The future of smart motorways

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avtur
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Re: The future of smart motorways

Post by avtur »

Herned wrote: Sat Feb 13, 2021 10:12
Micro The Maniac wrote: Fri Feb 12, 2021 11:41 But I still maintain that every driver should be sufficiently aware of what is happening ahead to not crash into a stationary vehicle - whether on a controlled- or uncontrolled-motorway, a dual-carriageway or an urban road. In fact, has a duty of care to be!
Humans are absolutely useless at concentrating on repetitive tasks. I would suggest that anyone who claimed to give driving 100% of their attention 100% of the time is a liar... so the reality is it could happen to anyone. This also applies to people paid to watch CCTV for hours
Totally agree, as long as there are humans involved the plan must include human failure, the perfect human simply does not exist.
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Re: The future of smart motorways

Post by Marty »

If it has already been mentioned then my apologies but...


...if you have broken down on a managed motorway and have, by good fortune, managed to drift into a refuge area, how are you expected to get out of the refuge area given that there is very little room to accelerate to reach the speed of traffic using lane 1 even if there should happen to be a gap (which there usually isn't otherwise ALR wouldn't be in use)?
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KeithW
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Re: The future of smart motorways

Post by KeithW »

Marty wrote: Sat Feb 13, 2021 14:38 If it has already been mentioned then my apologies but...


...if you have broken down on a managed motorway and have, by good fortune, managed to drift into a refuge area, how are you expected to get out of the refuge area given that there is very little room to accelerate to reach the speed of traffic using lane 1 even if there should happen to be a gap (which there usually isn't otherwise ALR wouldn't be in use)?

One way is to set the signs to show lane 1 closed while you do this. Where there are no smart signs, as on the D2 A1 they will set up a rolling road block to let you out. Of course some drivers feel so entitled they simply drive around the block car even when its a fully marked police vehicle.
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jackal
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Re: The future of smart motorways

Post by jackal »

WHBM wrote: Thu Feb 11, 2021 13:00 You are right to question the M25 section by Heathrow. Joining it clockwise at J14 from Heathrow terminal 5 and trying to get across to lanes 4 to 6 that are the M25 continuation and commonly jammed, when lanes 1 to 3 for the M4 are free-flowing at speed, is indeed hazardous, and exactly the situation we engineered out in Glasgow. Why was there the money (and design standard integrity) to do this in 1970 but not in 2010 ?
I think it was open around 2006?

Anyway, C/D designs were drawn up (though I have never seen them) and rejected on cost/environmental grounds. I would guess the section through Egham especially would be a huge sticking point - they could have put in C/D lanes north of there but perhaps the benefits aren't really worth it if capacity is squeezed at Egham.

Roughly contemporaneous schemes on the M20 and M60 with fewer constraints were built with C/D lanes.

An interesting case is the proposed widening between M25 J29 and the LTC - it will have C/D lanes northbound, and a single five lane carriageway southbound.
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Re: The future of smart motorways

Post by Bendo »

Marty wrote: Sat Feb 13, 2021 14:38 If it has already been mentioned then my apologies but...


...if you have broken down on a managed motorway and have, by good fortune, managed to drift into a refuge area, how are you expected to get out of the refuge area given that there is very little room to accelerate to reach the speed of traffic using lane 1 even if there should happen to be a gap (which there usually isn't otherwise ALR wouldn't be in use)?
You are supposed to use the emergency phone and they will close L1.
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Stevie D
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Re: The future of smart motorways

Post by Stevie D »

Marty wrote: Sat Feb 13, 2021 14:38 If it has already been mentioned then my apologies but...

...if you have broken down on a managed motorway and have, by good fortune, managed to drift into a refuge area, how are you expected to get out of the refuge area given that there is very little room to accelerate to reach the speed of traffic using lane 1 even if there should happen to be a gap (which there usually isn't otherwise ALR wouldn't be in use)?
You use the emergency phone there to contact the control centre. They will then activate the gantry signs to close lane 1 on the approach to the refuge area and create a safe space for you to rejoin the carriageway from a standing start without the need to lay down rubber as you go, and will then reopen the lane once they can see on the CCTV that you are up to speed.

