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‘Smart’ motorways – a closer look at the M25 and M3

04 April 2018

Many of us will have spent some of the Bank Holiday weekend navigating motorways.

We recently spent a very useful day with Highways England and Balfour Beatty (one of its main contractors) experiencing the M25 and the newly-opened four-lane sections of the M3 from junctions 2 to 4A.

You may remember this stretch of the M3 had suffered for the last few years from very lengthy roadworks; the relatively narrow lanes caused a lot of comment and partly led to the decision to shorten roadwork lengths – a decision which matches our own research.

We carried out an in-depth look at the user experience of ‘smart’ motorways: Getting to the heart of smart

It found that users, unless prompted, seemed relatively relaxed about the lack of hard shoulders on ‘all-lane running’ sections of motorways. However, more information about how these motorways work in practice and what happens if you do break down would reassure. Also users wanted to see better use of the variable speed limits and messages – often they don’t seem to reflect what is actually going on.

The new section of the M3 is impressively well built into a very tight space in places – cables, signs and refuge areas have to fit in built-up areas and places of environmental sensitivity. Some of the engineering is impressive to ensure embankments stay solid.

The use of detectors under the tarmac to sense when traffic slows or stops (and automatically set speed limits or signs), and the increasing deployment of radar and CCTV means the network is under pretty constant surveillance. We later went to the control centre at Godstone and saw this in action, including an accident on the M25 being dealt with.

Seeing and understanding the community and user involvement in the construction of a replacement bridge over the M3 at Windlesham also highlighted the detailed planning needed. Interesting also to see the new coloured refuge areas intended to stand out much more.

A few thoughts:

  • There is no space to add still more lanes. This is it! Future traffic demand will have to be managed through information to inform drivers when it is busy
  • The active use of technology should be more widely promoted – it’s pretty impressive what goes on 24 hours a day and should perhaps be rolled out more widely to other parts of the network?
  • The system is starting to feel a bit like a railway with signals and more useful information – a more managed network.
  • The proposed changes to the spacing of refuge areas is welcome, but it seems this will only be done on schemes that aren’t yet in the construction pipeline. There are big smart motorway projects where building is about to start (the M62 for example) where achieving the new standard is deemed too difficult. Planning and environmental assessments would have to be re-done. This doesn’t feel right – we’re having new standards, but not just yet. Is it really impossible to tweak the design for projects where works haven’t yet started?
  • The decision to install concrete central barriers makes sense from a safety point of view, but the number of gaps seems low. Turning back traffic in the event of tailbacks becomes more difficult.

One side observation which again backs up our user research that road surface quality is the number one priority for improvement, is the ride on the M25 between junctions 8 to 10 – it is terrible. Concrete rumble.

So, overall, the management of the network is becoming more widespread and the refuge areas more visible. Using the space where the hard shoulder was remains a pragmatic way of boosting capacity without more land take.

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