No new M4…so what instead?

A quick brain dump of some ideas (which is a follow up to my earlier piece on why I agree with the WG decision in respect of the M4)..….nothing new under the sun! I have also made a few tweaks and updated the map in response to some comments/suggestions…

….I also penned an article in Summer 2020 to reflect my submission to the South East Wales Transport Commission

You can download a PDF of that “map” here

So, Welsh Government and First Minister Mark Drakeford have made their decision[i]. There will be no new M4 around Newport.  As you know I changed my mind and agree with that decision.

Before I get into what we might do instead, just a couple more observations on the decision and the phenomena of induced road demand. Almost without exception roads in major urban areas fill up at peak times.

In UK terms alone, according to Inrix[ii], Cardiff is not even in the top ten of the UK’s most congested cities Figure 4 (Cardiff is 12th) and the DfT’s[iii] own data shows that congestion is a feature of all major roads. For example Figure 1 shows that some roads in England are experiencing average delays in excess of 15 seconds per vehicle per mile; and Figure 2 shows “volume over capacity”  of over 0.45 (defined as moderate congestion) impedes most of the major roads in England and Wales.  One might argue therefore, that the economic costs of congestion on the M4 are no worse than many other parts of the UK; try the M60, M62, M25, M6, etc at peak times. Even in South Wales there are serious issues of congestion on the M4 around Swansea and Port Talbot as well as Newport. 

Figure 1 Average delay on Strategic Road Network in England 2018 (DfT)

Figure 2 DfT 2018, Volume over Capacity in 2015

Figure 3 Inrix ranking of cities with most hours lost in congestion

Figure 4 Inrix – top ten most congested cities in the UK

Most US cities also suffer huge issues of road congestion; Boston, Washington, Los Angeles (my sister often calls me from her car on her daily commute on the 101 to Calabasas from Sherman Oaks).

Everywhere we build roads in urban areas we generate more traffic and over the longer term encourage car-based development that generates more traffic. So, I think I am reasonably confident in stating that if we reduced the “bottleneck” around Newport we will almost certainly “induce” more traffic which will result in further congestion elsewhere on the M4, including around Cardiff (A48M/Eastern Avenue) and Swansea. 

The DfT actually undertook a review of case studies and academic evidence[iv]  related to the phenomenon of induced demand in 2018 and reached the same conclusion – for example, and relevant to the M4 relief road, it found:

  • More induced traffic is associated with road capacity increases where there is a high level of congestion and suppressed demand

  • … traffic level increases on new routes were not offset by corresponding reductions in traffic on equivalent unimproved routes (consistent with the finding of the 1994 SACTRA report).[v]

  • The size of the induced demand effect relative to background traffic growth in the long run is not clear.

In fact, in the former circumstances, most studies that report elasticities indicate that a 10 per cent increase in capacity would result in at least 5 per cent induced traffic.  I haven’t and don’t intend to pour through all the M4 studies and appraisals, but I am sure this “short term” induced demand impact, whilst not desirable given the environmental impacts, would have been explored.

However, I think it is the latter finding that is the most concern, given the long-term spatial changes (i.e. where we build homes, retail, public service, etc).  which in South Wales have locked in more car dependency.  We have designed our “world” around cars, generating the need for more car trips.

Whilst we have a better quantitative appreciation of the shorter-term impacts such as congestion, carbon emissions etc, it is a concern that we have more limited quantitative appreciation of the long-term impacts. It is these long-term impacts and external costs that I think are having a more damaging environmental impact given we are continuing to build 000s of homes, offices and hospitals, that are dependent on car access! We have to break this unvirtuous circle! 

So, we have to find alternatives (esp. given Climate Emergency) whilst at the same time making the current M4 safe and reliable….

Developing a coherent response to the “M4” issue

What I have set out below is the outline of a strategic approach for delivering a major uplift in public transport capacity along the M4 corridor that draws together existing proposals from a number of sources, including my own earlier work.

