Just as we fail to report on buses as much as we should, we tend to not report on London’s roads – in part because there is normally little that attracts our attention. It must not be forgotten though, if a total solution for London’s transport issues is sought, that one has to consider the inter-relationship of all modes and it would be impossible to ignore roads. It is therefore particularly appropriate, as well as a bit of a change, to look at how TfL’s plans for roads fit into the future.
On the 9th April TfL’s Surface Transport Panel (STP) received a report and presentation from TfL’s MD Planning, Michèle Dix. She provided a wide-ranging update on progress since last year’s Roads Task Force (RTF) report, itself looking towards the year 2031, and the capacity and congestion conditions faced then by surface transport. It is consistent with the longer term planning underway for 2050.
The STP report (which can be found here in the appendices of this Roads Task Force Update) reveals that TfL have already undertaken a number of studies as a package of additional transport measures up to 2031, and have concluded that these don’t keep congestion sufficiently under control. So TfL are now going ahead with four more studies (largely road based), in addition to the first package, in order “to explore how the capital’s road network can cope with TfL’s prediction of burgeoning travel demand and rising travel congestion”. The objectives are to try to reduce congestion further, improve the London street environment and open up other growth and housing-related opportunities.
Investment levels foreseen in the RTF report were for £30bn being needed over the next 20 years – a comparable level of investment to that planned in Underground and rail for the same period. The STP documents look to more radical measures being assessed in the new studies, including combinations of demand management and tolled road tunnels. The previously mentioned Roads Task Force Update says that “strategic measures, such as tunnels, would require funding over and above that [£30bn]”. One tolled tunnel might be able to replace the Inner Relief Road, the former LCC ‘A’ Ring around and through central London.
Readers may like to review the Roads Task Force Update found in the appendices in the context of our recent look at London 2050 planning.
It’s that population issue (again)
Michèle Dix has stated that the GLA’s revised population forecast “of an extra 1.6 million people living in the capital by 2031 would place increased pressures on the capital’s roads, with ‘significant increases’ in road congestion expected”. To clarify what the report is about she has said that “This is about understanding the high level feasibility of potential options, not about designing projects”.
The curly brace on the right hand side shows the level of increase of congestion in central London that would be expected in 2031 despite mitigation measures being introduced.
One graph (pictured above) is clear in highlighting the expected gap between congestion in Central London, forecast as up 60% in 2031 over 2007, even after baseline measures are undertaken. So bear in mind that this is not a standstill but involves investment and traffic management policies from 2007 to 2031 and yet congestion is still forecast to rise greatly.
Additional proposals to further tackle congestion
The slide shows the proportional contribution in central London of the package of transport initiatives which have already been studied in more detail. These are easier measures that might reduce congestion, such as more traffic control technology, freight and personal travel demand management, and public transport investment beyond that already set out in the Mayor’s transport strategy.
That detailed package included:
- Extending SCOOT traffic signal control to the whole road network
- Active network management to manage flows into congested areas especially central London
- 3% of car trips replaced by other modes or home working
- Reduction in Heavy Goods Vehicles in peak hours
- Bus capacity increase in line with population growth
- Conceptual new outer London orbital rail service
It is the relative contribution of those elements to reducing congestion which are highlighted in the slide above for central London. Compared with 2007, congestion is forecast to increase by 60% in central London (as noted above), 25% in inner London and 15% in outer London. The relative contribution of those elements is likely to be different in other parts of London. For example, it is not very surprising that the congestion reduction benefits in central London of an outer orbital rail service are minimal. They should be greater in inner London and greatest in outer London, along with the benefits of suburban bus enhancements. Graphs were not shown for those zones.
Measures to implement the proposals
The STP paper begins with a restatement of the ten measures recommended by last year’s Roads Task Force (RTF):
- The case is made for a far greater programme of investment in London’s streets and roads..
- The core principle is that the strategy must deliver overall against all three aims of
- Transforming conditions for walking, cycling and public transport
- Delivering better, active and inclusive places and new city destinations
- Maintaining an efficient road network for movement and access.
- A bold approach is needed, including tools not yet fully applied, including demand management and new/improved infrastructure. It will not be possible to cater fully and equally for everyone, everywhere, at the same time.
- TfL will work with stakeholders to undertake initial feasibility studies. In the interim, a plan for the Inner Ring Road must be developed urgently, given the cumulative development pressures.
- All organisations involved in the totality of street management must have ‘fit for purpose culture’, governance and resources to deliver. This will require changes to how things are done, as well as what is done.
