M4 Junction 3 to 12 Smart Motorway

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WHBM
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Re: M4 Junction 3 to 12 Smart Motorway

Post by WHBM » Thu Dec 05, 2019 18:13

Bryn666 wrote:
Thu Dec 05, 2019 17:38
Are they going to sort out the abysmal J4B eastbound layout?

Should quite simply be:

M25 N | M25 S | M4 | M4
It is apparently going to be 5 lanes.

As I've written before, on the J4B eastbound approach I pass more collisions being sorted out than anywhere else, and I suspect in some years I've passed more there than in the whole of the rest of my driving. If the hard shoulder there, littered with broken glass and bumpers etc, is going to be taken away, that is just ridiculous.

Sadness to see there only last half term shocked children and tearful mother sat on the Armco, family car smashed front and rear, Polish HGV behind them that has done the squashing at least providing some cushion protection. No wonder Berks Fire & Rescue have to maintain a station just off J5 on the A4 Slough road.

You can experience there lane 1, which is a lane gain from the J5 on-ramp, at a stand from the merge, through traffic on the M4 wanting to exit slows or stops in what is now lane 2, vehicles behind them swing out into lane 3 from a standing start, through vehicles in lane 3 at full speed ...

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Chris5156 » Thu Dec 05, 2019 20:24

Bryn666 wrote:
Thu Dec 05, 2019 17:38
Are they going to sort out the abysmal J4B eastbound layout?

Should quite simply be:

M25 N | M25 S | M4 | M4
I’m not sure they are, but it sorely needs it. Two through lanes on the M4 would easily suffice, giving three for the exit. Much more sensible, with the only caveat being that entering at J5 and staying on the M4 would be difficult.

Similar measures would help on the M1 southbound, where two lanes exiting to the M25 would make sense - perhaps even with a tiger tail from lane 3 - and the third lane re-gained from J6 where the merge length is short and the turn onto the motorway means that traffic is joining at low speed.

These things are signing and lining jobs and shouldn’t be difficult to execute.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Bryn666 » Thu Dec 05, 2019 20:43

Chris5156 wrote:
Thu Dec 05, 2019 20:24
Bryn666 wrote:
Thu Dec 05, 2019 17:38
Are they going to sort out the abysmal J4B eastbound layout?

Should quite simply be:

M25 N | M25 S | M4 | M4
I’m not sure they are, but it sorely needs it. Two through lanes on the M4 would easily suffice, giving three for the exit. Much more sensible, with the only caveat being that entering at J5 and staying on the M4 would be difficult.

Similar measures would help on the M1 southbound, where two lanes exiting to the M25 would make sense - perhaps even with a tiger tail from lane 3 - and the third lane re-gained from J6 where the merge length is short and the turn onto the motorway means that traffic is joining at low speed.

These things are signing and lining jobs and shouldn’t be difficult to execute.
They didn't change M60 J15 either which was a total missed opportunity.

Apparently drivers would be confused by "too many exits". Drivel.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by owen b » Thu Dec 05, 2019 23:39

Chris5156 wrote:
Thu Dec 05, 2019 20:24
Bryn666 wrote:
Thu Dec 05, 2019 17:38
Are they going to sort out the abysmal J4B eastbound layout?

Should quite simply be:

M25 N | M25 S | M4 | M4
I’m not sure they are, but it sorely needs it. Two through lanes on the M4 would easily suffice, giving three for the exit. Much more sensible, with the only caveat being that entering at J5 and staying on the M4 would be difficult.

Similar measures would help on the M1 southbound, where two lanes exiting to the M25 would make sense - perhaps even with a tiger tail from lane 3 - and the third lane re-gained from J6 where the merge length is short and the turn onto the motorway means that traffic is joining at low speed.

These things are signing and lining jobs and shouldn’t be difficult to execute.
Agreed. M1 southbound approaching the M25 has probably 60-70% of the traffic turning off, but only one lane for the M25, three for the M1. It does widen approaching the gore, but that only seems to encourage late swooping from lane two of the mainline.

There's a similar issue on the M25 clockwise approaching the M1. Again three lanes for the mainline and only one for the exit, but not quite so bad here as a lower proportion of traffic is turning off and traffic heading for the M1 can only go north so there's no further division of traffic into two directions once on the slip.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by EpicChef » Fri Dec 06, 2019 18:19

owen b wrote:
Thu Dec 05, 2019 23:39
Chris5156 wrote:
Thu Dec 05, 2019 20:24
Bryn666 wrote:
Thu Dec 05, 2019 17:38
Are they going to sort out the abysmal J4B eastbound layout?