Before I do that, I want to suggest some measure that could help reduce the “demand” for peak time road space.  In all case it is better to supress demand rather than loosen one’s belt! Some of these are as set out by the Minister in his statement:

  • additional traffic officers to reduce incidents and lane closures as employed during major events

  • dedicated on call recovery vehicles to support traffic officers by quickly removing obstructions when they occur as we would in roadworks

  • live journey time information to inform better choices

  • exploring the operation of junctions to reduce the load on the Brynglas tunnels

  • a driver behaviour campaign to make best use of the available road space.

I would add the following:

  • Can we work with Newport and other local authorities in the region to explore, for example, staggered opening times for schools; can we do the same with other public sector employees? Can we really test more flexible working hours and some remote/home working where practical?

  • I think we may need to look again at junction closure measures – and accept this will have local impacts

  • How might we encourage other users (e.g. freight) to use the road when it is less busy (especially overnight).  In fact, perhaps counter intuitively rather than encourage more freight onto our congested rail network (which needs to carry more people) we may find it is possible in future to accommodate more Autonomous Electric freight vehicles on our motorways, moving mainly overnight?

  • More strategically we need to review our planning – and especially what we build and where.  There are probably 30,000 new homes consented in SE Wales most of which depends on car access – we need to review whether it is possible to withdraw most of the consents to those developments that can’t easily or affordably be “retrofitted” with effective and affordable public transport options!

  • There are probably more….

The Commission

Welsh Government have also signalled an intent to establish a commission chaired by Lord Terry Burns[vi]  to really test the alternatives to the M4 Relief Road. 

The Commission will consider the problems, opportunities, challenges and objectives for tackling congestion on the M4 in south east Wales, and make recommendations to the Welsh Government on a suite of alternative solutions in the light of the First Minister’s statement of 4 June 2019 that the ‘Black Route’ proposal should not proceed.

Whilst its remit is focussed on more tactical measure that can be delivered in the next five years it will, in my view, conclude that part of the solution requires a major investment in public transport services and infrastructure along the M4 corridor.  This will inevitably include enhancements to rail infrastructure and services and immediately rub up again the issues of rail infrastructure being non-devolved and the realisation that Wales has been seriously underfunded Vs UK average in this regard for decades.

My Case for Investment for Welsh Government in 2018[vii] made this point and set out some ambitious proposals for the South Wales Main Line (SWML) that should really be addressed as part of the commission’s work.  The UK Government will need to engage seriously with this issue and their obligations to the Welsh rail network – the notion of a Western Powerhouse is seriously diminished by the relatively poor rail connectivity between Bristol Temple Meads and Newport, Cardiff and Swansea. 

I also think the Cardiff Capital Region has a role to play and should be expected to contribute to some of the costs alongside UK and WG to some of the emerging proposals.  We also all need to get our heads around road user charging.   None of us have been paying the costs of the full environmental impact of car based personal mobility for decades!

Misunderstandings of what the Metro can do to help address the issue of congestion

It has been suggested that the Metro won’t address the issues associated with congestion on the M4. Well its true the current phase of the Metro (which is rightly focused in delivering faster and more frequent services on the valley lines north of Cardiff) will have only a minimal impact on mobility along the M4 corridor. 

However, it is relevant to note that the strategy presented in the 2013 Metro Impact Study[viii] (and in part reflecting earlier work of groups like SEWTA and my own 2011 report A Metro for Wales Capital City Region) set out several phases of Metro development and implementation; what is in progress now through Transport for Wales (TfW)[ix] is really only the first of several phases.  Those subsequent recommended phases have not progressed to delivery or even to Outline Business Case (albeit there has been some development work undertaken on some parts of those proposals and variants thereof). 

The priorities  Figure 5 set out in 2013 and relevant to the M4 discussions, included:

  • Priority enhancement of the Existing Network – new stations, higher frequency services, P&R and station/ interchange enhancements. Early scope defined within quick wins. Will include infrastructure enhancements to enable higher frequencies and new stations. 
  • This is in effect the current phase of Metro, focussed on the core valley lines north of Cardiff, being delivered by TfW by 2023/4

  • Ebbw Vale Town to Newport – enhancements to deliver at least 2 trains per hour (tph) and a service to Newport

  • Cardiff North West Corridor – new routes and stations to facilitate the medium term expansion of Cardiff, from Cardiff Bay to RCT via Creigiau and a link to Taffs Well to support redevelopment and help alleviate congestion on the A470.