- A ‘street-family’ and street-types approach is required. This should be assisted by pilot schemes, framework and performance standards, and completed initial schemes before the end of 2014.
- Adopt innovation, and trial new approaches, with five pilot schemes by the end of 2014. Work on regulatory barriers, linked to the Government’s Red Tape Challenge.
- London to be a world leader in traffic and road network management, and ‘smart city’ mobility management and planning. New technology and data sources to include real time communications with road users, with benefits for reliability, customer experience, safety and the environment.
- TfL to increase evaluation, monitoring, reviews of specific schemes, and an annual review of progress against the RTF aims and recommendations.
- The vision should be set out and a programme of engagement undertaken with Londoners and stakeholders, in ways which increase understanding about challenges and trade-offs and the need for action.
Not radical enough says TfL
In its response last year to the Roads Task Force report, TfL said:
“An increased demand on limited road space means congestion is likely to remain a feature of the network in 2021/22. To address this, we will need to consider new ways of managing demand and providing capacity for living and moving. To understand the scope of change needed and the role of strategic measures, we will begin a series of further studies to understand their application more fully. These will include:
- A study of the Inner Ring Road, to assess its strategic ‘moving’ function and role in enabling new development
- Assessment of further measures to tackle congestion including increases in junction and link capacity, and enhancements to orbital capacity
- Feasibility studies to assess more radical solutions. For example, physical measures to improve the public realm cater for growth, and increased levels of cycling and pedestrian activity while providing alternative space for vehicle movement
- Assessment of measures to further manage demand in Inner and Outer London, including: ‘maximum’ application of smarter travel initiatives; time or area-based HGV restrictions; a tougher town centre first higher density, mixed development policy, including parking restraint; and ‘car-lite’ housing development
- Development of a longer term strategy for delivery and servicing activity in London, potentially complementing work to develop an Ultra Low Emission Zone and including consideration of restrictions on vehicle access to central London
TfL will start these studies immediately, and aim to complete them by late 2015”
Work streams and major new studies
The report and presentation to the Surface Transport panel on 9th April 2014 confirmed that TfL is adopting the RTF vision. It has seven work streams underway, which collectively address the ten RTF recommendations:
- Project development and delivery – Adopt RTF’s three aims, Use world leading technology, Be Bold.
- High level vision and strategy – Develop strategic measures (infrastructure such as tunnels counts as strategic).
- Street types and service levels – Adopt the street-family approach.
- Capability and partnership development – Improve governance
- Pilots – Innovate
- Communications and stakeholder engagement – Engage for action
- Monitoring and evaluation – Enhance evaluation and review.
The existing studies already undertaken in the detailed package described above, are measures which are worthwhile but would be insufficiently effective by themselves, and “will in fact only provide a few years of mitigation” according to the accompanying report.
We now take a brief look at the four major new studies now underway.
Study 1: Central/Inner London
This “is intended to better understand the long term vision for central London and the role of the Inner Ring Road (IRR)”. The IRR is “key to movement” in inner London but much of the IRR is “equally important for its ‘place’ function”. A series of major developments are underway or planned at locations such as Vauxhall, Battersea, Nine Elms, Elephant and Euston. The study “will seek to understand the extent (and benefits) of place ambition, how it may be achieved, and to what extent traffic congestion might increase”. Replacement capacity in a tolled tunnel “elsewhere in inner London” will also be studied, as an alternative to sustain the network function. There will be a 5-20 year strategy balancing movement and place.
The historic Inner Ring Road. The Congestion Charge Zone boundary follows this route for much of its length.
It is a material question what “elsewhere in inner London” might mean in terms of high level feasibility (and not about designing projects) if seeking to locate a tolled tunnel to replace the Inner Ring Road. Possibly the surface junctions with a tolled tunnel could be a sensitive issue, as they were with the North/East/South/West Cross Routes in the 1960s and 70s. Conceptually, if relying on such feasibility, one might look at existing extensive road junctions, or new junctions in opportunity areas where wider land-use changes and mitigation of impacts could be possible.
A tolled tunnel option for the Inner Relief Road might achieve the congestion relief modelled for central London.
Study 2: Outer London
A similar study to the one for inner London is underway for the rest of London, to transform key corridors in terms of tackling congestion, unlocking growth and improving community impact. Fly-unders and tolled tunnels will be considered, and also decking over sections of road to free up land for housing. This will include the North and South Circular Roads.
It seems that that land is at such a premium in London that TfL not only will TfL be considering new tunnels, they will consider decking over existing roads.