Should quite simply be:

M25 N | M25 S | M4 | M4
I’m not sure they are, but it sorely needs it. Two through lanes on the M4 would easily suffice, giving three for the exit. Much more sensible, with the only caveat being that entering at J5 and staying on the M4 would be difficult.

Similar measures would help on the M1 southbound, where two lanes exiting to the M25 would make sense - perhaps even with a tiger tail from lane 3 - and the third lane re-gained from J6 where the merge length is short and the turn onto the motorway means that traffic is joining at low speed.

These things are signing and lining jobs and shouldn’t be difficult to execute.
Agreed. M1 southbound approaching the M25 has probably 60-70% of the traffic turning off, but only one lane for the M25, three for the M1. It does widen approaching the gore, but that only seems to encourage late swooping from lane two of the mainline.

There's a similar issue on the M25 clockwise approaching the M1. Again three lanes for the mainline and only one for the exit, but not quite so bad here as a lower proportion of traffic is turning off and traffic heading for the M1 can only go north so there's no further division of traffic into two directions once on the slip.
The best approach IMO is to run the hard shoulder approaching the junction to create an extra lane.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by mathmo » Mon Jan 13, 2020 23:32

SPECS are gradually going up in the current gap between the two sections of roadworks (roughly between junctions 6 and 5) so it looks like we will have traffic management along the full length of the works before long :(

Westbound traffic at junction 7 is now using a temporary bridge (with weight, length and width limits) and the old bridge will be demolished this coming weekend.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by EpicChef » Tue Jan 14, 2020 16:43

They’ve made it a point not to have people moving from junctions 3-12 at 50mph. They’ll probably put in a 60 limit at least for the more advanced bits - which means people aren’t held up.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by WHBM » Tue Jan 14, 2020 16:54

WHBM wrote:
Thu Dec 05, 2019 18:13
As I've written before, on the J4B eastbound approach I pass more collisions being sorted out than anywhere else, and I suspect in some years I've passed more there than in the whole of the rest of my driving. If the hard shoulder there, littered with broken glass and bumpers etc, is going to be taken away, that is just ridiculous.
Yet another big smash there this morning, with vehicle remains and emergency services on the hard shoulder. I just wonder how it's thought this will work when the shoulder has gone (which can't be long now).

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Re: M4 Junction 3 to 12 Smart Motorway

Post by EpicChef » Tue Jan 14, 2020 16:59

Red X if you’re lucky. If you aren’t the police will tell your loved ones and their lives will be forever damaged. You know the drill.

If we don’t fit stopped vehicle detection then more people will fall victim to this. They promise us technology which is nowhere near as efficient as they say. Smart motorways are some technology and an unhealthy touch of pure PR nonsense. I used to hugely back them, and I still do to a big extent, but if there is no URGENT improvement I know what’s more important: lanes vs lives.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by RichardA35 » Tue Jan 14, 2020 17:09

EpicChef wrote:
Tue Jan 14, 2020 16:59
Red X if you’re lucky. If you aren’t the police will tell your loved ones and their lives will be forever damaged. You know the drill.

If we don’t fit stopped vehicle detection then more people will fall victim to this. They promise us technology which is nowhere near as efficient as they say. Smart motorways are some technology and an unhealthy touch of pure PR nonsense. I used to hugely back them, and I still do to a big extent, but if there is no URGENT improvement I know what’s more important: lanes vs lives.
Unfortunately there is a price on a life in the evaluation of the benefits of a scheme over the years of its operation. People wearing long trousers have to take decisions based upon evidence and forecasts of collision and injury reduction not their absolute elimination.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Bryn666 » Tue Jan 14, 2020 17:19

Just reallocating which lanes go where would save several last minute change collisions but this seems beyond the wit of those long trousered sorts.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by WHBM » Tue Jan 14, 2020 17:51

Bryn666 wrote:
Tue Jan 14, 2020 17:19
Just reallocating which lanes go where would save several last minute change collisions but this seems beyond the wit of those long trousered sorts.
I don't think it's last minute lane changing, but those on the mainline pass J5 eastbound and at the lane gain find the added nearside lane is already full, backed up from back down the on-ramp and stationary for the J4B exit a mile ahead.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Micro The Maniac » Tue Jan 14, 2020 18:37

Bryn666 wrote:
Tue Jan 14, 2020 17:19
Just reallocating which lanes go where would save several last minute change collisions but this seems beyond the wit of those long trousered sorts.
I'm not convinced by this...

The evidence of M3/J2 (with the M25) is that people are incapable of reading signs two miles before the junction, and wait until the hatching before realizing that they are in the wrong lane.

