Traffic lights at Roundabouts
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From: Clive George on 27 Apr 2010 08:09 On 27/04/2010 08:17, Ian Jackson wrote: > In message <n8ednfDl5OyDvUvWnZ2dnUVZ8hGdnZ2d(a)brightview.co.uk>, Clive > George <clive(a)xxxx-x.fsnet.co.uk> writes >> On 26/04/2010 22:28, Ian Jackson wrote: >> >>> I'm firmly convinced that the people who are responsible for the design >>> and implementation of these traffic systems only 'go through the >>> motions', and have absolutely no interest in optimising the flow of >>> traffic. >> >> The professionals who do this sort of thing for a living would disagree. > > I'm sure they would! And with good reason. >> There's a lot of modelling going on > > Probably using of plasticine and Dinky toys. There's a healthy market in traffic simulation software, and it's pretty sophisticated. >> , and stuff which isn't necessarily obvious > > It's pretty obvious to those who actually have to use the roads! These things are often a lot harder than it appears to many. >> (why ped xings are staggered was one which I learned a few months ago). >> > I'm not aware of this major breakthrough in traffic management. It's not a major breakthrough, it's something they've known for years. I merely learned about it recently through chance conversation. >> Doesn't stop them cocking it up sometimes, eg the A43/M40 junction >> where the crossing streams makes traffic leaving the motorway stop at >> bust times. >> > I don't know about the A43/M40 junction, but the A34/M40 junction > (especially southbound) continues to be an absolute disaster. Traffic > leaving the M40 to take the A34 regularly backs up in Lane 1 (and even > Lane 2) - often for the best part of a mile, when traffic is heavy. I never take that one when it's busy. >> Re comments about ratcheting round them - on the ones I use, I'm on >> the popular route, and most often get to go round in one go after >> joining the roundabout. > > Maybe you're quicker off the mark than I am! I rarely get past the next > light. I tend to have an engine when I'm on these roundabouts.
From: Ian Jackson on 27 Apr 2010 08:20 In message <4fKdne58mfCoSUvWnZ2dnUVZ7rKdnZ2d(a)brightview.co.uk>, Clive George <clive(a)xxxx-x.fsnet.co.uk> writes > > >There's a healthy market in traffic simulation software, and it's >pretty sophisticated. Is that the same sort of software that they used to predict the spread of the Icelandic ash? > -- Ian
From: Brimstone on 27 Apr 2010 09:13 "Nkosi (ama-ecosse)" <minankosi(a)googlemail.com> wrote in message news:795152cf-8bec-4cf1-88e1-a43ce55990b8(a)s9g2000yqa.googlegroups.com... > On 26 Apr, 22:55, JNugent <J...(a)noparticularplacetogo.com> wrote: >> Brimstone wrote: >> >> > "JNugent" <J...(a)noparticularplacetogo.com> wrote in message >> >news:cPWdnVLJh9_dmUvWnZ2dnUVZ8j2dnZ2d(a)pipex.net... >> >> Ret. wrote: >> >>> Ian Jackson wrote: >> >>>> In message <Ys2dnWruDNukIUjWnZ2dnUVZ8j-dn...(a)brightview.co.uk>, >> >>>> Mortimer <m...(a)privacy.net> writes >> >>>>> "ChelseaTractorMan" <mr.c.trac...(a)hotmail.co.uk> wrote in message >> >>>>>news:spcbt5lnro8c6cbjfkd9nikvvii7eucq8h(a)4ax.com... >> >>>>>> On Mon, 26 Apr 2010 16:07:35 +0100, JNugent >> >>>>>> <J...