the driving equivalent of a programming kludge and doesn't fix the actual problem that the lights are set up stupidly.

            Did I just make a computer analogy to better explain something about cars?

            • Re:It astounds me (Score:5, Interesting)

              by ztransform ( 929641 ) on Friday June 04, 2010 @02:44AM (#32455452)

              U-Turns aren't legal here, but I frequently turn right, then turn around in a driveway or parking lot, and still get back to the intersection in plenty of time to beat the light change.

              You have to love Australia. That particular manoeuvre is illegal there. Also illegal is exiting a roundabout from the same road you entered.

              Truth is everybody in Australia is a criminal. You just have to wait until some prosecuting authority thinks it's your turn and they find the rule to nail you with.

              • by Eevee ( 535658 ) on Friday June 04, 2010 @07:11AM (#32456752)

                Truth is everybody in Australia is a criminal.

                ...Because iocaine comes from Australia, as everyone knows. And Australia is entirely peopled with criminals. And criminals are used to having people not trust them, as you are not trusted by me...

        • Re:It astounds me (Score:5, Informative)

          by no1home ( 1271260 ) on Thursday June 03, 2010 @11:20PM (#32454486)

          As a motorcyclist, I run into this some as well, though they have improved greatly (or it's because I have a bigger bike now). I have been pulled over once in my hometown for running a red. I explained to the nice officer (she was hot too, BTW) that I had waited through three cycles of the lights and never was given a green for my left turn, so, when it was clearly safe, I went. She let me go. Now, I hear rumor this is legal, but don't depend on it. It might not be for your jurisdiction (or even mine). However, it might be legal simply based on the idea that the signal is malfunctioning and you must therefore take matters into your own hands. You can solve your problem with a rare-earth magnet stuck to the bottom bracket of your bicycle. I know some bikers who use it and it has helped them.

          • Re:It astounds me (Score:4, Interesting)

            by veganboyjosh ( 896761 ) on Friday June 04, 2010 @12:06AM (#32454672)
            In most places, provided you do wait for the numerous cycles of light changes, and it never does change for your motorcycle or bicycle, you are legally allowed to treat the signal as malfunctioning. It's not registering a legal vehicle, therefore it is malfunctioning. Treat it like a stop sign, and go through the intersection when it's safe. I am not a lawyer. I do work in/with bicycle advocacy and have heard this from several independent sources.
        • Re:It astounds me (Score:4, Interesting)

          by daid303 ( 843777 ) on Friday June 04, 2010 @03:41AM (#32455772)

          Don't complain at slashdot, complain at the city council. It is possible to detect cyclists with inductive sensors, but they are not installed 99% of the time due to the extra costs. I work at a company that supplies traffic-lights, and I found out recently that one of the lights I used to cycle past as a kid was produced by us. And it had no problems detecting me, giving me green light without stopping.

          Also, you don't get a lot of green as a cyclist because cyclist green is 'expensive' in time. They have to set the clearance time to the slowest cyclist. So all that time they cannot give green to any lights that would cross your cycle route, which impacts the flow of traffic a lot. But don't fear yellow lights if you have enough speed, you have plenty time. And if you know the intersection a bit then the beginning of red can also be safe for you. But you might need to do some explaining to the local cop from time to time.

          And as last, green waves are not controlled by cameras or induction sensors but by strict timing and communication between the intersections. The first intersection just signals the rest that a group of cars is coming so the rest can prepare for that. Or, in cheap cases, the intersections just run on fixed programs designed so that the green wave always happens (totally sucks for low traffic situations, like at night)

          Green waves for fuel is nothing new, we've been doing so for quite some time already. What's new here is the communication between the vehicles and the intersections (which is pretty much still in heavy research state, and involves a lot more partners then just Audi and BMW)

      • Re: (Score:3, Interesting)

        Comment removed based on user account deletion
      • Re:It astounds me (Score:4, Insightful)

        by Dare nMc ( 468959 ) on Thursday June 03, 2010 @10:09PM (#32454114)

        most of the inductive sensors I have experienced are at the intersection, so you have stopped before they work, thus saving no fuel. They also pick up a single car and only optimize for that one car, and usually only on the lessor used roads, paying no heed to what they are stopping, and for how many. IE the ones I use see a single car (wanting to make a right turn 90% of the time) from a 30 mph lane turning on to a 65 mph highway, and the light will stop a string of a dozen cars going 70. With A very smart camera it would be possible to picking up how many cars, trucks, and where is the next opening. Need dozens of loop sensors to do that.