  • M4 Corridor – new routes and stations to provide a commuter network for East Cardiff and Newport by introducing rail/tram-train services on the electrified relief lines between Cardiff and Severn Tunnel Junction (STJ) and the use of Bus Rapid Transit (BRT)
  • This is where we perhaps need most action in respect of the M4 around Newport, I represent some of those ideas below

Figure 5 Spatial priorities for Metro Development from 2013 Metro Impact Study

Figure 6 PT proposal for M4 corridor set out in Metro Impact Study in 2013

One key phase was for a major enhancement in public transport infrastructure and services along the M4 corridor using heavy rail, tram-train and Bus Rapid Transit (BRT). See illustrations in  Figure 7 and  Figure 6.  Welsh Government also set out some of the potential future expansion options when the First Minister Carwyn Jones  launched the South Wales Metro programme in 2015[x].  Quite rightly though, TfW have to focus on delivering the next phase by 2023/4; after that though they should be in a position to further expand the network and services – and the M4 corridor is perhaps the most in need of enhancement and investment in public transport provision.

Figure 7 Spatial proposals (in BRT and tram-train) for Newport in 2013 Metro Impact Study

Key Questions: Rail accessibility & mode share

Before all that though can I’d like to share a couple of pieces of data I think is entirely relevant to the question. 

First, access to rail services in South East Wales which was assessed as part of the 2103 Metro Impact Study. That work found that the highest and most densely populated part of SE Wales with the least access to rail services are in Newport and the East of Cardiff  Figure 8 .   A very large number of people (est over 300k) in east Cardiff and Newport have, in effect, no access to rail services…and those that are near a local station are perhaps only offered services of 2tph or less ( e.g. Pye Corner, Rogerstone, Coryton Line).

In fact, between Cardiff Central and Severn Tunnel Junction there is only one rail station offering 4tph or more – that is Newport itself. When one adds the relatively poor provision of bus services then that begins to explain why so many local journeys are car based – there is not a viable public transport option for many people in this part of SE Wales.

It is no surprise therefore, that this is where a significant proportion of the traffic on the M4 comes from. Furthermore, over the last 30 years this dependence on car mobility has been exacerbated by more out of town development: housing (sites strung out along the M4), employment (e.g. the ring of business parks around Newport – Langstone, Celtic Springs, etc and Cardiff Gate at J30 ) and public services (the new Llanfrechfa Grange hospital near Cwmbran located with limited connections to PT network).  This then generates the long-term induced demand for car usage which is damaging our environment.

Figure 8 Most densely populated and most rail disconnected LSOAs in SE Wales

There is another harsh reality to face when dealing with this issue. Most of us commute in cars; in fact in 2017  Figure 9  over 80% of us used cars with only 4% on train and another 4% on bus. So even doubling that level of PT only scratches at the surface of car usage. On the   M4 corridor this is perhaps even more stark and overwhelmingly dependant on car movements for capacity; in fact the ratio of passenger in cars vs public transport is I would estimate about 10:1

Figure 9 Welsh Gov, 2017 Mode Share in Wales for Commuting

I think a reasonable target is to get car usage down to 60% or less (from 80%); so a 25% reduction. That suggest we need to go from 8% to nearer 30% public transport (bus and rail). If we assume some demand side measure lets for the sake of this exercise assume at least a trebling of public transport capacity!  That is a lot! It also has to be economically more affordable to actually attract and sustain that increased demand.  Therefore we have to look at fares and a means to apportion more of the long term external costs of car use to the user (sorry!).

What Might a Strategic Approach to enhancing public transport look like?

The primary question, in addition to the demand side measure, is what we do instead of building the M4 to provide a viable and attractive option for mobility along the M4 corridor between Bridgend and Severn Tunnel Junction (I have made some suggestion for Swansea Bay in another article) that can treble the service capacity.

I think we should be targeting a programme that can enable at least 3~4 times more people to use public transport within 10~15 years. This should be the primary objective of any WelTAG transports appraisal process.

