How many of you feel the need to "re-engineer" the stop lights at intersections?

Don MDon M Posts: 1,553
How many times have you had to stop at a light when there aren't any vehicles in the intersecting lanes and they have the in-ground proximity sensors? The light just changes. Drives me nuts.

Also the length of time that the turn lane light stays green... sometimes only gets a few cars through.

Seems like there could be a lot more logic built in to this that what they have now.
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  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 21,403
    edited November 22 Vote Up0Vote Down
    I guess I'm pretty lucky where I live. The sensor-based stoplights here work really well, and I haven't seen any of the issues you report. The left-turn arrows last as long as there is traffic making the turn.

    The only matter that still kind of irks me is the single stoplight in the downtown historical district. When the state DOT installed it, it was one of those huge cantilevered designs that hung over the street. And it had sensors in the street. The city fathers objected that it was not in keeping with the historical theme of the downtown and requested that corner lights on posts be installed instead. The DOT complied but stated that they could not use the sensors and had to be on a strict timing sequence. Obvious nonsense. It was just the state's way of getting back at the city for making them remove the monstrous cantilevered lights.

    -Phil
    “Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
  • Traffic control software was among the first programs Bill Gates and his partner Paul Allen worked on, before they headed for greener pastures.

    Depending on the town, it's all done by running computer simulations these days, though the lights may not be synchronized or optimized to everyone's liking. Stopping you when there's no cross-traffic is a common safety measure, especially if they think the cars go through the boulevard too fast. Intersection timing isn't just for the cars to pass through, but serves a much larger traffic safety effort.

    Still, this doesn't mean they always get it right. I hated a certain intersection on the main road I always had to take, because it was timed to reset on the cross traffic if an emergency vehicle came through (detected using an Opticon or other preemption device). My lane always had to wait two, and sometimes three!, full cycles to get going again. Unfortunately, this particular intersection was for the main hospital access, so it got preempted a lot of times. (They've since redone the entire intersection, with additional lanes, and things run much more smoothly.)

    If you feel a controlled intersection is not properly programmed, you should contact the traffic engineering public works department in your town. They might even let you see some of the alternative simulations, assuming they run them.
  • Haha, ALWAYS!

    My idea is if number plates were short-range transponders (much like toll road transponders) that issued basic vehicle type and direction identification (for privacy concerns perhaps) then traffic lights could be a lot smarter and not rely on simple induction loops either. There are always basic minimum timings locked into the operation to ensure safety anyway. If privacy weren't a concern then big brother could help us get to where we need to or should be going a lot faster :)
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  • Funny you should ask that. I write the software that runs all the traffic light in the very large city where I work, as well as set the timing of the lights along with my staff of engineers. There is considerable logic in the traffic signal controller, as well as the central control system. Much more than the average driver knows about. And the operation selected for a particular intersection, or street, or network of signals, is not always obvious when viewed from one place.

    Yes, the detectors do fail, and they automatically recall the green light so vehicles aren't left undetected. This can cause changes of the light when no one is there, and a fixed amount of time when there are vehicles there. We also use timing to limit traffic flow at certain locations because of capacity restrictions downstream, or because the other street has more traffic. But overall, the goal is to keep traffic moving, though not on all streets at all times.

    This branch of engineering is somewhat unique because it involves both control system logic and human behavior, and the two don't always align. We are also guided and governed by certain rules and regulations the specify what can and can't be done.
    Sapphire
  • Always, but I never talk about it publicly, lol..... https://hackaday.com/2017/05/08/the-dangers-of-engineering-while-unlicensed/

    Anyhow, with my brain's OS being limited to the equivalent of ladder logic most of the time, I constantly see issues with street light configurations. Most of the issues I see on my commute are due to outdated set ups. Several lights are fairly new, so they work fine. The older lights on my commute however, don't work as clean with the new pattern of traffic. As the flow of traffic on roads changes, inadequate configurations for lights in the area of those changes suddenly become noticeable.
    I also noticed this last week when I came in really early one day (about 3 hours early). The traffic flow at two of the main intersections in my commute was different than what I am used to, so the street light I usually have to sit at, was a breeze, yet the street light that is almost always green for my direction, was green forever for cross traffic. So, this leads me to believe that the lights are configured for the heavy flow commute times, so when I came through with minimal traffic going with me, my commute dynamic was way off.

