M4 Junction 3 to 12 Smart Motorway

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A303Chris
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M4 Junction 3 to 12 Smart Motorway

Post by A303Chris » Thu Feb 27, 2014 10:21

I have been aware of the HA works for a few months but have not been able to put anything on here as they were not in the public domain, but now they are.

On the HA's scheme page under publications is a presentation the HA gave to the planning inspectorate as well as the local LEP / Local Authorities. Bascially the M4 between 3 and 12 will be 4ALR through all junctions except J10 and J4B and 5ALR between J4 and J5.

However the document contains some gems. As you will now J5 to J8/9 was rapid widend from D2 to D3 in 1972 just before the extension to Bristol was opened. As a result the hard shoulders are not consistent due to it being lost at every structure . However the HA in this document have stated they will build new structures between J8/9 and J5 to accomodate ALR and not D4 with HS. Is it me but if you are spending all this money on new structures why not build them to accomodate a HS as well.

The other gem is that with ALR the safety record is the same and in some cases improved over the existing D3 with HS. Given that this length has an above average accident record is 4ALR safe therefore. This goes back to the the so environmental 60mph limits prposed for the M1 and M3 4ALR, which I beleive have nothing to do with the environment but the fact that 4ALR is unsafe.

The document is here
Last edited by A303Chris on Thu Feb 27, 2014 11:44, edited 2 times in total.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by Chris5156 » Thu Feb 27, 2014 10:58

This is really interesting.
A303Chris wrote:On the HA's scheme page under publications is a presentation the HA gave to the planning inspectorate as well as the local LEP / Local Authorities. Bascially the M4 between 3 and 12 will be 4ALR through all junctions except J10 and J4B and 5ALR between J4 and J5.
I don't understand why four lanes is considered wise or necessary between J3 and 4. Eastbound the road is about to reduce to two lanes; unless literally half the traffic exits at J3 and they will drop two lanes there it seems a pointless exercise. Westbound traffic has just come off a two lane section and the three lane part east of J3 seems quiet - is a third lane for traffic joining from J3 not enough?

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Re: M4 Junction 3 to 12 Smart Motorway

Post by MiChaos » Thu Feb 27, 2014 11:16

I know I've said this before but I'll say it again, the "new" Smart Motorway standards, using MS4s instead of gantries with signals above each lane and with the emergency refuge every 2.5km is so horribly bad IMO.

I also hope they're going to re-allocate the lanes appropriately coming eastbound towards 4a, so at least two (preferably three) lanes are available for the M25-bound traffic. I wonder if these lanes will vary according to time-of-day / how busy this section is.

And yeah, if the bridges / underpasses are going to be replaced, PLEASE HA can you future-proof these for 4 lanes plus Hard Shoulder?

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Re: M4 Junction 3 to 12 Smart Motorway

Post by Sou'wester » Sat Mar 01, 2014 15:37

5 years of construction, oh my. :(

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Re: M4 Junction 3 to 12 Smart Motorway

Post by mathmo » Sat Mar 01, 2014 18:07

Sou'wester wrote:5 years of construction, oh my. :(
I hope that's phased and not all at once or it will be a miserable drive. I will be commuting along part of this route daily from next month (I currently use it about twice per week) so the prospect of lots more roadworks doesn't fill me with joy. It is a busy section of road and could mostly do with four lanes but I don't like the sound of this Smart Motorway scheme. I guess we'll have to see how it goes on the M25 - what's the status of that?

I notice the diagram only shows 5-lane ALR between 4b and 4, but not 5-4b. 5-4b is already 4 lanes with hard shoulder so that must be a mistake of some sort. 4 lanes between 4 and 3 does sound unnecessary but I almost never use that section so can't really comment.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by WHBM » Sat Mar 01, 2014 21:44

A303Chris wrote:5ALR between J4 and J5
That section eastbound approaching the M25 at 4B (westbound is OK) has the worst accident record, based on what I pass, on the entire UK network. I would say 10% of the time I go along there, there are the residuals of a collision stopped on the hard shoulder. Whatever will it be like with none ?
I don't understand why four lanes is considered wise or necessary between J3 and 4. Eastbound the road is about to reduce to two lanes; unless literally half the traffic exits at J3 and they will drop two lanes there it seems a pointless exercise.
Eastbound those exiting at J3 regularly back up onto the main carriageway for extended periods morning and evening. In fact, it's not uncommon for lane 1 to be stop-start right back to J4.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by A428_Owen » Sun Mar 02, 2014 19:31

I have just spent a few minutes looking at this. The 'NPV ratio' caught my eye as I have done a course where the exam required some calculations for NPV.

Does anyone on the forum know what time period for payback does the Highways Agency use: I am expecting something in the region of 20-25 years? What discount rate do they use: 6% seems normal in government?

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Re: M4 Junction 3 to 12 Smart Motorway

Post by DavidB » Tue Mar 18, 2014 10:22

http://www.bbc.co.uk/news/uk-england-26624917
M4 Heathrow to Theale motorway expansion plans revealed

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Plans to increase capacity on the M4 have been announced by the government.

The scheme will see variable speed limits and the hard shoulder converted to a traffic lane for 31 miles between the A312 at Heathrow Airport to Theale.

The changes, which the Highways Agency estimates will cost between £614m and £862m, aim to reduce congestion, improve journey times and cut air pollution.

Exhibitions on the plans are being held between 18-29 March.

