To Thread - Forum Home

The Mudcat Café TM
https://mudcat.org/thread.cfm?threadid=165036
46 messages

BS: 'Not so Smart' Motorways.

11 Oct 18 - 09:44 AM (#3956049)
Subject: BS: 'Not so Smart' Motorways.
From: Acorn4

Recently we've encountered some of these new fangled "smart" motorways; basically this means abolishing the hard shoulder to put in an extra lane.

Recently while going down to London I was in the inside lane and saw the breaklights of the car in front whioch then ground to a halt and soon the whole lane had come to a standstill.

Someone three cars in front had either broken down or ran out of fuel.

This led to a tailback in the lane with a whole stream of vehicles trying to pull out into two lanes of fast traffic.

How long is it before there are major pile-ups - and how are emergency vehicles supposed to get to the scene when there is no hard shoulder.

There is a small lay-by type thing about every 1.5 miles but a broken down vehicle would, in all probability not be able to get to it.


11 Oct 18 - 10:47 AM (#3956060)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Tattie Bogle

Totally agree with you, Acorn 4. Have encountered these around Birmingham during our long drives North and they scare me rigid! The idea is supposed to be to reduce congestion at peak times, but as you say, if you are unlucky enough to break down, you literally have nowhere to go!
It seems to be in direct contradiction to what the Police are saying on the current "A1" series on BBC TV, that broken down vehicles MUST get out of "live lanes". Well if you make all lanes, including the hard shoulder "live", where to go?


11 Oct 18 - 11:09 AM (#3956064)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Will Fly

I've been 'enjoying' the regular congestion on the M23 and sections of the M6 which - replete with cones - are being converted into "smart" motorways.

When I first saw the tag "smart motorway", I thought: "What the fuck is that - a motorway with 5 GCSEs, or a degree in tarmac?"

Anyway, thank god for the M6 toll. It's worth paying a few quid for a few miles of pleasant driving and missing out Birmingham.


11 Oct 18 - 11:31 AM (#3956071)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

Well I don't agree at all with any of the above posters. I drive at least 12000 miles per annum on our motorways and I'm an extremely frequent user of the smart motorways around both Bristol and Birmingham, and, compared with the pre-smart days, my passages through these areas have been much eased. Yes there's massive disruption that goes on for years via lengthy roadworks as the new system is put in place, but even in those roadworks the traffic flows pretty well most of the time thanks to the average-speed cameras. On the smart motorways the variable speed limits, operated by computerised camera systems that monitor flow and relay the recommended limits to the overhead gantries, ensure that everyone travels at an appropriate speed so that bunching is avoided. There are yellow speed cameras typically on every other gantry, at the side, not overhead, and they are well-recognised and the limits are generally obeyed. Of course, breakdowns or accidents can still cause congestion, as has always been the case, but bunching-congestion, a routine horror on busy non-smart motorways, has been much-reduced. So I'm a bit of a fan. Everybody knows that simply widening motorways just doesn't work, as anyone who has to endure Death Valley on the M60 would tell you.


11 Oct 18 - 11:41 AM (#3956073)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Will Fly

Mmm... varied experiences I think. A few weeks ago, I had the most bloody journey on the smart sections of the M25, with long waits in static queues, and the camera controlled speeds going down to 40 at every intersection. No accidents either.

Having said that, I decided to risk the M25 both ways recently on a journey to Scotland, and had unexpectedly easy journeys both ways. So, a mixed bag for me.


11 Oct 18 - 11:45 AM (#3956077)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

Well I had to use the M25 twice last week and it was a breeze both times.


11 Oct 18 - 11:52 AM (#3956078)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Will Fly

I was travelling mid-morning on the up journey and mid-afternoon on the down journey - perhaps the travel time, i.e. missing rush hours, is the key.


11 Oct 18 - 12:09 PM (#3956081)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

If you're using the M6/M5 to bypass Birmingham, the M6 Toll isn't worth it. It's a huge loop, adding miles to the journey, and it costs money. Nine times out of ten you'll sail through on the old motorways reasonably well these days. Worth the risk. If the gantries say "long delays" well maybe.


11 Oct 18 - 06:13 PM (#3956154)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Tattie Bogle

Used the SW sector of the M25 twice in our recent July holiday: both times reduced to "That famous parking lot called the M25", i.e total standstill for long periods. OK, it was holiday time, but all of our journeys took hours over the estimated time on Google maps!
But, no, cannot understand how on earth effectively abolishing the hard shoulder could be deemed safer.


