Is ramp metering dead?

[ManomayLR]

Does the M42 ATM pilot scheme have ramp metering?

[jabbaboy]

The A66 at Teesside Park still has them and regularly work aswell. Believe there's a few on the A19 aswell.

[Chris5156]

I had no idea there was any in place on the A3 slips.

Yes, there’s a set at the southbound entry from the A25 at Wooden Bridge. I pass semi-regularly these days and have never seen them on.

[ais523]

Does the M42 ATM pilot scheme have ramp metering?

Ramp metering lights are installed. I've only seen them in use once, though, and they were malfunctioning at the time. That said, I normally don't join the M42 at busy times, so it's possible that I simply haven't been there at times which warrant their use.

[welly_j]

M60 junction 2 has them. It's been a while since I when through there during the rush hour but they are still in place. And very much still in use at jct 2 on the M56 yesterday. I'd be happy for them to be installed at the eastbound A34 on slip onto the M60 at Jct 3 where nose to tail traffic expects the vehicles in lane one to give way to them.....

If it's nose to tail traffic then what's the problem with allowing joining vehicles to merge in turn. I agree it's the last of a lousy series of junctions, but in reality at that point the left hand lane is marked as for use only being by vehicles wanting to exit at Cheadle junction 2- anyone on a through route should be using the 3 other lanes.

In my experience there is a similar number of vehicles joining at 3 to those exiting at 2, all within a less than 400m stretch - they just need to negotiate each other sensibly.

[Barkstar]

M60 junction 2 has them. It's been a while since I when through there during the rush hour but they are still in place. And very much still in use at jct 2 on the M56 yesterday. I'd be happy for them to be installed at the eastbound A34 on slip onto the M60 at Jct 3 where nose to tail traffic expects the vehicles in lane one to give way to them.....

If it's nose to tail traffic then what's the problem with allowing joining vehicles to merge in turn. I agree it's the last of a lousy series of junctions, but in reality at that point the left hand lane is marked as for use only being by vehicles wanting to exit at Cheadle junction 2- anyone on a through route should be using the 3 other lanes.

In my experience there is a similar number of vehicles joining at 3 to those exiting at 2, all within a less than 400m stretch - they just need to negotiate each other sensibly. (My Bold)

I do indeed exit at Jct 2 and if only the vehicles joining at 3 did act sensibly. And you could argue there's no negotiating to be had, the vehicles joining are to give way, something that often doesn't happen - exacerbated by the sight lines and that very very short give way line. it is a pigs ear of a layout.

[ElsieSeedlow]

Not dead. Atkins and Dynniq have been doing work for HE for '2nd Generation Ramp Metering'. interesting paper here:
http://www.jctconsultancy.co.uk/Symposi ... tering.pdf

Important to remember that if the ramp signals are on but the main line is not queuing it is working.

(link fixed now)

[Bryn666]

Not dead. Atkins and Dynniq have been doing work for HE for '2nd Generation Ramp Metering'. interesting paper here:
http://www.jctconsultancy.co.uk/Symposi ... tering.pdf

Important to remember that if the ramp signals are on but the main line is not queuing it is working.

(link fixed now)

The problem with that theory is if the mainline isn't queueing the local road network probably is, but that's not HEs problem so they don't care about the effects this has on everyone else.

[c2R]

Not dead. Atkins and Dynniq have been doing work for HE for '2nd Generation Ramp Metering'. interesting paper here:
http://www.jctconsultancy.co.uk/Symposi ... tering.pdf

Important to remember that if the ramp signals are on but the main line is not queuing it is working.

(link fixed now)

The problem with that theory is if the mainline isn't queueing the local road network probably is, but that's not HEs problem so they don't care about the effects this has on everyone else.

It depends I think on whether the beneficial effect on keeping the main line moving has an additional beneficial effect on the local road network when the whole area is analysed. The A40 in Germany makes extensive use of it as it goes through the cities of the Rhein-Ruhr conurbation https://www.google.com/maps/@51.4949747 ... 312!8i6656 The Germans must have played with the timings and done studies about when the system is on/off on particular days to see what happens, and computer modeled the impact on the area as a whole...

[traffic-light-man]

Not dead. Atkins and Dynniq have been doing work for HE for '2nd Generation Ramp Metering'. interesting paper here:
http://www.jctconsultancy.co.uk/Symposi ... tering.pdf

Important to remember that if the ramp signals are on but the main line is not queuing it is working.

(link fixed now)

The problem with that theory is if the mainline isn't queueing the local road network probably is, but that's not HEs problem so they don't care about the effects this has on everyone else.

It doesn't particularly change the fact that a queue is a queue, but I was under the impression that the previous versions have had occupancy loops at the top of the on slip, where the signals will switch off in the event of queues reaching back that far. I might have got that wrong, though.

Also, surely these latest incarnations are 3rd generation, or have they just filed the 80s version away as 'didn't happen'?

IMV, the new generation is ultimately just harnessing new signals technology and better IT solutions to reach the same outcome more efficiently and economically, so I'm not sure it will necessarily save metering from a death in those situations where its already being retired on the grounds of no longer being required.