Refuge bays will be placed along the motorway in place of the hard shoulder, where people in broken-down cars will be able to wait for rescue services - monitored by CCTV cameras.

'Educate motorists'

If approved, the scheme could start in the early years of the next spending review period (post 2015).

Malcolm Bingham, from the Freight Transport Association, said: "Using all four lanes is new so we've got to look to see how we can educate the motorists so they're not confused by it."

It comes as plans to introduce a 60mph speed restriction on a 2.8-mile section of the M3 between Junction 3 at Lightwater and Junction 4 near Farnborough to cut air pollution have been criticised by the AA.

Paul Watters, from the AA, said: "Most of the pollution is coming from the lorries which themselves run at 60mph anyway and they won't have to slow down.

"The cars will have to slow down and yet they are the cleaner vehicles amongst the motorway traffic so it seems a bit ironic to invest all this money in the motorway and then have to screw the speed limit down.

"Its the lorries that cause PM10 [particulate matter up to 10 micrometres in size] - it's going to hit people that it doesn't need to."

The Highways Agency said the new restriction of 60mph would apply from 07:00 to 19:00, seven days a week.

Motorists and other interested parties have until 11 April to comment on the M3 proposals.

It follows a similar plan for a 32-mile stretch of the M1 which was announced in January.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by MiChaos » Tue Mar 18, 2014 10:53

Do news organisations have no stock photos of locations these days and always have to use Google :laugh:

The AA are spot on about the reduced speed limits on motorways, you have to wonder what the Highways Agency are playing at with this one.

Would be interested to see more plans on the M4 plan though, such as how far the emergency refuges are going to be, etc.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by pjkh » Tue Mar 18, 2014 11:27

Extending the A329(M) aka M31 down to the M3 would make a lot more sense. There's a vast expanse of open space which they could surely cut and cover.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by A303Chris » Tue Mar 18, 2014 12:55

The HA are having exhbitions along this length of the M4 over the next 2 weeks. The first is today. The list of venues is here. I will go to the one at Winnersh next week.

There was also an article on South Today about this, this morning where the HA representative said there would be an emergency layby approximately every 1 mile and they expect 50% of breakdowns to reach one. In other cases they will close the lane.

Really safe that.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by sotonsteve » Tue Mar 18, 2014 19:42

The interesting thing about this hard shoulder conversion scheme compared with previous schemes is that the hard shoulder disappears at a number of bridges, so they are going to have to spend a fair amount of money on structural works.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by A329Mdren » Tue Mar 18, 2014 20:01

pjkh wrote:Extending the A329(M) aka M31 down to the M3 would make a lot more sense. There's a vast expanse of open space which they could surely cut and cover.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by A303Chris » Mon Nov 10, 2014 17:37

Time to bump this thread as the official DfT consultation on these proposals was posted on line today and it can be found here

They are progressing with ALR and still admit that between J8/9 and J5 all the bridges will have to be re-built as there is currently not a continuous hard shoulder. But instead of doing it properly by widening all the structures and creating a D4M they are going to widen them just for 4 lane ALR. Surely the extra cost is minimal.

The deadline for replies is the 21st December.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by RichardA35 » Mon Nov 10, 2014 20:34

A303Chris wrote:Time to bump this thread as the official DfT consultation on these proposals was posted on line today and it can be found here

They are progressing with ALR and still admit that between J8/9 and J5 all the bridges will have to be re-built as there is currently not a continuous hard shoulder. But instead of doing it properly by widening all the structures and creating a D4M they are going to widen them just for 4 lane ALR. Surely the extra cost is minimal.

The deadline for replies is the 21st December.
I would expect the cost benefit work to consider a range of scenarios for the widening to arrive at a preferred scheme. Gut feel is that orders would be needed for mainline widening to D4+HS as the boundary is very tight especially where adjacent to the road to Datchet as it was set out for D2M originally. Just going for side road orders means the scheme gets a more limited scrutiny than if mainline orders + CPO were needed.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by A303Chris » Mon Nov 24, 2014 12:13

First open consultation last week and the concerns over no hard shoulder on such a busy route already starting as detailed here.

However the same concerns have been aired on the M1 and M25 schemes but the HA will just wash these under the carpet. These consultations are a Fati Compli (or however you spell it my Latin isn't that good) as the HA have made there mind up, so be it.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by Truvelo » Mon Nov 24, 2014 14:41

One wonders why go the hassle of holding these consultations if the decision is already made unless the consultation is a statutory requirement.
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Re: M4 Junction 3 to 12 Smart Motorway

Post by Johnathan404 » Mon Nov 24, 2014 14:57

It has been years since I've been to one. What sort of reception do they get?
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Re: M4 Junction 3 to 12 Smart Motorway

Post by WHBM » Mon Nov 24, 2014 15:00

Truvelo wrote:One wonders why go the hassle of holding these consultations if the decision is already made unless the consultation is a statutory requirement.
It is indeed a legal requirement but they must never admit it is a fait accompli as otherwise their whole process can be subject to a legal challenge.

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Re: M4 Junction 3 to 12 Smart Motorway

Post by SouthWest Philip » Mon Nov 24, 2014 19:07

The HA has released details of a planned webchat on this consultation to be held next week.

M4 Consultation Webchat Press Release

With future traffic flows of 160,000 vehicles a day preducted, that must surely be at the higher end of the all-lane running schemes with no hard shoulder?

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