I respectfully suggest that this junction is a challenger for M4/J4B as the worst junction for accidents... it is near enough a daily occurrence :(

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Re: M4 Junction 3 to 12 Smart Motorway

Post by EpicChef » Wed Jan 15, 2020 18:57

Why can they not fit stopped vehicle detection? They said they're going to use "other emerging technology" but that is so hard to believe.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by Chris5156 » Wed Jan 15, 2020 19:40

EpicChef wrote:
Wed Jan 15, 2020 18:57
Why can they not fit stopped vehicle detection?
Does it exist, as a mature, reliable, maintainable technology? If not, that's the answer.

If it does - what does it cost, what new infrastructure at the roadside does it require, what new infrastructure in control centres would be needed, and what would it cost to maintain?

Stopped vehicle detection on every inch of every existing Smart Motorway can't just be magicked out of the air.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Jeni » Wed Jan 15, 2020 19:48

Chris5156 wrote:
Wed Jan 15, 2020 19:40
EpicChef wrote:
Wed Jan 15, 2020 18:57
Why can they not fit stopped vehicle detection?
Does it exist, as a mature, reliable, maintainable technology? If not, that's the answer.

If it does - what does it cost, what new infrastructure at the roadside does it require, what new infrastructure in control centres would be needed, and what would it cost to maintain?

Stopped vehicle detection on every inch of every existing Smart Motorway can't just be magicked out of the air.
I believe similar tech is used on upgraded level crossings, but that's obviously a much smaller scale.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Chris5156 » Wed Jan 15, 2020 20:05

Jeni wrote:
Wed Jan 15, 2020 19:48
I believe similar tech is used on upgraded level crossings, but that's obviously a much smaller scale.
I think you're right. Technology to recognise individual objects within a video, in real time, and detect changes in their state (such as starting moving or stopping moving or moving in a certain direction) does exist, but I strongly suspect that technology that can do all those things for dozens of vehicles all at once, on a fast-moving motorway, reliably, in all weathers and in the dark as well as in the light, on a scale that could be rolled out nationwide... does not.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Jeni » Wed Jan 15, 2020 20:52

Chris5156 wrote:
Wed Jan 15, 2020 20:05
I think you're right. Technology to recognise individual objects within a video, in real time, and detect changes in their state (such as starting moving or stopping moving or moving in a certain direction) does exist, but I strongly suspect that technology that can do all those things for dozens of vehicles all at once, on a fast-moving motorway, reliably, in all weathers and in the dark as well as in the light, on a scale that could be rolled out nationwide... does not.
Looks like this is the kind of thing used on level crossings

I suspect something similar would be prohibitively expensive to roll out over the entire smart motorway network. And yes, sadly, those that decide these things do put a price on a human life.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Bryn666 » Wed Jan 15, 2020 21:08

That said a decently staffed control room should not be beyond the wit of HE.

Maybe if they spent more on staff and less on self-congratulatory glossy brochures the smart motorways programme wouldn't be under such vicious scrutiny.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by jackal » Wed Jan 15, 2020 22:09

The chair pressured both Mr O'Sullivan and Mr Wilson on the issue of stopped vehicle detection on smart motorways, particularly as the transport select committee had raised concerns in 2016 on the issue.

Mr Wilson had assured the committee in 2016 that it would be part of the standard roll out of smart motorways going forward and be retrofitted to existing schemes.

Ms Greenwood questioned why it was taking so long.

Mr O'Sullivan said: 'We are trailblazing the use of it This is groundbreaking technology. We had to prove it before we could roll it out. We are rolling this out as quickly as we can it's not just the technology is the complete case we have to be satisfied with the results in M25. You can't roll out something this complex on a prototype basis.

'We are currently developing plans for this. It has to be 'productionised'. There are a number of challenges but now we know it works - we have three years' experience on the M25 - our first retrofit for stopped vehicle detection will be on the M3 and we are doing that this year.

'We are productionising it so we can roll it out over 100s of miles it is quite a challenge. It will be incorporated in all schemes after 2020.

'Retrofit has a number rod challenges. Firstly, the equipment: he how does the new equipment fit with the old? It has to fit physically and it has to fit electronically.

'We also have to make sure the radio signals don't conflict. Most importantly you have to know the traffic management plan for extensive lane closures. We have to understand how we do the retrofit before we roll out the full plan but our intention is ultimately to do it for all these.'

He also revealed the government-owned company only has one supplier 'so there is a difficulty in scaling up'.

When asked why they didn't use the German system common on autobahns, Mr Wilson said the primary technology came from Sweden and had been used in tunnels.

He did not have the reasons to hand why the German system would not have been suitable but, Mr O'Sullivan argued it would have been looked and rejected.
Possibly an automated transcript!

https://www.transport-network.co.uk/Hig ... ives/16238

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