11 Oct 18 - 06:39 PM (#3956157)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

Well it's true that you have to be a bit canny apropos of your travelling times. If you really have to be at Heathrow/Gatwick/Stansted (God help you) at a particular time, your options are limited. We've taken to using B&Bs near Bristol and Gatwick airports the night before our flights. We can travel up in the evenings before (equals quiet roads), and the B&Bs look after our car for the week at no greater cost than a frenetic last-minute drive to the airport car park which costs a fortune and forces you to drag your bags half a mile to the terminal. The B&Bs we use give us a free lift there and back direct to the airport terminal. I can give you details of really good ones at Gatwick and Bristol.

Avoid Friday travel during the day at any time of year. Avoid Saturday travel in summer. Avoid beginnings and ends of bank holiday weekends. Give yourself a game chance!

Steve (motorway denizen par excellence...)


11 Oct 18 - 07:21 PM (#3956164)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

Also, in my travels I've noticed that many lorries now use the motorways at night.


11 Oct 18 - 08:13 PM (#3956172)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Tattie Bogle

"Now"? They always have! Driving around West Lothian in the middle of the night on house calls 20 years ago, the only traffic on the road apart from Drs on call was lorries!


11 Oct 18 - 08:38 PM (#3956175)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

So fewer during the day...


12 Oct 18 - 02:02 AM (#3956200)
Subject: RE: BS: 'Not so Smart' Motorways.
From: DMcG

I suspect "Smart Motorways" fail on their own terms. They are basically about trying to increase the capacity of the motorway without the expense and legal complexities of actually widening the motorway itself. But the main cost is that any breakdown or accident is more disruptive. Consequently the traffic flow is reduced. Depending on the number of breakdowns etc the average time to complete a journey may go up, not down.


12 Oct 18 - 03:28 AM (#3956204)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Dave the Gnome

Have you done death valley now the smart roadworks are complete, Steve? It does seem a lot better but I may be just comparing it with the last 10 years or so of roadworks!


12 Oct 18 - 04:39 AM (#3956216)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

I have, Dave, and will be again shortly. It did seem better but I'd need to judge it over a few more transits. Can't bloody wait... At least when I get there after me northbound trip from Bude I know that the light's at the end of the tunnel and that I'll soon be at Besses M&S Simply Food to buy a butty, followed by a gentle warming down as I head up the A56 towards Bury and the folks. Oddly, going back home heading for the M6 I haven't been stuck in any huge jams on the M60/M62 for quite a long time now. Those 50 limits and yellow average speed jobbies keep things moving.

I don't think that smartening motorways is about trying to increase their capacity, DMcG. They're about imposing much-needed discipline on drivers, especially at busy periods, to keep traffic moving. I haven't seen any stats but I suspect that there are far fewer accidents in those stretches. Almost every driver is aware of the frequent speed cameras and hardly anyone exceeds the gantry limits by more than a couple of miles per hour.


12 Oct 18 - 05:02 AM (#3956224)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Mr Red

a motorway with 5 GCSEs, or a degree in tarmac? - well there are degrees of tarmac - some are almost concrete.

M6 toll. It's worth paying a few quid for a few miles of pleasant driving and missing out Birmingham.
While I would concur that missing out Birmingham (It missed out on a lot things - owr kid) is to be desired, but............ The M6 Toll misses out rural Staffordshire, and the cobbled parts of the M6. And Tam'th mah mon.
To experience the delights of the turnpike (from Lundun innit?) you have already traversed the more bucolic parts of Perry Barr, replete with spaghetti, or, via the M40/M42 - skirted the posher parts of Solihull that, er, um, well, has smart hard shoulders - to cry on.


12 Oct 18 - 05:11 AM (#3956227)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Jos

Call me naïve, but if it's the 50 limits and yellow average speed thingies that bring about the improvements, couldn't they just do that without getting rid of the hard shoulder?


12 Oct 18 - 05:31 AM (#3956230)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Mr Red

FWIW the definition of full capacity as applied to motorways is when all lanes are going at the same peed. And that speed needs no number. It can be fast or standstill, because there is nowhere for cars to avoid the car in front or in any direction.

So adding another lane increases the capacity (max or otherwise).

They must have reasoned that it is cheaper to use wot ya got and also the occasional breakdown can be balanced with 18 months (& more) of traffic cones, reducing the capacity. Traffic coned lanes are almost as dangerous as breakdowns IMHO. And ever present.

Not easy trading rare occurrences for permanent disruptions, but we rail at roadworks and are thankful we are not the guy who broke down. And the planners are car drivers, so is their psychology driven from within?