It is worth observing that these are the same roads that in the 1960s and early 1970s were to be part of the GLC primary roads and Ringways policies. Some main roads were then still under direct Transport Ministry control. The future ‘direction of travel’ for this primary road network will be an important policy development, when the studies are concluded.
Study 3: Demand Management Measures
TfL is assessing the effectiveness of a range of measures to encourage the use of walking, cycling, the use of public transport, ‘car lite’ developments, and the use of car clubs as well as more radical demand management measures.
Study 4: Freight
The fourth and final study is considering freight issues, with options from voluntary measures through to regulation, to reduce impacts on congestion, safety and the environment.
More consultation and more reports
The studies are underway, and TfL is maintaining extensive stakeholder engagement. Prior to the 9th April report and presentation, TfL had shared work to date at a stakeholder event on 3rd March 2014. Updates on the four new studies will be provided in summer 2014, interim reports in late autumn 2014, and TfL aims to complete them by late 2015. We’ll obviously report on them here as they reveal more information.
These timescales can be contrasted with publication of the draft 2050 infrastructure report in early summer 2014, and its completion in autumn 2014. It follows that initial outcomes from the new roads studies can be expected to feed into the 2050 thinking.
The Mayor has just announced two long road tunnels, one from the A40 in Park Royal to the A12 at Hackney Wick, the second from the A4 at Chiswick to the A13 at Beckton. The first, to be known as the Northern Cross City Corridor. Both would be built by the private sector and the costs recouped as tolls. The ideas both seem absurd.
The estimated costs have not been quoted but as bored tunnelling costs (cut and cover would surely be unacceptable) are said to be in proportion to the square of the diameter and the diameter would need to be about twice that of a cross rail tunnel, this suggests that the first one would be in the order of £30bn and the second somewhat more. Just the £30bn could provide the best part of Crossrails 2 and 3.
The costs are such that even if the first tunnel was to run at full capacity, 24 hours a day, 7 days a week, they would need to charge a toll about £15 per trip in order to recover the costs and make a reasonable profit in a reasonable period of time. Of course the tunnels could not run at full capacity full time. Not only could the A40 and A12 not provide enough traffic to fill the tunnels but traffic levels are much lighter at least a fair proportion of the day. This would suggest a more realistic toll of at least £25 per trip. As it happens, the numbers of vehicles actually wanting to go from Park Royal to Hackney Wick are far, far fewer than the capacity of a road with two lanes in each direction, so the only way to fill the tunnels would be to insert 5 or 6 junctions in between Park Royal and Hackney Wick.
At each entrance to the tunnel, the ramps form a trench about 250m long and 25m wide which would create significant severance and would require very substantial property take in their own right (this alone is likely to sink the Hammersmith fly under scheme) and any intermediate junctions would just flood the existing road network in those areas.
This all seems to be part of a craze which resurfaces every few years where people who should know better think long tunnels are ‘the answer’. It happened in London in the 1970s, with a proposal for an immersed tube along the bed of the Thames from Gunnersbury to Woolwich with a junction at Westminster Bridge, and in Paris in the 1990s where 4 or 5 tunnels were to be dug across Paris linking different sides of the Boulevard Peripherique. Both schemes attracted serious attention from policy makers and then, of course, sank without trace.
@ Quinlet – completely agree with your last paragraph about this being a craze. It’s almost as if the road loonies are let out of their cage every 10 years or so and get the chance to whisper sweet nothings in the ears of gullible politicians. To then have the TfL Commissioner make “ooh ahh” noises (and yes I know his boss was nearby) is even worse. Massive road building gets us nowhere in London and is likely to founder on environmental / legal grounds given nothing of any substance has happened to improve air quality. I also don’t see how you can possibly square building massive junctions into these tunnels with the need to build more housing / avoid destroying existing neighbourhoods and forcing people out of their homes. It’s not the 1980s /90s where you can demolish half of Leyton and Leytonstone to construct the A12.
I also note the indecent haste with which the Silvertown Tunnel project has been shoved through the TfL Board to allow TfL to seek a development consent order. This is supposed to happen in Spring 2016 – I thought we were still in Winter 2016. Have TfL even summarised the recent consultation before going to the Board never mind published a full assessment of the consultation responses and answers to the questions raised? Nope!