We are not short of ideas as there has been much work a range of options along the M4 corridor from various sources, including:

  • The Metro Impact Study in 2013 appraised a range of tram-train and BRT measures. (worth looking at the Appraisal Report and the other accompanying reports)

  • WG Case for Investment from 2018

  • SEWTA Rail studies for 2000-2014

  • Various Local Authority Studies

  • Future Generations Commission Report on the M4 in 2018.

In terms or developing an approach, I think we should separate short term (some within 5 years) and longer term (5-15 years) schemes. I think we absolutely need some of the latter if this issue is to be addressed adequately.

Short Term Measures

In advance of major work to enhance the line speed and capacity of the SWML (as set out in WG Case for Investment) and develop complementary new tram-train and Bus Rapid Transit (BRT) services we should explore:

  • Additional rail services on the existing infrastructure
    • Additional main line services from Bristol Temple Meads (the case for Investment set out need for 4tph from BTM – some express and some all stopper)
    • Additional Ebbw Vale line services (this may require further infrastructure investment)

  • NR to accelerate its current proposals to upgrade the line speed and capacity of the relief lines between STJ and Cardiff, and to extend the implementation of tactical measures (like closing/replacing level crossings) all the way to West Wales.  In some cases, the network is constrained by line speed restrictions that are no longer relevant (or can easily be removed with minor interventions) or timetable padding that has been introduced for commercial reasons.

  • In parallel introduce a number of additional stations, for example:
    • Cardiff Parkway
    • Llanwern
    • Newport Rd/Rover Way
    • Magor
    • Newport West
    • Caerleon
    • Rumney
    • Ely Mill
    • Roath Park (for Heath Hospital)
    • Upper Boat (inc major P&R)

  • Enhance local bus services
    • More bus lanes across Cardiff and Newport
    • Increased subsidy to enable more bus services to operate
    • Accelerate work to deliver integrated rail and bus tickets and fares
    • Redesign bus network to enable better interchange with rail services

Medium – Longer Term Schemes

We also have to acknowledge that we need to augment the above with further substantive schemes that require protracted planning (e.g. Transport Work Acts) and significant financing and which also require the institutional challenges of a fragmented rail ecosystem and a depreciated rail asset, to be addressed.  I’ll just bullet point them here (more details of such schemes and their variants can be found in the various referenced documents).  All should be subject to a more detailed and quantitative appraisal by transport planners.

I have illustrated these proposals collectively in  Figure 12   which includes:

  • A major upgrade of the entire SWML from Severn Tunnel Junction (STJ) to West Wales to deliver more capacity and at least 100mph capability to allow fast express and more local stopper services

  • Bus Rapid Transit (BRT) system in Newport, East-West from Celtic Spring to the International Convention Centre (ICC), Langstone and Llanwern and north to Cwmbran & Llanfrechfa Hospital

  • Extend tram-train operation from Caerphilly to Newport with new on-street sections in the city centre to avoid conflicting with pathways on the main line; at the same time this will help development and regeneration in Newport City Centre Figure 10

  • To complement, a major upgrade of Marches line (inc further stations) to support more local services

  • In Cardiff further tram train measure to the north west into RCT and across the bay via Splott to Rover Way/Newport Rd – A Cardiff Crossrail!

  • A Cross Cardiff BRT service integrated with an express bus service to Newport

  • To maximise the benefits and positive impacts of the above we have to completely redesign our local bus networks (and future Demand Responsive Transit DRT services) to fully integrate with this backbone segregated network to provide the passenger a seamless end to end journey.

Its probably worth making a couple of technical/operational points here as well. In terms of the rail proposals it is overwhelmingly likely that there will need to be some choices and compromises. For example introducing that many new stations on the main/relief line will impact overall network and pathway capacity…we need to decide our priorities.

I am fairly sure that the application of tram-train technology beyond the current core valley lines could help (see image below). The issue of getting 4tph (or in reality more) services onto the Ebbw Valley line from the main line just west of Newport is a major headache given the “flat junction” and impacts on main line operations and capacity. A pure Heavy Rail solution via a flyover is probably not the best approach (and is probably undeliverable). In my view better for TfW/NR etc to get approval for tram-train operations on this part of the network and develop a flyover solution designed (at lower costs and with a smaller footprint) to tram-train standard. Although this may then require some electrification of the Ebbw Valley Line using the same standards proposed for the core valleys.