    Some other Hackaday articles worth reading:
    https://hackaday.com/2017/08/07/intro-to-the-north-american-traffic-signal/
    https://hackaday.com/2017/08/09/the-sensors-automating-your-commute/

    I have always wanted to create a datalogger that tracks GPS data, some vehicle data, and some environmental data (temperature, rain presence, etc) so that I could map this data out for the different days/times for my commute. Since my commute is only 14 miles, I think comparisons could be made to determine what the best time for me to drive to work would be as well as where I stop at lights the most, etc. (However, the first streetlight on my commute is 6 miles into it, so I would really only have 8 miles of streetlight impacted data)
  • GordonMcCombGordonMcComb Posts: 3,167
    edited November 22 Vote Up0Vote Down
    huge cantilevered designs

    Loop detectors are pretty lame for predicting traffic flow along the main artery. Unless there are loops WAY back from the intersection, there's not enough time to use them for preemption. They're best for registering side street flow, allowing stopped cars along the sub-artery to have their chance.

    The "arch-over" lighting can contain much more modern sensors, so it may not have been a bogus excuse. Your state DOT, which likely had jurisdiction of the intersection if it's a designated state highway, may not have had the interface to the old-style loop detectors.

    Remember that they no longer just rig things together. It all has to follow very prescribed policies and rules, or the city can find itself in legal hot water if there's a bad accident. Trial lawyers always look at the engineering of the traffic light to look for blame, as city/state governments have the deepest pockets of them all.

  • Sapphire wrote: »
    ...it involves both control system logic and human behavior, and the two don't always align.

    and the understatement of the year award goes to.....
  • "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • On the "human behavior" part: In the 70s, I lived in the Valley area of Los Angeles (pretty much a big grid of parallel streets). The lights were timed for 41 MPH, even though the posted speed limit was 35. It was more than obvious there would be major gridlock if the lights insisted on a 35 MPH timing!
  • There are lights near me that turn red on the busy path in an attempt to prevent some of the racing that has taken place in that area. They do turn green rather quickly once at the light, but they are typically red otherwise. However, there are some that are a bit bothersome since they seem to be on the same cycle in the middle of the night when there is less traffic as they do during the busy time of the day.

    I was in England a few years back and noticed the sequence was different than the US.

    - Red -- Stop
    - Red & Amber -- Stop, but light is about to change to Green
    - Green -- Okay to go but proceed with caution.

    In the US:
    - Red -- Stop if you feel like it
    - Yellow (Amber) -- Pedal to the Metal
    - Green -- Just Go Man!
  • Always, but I never talk about it publicly, lol..... https://hackaday.com/2017/05/08/the-dangers-of-engineering-while-unlicensed/

    California does not have the rule so I guess I'm safe. However, if a person is out of the state that they obtained the PE in, are they still allowed to call themselves an Engineer? Seems rather crazy to be able to call one self an Engineer just after taking some tests though.
  • Don M wrote: »
    How many times have you had to stop at a light when there aren't any vehicles in the intersecting lanes and they have the in-ground proximity sensors? The light just changes. Drives me nuts.

    Also the length of time that the turn lane light stays green... sometimes only gets a few cars through.

    Seems like there could be a lot more logic built in to this that what they have now.

    In 100% agreement. Traffic light software should be re-engineered to take advantage sensors and communications to reduce idling time at red lights when there is no cross traffic, enhance flow by adjusting timing based on traffic volume and communications with surrounding traffic light controllers.

