Hamburger/Throughabout Controversy

[Bryn666]

https://assets.publishing.service.gov.u ... eriods.pdf AECOM report into the practice here. It's known as VA here, in the USA it will be called 'rest on red'.

But given this was over 10 years ago what has happened in terms of guidance from the government (which hasn't really changed)?
New standards, best practice guidance?
Or has it disappeared without trace?
Was it a civil service exercise for the government to be seen to pander to the motoring lobby?

Merely answering the question "does rest on red really exist"!

TSM 6 (https://assets.publishing.service.gov.u ... pter-6.pdf) details VA loops as part of speed discrimination (which can be used to trigger red signals as well as extend greens depending on requirement).

The AECOM report will have been an exercise into "can we change anything" to which the DfT response is always no. This country would benefit massively from using flashing ambers as a general caution signal instead of greens in several cases. This happens without issue in Europe, but that might be the problem. Even Ireland has them.

[jnty]

I believe many signals engineers prefer to set the signals to 'quiescent red' during the middle of the night when traffic flows are minimal. That is, instead of endlessly cycling through each stage, all phases are set to red until a demand is detected. This is to prevent those drivers who are out at night 'chasing greens', initially, if they have sense, they are going to slow down for the red signal, which should then go green once they are within the detection zone.

Hopefully, resting on all red should also prevent those drivers who 'amber gamble', insisting that no other traffic is about at that time of day, from coming to grief with the driver from a conflicting arm who is thinking the exact same thing.

Is this fact or supposition? I find it hard to believe it would be official policy. I've noticed nothing like this in the city I live in, which overwhelmingly uses signals instead of roundabouts and has several thousand signalised locations. The rest status favours the major flow. If travelling on the main through roads of Melbourne, in the dead of night, most signals will be on green as you approach and pass through.

I must have a mystic transmitter on my car! At silly o'clock, the A5/A38 signalised roundabout at Weeford often seems to be Green as I approach but change to Red before I get there, despite no other traffic around making me wait a full cycle for the next Green - particularly annoying when towing as every stop-start costs fuel - and emissions!

Much the same seems to happen at night on the A449 at the three sets of lights between Gailey and Coven. They seem determined to stop all traffic for a short while. Its like Staffordshire Council have stumbled upon a new method of traffic calming !

I don't know whether these comments were meant seriously. Surely these are cases of the well-known phenomenon where you only remember unfavourable instances, and not the favourable ones? Similar to how, in parallel queues to the bank tellers, it always seems that the queue you've randomly chosen moves more slowly than all the rest.

https://assets.publishing.service.gov.u ... eriods.pdf AECOM report into the practice here. It's known as VA here, in the USA it will be called 'rest on red'.

Priority operation could only be
achieved if the appropriate signs and markings were displayed as would be expected at a
normal priority junction; initial investigations looked at the viability of using Variable Message
signs to display a ‘Give Way’ sign on the approach from the minor road.

Or...we could display the slightest hint of ambition and change the law rather than throwing millions at technology which other countries manage to avoid with a single flashing light.

[Bryn666]

Or...we could display the slightest hint of ambition and change the law rather than throwing millions at technology which other countries manage to avoid with a single flashing light.

BURN THE WITCH!

I said the same thing just above you, actually

[jnty]

Or...we could display the slightest hint of ambition and change the law rather than throwing millions at technology which other countries manage to avoid with a single flashing light.

BURN THE WITCH!

I said the same thing just above you, actually

Yes I just missed that but thanks for pre-emptively agreeing with me, I appreciate it.

[Bryn666]

Or...we could display the slightest hint of ambition and change the law rather than throwing millions at technology which other countries manage to avoid with a single flashing light.

BURN THE WITCH!

I said the same thing just above you, actually

Yes I just missed that but thanks for pre-emptively agreeing with me, I appreciate it.

The problem remains a lack of ambition in the corridors of power - changing things is scary and expensive, even though all the evidence suggests doing it anyway.

We need huge reform of traffic signs legislation, the opportunity to do so in 2016 was trashed because the DfT were thrown in to dealing with the B word.

[Peter Freeman]

https://assets.publishing.service.gov.u ... eriods.pdf AECOM report into the practice here. It's known as VA here, in the USA it will be called 'rest on red'.

From my first quick read through that document, especially the table on page 12, 'rest-on-all-red' is not common in the UK. Only three of the local authorities reported reverting to 'all red' under low demand (LD), and only for isolated signals. Most reported that isolated signals at times of LD operated under VA (which means vehicle actuated), but with a different timing set. Signals acting under a master plan, are still timed but change to a different timing set.

Australian practise, where all signals have VA and most are under master control, perhaps has more scope for dealing with LD. As I stated in my earlier post) there is no rest-on-all-red. My observation is that, under low or no demand, our signals rest on green for the major flow. Therefore the minor flows would appear to see 'rest-on-red'. They do not continuously cycle.