This could enable, for example, additional Ebbw Valley services to operate as tram-train toward Cardiff (as well as into Newport via an on street section) and instead of routing into Cardiff Central could operate via Tidal Sidings and the bay onto the bay line toward Central. This might help avoid pathway/platform constraints at Cardiff Central. The point being is that we need to be a little more imaginative in designing services, diagrams and infrastructure so that we make full use of the capabilities of tram-train technology.

We have a similar challenge at the Cardiff West junction in Canton (which currently limits City Line Services to 2tph) which also needs a tramway standard flyover to enable more capacity on both City Line and importantly the Vale of Glamorgan Line.

Figure 10 Concept Tram-train service from Caerphilly/Ebbw Valley into Newport and/or Relief Lines

Figure 11 X-valley connectivity for the South Wales Metro

Figure 12 Public Transport Concept for the M4 Corridor

What next…

Well if it was up to me I would:

  • State an overall objective of delivering 3 to 4 times more public transport use across South Wales to secure a ~30% mode share and a corresponding reduction of commuting by car to less than 60%. (Yes someone needs to articulate what those numbers should actually be – I just want to make the case that a step change is needed)

  • Direct TfW to undertake a Strategic Outline Case for the M4 corridor to better test and develop some of the more strategic schemes (including those above) – and to explicitly not include and appraise small, local and tactical schemes (which is a trap we too often fall into when trying to be strategic).  The objective should be to recommend a number of specific schemes that can be taken into more detailed OBC and scheme development.  I would suggest this could be undertaken in 6-9 months.  The question is though, should this cover the whole of SE Wales? I think perhaps it should.

  • In parallel I think a “rapid review” and appraisal of a number of “short term” (i.e. less than five years) tactical measures (e.g. new stations and rail/bus services) should be undertaken; the commission should lead and NR and the ToCs, TfW and WG (and UK Gov) need to sit around the table.  I would prefer the full devolution of rail powers and funding to limit the input from the DfT to matters related to more/extended x-border ToC services, but we are where we are.  This could be undertaken in 6 months.

  • We also need to get our heads around the funding…. the capex for all of the above is prob £1-2Bn and will be associated with further revenue costs to provide necessary subsidy.  Albeit we can expect massive improvement in efficiency and a reduction of subsidy per passenger mile as a result of the capital programme.  On the former I am persuaded we need a regional road user charge. This can be phased, but we have to start apportioning the full environment and external costs of personal car use.

  • Finally, we need to sort our Land Use Planning.  In the short term lets withdraw consents’ where relevant. More seriously develop an SDP framework for the CCR and another for Swansea Bay that only supports major new developments that have the appropriate level of public transport infrastructure. I don’t mean funding for a bus stop or a year’s contribution to a bus service; I mean it is connected to a high quality and dedicated segregated PT service offering at least 4tph.  In most cases this is an opportunity to direct TOD to our existing towns and city centres.

Stepping back from the issue of the M4 I think we have some larger scale societal and economic challenges.  I certainly think we need to re-think our relationship with the car; and I penned a few words on this in 2017.  More seriously and a recent “epiphany” for me, we need to acknowledge that we have to fundamentally re-think how our whole economy works and especially the impact of consumerism and its consequential waste, and long supply chains.  I did a little rant on this a couple of months ago!

Can I also add….I think in a few years the decision of Mark Drakeford and the Welsh Government will be viewed globally as one of the pivotal  moments we collectively as a species started to really take seriously our responsibilities to the planet and to honestly face the reality of climate change and environmental damage head on.




Click to access Traffic_Scorecard_Infographic_2018_UK_FINAL__v2_.pdf


Click to access road-use-statistics.pdf

Click to access road-traffic-estimates-in-great-britain-2017.pdf








7 thoughts on “No new M4…so what instead?

  1. Really glad I am not alone in thinking cancelling this new M4 was a good move and that alternatives to car culture have to be found. Some of these the potential changes, limiting access from some M$ junctions or changing opening times of schools – teenage boys need more sleep in the mornings – cost very little.
    I would add that trains and buses can be much more attractive with electric traction and open peoples minds to electric cars.