The risk is those mayoral candidates who would just jump on the bandwagon without thinking on the basis of being seen to do something. The idea of the Hammersmith fly under is very popular locally because residents think it would take traffic away from the gyratory and reduce severance from the river. There have been no detailed designs yet, but the outlines actually show that none of the schemes will reduce traffic in the gyrator and 2 of the 3 will increase it significantly, and that all of the schemes actually increase severance because of the portal ramps. Once this is realised I think support will evaporate, but it’s there at the moment and some mayoral candidates might see this as general support for tunnels.
Walthamstow Writer,
Although I tend to agree with you, I don’t think this can be dismissed entirely.
Exceptionally, I have deleted your final paragraph which I regarded as political comment and did not wish to have to deal the challenges of moderating the responses it may have generated. I also considered it misleading as this is, by and large, a TfL proposal supported by the current Mayor though I accept that looking into it may have been prompted by the Mayor.
I think you have underestimated the importance of freight 20 or 30 years from now and the value that will be placed by companies on time saving and vehicle wear saving as well as offering a more attractive door-to-door delivery. I can see charges, on a mileage scale, that could be quite high for some sectors and companies willing to pay for them.
A lot also depends on the purposes of these tunnels. There will be locations where the improved amenity to locals will improve, if well designed, but of course there will probably have to a fiscal price to them to pay towards it too. As you point out, it would be expensive. Exceptionally, it could unlock development that could contribute something.
I think this has been badly handled (shades of HS2 and getting the speed rather than the capacity message across). Some in TfL are emphasising the idea of reclaiming land and it is not about increasing road capacity whereas there is silence on this issue elsewhere.
I have not examined the proposals in detail (not sure if the detail exists) but I don’t remember any suggestion that it should be entirely funded from tolls. However, if it was even largely funded though tolls and other development opportunities that could be sold, arguments about how many Crossrails you can build for that are largely irrelevant.
I remain sceptical but we should not just dismiss something offhand just because of initial doubts or because it is associated with a Mayor that one might not have a high opinion of.
The best way to kill off a dubious project is not to use rhetoric to oppose it but to ensure thorough analytical detail and investigation is carried out to expose its flaws – but at the same time if they produce something positive we may have to rethink.
The Hindhead tunnel cost £370 million, including 1.8km of bored tunnel, of a similar standard to what I assume would be built here. There will have been inflation since then, but I doubt that will as much as double the price. So for a tunnel from Park Royal to Hackney Wick, which is 18km, I’d expect somewhere around £5bn. Actually I doubt it scales linearly with length so it’s probably rather less.
There’s no reason for the actual tunnelling to be more expensive in London, indeed as I understand it the geological conditions should make it cheaper.
What will be expensive is constructing underground interchanges, and acquiring the land for the tunnel portals and associated ramps. But I can’t see it being close to your £30bn estimate.
And, of course, even ignoring the vast ramps ( not that the whole thing isn’t a constructor’s “ramp”, Marples-style ) where are these tunnels going to go in central London?
They will have to avoid all the exiting tube/sewer/rail tunnels, so how deep would they be?
Agree with WW – utterly, totally bonkers…..
I agree with PoP that analysis is better than ridicule for defeating daft projects. However, when something seems so “obviously wrong” as this tunnel scheme, one does rather resent the waste of money in even putting it forward and making such analysis necessary.
Of course, the catch is that some “obviously wrong” schemes have actually turned out to be quite a good idea (cross-channel hovercraft, for instance).
As for the chosen routes, I suspect the tunnels, if built, may get nicknamed the “conservatory to lounge” and “kitchen to study” passages.
@Mark
The Mayor estimates that each tunnel would cost £15bn – which is clearly a rough approximation as the one tunnel is nearly 40% longer than the other. Tunnelling costs for roads (even Hindhead) have been notoriously underestimated. The Big Dig in Boston ended up costing 10 times the original estimate!
@PoP
Tunnels can, indeed, improve local amenity if they reduce the traffic flow on the surface. This gives some additional space for other purposes. The longer the tunnel, though, the more local traffic remains on the surface – because the tunnel takes them far too far away. The estimates for Hammersmith for the ‘long tunnel’ options of about 4km are that less than half of the traffic currently using the flyover would want to use the tunnel. As the length of the tunnel increases, the share of existing traffic wanting to use it would drop further to the point where the noticeable impact on traffic reduction on the surface shrinks almost to the point of invisibility.
This can be overcome by inserting a number of intermediate junctions – not currently proposed – but the each of the junctions has significant environmental and traffic impacts locally.
Those who think this is a political winner (and cheap to boot) should dust off the plans for the innermost motorway box – the Euston Road interchange alone required the demolition of the whole of Bloomsbury. Besides the immense cost of the rampage (?), there is the small matter of ventilation and emergency exit shafts. These too will be popular in central London.