There should be signs in the refuge area that tell you this (which will be more obvious once you're there and stopped than when you're whizzing past at 70mph, I'm not suggesting that you should have seen them!) so it doesn't rely on people knowing in advance.
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Re: The future of smart motorways

Post by ManomayLR »

Stevie D wrote: Sat Feb 13, 2021 17:28 There should be signs in the refuge area that tell you this (which will be more obvious once you're there and stopped than when you're whizzing past at 70mph, I'm not suggesting that you should have seen them!) so it doesn't rely on people knowing in advance.
The text of the sign says “Drivers MUST use SOS and await advice before rejoining main carriageway”

IMO there should be a sign saying “Leaving an Emergency Area into a live running lane is very dangerous. You should use the emergency phone provided, so we can help you rejoin the motorway safely.”
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Re: The future of smart motorways

Post by Micro The Maniac »

EpicChef wrote: Sat Feb 13, 2021 18:02 The text of the sign says “Drivers MUST use SOS and await advice before rejoining main carriageway”

IMO there should be a sign saying “Leaving an Emergency Area into a live running lane is very dangerous. You should use the emergency phone provided, so we can help you rejoin the motorway safely.”
MUST is mandatory... SHOULD is advisory.
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Re: The future of smart motorways

Post by Peter Freeman »

jackal wrote: Sat Feb 13, 2021 15:28
WHBM wrote: Thu Feb 11, 2021 13:00 You are right to question the M25 section by Heathrow. Joining it clockwise at J14 from Heathrow terminal 5 and trying to get across to lanes 4 to 6 that are the M25 continuation and commonly jammed, when lanes 1 to 3 for the M4 are free-flowing at speed, is indeed hazardous, and exactly the situation we engineered out in Glasgow. Why ...
... Anyway, C/D designs were drawn up (though I have never seen them) and rejected on cost/environmental grounds. I would guess the section through Egham especially would be a huge sticking point - they could have put in C/D lanes north of there but perhaps the benefits aren't really worth it if capacity is squeezed at Egham.

Roughly contemporaneous schemes on the M20 and M60 with fewer constraints were built with C/D lanes.

An interesting case is the proposed widening between M25 J29 and the LTC - it will have C/D lanes northbound, and a single five lane carriageway southbound.
M25 clockwise J14A-J15 is terrible, but could be fixed with some imaginative engineering and $$$ - you braid that section. Yes, I know it looks tight, but there is space for some creativity within the stack's footprint. That removes the J14A-M25 problem of the 'mad dash' across 3 lanes of fast-moving traffic that's aiming for M4. There would still be a capacity problem on M25 northbound through J15, unless a 4th lane could be squeezed in. Anti-clockwise needs a similar fix.

In general, I think the problem of too-closely-spaced junctions should be mitigated by using the simplest option that works. This diagram shows, in increasing complexity, the options as I see them. They all work. Which one to implement depends on the weaving severity and particular local circumstances.

merging.png

The Melbourne urban network has examples of all these options, and combinations. Auxiliary lanes fix most issues: more lanes means that traffic with no interest in an interchange stays to the right, well clear, so the joining and leaving traffic has space to fight it out. That M25 D6 was an attempt to solve by auxiliary lanes, but it was not the correct solution there because too many lanes drop at the same time.

C-D lanes are really just separated auxiliary lanes They offer little advantage, except as part of schemes where express lanes skip junctions, and they waste space.

The gold standard is braiding, but it takes space and $$$.

I take issue with the shunning of wider roads. Extra lanes make most manoeuvres easier and safer. However, I fully appreciate the problem of constrained right-of-way, especially for upgrades in the UK.

A final point is that the laissez-faire lane usage rules in AU and USA help in some of these situations. While AU has a general recommendation to keep left unless overtaking, it is often and acceptably overridden by traffic circumstances and destination. There is no specific rule against overtaking on the left, and it is common and normal
Last edited by Peter Freeman on Mon Feb 15, 2021 03:11, edited 1 time in total.
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Re: The future of smart motorways

Post by Bomag »

Micro The Maniac wrote: Sun Feb 14, 2021 10:54
EpicChef wrote: Sat Feb 13, 2021 18:02 The text of the sign says “Drivers MUST use SOS and await advice before rejoining main carriageway”

IMO there should be a sign saying “Leaving an Emergency Area into a live running lane is very dangerous. You should use the emergency phone provided, so we can help you rejoin the motorway safely.”
MUST is mandatory... SHOULD is advisory.
Unless somebody has re-writen the motorway regs there is no legal requirement to do so. That sign doesn't look to be authorised as a Section 36 sign.
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Re: The future of smart motorways

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EpicChef wrote: Sat Feb 13, 2021 18:02 The text of the sign says “Drivers MUST use SOS and await advice before rejoining main carriageway”
I understand more than 50% of those who stop in an ERA do not do so before rejoining. This must be embarrassing to those who put the Risk Assessment together and stated that everyone would ...