12 Oct 18 - 06:06 AM (#3956240)
Subject: RE: BS: 'Not so Smart' Motorways.
From: JHW

Bad idea abandoning the hard shoulder, a largely continuous layby for breakdowns and a way in for emergency services. Sure four lanes might get more traffic through than three but I'd rather have the hard shoulder. Scary Mway driving without one.
For a long time there were holdups on the M6 and M5 (heading down to Sidmouth say) as 'smart Mways' were installed. However on the M5 traffic still stops dead all lanes for no reason and the now operational so called 'smart Mway' gives no warning or instruction.


12 Oct 18 - 12:46 PM (#3956309)
Subject: RE: BS: 'Not so Smart' Motorways.
From: DMcG

Thanks for that, Mr Red. Traffic management is one of the vast array of subjects I know nothing about, and of course you are right that one definition of the capacity of a motorway is when every square metre of the tarmac is covered by a car. Clearly you can't get any more cars on there, so you could call that the capacity. But that does seem to omit any idea that the people in the cars want to get somewhere, and if everyone was stopped the capacity would be the same as the less likely position where everyone is moving at the same non-zero speed.

Here is one paper that uses a different definition, which I have copied below.


1.1.2 Capacity The definition of capacity varies depending on the context applied. Two distinctly different definitions are attributed to the terms “flow rate” and “maximum number of vehicles”. The Highway Capacity Manual (2000) defines capacity as the following:
“The maximum sustainable flow rate at which vehicles or persons reasonably can be expected to traverse a point or uniform segment of a lane or roadway during a specified time period under given roadway, geometric, traffic, environmental, and control conditions; usually expressed as vehicles per hour, passenger cars per hour, or persons per hour.” (Transport Research Board, 2000, Chapter 5)
This definition presents an idea of throughput while accounting for the various factors of friction that inhibit vehicles. By comparison, the literature in the VISSIM manual (PTV, 2007) refers to flow rates as a “saturation flow”. The term of saturation flow in the Highway Capacity Manual specifically refers to signalised intersections and available green time (Transport Research Board, 2000, Chapter 5). Throughout this paper, the term saturation flow as identified in the VISSIM manual is applied as the maximum traffic flow volumes that can be achieved over an hour long interval. Capacity will be referred to as the maximum achievable throughput given the constraints that limit the traffic flow, such as weaving, grade, traffic composition and geometric bottlenecks. The variation between the two terms is that saturation flow refers to potential hourly flow volumes if the inhibiting factors were not present (under ideal conditions). The other definition reflects an achievable throughput that is subject to the constraints in the network. The capacity of a section of freeway could therefore be significantly less than the saturation flow.


Hardly enthralling reading, but in short the definition they use is about flow, which seems more reasonable to me.

Using the idea of flow, it seems to me that the objective of the smart motorway is to increase the flow, but that it does so in a way that greatly increases the risk of turbulent flow - caused by obstacles andlane-changing amongst other things. THey have tried to increase the total number of vehicles on the motorway at the cost of increasing this risk.


Conversely, you can increase flow by eliminating the sources of turbulence, which are the kind of things Steve.


I am grateful to the OP and various commentators that have persuaded me to read up a little on this subject.


12 Oct 18 - 12:49 PM (#3956310)
Subject: RE: BS: 'Not so Smart' Motorways.
From: DMcG

I meant "Steve mentioned" in the above.


13 Oct 18 - 02:48 AM (#3956391)
Subject: RE: BS: 'Not so Smart' Motorways.
From: BobL

The Highway Code recommends, IIRC, keeping a two-second gap from the vehicle in front. To my mathematical mind, this means a theoretical maximum flow rate of 1800 vehicles per hour per lane. You can get closer to this with higher speeds, when the 2-second gap distance is large compared to vehicle lengths.

N.B. I did say "theoretical".


13 Oct 18 - 01:04 PM (#3956457)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Mr Red

A policeman once told me that a sudden stop, like an accident across all lanes, cause the tailback to shoot back up the motorway at 60mph. If you think about it, if the average speed is, and is, 65mph then the growth of a tailback is only a smidgen less that the average.

Tailbacks that appear without apparent cause are a symptom of a motorway nearing capacity. Something like a stupid driver lane changing without warning and people slow down, and near capacity there is little opportunity to drive round the problem in any part of the growing tailback. If they did they would cause a snowball effect. It needs time for people to respond and it is coming at them at 60mph head on!