[Peter Freeman]

... interesting paper here:
http://www.jctconsultancy.co.uk/Symposi ... tering.pdf

That's an interesting paper, but there's little detail there. There are good technical descriptions of the Australian system (designed originally by the University of Crete, Greece!) if you search the web. Try Alinea algorithms and 'Hero' multi-ramp integration by upstream recruitment.

Important to remember that if the ramp signals are on but the main line is not queuing it is working.

That's statement's a start, but is very simplistic.

[Peter Freeman]

... I was under the impression that the previous versions have had occupancy loops at the top of the on slip, where the signals will switch off in the event of queues reaching back that far. I might have got that wrong, though.

The best modern systems do have this feature. They also have a mid-ramp sensor that triggers recruitment of signals on the next ramp upstream: a 'call for help'.

IMV, the new generation is ultimately just harnessing new signals technology and better IT solutions to reach the same outcome more efficiently and economically, so I'm not sure it will necessarily save metering from a death in those situations where its already being retired on the grounds of no longer being required.

If "it's already being retired on the grounds of no longer being required", then OK, it's no longer required so don't use it. But where it is required, then modern systems can do the job. The problem with most UK experiments was that they released platoons of vehicles. Platoons trying to merge are the problem! Single vehicle merging is the feature that makes it work.

Australian systems actually release up to three vehicles simultaneously, but from a side-by-side standing start. By the time they merge, in single file, they've drag-raced themselves into three single vehicles.

[Peter Freeman]

... The A40 in Germany makes extensive use of it as it goes through the cities of the Rhein-Ruhr conurbation https://www.google.com/maps/@51.4949747 ... 312!8i6656 ...

Notice on that image the words "one vehicle per green". AU signals are signed "one vehicle per green each lane". There is no enforcement by camera, but we are an obedient lot!

I have seen a picture of a ramp signal (somewhere in Scandinavia, I think) that has a sign "one green, one vehicle; one red, one photo".

[darkcape]

Not dead. Atkins and Dynniq have been doing work for HE for '2nd Generation Ramp Metering'. interesting paper here:
http://www.jctconsultancy.co.uk/Symposi ... tering.pdf

Important to remember that if the ramp signals are on but the main line is not queuing it is working.

(link fixed now)

The problem with that theory is if the mainline isn't queueing the local road network probably is, but that's not HEs problem so they don't care about the effects this has on everyone else.

It doesn't particularly change the fact that a queue is a queue, but I was under the impression that the previous versions have had occupancy loops at the top of the on slip, where the signals will switch off in the event of queues reaching back that far. I might have got that wrong, though.

Also, surely these latest incarnations are 3rd generation, or have they just filed the 80s version away as 'didn't happen'?

IMV, the new generation is ultimately just harnessing new signals technology and better IT solutions to reach the same outcome more efficiently and economically, so I'm not sure it will necessarily save metering from a death in those situations where its already being retired on the grounds of no longer being required.

Yes most existing sites have loops at the top of the slip e.g here at the M1 J25 SB onslip. From these loops another 5-6 vehicles can queue to the roundabout nosing and when the lights were working well, the roundabout stayed mostly clear. Once flow completely broke down on the main carriageway the lights had no effect and so the traffic would stack back onto the roundabout anyway.

In addition to my earlier post about J24a, the M1 NB J24 onslip site has also been retained after the Smart Motorway works

[traffic-light-man]

The problem with most UK experiments was that they released platoons of vehicles. Platoons trying to merge are the problem! Single vehicle merging is the feature that makes it work.

I don't think that's a feature of only 'most UK experiments', that's a feature of any UK RM site with more than one lane, on the basis that we don't signal each lane individually like other countries do. Additionally, in the UK, the signals vary the green (and red) times, so different sized platoons are released according to the flow of the main carriageway.

But if single vehicle merging is the feature that makes it work, then I doubt many of the UK sites are successful, because most I can think of have two lanes across the stop line.

[ElsieSeedlow]

... interesting paper here:
http://www.jctconsultancy.co.uk/Symposi ... tering.pdf

That's an interesting paper, but there's little detail there. There are good technical descriptions of the Australian system (designed originally by the University of Crete, Greece!) if you search the web. Try Alinea algorithms and 'Hero' multi-ramp integration by upstream recruitment.

Important to remember that if the ramp signals are on but the main line is not queuing it is working.

That's statement's a start, but is very simplistic.

Unnecessarily condescending.

English Ramp Metering algorithms have also long been based on the work of Markos Papageorgiou of the Technical University of Crete, he is an acknowledged world expert. I attended a presentation by him in the early 2000s when experiments, including the use of ALINEA were taking place. The big bang of sites on HA motorways from 2006 were not experimental.

The Atkins paper (and the presentation I saw on the new system) makes it clear that it can use a variety of algorithms than can be downloaded and stored directly at the site.

[Matthew]

I had no idea there was any in place on the A3 slips.

