4 ms·

Should traffic lights be abolished? No. Phased out over time in some places maybe, not abolished. Implemented in some new developments, absolutely. While ro

Should traffic lights be abolished? No. Phased out over time in some places maybe, not abolished. Implemented in some new developments, absolutely. While roundabouts can work more efficiently they require the roads and traffic usage patterns to accommodate them. Additionally existing intersections designed for lights and putting in roundabouts would require cities in many cases to use eminent domain to acquire the land around them or to buy out land/properties from people. The excessive use of eminent domain would lead to endless legal battles that would deplete city budgets. Some existing large intersections could be retrofitted for a roundabout and some small cities are in fact doing this. I've also witnessed this occurring in rural areas that have intersecting highways where the state already owns the land around the highways. This reduces brake dust, engine brake noise and keeps freight moving.

bubbleRefuge 4y ago
Didn't read the article but flyovers maybe expense but can get the job done. Wish there were more of them at major intesections
andsoitis 4y ago
Concur with your thinking. At the same time, I took "abolish traffic lights" as a North Star for future design as well as making changes to existing infrastructure where economically and physically feasible (i.e. stay practical). Not rip out all traffic lights everywhere and replace them with roundabouts or rotaries, as the case might be.
gpderetta 4y ago
And then you get roundabouts with traffic lights like in the UK. I'm sure there are good reasons for that, but, as someone that hardly drives in the UK, I was very very surprised the first time I encountered them.
- anyonecancode 4y ago
  Oh, that's nothing. Here in New Jersey, we have what my wife refers to as a "traffic theta". Here's an example: https://www.google.com/maps/@40.7957351,-74.3405952,17z https://www.google.com/maps/@40.7957351,-74.3405952,17z It's a circle, with traffic light, but also still an intersection. Fun!
- d1sxeyes 4y ago
  You generally get these when the roundabout has one or more clear 'through traffic' routes, to the point that you're always 'giving way to the right' and not able to enter the roundabout. If you imagine traffic on a motorway going North/South and an A-road running East-West, at busy times, the traffic going from East to West and West to East will be significant enough that traffic coming off the motorway is not able to find enough space to enter the roundabout (or, not enough to meet the demand). Without traffic lights, traffic will soon back up down the slip road onto the motorway, or worse, will try to force its way onto the roundabout instead of giving way to the right. Traffic lights make this much safer.
  - alistairSH 4y ago
    Or some arrangement of flyovers, ramps, etc (double diamond interchange being the current flavor of the month here in the US mid-Atlantic). Obviously, only makes sense for actual motorways, not going to get one in mid-town London, hopefully.
    - avianlyric 4y ago
      Land is expensive enough, and built up enough, in the UK that flyovers are pretty much not an option near any major road anymore. In general the UK has very few flyovers. I sometimes suspect the SF Bay Area has more flyovers than the entire of the UK.
- cameronh90 4y ago