13 Oct 18 - 04:41 PM (#3956485)
Subject: RE: BS: 'Not so Smart' Motorways.
From: The Sandman

"I don't think that smartening motorways is about trying to increase their capacity,"
well that seems to happen eventually.
imo we need to improve railway services and encourage people off the roads


15 Oct 18 - 04:08 AM (#3956707)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Mr Red

And both the Rail and Bus companies have to use their own services, for real. That way they would realise that changing the timetable en mass and every 3 months (I ain'ta kidding round here) that it takes time for the wrinkles to reveal. Like the times in yer head. Small changes work. Our local bus service had to revise their idea of the new timetable as soon as the paper version was on the streets, and it took 6 weeks to get the revised paperwork out. The problem is so bad that bus stops are not kept up to date and the county council timetable booklet now doesn't list any Stagecoach routes because the Stagecoach bastards change whenever some idiot in a distant town gets the urge to tinker with his spreadsheet. Believe me 3 months is an improvement on their worst conceits.

And add in the fiasco of train timetables, the image of public transport is one of unreliability. The driver of yer own car cannot possibly be unreliable.............. (s)he is, dare I say, street smart?


16 Oct 18 - 03:58 AM (#3956844)
Subject: RE: BS: 'Not so Smart' Motorways.
From: The Sandman

The driver of yer own car cannot possibly be unreliable"
are you joking


16 Oct 18 - 04:06 AM (#3956846)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Will Fly

Dick, I think what Mr. Red is getting at is that, unlike rail and bus, where you're at the beck and call of timetables and unknown disruptions to timetables, the car driver at least knows when he/she wants to go and can go at that time, etc.

I don't think it's about the driving reliability or skill, or otherwise of the actual driver. That's always open to question!


16 Oct 18 - 05:58 PM (#3956989)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

I had to make an emergency trip up the A30/M5/M62/M60 last Saturday from Cornwall to Bury. Not a day of the week I'd ever choose to travel voluntarily. All the roads were busy but I sailed through every section of smart motorway and, on top of that, through every section of roadworks on the M6 which currently take up around three-quarters of the motorway between Birmingham and Manchester. In spite of a leisurely sojourn at the wonderful Gloucester Services (where I bought some lovely ox cheek for my next casserole for under a fiver), I made the 325-mile trip in five and a half hours. The fears of a lack of hard shoulder are unfounded. If there is an emergency that requires hard-shoulder access, that lane is immediately shut off to traffic via a big red cross on the gantries. If you drive in a lane that is indicated by a red cross, you are breaking the law. I drive thousands of miles on motorways every year, in fact they constitute most of my driving miles. Smart motorways work. Hats off to the people who devised the idea.


16 Oct 18 - 06:01 PM (#3956991)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

I missed out the M6 from my motorway list in that post. Wish I could miss out the M6 every trip!   Must've been something subliminal there...


16 Oct 18 - 10:32 PM (#3957029)
Subject: RE: BS: 'Not so Smart' Motorways.
From: The Sandman

of course the driver can set off on time ,but no guarantee with traffic jams and increased car usage of getting there on time.


17 Oct 18 - 03:11 AM (#3957049)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Mr Red

I was being ironic/sarcastic. Most motorists are predicatble to a greater extent. But there are those, and with the volume of traffic you see plenty, that are assertive/stupid/self-obsessed when you don't predict their movements. You rely on good behaviour. And are surprise by other forms. They cause accidents.

But if you dun gotta be there punctually - public transport is a gamble. I use buses a lot and it affords a view not entirely possible while driving, especially from the top deck. My thread on Goggle Earth may highlight what I look for. And buses, being relatively slower, you see a fair number of impatient motorists. And I haven't even started on where they park!


17 Oct 18 - 03:16 AM (#3957050)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Dave the Gnome

I had the stop/start thing described to me by someone who studies these things as the concertina effect, so it fits right in with a folk music forum! It is so called because if you look at the bellows of a concertina, or any bellows instrument, they start off bunched together, then spread out, then start to bunch together again and so on.

In traffic spread across several miles this effect is magnified so you get the periods of stop/start that we all see. By keeping the traffic at a steady speed, usually lower if the traffic is very busy, you do lessen this effect. The other thing he mentioned, which makes sense, is if you get a single lane with a car doing, say, 55MPH and a car behind is doing 60MPH then the average speed of the traffic will still be 55MPH. The car behind has to keep to the average so he will slow down to less than 55MPH and then speed up with the resultant braking and acceleration. The longer the queue the more pronounced this becomes but, if they all keep at 55MPH then the concertina effect is removed.

Probably not explained it as well as he did. It does make sense to me anyway.


17 Oct 18 - 06:46 AM (#3957081)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Nigel Parsons

Fairly good description from BBC


17 Oct 18 - 04:41 PM (#3957178)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Mr Red

turbulence would be a good description. We see individual vehicles, but to understand the process you have to look at hundreds and compare it with other fluids.