        It would be a huge fuel savings if the lights know for example we have 3 loaded semi-trucks and 5 cars going 70 wait for them to pass and make the slow moving car wait longer. It would also be extremely helpful if we could get info sharing on light timing into something like the google map android phone applications, so that it could tell me to adjust speeds to hit lights, or to create a gap, or turn earlier to avoid a string of bad lights (or join a small group of cars...)

      • Most traffic signals that I know of are either timer based, or combine timers with inductive loops. If there's a vehicle (except motorcycles and bicycles, apparently), it should trigger the light sooner. When I rode motorcycles, I never had an inductive loop pick it up. Even in my car, I usually have to rev the engine slightly (like to 2,000 rpm for about 5 seconds) for it to see me. (larger magnetic field, better impression for the loop to see). Here's some info [advrider.com] for bikers on tripping th

    • by tepples ( 727027 ) <.tepples. .at. .gmail.com.> on Thursday June 03, 2010 @08:19PM (#32453444) Homepage Journal

      With all the red light cameras everywhere (for safety), you'd think they could put a few out there that would make it so I don't spend 3 minutes every morning staring at an empty intersection.

      A lot of traffic signals are on a fixed cycle because the sensors buried in the street often fail to reliably detect a bicycle waiting to turn left (US; mirror in UK/AU/JP), even when the bicycle's wheels are directly over the edge of the loop.

      • they have video traffic detection cameras at some light as well sensors at others.

      • by Jaime2 ( 824950 )
        I'm not surprised, most of the sensors I drive over fail to detect my 532 pound motorcycle. I be more surprised if one of them did detect a bicycle.
        • by Kozz ( 7764 )

          Glue a rare-earth magnet to the underside or insole of your shoe or boot. That should trip the induction coil, or whatever the sensor is made of.

        • They don't detect weight. Metal bicycle rims can be easily detected provided they are placed directly over the wire. For the figure-8 loops the middle section has two wires providing effectively twice the sensitivity and is more reliable. If the road has been repaved and the loop cuts are no longer visible this task can be challenging to futile. The same applies for motorcycles. You can't just stop in the general area and expect it to work like with a car.

      • by yotto ( 590067 )

        A lot of traffic signals are on a fixed cycle because the sensors buried in the street often fail to reliably detect a bicycle waiting to turn left (US; mirror in UK/AU/JP), even when the bicycle's wheels are directly over the edge of the loop.

        Is there some reason I can't think of why they can't do both?

      • Re: (Score:3, Informative)

        by dougmc ( 70836 )
        Then the sensors are faulty. Properly adjusted, they will reliably pick up a bicycle. Even a bicycle with a carbon fiber frame -- the wheels alone are enough to trigger a properly adjusted sensor.

        In Austin, you can call 311 (the non-emergency line) and report an intersection where it doesn't work and they'll fix it in a few days.

    • Re:It astounds me (Score:5, Interesting)

      by NeutronCowboy ( 896098 ) on Thursday June 03, 2010 @08:21PM (#32453454)

      Not only is it astounding that this isn't done, it's old hat. Where I grew up, the main arteries were all set up so that if you traveled at the speed limit, you'd hit all green lights in one direction in the morning, and all green lights going the other direction in the evening. It saved gas, dramatically reduced average travel times and kept everyone going at the speed limit.

      Instead, the main arteries where I live now are all set up to turn red when a car triggers a sensor on a cross street. The end result of that is that a 5 lane thoroughfare stops 15 cars every 50-100 yards because one care on a tiny side street is making a right turn onto the thoroughfare. A 2 mile drive can easily take 5-10 minutes with no traffic, just because the lights are setup so stupidly. And god help us if there's traffic (like, say on Black Friday or something like that): going half a mile to get on the freeway easily takes me 15 minutes, just because there's a light every 50 yards, they're not coordinated, and only 2-3 cars are actually able to cross the intersection at a time.

      I'm always wondering if I should go to the city council meeting and ask why they're supporting terrorists with this inane system. The loss in gas mileage is atrocious, and the reason for it is just plain stupidity.

      • by tepples ( 727027 )

        The end result of that is that a 5 lane thoroughfare stops 15 cars every 50-100 yards because one care on a tiny side street is making a right turn onto the thoroughfare.

        Would you rather have the light remain red for ten minutes at a time while you wait to turn onto the thoroughfare? There's an intersection [google.com] where this has happened to me.