It seems that Australian signal practise is ahead of UK regarding area-wide master control of signals. Probably this is because signals, not roundabouts, have always predominated. Our system, called SCATS, is similar to UK SCOOT, I think, but has been refined and enhanced over a very long history, and has much wider spans of control. For eample, over 4000 signal sets in Melbourne. It was initiated in Sydney around 1970, implemented in Melbourne in 1982, and is now used in every major AU city and many locations around the world. I don't know the details, but I assume its presence strongly influences how to deal with LD.

An AU difference is that we are dealing mainly with urban settings. There are few isolated traffic signal sets, ie. not under the master control, whereas in the UK they will be common. From the pedestrian and NMU safety angle, I believe that virtually all traffic signals here have request buttons. UK? Regarding 'red light jumping', I've hardly ever observed it. As I've noted before, we're a rather compliant lot! Make of that what you will.

[Bryn666]

https://assets.publishing.service.gov.u ... eriods.pdf AECOM report into the practice here. It's known as VA here, in the USA it will be called 'rest on red'.

From my first quick read through that document, especially the table on page 12, 'rest-on-all-red' is not common in the UK. Only three of the local authorities reported reverting to 'all red' under low demand (LD), and only for isolated signals. Most reported that isolated signals at times of LD operated under VA (which means vehicle actuated), but with a different timing set. Signals acting under a master plan, are still timed but change to a different timing set.

Australian practise, where all signals have VA and most are under master control, perhaps has more scope for dealing with LD. As I stated in my earlier post) there is no rest-on-all-red. My observation is that, under low or no demand, our signals rest on green for the major flow. Therefore the minor flows would appear to see 'rest-on-red'. They do not continuously cycle.

It seems that Australian signal practise is ahead of UK regarding area-wide master control of signals. Probably this is because signals, not roundabouts, have always predominated. Our system, called SCATS, is similar to UK SCOOT, I think, but has been refined and enhanced over a very long history, and has much wider spans of control. For eample, over 4000 signal sets in Melbourne. It was initiated in Sydney around 1970, implemented in Melbourne in 1982, and is now used in every major AU city and many locations around the world. I don't know the details, but I assume its presence strongly influences how to deal with LD.

An AU difference is that we are dealing mainly with urban settings. There are few isolated traffic signal sets, ie. not under the master control, whereas in the UK they will be common. From the pedestrian and NMU safety angle, I believe that virtually all traffic signals here have request buttons. UK? Regarding 'red light jumping', I've hardly ever observed it. As I've noted before, we're a rather compliant lot! Make of that what you will.

For the record I would agree that other countries do seem to be ahead of us. Like with roundabout design, we set the ball rolling and then gave up whilst the rest of the world moved on with the concept.

[Peter Freeman]

Thanks for finding that document, BTW. Very useful.

[the cheesecake man]

I found this one in Bradford to be an improvement because the roundabout wasn't really big enough for the three lanes of traffic that were supposed to go round it.

Off topic I remember once upon a time the church on the right advertising "last services before motorway"

[Peter Freeman]

I believe many signals engineers prefer to set the signals to 'quiescent red' during the middle of the night when traffic flows are minimal.

Is this fact or supposition? I find it hard to believe it would be official policy. I've noticed nothing like this in the city I live in, which overwhelmingly uses signals instead of roundabouts and has several thousand signalised locations. The rest status favours the major flow. If travelling on the main through roads of Melbourne, in the dead of night, most signals will be on green as you approach and pass through.

I wrote that on Friday. Today is Monday. Completely at random, as I was out at dinner tonight and had to drive back home through inner-suburban Melbourne AU, I noted the signal conditions. Time 22h30: not exactly 'dead-of-night'. From Prahran to Burwood East, all dense suburban built-up, S2 and some S4, conditions dark but streetlit, dry, adhered to 60km/hr limit, very light traffic, three roads used (High Street, Warrigal Road, Highbury Road). Journey was 15km, took just under 20 minutes. I passed through 18 sets of signals (nearly all crossroads), stopped at none: all were green or just turning to green. A good run, but not abnormal.

I think the AU experience of traffic signals is greatly different from the UK's.

Edit: to add another random late-night journey experience -

Two days later, today is Wednesday. I was out to see a movie tonight and again drove back home (and no, my social life does not normally extend to every second night out!). Time 21h00. From Prahran to Burwood East, by a different route to the previous journey. Suburban main roads, D4-D3-D2-S4-S2, conditions dark but streetlit, dry, adhered to 80 and 60km/hr limits, light traffic, three roads used (Princes Highway, Stephensons Road, Highbury Road). Journey was 17km, took 21 minutes. I passed through 25 sets of signals (nearly all crossroads), stopped at 4, no wait more than 30 seconds. Another good run, and typical.

[Bryn666]

I think the AU experience of traffic signals is greatly different from the UK's.

AU appears to still have a largely competent highways industry not flooded with project managers and spreadsheet watchers it seems.

[solocle]

Properly designed junctions all have detector loops or microwave detection. Sites running fixed time are because there is a fault somewhere which either has been reported to the relevant UTMC or hasn't.

Very few, if any, junctions are built today to run fixed time and nothing else. It's another SABRE myth posted without any fact checking.