17 Oct 18 - 05:35 PM (#3957185)
Subject: RE: BS: 'Not so Smart' Motorways.
From: G-Force

I heard it described as a shockwave.


18 Oct 18 - 03:03 AM (#3957225)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Mr Red

Yup, that would do it, for the ones where there was no accident. A bit like when you flick a rope and watch the wave travel along.


18 Oct 18 - 03:37 AM (#3957227)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Senoufou

Nothing can prevent the sort of accident that occurred a couple of days ago on the M40. An elderly couple with foreign number plates were towing a caravan (going at 70mph!) the wrong way up the fast lane!! They caused a massive collision and they and another driver lost their lives.

Police Interceptors received dozens of calls from the public, but couldn't reach the vehicle until the crash had happened.

I am never ever going to drive on a motorway again. Fortunately, there aren't any in Norfolk, just 'A' roads.


18 Oct 18 - 07:47 AM (#3957249)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Will Fly

Well, I've just been up and down the A23, M23, M25, M4 and A4 from home to Langley (Slough) nd back. Allowing for the 50mph limit on the M23, which is currently being converted to a "smart" motorway, it was a perfect journey. 75 minutes each way on a nice sunny day.

And I came home with lovely, 20-year old Lowden guitar!


18 Oct 18 - 06:07 PM (#3957322)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Tattie Bogle

Scenario: you are driving in the smart lane: tyre blows out or engine seizes, and car rapidly becomes immobile. What are the chances then of a pile-up? Nowhere to go, and emergency services don't yet know there is a problem, so no red X over the smart lane.
Many years ago, my husband DID have a blowout on a stretch of the M6 in Lancs that has no hard shoulder. Scariest thing ever! Only saved by the fact that it wasn't at its busiest then.


18 Oct 18 - 08:18 PM (#3957346)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Steve Shaw

Well I've just got back to Cornwall from Radcliffe. The low sun was in my eyes all the way, and the M5 roadworks just after the M6/M5 junction were a bit of a bugger, but all the smart motorway sections worked a treat, despite the rush hour round Bristol. Five and three-quarter hours including a cup o' char and the purchase of a free-range herb-fed chicken and a goodly lump of Bath Blue cheese at Gloucester Services. Raise a glass to me dad, chaps...


19 Oct 18 - 02:41 AM (#3957366)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Mr Red

There was a TV programme last night on BB4, on the Motorways around Brum. Motorway: the need for speed

it doesn't make for pleasant viewing at times. Pothole repair, breakdowns, accidents and worse! Anyone fancy a job of stopping idiots at 70 (allegedly) mph so a team of brave navvies can dump tarmac for 5 minutes?

Anyone?

Thought not!


19 Oct 18 - 02:56 AM (#3957368)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Jon Freeman

This is way OT but may comments on potholes/sufacing sparked this off.

We rarely went on motorways but years ago, must be 70s, was there an experimental road surface that could cause weird noises like a choir humming?


19 Oct 18 - 03:27 AM (#3957370)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Will Fly

That was the M1 - regularly mentioned by John Peel on his radio programme!


24 Oct 18 - 12:29 PM (#3958137)
Subject: RE: BS: 'Not so Smart' Motorways.
From: FreddyHeadey

JF
musical motorways ...
"In the Netherlands, the local government decided to replace rumble strips outside of a village with musical strips. Officials chose the regional anthem, and if you see video of cars driving over it, the melody is quite clear. The problem with this innovation is that people who lived in the area hated it, so they begged the government to get rid of the musical strip, which it did.

We have two musical roads in the United States. The first is located on a strip of historic Route 66, situated east of Albuquerque, New Mexico on the way to the mountain town Tijeras. If drivers go 45 mph they’re treated to America the Beautiful, something that seems fitting for such an iconic road."
more :
https://blog.grabcad.com/blog/2018/07/23/japans-strange-musical-roads/ 


25 Oct 18 - 05:30 PM (#3958380)
Subject: RE: BS: 'Not so Smart' Motorways.
From: Senoufou

I've just been watching a documentary on BBC2 (Life In The Fast Lane)
and the poor workers were dealing with breakdowns and accidents on the hard shoulder of the M6, which is now a Smart Motorway, so the hard shoulder is always a 'live' lane.

They had to put cones out to keep the traffic off while they worked, but many drivers ignored these and the workers were in mortal danger of being killed by huge lorries and fast cars steaming towards them.
They showed actual footage of an example of this.

Several of these folk are killed each year working beside UK Motorways.
One poor chap told the camera that he had taken out Life Insurance, and settled his affairs for his wife in the event of his death. Very shocking.