(a)noparticularplacetogo.com> wrote: >> >> >>>>>>> There just shouldn't be traffic lights at roundabouts. >> >> >>>>>> an admission of failure really! There's a tiny roundabout near >> >>>>>> Lakeside shopping centre, (Essex) with lights on all the (I think) >> >>>>>> 5 >> >>>>>> entries, they seem permanently switched off, I suspect because the >> >>>>>> traffic flows better without them. >> >> >>>>> There was a lot of disruption last year while the Hopgrove >> >>>>> roundabout >> >>>>> near York (A64 goes from dual-carriageway to single-carriageway and >> >>>>> meets the northern ring road) was modified. One of the changes was >> >>>>> to >> >>>>> put traffic lights on the roundabout. >> >> >>>>> Throughput on the roundabout is worse than ever, with long queues >> >>>>> on >> >>>>> the single and dual sections of the A64 and on the ring road, at >> >>>>> peak >> >>>>> times. >> >> >>>>> For some reason, the traffic lights are 24-hour, rather than peak >> >>>>> periods only. It is infuriating to have to wait at the roundabout >> >>>>> for >> >>>>> ages until the lights change, when you are the only car around late >> >>>>> at night! >> >> >>>>> The Milton Interchange roundabout under the A34 near Didcot was >> >>>>> redesigned and traffic lights were put on it. They have >> >>>>> dramatically >> >>>>> improved the throughput of the roundabout - especially at peak >> >>>>> periods when traffic used to queue for ages to get out of the >> >>>>> Milton >> >>>>> Park business park onto the roundabout. However the phasing of the >> >>>>> lights is very poor: traffic coming from Milton Park faces two sets >> >>>>> of lights, very close together (one to enter the roundabout, one to >> >>>>> let traffic join from Didcot) and they are phased so when one set >> >>>>> of >> >>>>> lights goes green, the next set turns red about five seconds later. >> >>>>> Often you get the lead car at the first lights doing a wheelspin >> >>>>> start to try to get through the second lights before it changes. >> >> >>>> On these large intersections, I hate the way that the phasing of the >> >>>> lights forces you to 'ratchet' your way around the roundabout, from >> >>>> traffic light to traffic light. Once you actually get onto the >> >>>> roundabout, I would have thought that it would be more efficient if >> >>>> you were allowed proceed through two (or even more) sets of lights. >> >> >>> It would make more sense to get rid of the roundabout and just have a >> >>> traffic light controlled crossroads! They seem to manage perfectly >> >>> well without roundabouts in the US. >> >> >> For certain values of "perfectly well"; with a set of traffic lights >> >> at almost every *single* intersection on the grid-iron of Manhattan, >> >> progress is painfully slow, whether by vehicle or on foot. >> >> >> The whole idea of a roundabout is to keep traffic moving without >> >> unnecessary delays. Using lights on the carriageway of a roundabout is >> >> absolutely crazy since it prevents the natural function of the >> >> gyratory system by herding the traffic together which reduces the >> >> space necessary for the essential lane-changing. >> >> >> *If* there is a pre-empting flow of traffic from one or more >> >> directions into the roundabout, that could be balanced by a >> >> free-standing set of lights controlling the flow into the roundabout >> >> from those directions only, rather like the "ramp-metering" now used >> >> on some motorway slip-roads. >> >> > Surely the most sensible solution for that type of junction is a >> > flyover/under for the route carrying the majority of the traffic, i.e. >> > motorway style. >> >> That would mean spending the odd million of the billions collected from >> road-users.- Hide quoted text - >> >> - Show quoted text - > > Heaven forbid they would actually do road improvements. > If "they" haven't spent any of the money taken from motorists and the rest of the tax paying public, how is it that we now have motorways, bypasses, flyovers, underpasses and all the other features of current roads built since the 1930s that most people now take for granted?