Given the length of time it took the control room to cotton on to the evolving situation covered by the recent South Yorkshire inquest (nearly half an hour), I wonder how long it actually takes before drivers can be officially released. Does the "advice" include just saying to be careful, or do you have to wait for the HE Traffic Officer to turn up, which may likely be an hour or more.
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Stevie D
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Re: The future of smart motorways

Post by Stevie D »

WHBM wrote: Sun Feb 14, 2021 15:59I understand more than 50% of those who stop in an ERA do not do so before rejoining. This must be embarrassing to those who put the Risk Assessment together and stated that everyone would ...

Given the length of time it took the control room to cotton on to the evolving situation covered by the recent South Yorkshire inquest (nearly half an hour), I wonder how long it actually takes before drivers can be officially released. Does the "advice" include just saying to be careful, or do you have to wait for the HE Traffic Officer to turn up, which may likely be an hour or more.
I suspect that quite a few of the people who don't phone the control centre before leaving the ERA are people who shouldn't have stopped there in the first place and don't want to risk getting into trouble if they had to admit that they stopped to make a phone call or whatever.

As far as I know, the procedure is that the control centre then sets the signals on the approach to close lane 1, and when the CCTV shows that all vehicles in the vicinity have moved out to lane 2 then the driver it is clear to go. Certainly no need to wait for the HETO to turn up.
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Re: The future of smart motorways

Post by XC70 »

Bomag wrote: Sun Feb 14, 2021 14:32
Micro The Maniac wrote: Sun Feb 14, 2021 10:54
EpicChef wrote: Sat Feb 13, 2021 18:02 The text of the sign says “Drivers MUST use SOS and await advice before rejoining main carriageway”

IMO there should be a sign saying “Leaving an Emergency Area into a live running lane is very dangerous. You should use the emergency phone provided, so we can help you rejoin the motorway safely.”
MUST is mandatory... SHOULD is advisory.
Unless somebody has re-writen the motorway regs there is no legal requirement to do so. That sign doesn't look to be authorised as a Section 36 sign.
So even though it says "must" it is actually not mandatory?

Anyway it just says you have to phone them and get advice, it doesn't say you have to do what they say..... :-)
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Re: The future of smart motorways

Post by Conekicker »

Bomag wrote: Sun Feb 14, 2021 14:32
Micro The Maniac wrote: Sun Feb 14, 2021 10:54
EpicChef wrote: Sat Feb 13, 2021 18:02 The text of the sign says “Drivers MUST use SOS and await advice before rejoining main carriageway”

IMO there should be a sign saying “Leaving an Emergency Area into a live running lane is very dangerous. You should use the emergency phone provided, so we can help you rejoin the motorway safely.”
MUST is mandatory... SHOULD is advisory.
Unless somebody has re-writen the motorway regs there is no legal requirement to do so. That sign doesn't look to be authorised as a Section 36 sign.
The sign is shown on working drawing NP 2937, dated 17.7.13. The authorisation PDF I've got has a reference HA 26-28-15 (TS13-6B) on it, whatever that means. It's not listed on the DfT authorisations webpage. I've a few other authorisation PDFs for other SM signs, none of them are on the DfT webpage either for some reason.
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Re: The future of smart motorways

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Peter Freeman wrote: Fri Feb 12, 2021 08:40I heard this stated in the late 1960's as "no motorway should be built wider than three lanes in each direction - if more capacity is needed then build another motorway." It might, at that time, have been merely a 'rule-of-thumb' (did DMRB exist then?) or a roads authority official's opinion.
That was indeed MOT policy at some point during the 1960s. DMRB did not exist, or didn't exist in anything like its present form, and motorway design was based on circulars sent out from Whitehall and other rapidly evolving documents.