The Hindhead tunnel is not really a useful benchmark. Both portals are in countryside, where land costs are far lower. The tunnel runs through a ridge, in a steady gradient from one end to the other, making drainage a non-issue, whereas a tunnel under London would necessarily be deeper in the middle than at the ends, requiring constant pumping to drain the sump. And it is short enough that it does not need any evacuation routes other than the portals.
@ PoP – we must therefore disagree. Where is the detail and where are the “facts” that would allow the analysis? Doesn’t exist in the public realm so your preferred stance is not feasible at the present time. It is well known that if you expand road capacity you do not solve anything. You create a bigger problem because traffic expands to fill the additional capacity. The last thing London needs is more vehicular traffic. As for freight well maybe I didn’t consider it. However I have, in the past, commented here about the lunacy of denuding London of its industrial infrastructure. All we are doing is kicking industry out thus creating more and more logistical and commuting demand over ever longer distances thus worsening congestion and pollution. That is economically illiterate. Also the tunnel schemes are not being promoted as something for freight. They are being promoted as some sort of “magic cure” for traffic congestion and to somehow create “wonderful” new communities because homes will be built over the tunnels. As others have said what about the severance created by new junctions plus the pollution impact of shafts in new and existing residential areas. It makes no sense I am afraid. The way to make room for freight is well known – you shift other traffic on to other more efficient modes thus raising the efficiency of the networks you already have.
I am afraid I also disagree with you about where the “push” for this stuff is coming from – TfL do what the Mayor wants. There may well be some organisational “preferences” for certain pet schemes – a road based river crossing in East London seems to be one such – but TfL can’t run off and do these things itself.
I think the same road lobbying organisations still lurk in the shadows quietly fuming that they have yet to build ringways all round London. They wait their time and then go into lobbying mode with every Mayor. Happened with Ken, has happened with Boris and will no doubt happen with whoever is next. What is more worrying is that as things stand now no one with a chance of winning has much to say on the direction of London’s transport policy. Nailing a jelly to the wall would be easier than knowing what the general thrust of policy will be from 2016 to 2020 and beyond. Note my use of “general thrust” which is what I’d expect to know *now*. Detail and manifestos follow later.
I thought I had posted the following link above but could not see it. It shows that 1937 plans for Inner London, includes tunnels under Kensington Gardens and Soho. Plus sa change….
http://www.sabre-roads.org.uk/maps/index.php?view=51.48171,-0.30577&map=NPEMap&zoom=16&layer=3&markers=51.48081,-0.30501
Looking at the map of the Northern Scheme, It starts at Hanger Lane Gyratory on the A40, connects at White City and then swerves North to Swiss Cottage (?), Camden (?) and then Highbury Corner before connecting to the A12 at Hackney Wick.
Starting the scheme at the North Circular , would allow the old A40 to be properly converted into a urban Boulevard, allow existing traffic to avoid the two worst junctions on the route and probably allow extra traffic to access the Old Oak Common site.
The tunnel in effect after this point becomes the Northern side of the Inner Ring Road. This avoids the complex web of tube tunnels in the CAZ and will. The real challenge is where do the put the local access tunnel ramps and how big do they have to be.
I can see nothing but a battle royale over these local access ramps in each of the chosen locations. It’s not as if there are any convenient industrial sites to set them in. Plus the idea of trying this anywhere near Camden is enough to give you the vapours.
As the city grows and the CAZ effectively expands outwards all these deliveries and trades need to get through somehow.
I also think that as neighbourhoods like Shorditch and Dalston fill up with businesses tied into the Central London Economy, then their need to physically trade and travel to other central neighbourhoods will probably increase. Rather than just the City or the West End, it might be equally important to get to Vauxhall, White City or Greenwich.
Walthamstow Writer,
Yes, the facts aren’t out there so without facts how can a judgement be formed.
It is well known that if you expand road capacity you do not solve anything.
Yes, I agree entirely, well almost entirely. One cannot take that as a given – just consider the simple example of increasing road capacity by added segregated bike lanes whilst keeping motor vehicle traffic at the same level. There are also bus schemes that increase road capacity overall e.g. Croydon bus bridge over the underpass. I was (and still am) wholly in favour of the Coulsdon bypass. It is what you do with that increased capacity that matters.