      • Re: (Score:3, Interesting)

        by gront ( 594175 )
        Lights are intentionally mis-timed for safety. During rush-hour around here, you can breeze past most lights, always catching the green. Once rush hour passes, the lights are set so you hit every single frickin' light and can't catch a green. Forces everyone to slow down, consume gas, but hey... think of the children!
      • by toastar ( 573882 )

        going half a mile to get on the freeway easily takes me 15 minutes, just because there's a light every 50 yards,

        Your freeways have lights?

        Here in houston, Mayor Bill white put down an edict that said all the lights in downtown in each direction(e/w, n/s) would be green at the same time. This lasted about 2 months because people threw a fit, Basically with the timed wave approach you can get All the way across downtown without hitting a red light, I'm suprised

        • They said "going half a mile TO GET on the freeway.."

        • all the lights in downtown in each direction(e/w, n/s) would be green at the same time.

          at times that is the best approach, because then half of all cars can move at once. At rush hour major streets become completely full, and thus if you don't turn all the lights in the same direction at the same time, then only a small group of cars get to move (having a green light does you no good if the cars have not cleared in front of you.) I think that is why they try to make it smarter, timing all the lights to allow cars going 30 to never stop does no good when none of the cars can go 30. So you o

      • Re:It astounds me (Score:4, Insightful)

        by ktappe ( 747125 ) on Thursday June 03, 2010 @09:01PM (#32453730)

        I'm always wondering if I should go to the city council meeting and ask why they're supporting terrorists with this inane system. The loss in gas mileage is atrocious, and the reason for it is just plain stupidity.

        Seems to me the reasons for stupidly-timed lights is threefold:
        1) Lowball bids from traffic light installers. To keep their bids low, a simple timer is way cheaper than a smart computer.
        2) Politicians who pull strings so their development's side-road gets priority over the main thoroughfare.
        3) Citizens like you and me who are too busy to attend council meetings and object.

        • Re:It astounds me (Score:4, Insightful)

          by Anonymous Struct ( 660658 ) on Thursday June 03, 2010 @10:55PM (#32454354)

          I'd add a fourth possible reason, though: I think traffic control may be a little more complicated than we give it credit for. When there's one main road and everybody's on it, it makes sense to try to get long synchronized trains of traffic flowing through green lights. But as soon as you start to get more than one big road, you have to also think about how much traffic you're allowing into different parts of the city at once. If you look at traffic management as a big picture, then giving people green lights doesn't get them off your plate, it just moves them to another part of your grid. If you're stuck at a red light for 30 seconds too long and nobody seems to be going, consider that it may be because 3 miles up the road, that bubble is intended to absorb some traffic from another busy intersection.

          Or, as you say, it could just be cheap systems.

      • That's not as easy as you suggest. It does depend somewhat on where you are, but unless you're living in a relatively new city, chances are it's not going to work. For instance around here, the blocks are a bit irregular, some don't go through and others are longer than the rest of the blocks. On top of that, there's significant areas where you can't build roads at all due to them running up a steep hill or trying to go along the center of a ravine.

        Then you're talking about the actual timing itself, adju
      • Re:It astounds me (Score:4, Informative)

        by pearl298 ( 1585049 ) <mikewatersaz@NosPaM.gmail.com> on Thursday June 03, 2010 @11:52PM (#32454606)
        In Scottsdale Az the lights are deliberately set to stop you at EVERY intersection! WHY you ask? According to the chief traffic engineer "So you will be "encouraged" to stop and shop at the local businesses along the way!!" Yes I actually heard this from his lips! Although his head did seem a little strange from a bad case of "recto-cranial inversion". I NEVER shop in Scottsdale because of this!
      • Re: (Score:3, Interesting)

        by ztransform ( 929641 )

        Not only is it astounding that this isn't done, it's old hat.

        What isn't old hat is that many drivers now have GPS systems and increasingly they are receive real-time feedback on road conditions. But is this really the best thing?

        Consider the stock market. You have a large number of people all trying to "beat the system" (much like drivers trying to avoid road blocks). When the price goes up, people try to sell, when the price goes down, people try to buy, but most importantly everybody is trying to out-guess everybody else.

        From a systems and control (engineering)

    • by CAIMLAS ( 41445 )

      Yes. This. THIS!

      I hit every single red light on the way home from work. Every. Single. Day. Sometimes twice, as one green light is too short to get through (allowing maybe 3 cars each time). People frequently run that light. I'm only 8 or so miles from work (just slightly too far to drive), and leaving late - or early - doesn't seem to help one damn bit. The drive regularly takes over half an hour.

      The only time I'm able to take this route and not hit every light is when there is absolutely no traffic (IE I'

    • They aren't for safety as much as they are revenue generation.

