3 ms·

A lot of junctions in the US have 'intelligent lights' (I don't know the exact term), where there are plates on some lanes, so it only turns on for a lane if th

by Svip 7y ago

A lot of junctions in the US have 'intelligent lights' (I don't know the exact term), where there are plates on some lanes, so it only turns on for a lane if there are cars in it. That is mostly noticeable for left-turning lanes. But in Europe, most traffic lights are programmed to act differently based on the time of day, hence allowing a smoother traffic in rush hour. Or in some European cities, the lights will switch to flashing yellow at night. I don't think traffic lights need to be that smart, just scheduled. I have definitely not heard that European traffic should be significantly worse than US traffic.

matwood 7y ago
The US uses all of those methods in conjunction.
- Svip 7y ago
  And in my opinion, the problem is that the cycle itself is too long. If they merely tweaked that, the impatience would be lowered, and you might even get smoother traffic.
  - delfinom 7y ago
    The cycle is entirely up to the local Department of Transportation be it a city, town or state. Where I live we have short cycle lights at heavy intersections and long cycle lights at intersections where keeping the primary/heavy road going longer is 100000% more worth it than some side secondary road with 3 cars every hour. There are also plenty of complex areas where all the lights on a road are interconnected for miles and the timing is set to match between them to more efficiently feed cars onto highways and move them along.
tehlike 7y ago
The one problem with us that might be different from europe is density. People usually work in further locations compared to europe, and lack of public transport is a major bummer. I think schedule-dependent is probably what i mean. Lanes here do have 8 shaped measurement systems to detect near real time traffic, and in theory government could collaborate with google who has this data as well. Run some simulations, and extract schedules and that should be a big improvement(assuming it is not already done)
bobthepanda 7y ago
The problem is that American land use is organized in a way that basically requires driving. If you want to do something as trivial as travel from one supermarket to another across the street, the roads are high-speed, the crosswalks are far away and inconvenient (fast walk cycle time, slow red time), and on top of that you have to cross large parking lots to get to and from the front door. Just look at the environment between this Trader Joe's and Whole Foods: https://www.google.com/maps/@40.86918,-73.1275739,464m/data=!3m1!1e3 https://www.google.com/maps/@40.86918,-73.1275739,464m/data=... We make everyone drive for the shortest of trips and then are shocked that we have so much traffic.
chomp 7y ago
In Houston we have also lights programmed to rush hour so that in the core downtown area, lights are timed so you can make it from one end to the other without hitting a red light if you drive the speed limit. The problem is that I don't think these lights can be remotely programmed, so after bad weather (tropical storms, etc) the power will inevitably go out and the lights will reset. And then it feels like they only get fixed when someone feels like making a 311 call. Repeat ad nauseum.
brewdad 7y ago
When I lived in Phoenix, they had those. The leading left green arrow would be triggered when there were three cars or more waiting to turn left, otherwise you would get normal green that needs to yield to oncoming traffic and it usually took the entire light cycle for traffic to clear. The first car would stop at the normal line. The second car would wait a full car length behind and only move forward when a third car arrived. This way, you could trigger the "intelligent" light with only two cars instead of three and save yourself a full light cycle.
delfinom 7y ago
>I don't think traffic lights need to be that smart, just scheduled. I have definitely not heard that European traffic should be significantly worse than US traffic. They absolutely are scheduled in the US anywhere that's population dense enough. Compensating for rush hour traffic flow is a huge thing that requires the adjustments.

by Svip 7y ago

matwood 7y ago

The US uses all of those methods in conjunction.

Svip 7y ago
And in my opinion, the problem is that the cycle itself is too long. If they merely tweaked that, the impatience would be lowered, and you might even get smoother traffic.
- delfinom 7y ago
  The cycle is entirely up to the local Department of Transportation be it a city, town or state. Where I live we have short cycle lights at heavy intersections and long cycle lights at intersections where keeping the primary/heavy road going longer is 100000% more worth it than some side secondary road with 3 cars every hour. There are also plenty of complex areas where all the lights on a road are interconnected for miles and the timing is set to match between them to more efficiently feed cars onto highways and move them along.

tehlike 7y ago

The one problem with us that might be different from europe is density. People usually work in further locations compared to europe, and lack of public transport is a major bummer. I think schedule-dependent is probably what i mean. Lanes here do have 8 shaped measurement systems to detect near real time traffic, and in theory government could collaborate with google who has this data as well. Run some simulations, and extract schedules and that should be a big improvement(assuming it is not already done)

bobthepanda 7y ago

The problem is that American land use is organized in a way that basically requires driving. If you want to do something as trivial as travel from one supermarket to another across the street, the roads are high-speed, the crosswalks are far away and inconvenient (fast walk cycle time, slow red time), and on top of that you have to cross large parking lots to get to and from the front door. Just look at the environment between this Trader Joe's and Whole Foods: https://www.google.com/maps/@40.86918,-73.1275739,464m/data=!3m1!1e3 https://www.google.com/maps/@40.86918,-73.1275739,464m/data=... We make everyone drive for the shortest of trips and then are shocked that we have so much traffic.

chomp 7y ago

In Houston we have also lights programmed to rush hour so that in the core downtown area, lights are timed so you can make it from one end to the other without hitting a red light if you drive the speed limit. The problem is that I don't think these lights can be remotely programmed, so after bad weather (tropical storms, etc) the power will inevitably go out and the lights will reset. And then it feels like they only get fixed when someone feels like making a 311 call. Repeat ad nauseum.

brewdad 7y ago

When I lived in Phoenix, they had those. The leading left green arrow would be triggered when there were three cars or more waiting to turn left, otherwise you would get normal green that needs to yield to oncoming traffic and it usually took the entire light cycle for traffic to clear. The first car would stop at the normal line. The second car would wait a full car length behind and only move forward when a third car arrived. This way, you could trigger the "intelligent" light with only two cars instead of three and save yourself a full light cycle.

delfinom 7y ago

>I don't think traffic lights need to be that smart, just scheduled. I have definitely not heard that European traffic should be significantly worse than US traffic. They absolutely are scheduled in the US anywhere that's population dense enough. Compensating for rush hour traffic flow is a huge thing that requires the adjustments.