Yes, there’s a set at the southbound entry from the A25 at Wooden Bridge. I pass semi-regularly these days and have never seen them on.

Well I never!

[Peter Freeman]

... interesting paper here:
http://www.jctconsultancy.co.uk/Symposi ... tering.pdf

That's an interesting paper, but there's little detail there. There are good technical descriptions of the Australian system (designed originally by the University of Crete, Greece!) if you search the web. Try Alinea algorithms and 'Hero' multi-ramp integration by upstream recruitment.

Important to remember that if the ramp signals are on but the main line is not queuing it is working.

That statement's a start, but is very simplistic.

Unnecessarily condescending.

My apologies: condescension unintended and not personal. However, that statement is over-simplistic as I'm sure you know. There are signaling regimes that could easily ensure the mainline does not queue, but which would cause collateral mayhem on the local roads and intersections.

... The big bang of sites on HA motorways from 2006 were not experimental.

Even accepting that they were not experimental, the (few?) 2006-onward sites were apparently not successful enough to stimulate significant uptake in the UK. The Atkins paper in the link implies that the two 2nd-generation sites are experimental.

Questions -

Do those sites release single vehicles (including side-by-side groups that will self-resolve into single vehicles), or still release platoons?

The sites are currently standalone, without interlinking. Is upstream recruitment applicable in the English motorway environment? Interchanges are generally well-separated in the UK, whereas spacings are typically 2km to 4km on Melbourne's freeways.

Does anyone local have experience of how effectively the two 2nd-generation sites are working? (M25 Junction 13 northbound slip road near Staines, and A3 Dennis Roundabout southbound slip road in Guildford).

[ElsieSeedlow]

... The big bang of sites on HA motorways from 2006 were not experimental.

Even accepting that they were not experimental, the (few?) 2006-onward sites were apparently not successful enough to stimulate significant uptake in the UK. The Atkins paper in the link implies that the two 2nd-generation sites are experimental.

Questions -

Do those sites release single vehicles (including side-by-side groups that will self-resolve into single vehicles), or still release platoons?

The sites are currently standalone, without interlinking. Is upstream recruitment applicable in the English motorway environment? Interchanges are generally well-separated in the UK, whereas spacings are typically 2km to 4km on Melbourne's freeways.

Does anyone local have experience of how effectively the two 2nd-generation sites are working? (M25 Junction 13 northbound slip road near Staines, and A3 Dennis Roundabout southbound slip road in Guildford).

Well, after the trial had been completed the number of sites in England increased to 88 by 2011, I'd say that was significant. The number has dropped since because of Smart Motorways. Many more were considered but rejected following traffic analysis or because of site geometry. Several sites in the 30 site experimental pilot switched on very rarely.

Single release is often a feature of 'Demand Capacity' algorithms as used extensively in the US and using upstream detection. This is not a feature of the English system which uses the MIDAS loops to provide upstream data to decide if the system should come on in an attempt to avoid flow breakdown. Release timings are based on mainline flow and detection on the ramp. Full release can occur if the ramp queue starts to back up into the junction. Take a look at this for more detail: http://www.ukroads.org/webfiles/mch2470b.pdf.

I've not driven the two 2nd generation trial sites, though I have heard they are working well. Not being linked to fixed position MIDAS loops is a big advantage.

[ManomayLR]

... The big bang of sites on HA motorways from 2006 were not experimental.

Even accepting that they were not experimental, the (few?) 2006-onward sites were apparently not successful enough to stimulate significant uptake in the UK. The Atkins paper in the link implies that the two 2nd-generation sites are experimental.

Questions -

Do those sites release single vehicles (including side-by-side groups that will self-resolve into single vehicles), or still release platoons?

The sites are currently standalone, without interlinking. Is upstream recruitment applicable in the English motorway environment? Interchanges are generally well-separated in the UK, whereas spacings are typically 2km to 4km on Melbourne's freeways.

Does anyone local have experience of how effectively the two 2nd-generation sites are working? (M25 Junction 13 northbound slip road near Staines, and A3 Dennis Roundabout southbound slip road in Guildford).

Well, after the trial had been completed the number of sites in England increased to 88 by 2011, I'd say that was significant. The number has dropped since because of Smart Motorways. Many more were considered but rejected following traffic analysis or because of site geometry. Several sites in the 30 site experimental pilot switched on very rarely.

Single release is often a feature of 'Demand Capacity' algorithms as used extensively in the US and using upstream detection. This is not a feature of the English system which uses the MIDAS loops to provide upstream data to decide if the system should come on in an attempt to avoid flow breakdown. Release timings are based on mainline flow and detection on the ramp. Full release can occur if the ramp queue starts to back up into the junction. Take a look at this for more detail: http://www.ukroads.org/webfiles/mch2470b.pdf.

I've not driven the two 2nd generation trial sites, though I have heard they are working well. Not being linked to fixed position MIDAS loops is a big advantage.

I think major junctions, and all junctions on the M25, should be fitted with MS4s on slip roads giving speed limit and lane info at all times as well as journey times, e.g. NSL - M40 25 mins, M4 35 mins