    • by Hadlock ( 143607 )

      This is done pretty much throughout the Dallas-Fort Worth area, to the point we're so used to properly timed lights that it's almost rage inducing when you come to a light that's out of sync with all the others. Most of the main artery roads here are 3 lanes in each direction and 40-55mph. Even in the thick of rush hour on a friday afternoon before a three day weekend, Preston Road out of downtown Dallas flows ~45mph all the way to northern Frisco, crossing four major highways. Most roads aren't that good,

    • That this isn't done everywhere. With all the red light cameras everywhere (for revenue), you'd think they could put a few out there that would make it so I don't spend 3 minutes every morning staring at an empty intersection.

      There, fixed that for you. Now the rest of your question is self answering.

    • by vidnet ( 580068 ) on Friday June 04, 2010 @02:59AM (#32455534) Homepage

      I'd like to smack the idiot who designed this intersection [xkcd.com].

      (Also happens to be my favourite xkcd ever, finally I get to use it)

  • Red Wave (Score:2, Interesting)

    by Anonymous Coward

    British Local Authorities used to have a policy of halting the green wave, and trying to set up traffic lights to catch everyone on every light. This raised fuel consumption and brought in more tax for the government because of the increase in the purchase of fuel. Most lights still seem to be set up like this, at least in my experiences.

    • by Sabriel ( 134364 )

      Governments all over seem intent on breaking windows to make money...

    • Re: (Score:3, Informative)

      This policy was changed in 2009 when the Department for Transport realised the error of its ways. It now encourages more of a 'green wave' approach where possible.

      Source [bbc.co.uk]

  • Here traffic lights are made to be a source of income. They are designed to stop you and increase your chances of running a yellow light so that the cops can pull you over and give you a ticket. Plus, it has the guise of making the roads safer (since people don't have as many green lights, they cannot speed as much), so much of the public is mostly ok with it. Unfortunately, in reality, we're just wasting fuel and making the roads more dangerous (more rear end crashes and angrier drivers).
    • Re: (Score:3, Interesting)

      I was always told, by marketing people working at large retailers, that large retailers bought traffic lights because they cause more people to stop in. Whether that is out of enter/exit convenience or that there is something to making people pause in front of your store I don't know, but do you know of any Wal-Marts that don't have a red light?
      • Re: (Score:3, Insightful)

        by tepples ( 727027 )

        do you know of any Wal-Marts that don't have a red light?

        This one in Fort Wayne, Indiana [google.com]. It's between a strip mall to the south and some other department stores to the north. The closest traffic signals are two blocks away in each direction.

      • In the early 1970s, most of the traffic lights in Phoenix, Arizona were evenly spaced and well synchronized for travel in either direction. That was back before they messed up the synchronization by adding all those extra stoplights in front of the Walmarts and other major shopping centers. The consistent even spacing between major intersections, made it possible to synchronize the lights for traveling at a specific speed such as 35 or 40 MPH. When driving, I could usually tell if I was encountering a light
  • Uphill battle (Score:4, Insightful)

    by seizurebattlerobot ( 265408 ) on Thursday June 03, 2010 @08:17PM (#32453422)

    Traffic signal timing is nothing new, we've known about it a long time. Unfortunately, there is much money to be made fleecing motorists for traffic violations. As a result, our road systems are tweaked to generate revenue, not expedite traffic. Good luck getting these algorithms used in anywhere but a handful of places without a fight.

  • Where the money is (Score:2, Insightful)

    by XiaoMing ( 1574363 )

    This is somewhat old hat. Companies that depend on urban transportation efficiency for a profit (FedEx and UPS) have long ago implemented systems that recommend routes to drivers. UPS for example uses technology to help reduce/eliminate left turns (usually involve sitting at an intersection idling and waiting, wasting gas and time): http://www.zdnet.com/blog/btl/ups-driving-cost-savings-by-eliminating-left-hand-turns/2190 [zdnet.com] (2005 article). True it hasn't been done on such a scale or for specifically this e

  • by RyanFenton ( 230700 ) on Thursday June 03, 2010 @08:27PM (#32453530)

    The perspective taken for this bit of problem solving is interesting, because it is stepping above the usual street engineering up to city planning - maximizing the number of people able to use shared resources, while minimizing resources used. This is decidedly NOT a perspective that is common in the US, as our cities tend to 'sprawl' at the whim of investors and politicians with 'complicated' priorities rather than anything as idealized as proper engineering to make best use of resources.