    Another thing I would like to see is more and smarter portable traffic lights used during road construction and repairs.
    In science there is no authority. There is only experiment.
    Life is unpredictable. Eat dessert first.
  • kwinn wrote:
    ...and communications with surrounding traffic light controllers.
    Yes. That's the next bleeding edge of traffic light controllers. Easy to say, though. Without proper balancing, you'll get surges and stoppages. It's all a huge PID loop!

    -Phil
    “Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
  • I am sure the traffic light sensors have facial recognition where I drive. I always seem to catch the red lights.

    But seriously, the crappy software leaves a lot to be desired except in and around Sydney where the traffic lights have been coordinated for decades.
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  • Actually, we're well past that point. All of our intersections communicate once-per-second to a central facility, reporting current status, traffic levels, and which phase is green. The central facility continuously processes this information and makes adjustments to the signal sequence in response to changing demand, special events, unplanned incidents or prescribed operational plans. All in real-time.

    What you don't see are the basic constraints of signal timing, which must be factored into the solution generated from all the data. In some cases, a little intersection has to hold a green light waiting for a nearby big intersection to release traffic, while other times it can quickly service the side street between platoons of traffic.

    Every city is different in the level of sophistication and the degree of control. Some settle for little more than fixed time plans that run in the morning and evening, while others implement fully adaptive control throughout the day.
    Sapphire
  • This is a hardware problem and not a software problem.

    That's why there switching to Roundabouts, Traffic Circles and Rotaries.

    Mike
  • Pretty sure some switch to red once in a while even when no cross traffic, just in case like a motorcycle don't set of the in-ground proximity sensors.
  • iseries wrote: »
    This is a hardware problem and not a software problem.

    That's why there switching to Roundabouts, Traffic Circles and Rotaries.

    Mike

    If it's not software then how are those awesome Hackers (or rather Crackers) able to crack into the Street Light grid and control the light sequence in them thar "Fast and something" movies? You know, that happens all the time in real life.

    Yeah, seeing more and more of those Roundabouts intersections where I live. The problem is that folks seem to either not know or care what 'Yield' means. It sure is a low tech solution though, but seems to be something that would hurt an areas revenue since it would be hard to ticket someone running through these.


    There is a Traffic21 Initiative by Carnegie Mellon University that is designed to address traffic flow and is using the Pittsburgh region as a testing ground. The whole "Smart City" thing seems to involve traffic movement as well.
    https://traffic21.heinz.cmu.edu/
  • ercoerco Posts: 18,558
    edited November 22 Vote Up0Vote Down
    Sorry for the hijack, all.

    Gordon: Your email isn't working, I've sent you replies & messages from 2 different accounts, including gmail. Messages bounce back. Fix it before your lottery winnings are forfeited!

    I PM'ed you here too.

    Now we return to our regularly scheduled program.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • tritoniumtritonium Posts: 211
    edited November 22 Vote Up0Vote Down
    Hi,

    Then there's the human element..
    Well what REALLY irks me is the number of times the person in the car in front is absorbed in their mobile phone- poking about in their lap, so that when the lights change they are oblivious, a long gap opens up- car horns blare, if we're lucky the driver wakes up with a jerk, leaps forward just as the lights change and slams on the breaks... and then start poking about in their laps .... argh!!!....
    ....did I say human??? wouldn't mind re-engineering them...

    Dave
  • Flip_TrafficLight.jpg
    As an educator looking for a way to offer students an Hour-of-Code lab with no chance of wiring errors I developed these traffic lights. Hundreds of students have programmed these little lights from 4th graders up to high school seniors. The red/yellow/green is easily conquered by all, but the pedestrian button and its white walk light does present a challenge when I demand that a brief tap of the button be detected at any time in their routine.