From: Nkosi (ama-ecosse) on 28 Apr 2010 07:57 On 27 Apr, 14:13, "Brimstone" <brimst...(a)hotmail.com> wrote: > "Nkosi (ama-ecosse)" <minank...(a)googlemail.com> wrote in message > > news:795152cf-8bec-4cf1-88e1-a43ce55990b8(a)s9g2000yqa.googlegroups.com... > > > > > On 26 Apr, 22:55, JNugent <J...(a)noparticularplacetogo.com> wrote: > >> Brimstone wrote: > > >> > "JNugent" <J...(a)noparticularplacetogo.com> wrote in message > >> >news:cPWdnVLJh9_dmUvWnZ2dnUVZ8j2dnZ2d(a)pipex.net... > >> >> Ret. wrote: > >> >>> Ian Jackson wrote: > >> >>>> In message <Ys2dnWruDNukIUjWnZ2dnUVZ8j-dn...(a)brightview.co.uk>, > >> >>>> Mortimer <m...(a)privacy.net> writes > >> >>>>> "ChelseaTractorMan" <mr.c.trac...(a)hotmail.co.uk> wrote in message > >> >>>>>news:spcbt5lnro8c6cbjfkd9nikvvii7eucq8h(a)4ax.com... > >> >>>>>> On Mon, 26 Apr 2010 16:07:35 +0100, JNugent > >> >>>>>> <J...(a)noparticularplacetogo.com> wrote: > > >> >>>>>>> There just shouldn't be traffic lights at roundabouts. > > >> >>>>>> an admission of failure really! There's a tiny roundabout near > >> >>>>>> Lakeside shopping centre, (Essex) with lights on all the (I think) > >> >>>>>> 5 > >> >>>>>> entries, they seem permanently switched off, I suspect because the > >> >>>>>> traffic flows better without them. > > >> >>>>> There was a lot of disruption last year while the Hopgrove > >> >>>>> roundabout > >> >>>>> near York (A64 goes from dual-carriageway to single-carriageway and > >> >>>>> meets the northern ring road) was modified. One of the changes was > >> >>>>> to > >> >>>>> put traffic lights on the roundabout. > > >> >>>>> Throughput on the roundabout is worse than ever, with long queues > >> >>>>> on > >> >>>>> the single and dual sections of the A64 and on the ring road, at > >> >>>>> peak > >> >>>>> times. > > >> >>>>> For some reason, the traffic lights are 24-hour, rather than peak > >> >>>>> periods only. It is infuriating to have to wait at the roundabout > >> >>>>> for > >> >>>>> ages until the lights change, when you are the only car around late > >> >>>>> at night! > > >> >>>>> The Milton Interchange roundabout under the A34 near Didcot was > >> >>>>> redesigned and traffic lights were put on it. They have > >> >>>>> dramatically > >> >>>>> improved the throughput of the roundabout - especially at peak > >> >>>>> periods when traffic used to queue for ages to get out of the > >> >>>>> Milton > >> >>>>> Park business park onto the roundabout. However the phasing of the > >> >>>>> lights is very poor: traffic coming from Milton Park faces two sets > >> >>>>> of lights, very close together (one to enter the roundabout, one to > >> >>>>> let traffic join from Didcot) and they are phased so when one set > >> >>>>> of > >> >>>>> lights goes green, the next set turns red about five seconds later. > >> >>>>> Often you get the lead car at the first lights doing a wheelspin > >> >>>>> start to try to get through the second lights before it changes. > > >> >>>> On these large intersections, I hate the way that the phasing of the > >> >>>> lights forces you to 'ratchet' your way around the roundabout, from > >> >>>> traffic light to traffic light. Once you actually get onto the > >> >>>> roundabout, I would have thought that it would be more efficient if > >> >>>> you were allowed proceed through two (or even more) sets of lights. > > >> >>> It would make more sense to get rid of the roundabout and just have a > >> >>> traffic light controlled crossroads! They seem to manage perfectly > >> >>> well without roundabouts in the US. > > >> >> For certain values of "perfectly well"; with a set of traffic lights > >> >> at almost every *single* intersection on the grid-iron of Manhattan, > >> >> progress is painfully slow, whether by vehicle or on foot. > > >> >> The whole idea of a roundabout is to keep traffic moving without > >> >> unnecessary delays. Using lights on the carriageway of a roundabout is > >> >> absolutely crazy since it prevents the natural function of the > >> >> gyratory system by herding the traffic together which reduces the > >> >> space necessary for the essential lane-changing. > > >> >> *If* there is a pre-empting flow of traffic from one or more > >> >> directions into the roundabout, that could be balanced by a > >> >> free-standing set of lights controlling the flow into the roundabout > >> >> from those directions only, rather like the "ramp-metering" now used > >> >> on some motorway slip-roads. > > >> > Surely the most sensible solution for that type of junction is a > >> > flyover/under for the route carrying the majority of the traffic, i.e. > >> > motorway style. > > >> That would mean spending the odd million of the billions collected from > >> road-users.