  In addition, in areas with very high traffic, like London, area-coordinated adaptive traffic light systems (see SCOOT/SCATS) are used to keep traffic flowing smoothly, stop congestion from blocking junctions, prioritise emergency services and more. These systems are very good at what they do. Traffic lights are also used to give priority to pedestrians and cyclists on junctions where it would be unsafe to rely on zebra crossings or pedestrian priority - think sharp and low visibility corners. As far as roundabouts go, the UK has been replacing big multi-lane roundabouts in areas with lots of pedestrians and cyclists with two-way-traffic horse shoes (e.g. Old Street and E&C, plus others outside of London). This allows the centre of the roundabout to be used as public space, and has been found to be safer for vulnerable road users. I'm all for light-free junctions where possible, and light-free roundabouts work REALLY well in low/medium traffic. But you can't just abolish traffic lights - unless we also abolish cars at the same time.
  - wizofaus 4y ago
    Do you have a link to one of these "two-way horse shoes" on Google maps or similar? I'm curious how they solve the problem of needing to taking the 3rd exit on a multi-lane roundabout while on a bicycle.
    - avianlyric 4y ago
      Pretty simple. The section of road between 3rd exit and the 4th (which is also where you enter) is completely removed. So taking the 3rd exit on a bike either means following the road all the way around, or just going directly from the entrance to the 3rd exit, as cycle lane is usually preserved where the road used to be.
      - wizofaus 4y ago
        I looked at that E&C "horseshoe" - it still looks hairy if you're riding north on the A3 and want to turn right into the A201, given the number of crossings of busy roads with no traffic signals. But better than some of the busy 3-lane roundabouts I've had to navigate here with no provision for bicycles (or pedestrians really) at all.
pjc50 4y ago
The UK "mini-roundabout" does not take up additional space. Roundabouts work best when the traffic is below a certain critical level; above that and you're still stuck for ages except with no automated system trying to bring "fairness". In some cases this can be solved by .. adding traffic lights to the roundabout.
- rascul 4y ago
  > The UK "mini-roundabout" does not take up additional space. There are plenty of small intersections with traffic lights that aren't any wider than two opposite lanes with no median and no shoulder, only big enough for two vehicles to pass in opposite directions. They would need to be expanded to put a circle of any size in the middle, especially if a big truck was expected to make it through safely.
  - mdpye 4y ago
    A mini-roundabout is a centre circle painted (not curbed), plus the priority rules (give way to your right - would be your left in the US). They don't take up any extra space, but they do probably require drivers to intuitively understand the concept and priorities before they can be introduced. Here's a satellite view of a random one near me: https://goo.gl/maps/NJ2KpYdMP1reQA1u5 https://goo.gl/maps/NJ2KpYdMP1reQA1u5 Its an upgrade of the American 4-way-stop with better defined priorities for entry.
    - genocidicbunny 4y ago
      That definitely takes up extra space. Notice all the room between the lanes. In many places in the US, you don't have even that. The intersection is literally only wide enough for two cars to go past each other, and _any_ amount of space taken up in the center means you need to widen the road.
      - deleted 4y ago
        [deleted]
      - 4y ago
taylodl 4y ago
My city has been going roundabout happy over the past few years. One issue they've had to contend with is existing intersections in congested urban areas don't have enough space to replace with a roundabout. Therefore it's been primarily the suburban areas that have been able to implement them.