The policy was mainly based on the fact that roads wider than three lanes each way were unknown in the UK and the way that drivers would react to them, and the way traffic flow would operate on them, was unknown. The rule was therefore a conservative one. It was also quite a sensible bit of network design advice (duplicate strategic routes to create resilience, don't widen and concentrate traffic on one corridor) at a time when building major new roads on greenfield sites was relatively cheap and easy to do.

The first D4M design was the M23 from Hooley to Streatham. Eagle-eyed viewers will note that this road was never built, but it was designed as D4M, and was done so on the basis that demand plainly existed for a road wider than D3M, but no feasible corridor existed to provide a duplicate motorway running parallel. As a result the rule had to be broken and the road had to have four lanes each way. Lots of research was done as part of the design work, and in subsequent years it was the test case for D4M roads wherever another was proposed - the early design of the M25 around Heathrow, which was built as D4M at the outset, heavily referenced the studies into the M23's four lane design and its central hard shoulders as pretty much the only available precedent.

I would hazard a guess that the acceptance of D4M as a design standard (and perhaps D5M for a time, if conversation upthread is anything to go by) was a result of the design work on the never-built M23, and informed the eventual guidance on roads wider than D3M.

As you say there's no special reason to think roads wider than D4M are wrong - they can only be right or wrong in context. But D6M on the M25 at Heathrow is plainly a cop-out!
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Re: The future of smart motorways

Post by Brenley Corner »

Chris5156 wrote: Sun Feb 14, 2021 20:54The first D4M design was the M23 from Hooley to Streatham. Eagle-eyed viewers will note that this road was never built, but it was designed as D4M, and was done so on the basis that demand plainly existed for a road wider than D3M, but no feasible corridor existed to provide a duplicate motorway running parallel.
I know this is straying a bit from thread topic, but I saw M23 and Hooley in the same sentence and had to jump in :P .
Technically speaking and being pedantic, a bit of that D4M did get built. The short section of M23 from Hooley to Merstham is built as D4M and is still configured as such southbound. So would that be the first D4M designed and built as such?
Hands up anyone for the first section M25 to be designed and built as 4 lanes each way from day 1?

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ManomayLR
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Re: The future of smart motorways

Post by ManomayLR »

OK - what about, for example, ALR of M1 J6A-10 to make a D5ALR?
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Re: The future of smart motorways

Post by WHBM »

Micro The Maniac wrote: Fri Feb 12, 2021 11:41 But I still maintain that every driver should be sufficiently aware of what is happening ahead to not crash into a stationary vehicle -
You are driving in lane 1 in the dark an adequate distance behind an HGV which is built out to full box dimensions. Motorway lighting has been removed. There is continuous traffic in lane 2. The HGV suddenly veers right into a gap in lane 2 traffic; there is a stopped vehicle just ahead.
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Re: The future of smart motorways

Post by Chris5156 »

Brenley Corner wrote: Sun Feb 14, 2021 21:07
Chris5156 wrote: Sun Feb 14, 2021 20:54The first D4M design was the M23 from Hooley to Streatham. Eagle-eyed viewers will note that this road was never built, but it was designed as D4M, and was done so on the basis that demand plainly existed for a road wider than D3M, but no feasible corridor existed to provide a duplicate motorway running parallel.
I know this is straying a bit from thread topic, but I saw M23 and Hooley in the same sentence and had to jump in :P .
Technically speaking and being pedantic, a bit of that D4M did get built. The short section of M23 from Hooley to Merstham is built as D4M and is still configured as such southbound. So would that be the first D4M designed and built as such?
Not sure if it was the first to be built (it opened ~1976, off the top of my head, which makes it later than the M61 at Linnyshaw Moss) but it must have been part of the first D4M to be designed.
Hands up anyone for the first section M25 to be designed and built as 4 lanes each way from day 1?
J14-15, I think?
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Re: The future of smart motorways

Post by Big L »

WHBM wrote: Sun Feb 14, 2021 21:41
Micro The Maniac wrote: Fri Feb 12, 2021 11:41 But I still maintain that every driver should be sufficiently aware of what is happening ahead to not crash into a stationary vehicle -
You are driving in lane 1 in the dark an adequate distance behind an HGV which is built out to full box dimensions. Motorway lighting has been removed. There is continuous traffic in lane 2. The HGV suddenly veers right into a gap in lane 2 traffic; there is a stopped vehicle just ahead.
You're an adequate distance behind so you will have no problem stopping safely.
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