If that's a SABRE myth then a lot of signalised roundabouts must be faulty and don't ever seem to get repaired - it's very noticeable in the early hours of the morning when there's little traffic about.

I believe many signals engineers prefer to set the signals to 'quiescent red' during the middle of the night when traffic flows are minimal. That is, instead of endlessly cycling through each stage, all phases are set to red until a demand is detected. This is to prevent those drivers who are out at night 'chasing greens', initially, if they have sense, they are going to slow down for the red signal, which should then go green once they are within the detection zone.

Hopefully, resting on all red should also prevent those drivers who 'amber gamble', insisting that no other traffic is about at that time of day, from coming to grief with the driver from a conflicting arm who is thinking the exact same thing.

Which backfires somewhat, as often on a late night snack run as a student I'd often take on this roundabout past midnight - B480 Cowley Road / A4142 Ring Road
The quiescent red would be OK if it detected cyclists. But it doesn't - after a couple of times I learnt this. So I'd generally blast through the red lights at about 20 mph. Perfectly safe to do so, just remember to give way to the left as well as the right (and any pedestrians too).

I don't jump lights unless I believe the light to be broken - which, on a bike, these were. But unless you have camera enforcement, the problem drivers are going to cotton on to this and may just go through on red - which causes a far more serious problem when that other person has a green light.

I'd rather see such junctions use part time signals. With throughabouts that's a bit more tricky.

[pjr10th]

I've noticed with UK Signalised roundabouts the default at low flow seems to be to run the full cycle anyway, rather than react to demand. I don't like crossing on red at a roundabout (you have to though otherwise you'll wait a decade). In this case, a van driver & I both arrive around the same time. I call my crossing. The lights do nothing. I'm half way down the next street by the time he gets going, having crossed on reds myself. Seems the lights let all the others go before us!

On another note: why is this through lane here on this roundabout: https://maps.app.goo.gl/8KAJ73fzmTsNVTsPA

It always goes green with the ahead movement for that approach, so it would surely have been more sensible to just put the right turners on the rotary road instead.

[Peter Freeman]

I'm finding it difficult to absorb the revelation that Sabre posters are admitting that passing through a red light is relatively normal and justified ...!?

[solocle]

I'm finding it difficult to absorb the revelation that Sabre posters are admitting that passing through a red light is relatively normal and justified ...!?

I don't think anyone is absolutist about these things:

It's then just a question of degrees.

[J N Winkler]

Spain uses them widely. Here's a mad explosion of hamburgers on Madrid's otherwise motorway inner ring road:

https://www.google.co.uk/maps/@40.48305 ... 066747,15z

It might take a local equivalent of HistoricAerials.com to confirm, but I strongly suspect the existence of these junctions has more to do with Spanish standards long calling for unsignalized hamburgers as a strategy for reducing and spatially separating conflict points at flat intersections, similar to jughandles, Michigan lefts, J-turns, etc. They have appeared as a standard layout in the upright signing manual (Norma 8.1-IC) at least as far back as 1991. Current guidance for the local equivalent of map-type signs calls for the hamburger to be rendered as a solid black blob with a cutout and arrow for the through movement, but in practice stack-type signs are often used.

Typical example at the intersection of the N-110 and SG-313 in Segovia province

[trickstat]

On another note: why is this through lane here on this roundabout: https://maps.app.goo.gl/8KAJ73fzmTsNVTsPA

It always goes green with the ahead movement for that approach, so it would surely have been more sensible to just put the right turners on the rotary road instead.

I'm not even sure you can actual call that junction a roundabout.

[ais523]

I'm finding it difficult to absorb the revelation that Sabre posters are admitting that passing through a red light is relatively normal and justified ...!?

I don't drive, and therefore I've never driven through a red light.

However, bad traffic light phasing definitely does encourage people to ignore the lights. I actually consider "lights showing red when it would be safe to pass them" to be a serious safety hazard, because it encourages people not to respect the red lights. This is true both for lights controlling vehicles on the road, and lights controlling pedestrian crossings – if a pedestrian light is frequently red when crossing the road would be safe, then people will ignore the lights and cross anyway, which can lead to unexpected conflicts when people forget what the junction phasing is.

[DB617]

The A4174 throughabouts have finally been killed off.

The Council has concluded that there is no longer a need for it due to post-Pandemic traffic reduction. I have to admit that I have noticed that reduction - though I would argue it is possibly due to constrictions upstream at Emersons Green, Bath Road in Brislington and the same in Saltford... They may get a shock in a few years' time.

[tom66]

My impression of Chowns Mill Roundabout (nr Rushden) is that it copes rather well with the flow.

https://www.google.com/maps/place/A45/@ ... -1.2427826

Conflict points from the A6 towards A45 are minimised; you can easily cross to the queueing point at the lights and wait for the phasing.

The worst part is the A6 merge in turn on the exit of the roundabout. I think that is too short given the size of the island, more space could be added to keep the conflict zone away from the burgerbout.

I rarely see queues here even at peak times, and this is a busy junction.