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Comment by ealexhudson | Hacker News Reader

I'm assuming this has something to do with being able to turn through a red light, which is illegal in London.

But yeah. I had trouble understanding the issue at all, as you note London has them, I've never noticed any issue at all - if anything, it gets the peds out of the road more timely...

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Indeed, in England pedestrians never cross when a vehicle has a green light over the path they are going to cross. I.e. completely separate pedestrian phases.

In the US, the walk lights go 'green' at the same time as traffic parallel to the crosswalk gets a green light, in a shared phase. So if the timer is getting close to zero, it means the vehicles are about to go to a red light, and the opposite direction is about to get the green light.

I'm a bit unsure exactly what it is you are describing. Pretty much all the crossings I use regularly in London follows an at least very similar pattern to what I'm used to seeing in the US when visiting, with traffic parallel to the crossing getting green at the same time as the pedestrian crossing in question

In fact, here's a discussion in the UK Parliament in 2004 where it was proposed to restrict the use of all-red phases in low traffic junctions, and where the person proposing the change saw it as necessary to describe why this was even an issue:

http://www.publications.parliament.uk/pa/cm200304/cmstand/a/...

"Mr. Redwood: Until a few years ago, no one would have understood why new clause 5 would be necessary. All traffic lights that motorists or cyclists encountered on our highways had a simple form of operation which meant that there was always one free route across the junction showing green. In the normal four-way junction where two roads intersected, one road had priority for one phase and the other road had the alternate priority. There could be more complicated variations at larger junctions, but there was always a green phase for vehicles on one part of the junction"

[The proposed clause 5: 'No authority shall be entitled to install or operate traffic signals with all red phases at road junctions where there is no hazard other than traffic.']

You may be right that no vehicles will have green light to cross the pedestrian crossing while pedestrians have a green light, though I'm not 100% sure that's true either - I seem to remember crossings in London at least where turning traffic will have green at the same time as pedestrians, but I don't drive so maybe that's just me as an impatient pedestrian misremembering, as I'll regularly cross on red.

As ealexhudson says here: https://news.ycombinator.com/item?id=7975422 , the difference is that in the UK, when you have a 'green man', there is a guarantee that traffic are not permitted to use any piece of road you are crossing.

I was describing the crossroads situation where all vehicles are allowed to travel in any direction when they have a green light (no filter light/lanes), as this is the most commonly occurring situation in towns in the US I think. Not including states where there is a propensity for 'no left turn' intersections.

In the US, this would mean two phases, with each one being a shared pedestrian and vehicle phase, pedestrians crossing in parallel to traffic. In the UK this would be three phases, two traffic and one dedicated pedestrian phase.

I personally prefer the UK system, as in the US as a pedestrian you are at the whim of drivers paying attention to pedestrian traffic, and even if they don't hit you they may well start turning the corner to pressure you to hurry up.

I think the confusion here is that in the UK there is a separate phase for drivers turning left into the junction, whereas in the U.S. drivers can turn right across the path of crossing pedestrians. Obviously the UK system is a lot safer.

I've never seen or heard of that in the UK: if the green man shows, no vehicle can cross the path. It's quite common for traffic to be moving while some part of the crossing is green, but they wouldn't be allowed to use that lane. Indeed, pedestrians will regularly cross at red man - that's allowed, and people know they need to look out in all directions.

All-red phases are a slightly different issue, and indeed, not all crossings have them

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