bubbleRefuge 4y ago

Didn't read the article but flyovers maybe expense but can get the job done. Wish there were more of them at major intesections

andsoitis 4y ago

Concur with your thinking. At the same time, I took "abolish traffic lights" as a North Star for future design as well as making changes to existing infrastructure where economically and physically feasible (i.e. stay practical). Not rip out all traffic lights everywhere and replace them with roundabouts or rotaries, as the case might be.

gpderetta 4y ago

And then you get roundabouts with traffic lights like in the UK. I'm sure there are good reasons for that, but, as someone that hardly drives in the UK, I was very very surprised the first time I encountered them.

anyonecancode 4y ago
Oh, that's nothing. Here in New Jersey, we have what my wife refers to as a "traffic theta". Here's an example: https://www.google.com/maps/@40.7957351,-74.3405952,17z https://www.google.com/maps/@40.7957351,-74.3405952,17z It's a circle, with traffic light, but also still an intersection. Fun!
d1sxeyes 4y ago
You generally get these when the roundabout has one or more clear 'through traffic' routes, to the point that you're always 'giving way to the right' and not able to enter the roundabout. If you imagine traffic on a motorway going North/South and an A-road running East-West, at busy times, the traffic going from East to West and West to East will be significant enough that traffic coming off the motorway is not able to find enough space to enter the roundabout (or, not enough to meet the demand). Without traffic lights, traffic will soon back up down the slip road onto the motorway, or worse, will try to force its way onto the roundabout instead of giving way to the right. Traffic lights make this much safer.
- alistairSH 4y ago
  Or some arrangement of flyovers, ramps, etc (double diamond interchange being the current flavor of the month here in the US mid-Atlantic). Obviously, only makes sense for actual motorways, not going to get one in mid-town London, hopefully.
  - avianlyric 4y ago
    Land is expensive enough, and built up enough, in the UK that flyovers are pretty much not an option near any major road anymore. In general the UK has very few flyovers. I sometimes suspect the SF Bay Area has more flyovers than the entire of the UK.
cameronh90 4y ago
In addition, in areas with very high traffic, like London, area-coordinated adaptive traffic light systems (see SCOOT/SCATS) are used to keep traffic flowing smoothly, stop congestion from blocking junctions, prioritise emergency services and more. These systems are very good at what they do. Traffic lights are also used to give priority to pedestrians and cyclists on junctions where it would be unsafe to rely on zebra crossings or pedestrian priority - think sharp and low visibility corners. As far as roundabouts go, the UK has been replacing big multi-lane roundabouts in areas with lots of pedestrians and cyclists with two-way-traffic horse shoes (e.g. Old Street and E&C, plus others outside of London). This allows the centre of the roundabout to be used as public space, and has been found to be safer for vulnerable road users. I'm all for light-free junctions where possible, and light-free roundabouts work REALLY well in low/medium traffic. But you can't just abolish traffic lights - unless we also abolish cars at the same time.
- wizofaus 4y ago
  Do you have a link to one of these "two-way horse shoes" on Google maps or similar? I'm curious how they solve the problem of needing to taking the 3rd exit on a multi-lane roundabout while on a bicycle.
  - avianlyric 4y ago
    Pretty simple. The section of road between 3rd exit and the 4th (which is also where you enter) is completely removed. So taking the 3rd exit on a bike either means following the road all the way around, or just going directly from the entrance to the 3rd exit, as cycle lane is usually preserved where the road used to be.
    - wizofaus 4y ago
      I looked at that E&C "horseshoe" - it still looks hairy if you're riding north on the A3 and want to turn right into the A201, given the number of crossings of busy roads with no traffic signals. But better than some of the busy 3-lane roundabouts I've had to navigate here with no provision for bicycles (or pedestrians really) at all.

pjc50 4y ago

The UK "mini-roundabout" does not take up additional space. Roundabouts work best when the traffic is below a certain critical level; above that and you're still stuck for ages except with no automated system trying to bring "fairness". In some cases this can be solved by .. adding traffic lights to the roundabout.

rascul 4y ago
> The UK "mini-roundabout" does not take up additional space. There are plenty of small intersections with traffic lights that aren't any wider than two opposite lanes with no median and no shoulder, only big enough for two vehicles to pass in opposite directions. They would need to be expanded to put a circle of any size in the middle, especially if a big truck was expected to make it through safely.
- mdpye 4y ago
  A mini-roundabout is a centre circle painted (not curbed), plus the priority rules (give way to your right - would be your left in the US). They don't take up any extra space, but they do probably require drivers to intuitively understand the concept and priorities before they can be introduced. Here's a satellite view of a random one near me: https://goo.gl/maps/NJ2KpYdMP1reQA1u5 https://goo.gl/maps/NJ2KpYdMP1reQA1u5 Its an upgrade of the American 4-way-stop with better defined priorities for entry.
  - genocidicbunny 4y ago
    That definitely takes up extra space. Notice all the room between the lanes. In many places in the US, you don't have even that. The intersection is literally only wide enough for two cars to go past each other, and _any_ amount of space taken up in the center means you need to widen the road.
    - deleted 4y ago
      [deleted]
    - 4y ago

taylodl 4y ago

My city has been going roundabout happy over the past few years. One issue they've had to contend with is existing intersections in congested urban areas don't have enough space to replace with a roundabout. Therefore it's been primarily the suburban areas that have been able to implement them.