    If you need traffic light engineers look to New Hampshire for your new hires.
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  • JonM wrote: »
    There are lights near me that turn red on the busy path in an attempt to prevent some of the racing that has taken place in that area. They do turn green rather quickly once at the light, but they are typically red otherwise. However, there are some that are a bit bothersome since they seem to be on the same cycle in the middle of the night when there is less traffic as they do during the busy time of the day.

    I was in England a few years back and noticed the sequence was different than the US.

    - Red -- Stop
    - Red & Amber -- Stop, but light is about to change to Green
    - Green -- Okay to go but proceed with caution.

    In the US:
    - Red -- Stop if you feel like it
    - Yellow (Amber) -- Pedal to the Metal
    - Green -- Just Go Man!

    Around here: SF Bay Area
    - Green -- Drive Like There's no Tomorrow
    - Yellow -- Slowing Down is a Sign of Weakness
    - Red -- Well... They Can't Mean =ME=



    Founder of the "Society for Aimless Tinkering and World Conquest"
  • In Sydney, Oz...

    Green: Go, go, go
    Orange: Pedal to the metal and go like hell to get to the intersection before it turns red.
    Red: Oh s**t! There's no way I can stop now. Best just keep going and hope for the best!
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  • In a large French City, eg. Paris
    Green: Go
    Orange: Go
    Red: Red is only a Suggestion -> Go
  • TorTor Posts: 1,813
    edited November 23 Vote Up0Vote Down
    Napoli (Naples)
    Green: What light?
    Yellow: What light?
    Red: What light?

    No joke.. the lights are 100% ignored at all times, including at pedestrian crossings. I'm told the reason is that everyone knows that the city gave the contract for the lights to the (then) city mayor's brother in law, so the whole thing isn't legit. Thus there's no reason to look at the lights at all.
  • I'd re-engineer them as roundabouts. Why stop when there's no other traffic. Not to mention the eyesore of the overhead cables.
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  • Sapphire wrote: »
    ... And the operation selected for a particular intersection, or street, or network of signals, is not always obvious when viewed from one place.

    Yes, the detectors do fail, and they automatically recall the green light so vehicles aren't left undetected.
    That's triggered a memory!
    When I live there is a few major arteries in the city I used to travel heavily for work, being a contractor at the time. They flowed impressively well for the shear amount of cars packed into them. They never really ground down to a stop. I used to think the sequencing must have been trimmed a lot.

    I move to a new job, can walk to work now, and haven't been travel during work time much at all for many years now ... Then the earthquakes struck ... On the odd times when I had to do a trip out in the middle of the day and I was in my old haunt it smacked me in the face how much more congestion there was! Those old arteries were not functioning like they used to.

    It is improving again now I think but this is 6+ years on.
    The Prisoner's Dilemma, in english - "Selfishness beats altruism within groups. Altruistic groups beat selfish groups." - Quoted part from 2007, D.S Wilson/E.O Wilson.
  • Mickster wrote: »
    I'd re-engineer them as roundabouts. Why stop when there's no other traffic. Not to mention the eyesore of the overhead cables.

    Agree with you on the roundabouts, but putting them in the city downtown where they are needed most is not usually an option. As for the eyesore cables, they can go underground where they are less of a maintenance problem.
    In science there is no authority. There is only experiment.
    Life is unpredictable. Eat dessert first.
  • MicksterMickster Posts: 981
    edited November 23 Vote Up0Vote Down
    Oh sure, I understand the problem. I'm a Brit who lived in the US for 30+ years and I used to always think; yeah gas is cheap but the pavement is crap and they took the cheap way out for the traffic lights.
    PropBASIC ROCKS!
  • JonM wrote: »

    I was in England a few years back and noticed the sequence was different than the US.

    - Red -- Stop
    - Red & Amber -- Stop, but light is about to change to Green
    - Green -- Okay to go but proceed with caution.
    and amber on its own means it is about to go red. And then there is flashing amber on pedestrian crossings.



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