- Hide quoted text - > > >> - Show quoted text - > > > Heaven forbid they would actually do road improvements. > > If "they" haven't spent any of the money taken from motorists and the rest > of the tax paying public, how is it that we now have motorways, bypasses, > flyovers, underpasses and all the other features of current roads built > since the 1930s that most people now take for granted?- Hide quoted text - > > - Show quoted text - You may have them in England but nothing ever came to Scotland for it, christ you even tried for years to not link the M6 with the A74(M) between Carlisle and Gretna. The A9 between Perth and Inverness should be a motorway as should the A90 Perth to Aberdeen. The A82 from Onich to Fort William needs drastically improving as do other parts of the same road. Of course if you give us our oil money back we could repair and upgrade them ourselves. Nkosi
From: Brimstone on 28 Apr 2010 09:47
"Nkosi (ama-ecosse)" <minankosi(a)googlemail.com> wrote in message news:d5b99214-e15f-4b83-aac2-defdac693be1(a)h27g2000yqm.googlegroups.com... > On 27 Apr, 14:13, "Brimstone" <brimst...(a)hotmail.com> wrote: >> "Nkosi (ama-ecosse)" <minank...(a)googlemail.com> wrote in message >> >> news:795152cf-8bec-4cf1-88e1-a43ce55990b8(a)s9g2000yqa.googlegroups.com... >> >> >> >> > On 26 Apr, 22:55, JNugent <J...(a)noparticularplacetogo.com> wrote: >> >> Brimstone wrote: >> >> >> > "JNugent" <J...(a)noparticularplacetogo.com> wrote in message >> >> >news:cPWdnVLJh9_dmUvWnZ2dnUVZ8j2dnZ2d(a)pipex.net... >> >> >> Ret. wrote: >> >> >>> Ian Jackson wrote: >> >> >>>> In message <Ys2dnWruDNukIUjWnZ2dnUVZ8j-dn...(a)brightview.co.uk>, >> >> >>>> Mortimer <m...(a)privacy.net> writes >> >> >>>>> "ChelseaTractorMan" <mr.c.trac...(a)hotmail.co.uk> wrote in >> >> >>>>> message >> >> >>>>>news:spcbt5lnro8c6cbjfkd9nikvvii7eucq8h(a)4ax.com... >> >> >>>>>> On Mon, 26 Apr 2010 16:07:35 +0100, JNugent >> >> >>>>>> <J...(a)noparticularplacetogo.com> wrote: >> >> >> >>>>>>> There just shouldn't be traffic lights at roundabouts. >> >> >> >>>>>> an admission of failure really! There's a tiny roundabout near >> >> >>>>>> Lakeside shopping centre, (Essex) with lights on all the (I >> >> >>>>>> think) >> >> >>>>>> 5 >> >> >>>>>> entries, they seem permanently switched off, I suspect because >> >> >>>>>> the >> >> >>>>>> traffic flows better without them. >> >> >> >>>>> There was a lot of disruption last year while the Hopgrove >> >> >>>>> roundabout >> >> >>>>> near York (A64 goes from dual-carriageway to single-carriageway >> >> >>>>> and >> >> >>>>> meets the northern ring road) was modified. One of the changes >> >> >>>>> was >> >> >>>>> to >> >> >>>>> put traffic lights on the roundabout. >> >> >> >>>>> Throughput on the roundabout is worse than ever, with long >> >> >>>>> queues >> >> >>>>> on >> >> >>>>> the single and dual sections of the A64 and on the ring road, at >> >> >>>>> peak >> >> >>>>> times. >> >> >> >>>>> For some reason, the traffic lights are 24-hour, rather than >> >> >>>>> peak >> >> >>>>> periods only. It is infuriating to have to wait at the >> >> >>>>> roundabout >> >> >>>>> for >> >> >>>>> ages until the lights change, when you are the only car around >> >> >>>>> late >> >> >>>>> at night! >> >> >> >>>>> The Milton Interchange roundabout under the A34 near Didcot was >> >> >>>>> redesigned and traffic lights were put on it. They have >> >> >>>>> dramatically >> >> >>>>> improved the throughput of the roundabout - especially at peak >> >> >>>>> periods when traffic used to queue for ages to get out of the >> >> >>>>> Milton >> >> >>>>> Park business park onto the roundabout. However the phasing of >> >> >>>>> the >> >> >>>>> lights is very poor: traffic coming from Milton Park faces two >> >> >>>>> sets >> >> >>>>> of lights, very close together (one to enter the roundabout, one >> >> >>>>> to >> >> >>>>> let traffic join from Didcot) and they are phased so when one >> >> >>>>> set >> >> >>>>> of >> >> >>>>> lights goes green, the next set turns red about five seconds >> >> >>>>> later. >> >> >>>>> Often you get the lead car at the first lights doing a wheelspin >> >> >>>>> start to try to get through the second lights before it changes. >> >> >> >>>> On these large intersections, I hate the way that the phasing of >> >> >>>> the >> >> >>>> lights forces you to 'ratchet' your way around the roundabout, >> >> >>>> from >> >> >>>> traffic light to traffic light. Once you actually get onto the >> >> >>>> roundabout, I would have thought that it would be more efficient >> >> >>>> if >> >> >>>> you were allowed proceed through two (or even more) sets of >> >> >>>> lights. >> >> >> >>> It would make more sense to get rid of the roundabout and just >> >> >>> have a >> >> >>> traffic light controlled crossroads! They seem to manage >> >> >>> perfectly >> >> >>> well without roundabouts in the US. >> >> >> >> For certain values of "perfectly well"; with a set of traffic >> >> >> lights >> >> >> at almost every *single* intersection on the grid-iron of >> >> >> Manhattan, >> >> >> progress is painfully slow, whether by vehicle or on foot. >> >> >> >> The whole idea of a roundabout is to keep traffic moving without >> >> >> unnecessary delays. Using lights on the carriageway of a roundabout >> >> >> is >> >> >> absolutely crazy since it prevents the natural function of the >> >> >> gyratory system by herding the traffic together which reduces the >> >> >> space necessary for the essential lane-changing. >> >> >> >> *If* there is a pre-empting flow of traffic from one or more >> >> >> directions into the roundabout, that could be balanced by a >> >> >> free-standing set of lights controlling the flow into the >> >> >> roundabout >> >> >> from those directions only, rather like the "ramp-metering" now >> >> >> used >> >> >> on some motorway slip-roads. >> >> >> > Surely the most sensible solution for that type of junction is a >> >> > flyover/under for the route carrying the majority of the traffic, >> >> > i.e. >> >> > motorway style. >> >> >> That would mean spending the odd million of the billions collected >> >> from >> >> road-users.- Hide quoted text - >> >> >> - Show quoted text - >> >> > Heaven forbid they would actually do road improvements. >> >> If "they" haven't spent any of the money taken from motorists and the >> rest >> of the tax paying public, how is it that we now have motorways, bypasses, >> flyovers, underpasses and all the other features of current roads built >> since the 1930s that most people now take for granted?- Hide quoted >> text - >> >> - Show quoted text - > > You may have them in England but nothing ever came to Scotland for it, > christ you even tried for years to not link the M6 with the A74(M) > between Carlisle and Gretna. The A9 between Perth and Inverness should > be a motorway as should the A90 Perth to Aberdeen. The A82 from Onich > to Fort William needs drastically improving as do other parts of the > same road. Of course if you give us our oil money back we could repair > and upgrade them ourselves. > Having very recently driven the A9 between its junction with the M9 and Perth before rejoining it south of Inverness from the A938 to drive through to its junction with the A99 and then rejoining it just north of Inverness from the A835 and travelling back down to the M9, I'd say it's had lots of money spent on it over the years. Indeed, I got held up at a number of places between Inverness and Perth where they're carrying out improvements. Given the volume of traffic on it, why does it need to be a motorway, which road/s would non-motorway traffic use if it was upgraded, what do you think the return on the substantial investment needed for such a project be and do you also believe the topography and geology to be suitable? When I was making trips to various parts of Scotland in the early 1990s I never had any trouble driving off the end of the M6 and on to the A74. There wasn't even a bump in the road surface, much less an intervening cart track as you seem to be implying. You've also got many miles of motorway in the heavily populated central belt between Glasgow/Edinburgh and up to Stirling and Perth plus many roads have been improved from their original condition over the years. In short, stop talking bollocks. |