  2. I think this decision by the First Minister (and the voices that opposed the new motorway before the Labour Government changed its mind on the matter should not be forgotten) does represent a turning point both in our politics and our history. Prior to this decision, the general attitude was that the Welsh Government’s job was to carry out locally what was regarded as Westminster policy. The borrowing powers given by the then Chancellor of the Exchequer, George Osborne, to the Welsh Assembly was in the hope and expectation that it would be spent as he suggested, namely to improve road connections between London and South Wales. The decision not to pursue this course has changed the focus back on to South Wales and Wales nationally to ask ourselves what do we want to do with our money and spend it on other solutions that suit our needs. We were also in danger of spending all the money in the south-east (as happens in England) and not considering the wider needs of an all-Wales transport infrastructure.
    Secondly it marks the point where environmental policy trumped economic development as the main criterion in a major development project. I am a very late convert to the green cause but, having heard Mary Robinson talk at Hay Festival on Climate Justice, I am now convinced this has to be path we have to take in terms of developing the Welsh economy. There are two conclusions I would draw from this: sustainability has to override growth as being the central tenet of economic policy and secondly that the new internationalism is that we share the same planet and that we have to help each other take care of it. In addition, we have to confront those nations that do not accept this responsibility.


  3. The 1994 SACTRA report you mention was indeed a watershed in strategic road thinking. Yet hardly penetrated to Wales. We could have more confidence that Drakeford’s decision marks a renewed watershed if he’d expressed some of your thinking – about new roads just stimulating more traffic to fill them and displacing congestion points not resolving them. He did not link the new-M4 rejection to the ‘climate emergency’ though this rather than saving the Gwent Levels is the real environmental imperative.


  4. Taking a dual road link from just after the Severn Bridges junction on the M4, in a north west route to east of Abergavenny on the A40 (A470). Use this as an alternative for travel to Swansea and West Wales (vice versa), thus missing the bottle neck of Newport and Cardiff ?
    Create Park and Ride areas linking to rail heads off A470 at Tower (Hirwaun), Merthyr and Rhumney?


  5. On the whole this looks very positive but I find the proposed extent of additional tram-train operation concerning. There is already considerable disquiet regarding the removal of toilets on the ValleyLines to Treherbert, Aberdare and Merthyr Tydfil. For the shorter routes (such as to Cardiff to Coryton) tram-trains are absolutely a great idea but their widespread use on journeys over 25-30 minutes should be avoided where heavy-rail trains are an option. To this end, I would suggest moving the tram-trains off the upper valleys and redeploying them on Taffs Well / Coryton – Cardiff Bay extended as you suggest through Splott to Cardiff Parkway.

    In the case of the Ebbw Vale branch, my feeling is that 4 heavy-rail trains per hour (two from Caerphilly and one each from Ebbw Vale and Abertillery) should take the existing single-track west to north-east side of the triangle junction into platforms 3 and 4 at Newport. To avoid occupying these platforms for too long, could these run on to a new turnback facility in the Caerleon area? Tram-train services could run via Royal Gwent Hospital as you suggest but only far as Bassaleg/Rogerstone where passengers could change onto heavy-rail trains between Cardiff and Ebbw Vale/Abertillery. Similarly tram-trains towards Talbot Green should only go as far as the M4 park and ride, running alongside proper trains which do the full journey from Cardiff to Llantrisant/Pontyclun.

    Finally; you mention consumerism and its consequential waste. Does this apply to the apparent desire for new trains just for the sake of reducing the average age of the fleet to under 7 years? The UK Government have set a target of removing diesel trains by 2040. The new DMUs proposed for TfW would only be 18 years old (at most) at that point. Buying another new fleet then does not seem sensible; TfW’s long-distance rolling stock plan needs a major rethink. If they cannot be future-proof hybrids (with the passive provision for conversion to electric or bi-mode units) then the existing class 158 and class 175 units should be kept to reduce the number of new diesels on-order. Plus, as long-distance trains, they shouldn’t have the suburban door layout and consequential large amount of standing space currently proposed.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s