    Greater use of mass transit to maximize available road where possible, waves of greens with appropriate buffers to keep congestion manageable to even extreme capacities, traffic system that work to inform the driver and minimize late decision making - these are good moves.

    I would hope we could use some of these moves to create a road system that would allow for us to approach automated driving systems - where you would decide where you needed to be, and an appropriate vehicle would pick you up within a few minutes, using the minimum amount of fuel for the entire city worth of people using the system, and giving non-automated drivers plenty of road space as they go. Nobody limited in choices - but maximizing efficiency and convenience for everyone.

    It probably won't happen here in the US (different priorities, as mentioned), but I hope such a system could be established in my lifetime.

    Ryan Fenton

    • Re: (Score:3, Insightful)

      by AK Marc ( 707885 )
      This is decidedly NOT a perspective that is common in the US, as our cities tend to 'sprawl' at the whim of investors and politicians with 'complicated' priorities rather than anything as idealized as proper engineering to make best use of resources.

      Bullshit. You can design 'sprawl' intelligently, or stupidly. There is no planning in the US, no matter who's doing it or when. NYC is not sprawled, and wasn't well planned. Same with Boston. Dallas is relatively new, and was planned better than many of t
  • 40 cars standing motionless at an intersection are getting exactly 0.0 mpg. With the added benefit of all that extra pollution that zero mpg brings.

    • Some cars burn much less gas while waiting for a light. It is true even in a Prius that the electricity consumed sitting does amount to fuel wasted at a light, even if the engine is off at that time. In a Hybrid, the loss is less.

  • HEADLINE NEWS (Score:3, Insightful)

    by thePowerOfGrayskull ( 905905 ) <marc,paradise&gmail,com> on Thursday June 03, 2010 @09:18PM (#32453802) Homepage Journal

    Through a test course in Munich, vehicles were able to post phenomenal fuel efficiency gains simply by adjusting the timing of traffic lights depending on traffic volume — to whatever speed provides a so-called 'green wave' of four or more synchronized signals."

    This just in! Stopping and idling at each of four consecutive lights uses much more gas than driving straight through them without stopping!

    • by iksbob ( 947407 )

      It's not even the idling that's the biggest problem... Accelerating once the light turns green uses far more fuel than either idling or cruising through a green light. When you step on the brakes to stop at a red light, you're converting your car's kinetic energy into waste heat via friction between the brake pads/shoes and the brake disks/drums. That wasted energy has to be replaced once the light turns green, or the car won't move. The faster the traffic flow, the greater the kinetic energy of each car

  • Here in the US, you have an on-ramp, and you have a traffic jam next to the on-ramp. It happens every day. Every day drivers get fucked.

    Then they have electric signs that tell you when the next traffic jam is coming up. The signs say (basically), "Traffic jam at next on-ramp."

    I realize that past a certain point in the day, there's enough cars that the traffic flow becomes unmanageable. But when you have traffic jams at 6am (60mph to gridlock and back to 60 again), it just says to me that voters, politic

  • From the article:

    "Likewise, if the light is about to change to yellow, the system prompts the driver and momentarily cuts power."

    Am I the only one who thinks that could end badly?
    •     Since I accelerate into lane changes to clear my blind spot, yes, that does look like a beautiful mix for an accident. I signal, I check to see if I can see anyone. I didn't see the car in my blindspot, but I accelerated and wouldn't have hit him. But instead, as I start accelerating and moving over, the light turns yellow, so now I just barely got in front and slowed down. That's a great plan, if you're in the body repair business too.

  • I actually wrote the local government entity that is in charge of designing and maintaining the highway system where I live (I forget what is called... its not the DOT) describing just this idea. They actually wrote back and said they were already implementing such a thing with cameras and a fiber-optic system.

    They have two lights rigged up with cameras so far. The weird thing about these cameras is that they actually judge the speed of the last car and get him to run a yellow so that the light is green
  • Hybrid or electric (Score:3, Informative)

    by foniksonik ( 573572 ) on Thursday June 03, 2010 @10:20PM (#32454184) Homepage Journal

    Hybrid or eletric cars don't use any fuel while stopped or even during normal in city acceleration.

  • Seriously, with the combination of North Sea oil and high fuel taxes, making the motorists stop and go at every set of lights by making sure they were deliberately out of sync seemed like an easy and inoffensive way to bring in tax revenue without hurting anyone.

    Only recently have they permitted traffic regulators to synchronize the lights for the benefit of motorists, society, the environment, and utlimately the tax coffers too.

    Systems thinking.. meh, they haven't even heard of it.

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