But back to increasing capacity, hence me raising the point that different people within TfL and advisors to the Mayor present this as different contradictory proposals. Some see it as increasing capacity and others say it is not about this at all but reclaiming land currently taken by road schemes. Until we know which it is and see some details and examples I fear this is just going to be a case of being presented as all things to all men.
The Mayor makes much of Chicago’s big dig which has meant a reclaimed waterfront. Paris is now, belatedly, realising that the banks of the Seine should not be handed over to motor vehicles and is doing what it takes to reclaim the are back for the people. Why should London not adopt the same approach?
Quite a few reports compare this proposal to Boston’s Big Dig project, but it is worth actually looking at that comparison.
The I-93 in Boston was a elevated motorway, similar to the Westway in London, with limited junctions and a severe impact to the city. Importantly, it was a strategic north-south route for the area, although the I-95 and I-495, which bypass Boston, now alleviate some of that load. The replacement tunnel is 3.9 miles or 5.6km long, took 15 years to build and is estimated to have cost $22 billion (around £15 billion). It has one junction connecting to the surface, and another junction connecting the existing Route 1A tunnel. The project also included a tunnel under the harbour which alleviated some of the load on the I-95 during the build. Once built, the land previously occupied by the elevated road was converted into a linear park, but the portals are huge, multi-level junctions.
This proposal is 18km long, 3 times the length of Boston’s project, and does not replace an obvious, strategic east-west route. These two facts alone would seem to make this a ridiculous proposal. How about sorting out Hammersmith first and see how that goes before building what is probably the worlds longest, urban motorway tunnel.
@Graham H
I think you are confusing actual proposals with theoretical exercise from ‘Traffic in Towns’ whereby Bloomsbury is transformed into a very car friendly place with grade-separated roads. The Motorway Box would have followed the Primrose Hill rail route in North London, and wouldn’t have gone anywhere near Bloomsbury or the Euston Road (it would have been horrible, but mostly as it was to be elevated)
I guess you might be talking about the ‘A Ring’ and it’s junction with Tottenham Court Road. However the linked 1956 map is the only reference to it in the 50s (though there are some hints like the M1 having a proposed terminus near Marble Arch in 1959) and the concept of it being a motorway only existed for 2 years from 1948 (where it was done to save building Abercrombie’s Routes X and Y motorways across the centre of London) to 1950 – not normally long enough to design junctions.
The claim that “It is well known that if you expand road capacity you do not solve anything.“. I share PoP’s reservations about this.
The thing that has been demonstrated fairly conclusively is that “If you expand road capacity in a town you do not increase average journey speed. You might have solved something else (in addition to road-builder’s profits) but average road speed in towns is insensitive to road capacity. In fact it stays near-equal to rail average speed, because if capacity changes, enough travellers are displaced between road and rail to bring them back equal. Hence, in order to speed up the roads, build railways!
I’m trying to work out whether the silly season has arrived particularly early this year, or someone has shares in TBMs. This reads like a new London Box but underground not on the surface, and as we’re talking about road vehicles then ventilation is going to be a major issue. The tube has the occasional vent shaft to the surface, but this would needs scores of them!
Given that inside the M25 is a low-emissions zone this would appear to be welcoming those same vehiclesto congregate further in. Whilst I suppose you could consider a cut-and-cover option under the existing too-busy roads rather than a route-under-everything the practicalities stop that idea before it is started.
The only thing some silly proposal like this does is create media attention. I wonder why someone might think that a good idea …
@Si – you are right, I am recalling the Traffic in Towns plan. However, the innermost box lived on into the late ’60s at least in the form of maps on my Highways colleagues’ walls (where I repaid them with careful study),together with other such partially built delights as the M31.
Sorry, I should have added that part of any box or not, the Bloomsbury plan illustrates very clearly what would be needed to access the sort of tunnel system now proposed.
“If you expand road capacity in a town you do not increase average journey speed”
Agreed, but maybe getting there faster isn’t the objective. The same argument must apply to expand rail or bus capacity – lengthening trains, or having double decker buses replace single deckers. Both increase capacity, but their effect on journey time is close to neutral (e.g longer trains have more doors so shorter dwell times, but take longer to clear junctions etc) But no-one is arguing against that.
I am wholly with WW on this. Brussels fell for this kind of lunacy in the 1960s and 1970s. It has wrecked whole swathes of the city and done nothing to fix congestion. More traffic is sucked in, as always happens when you expand capacity. The traffic jams just move to a different part of town. I had supposed that everyone realised all this by now, but apparently not.
@quinlet – the Hammersmith flyover was popular because the council only surveyed Hammersmith and Fulham and didn’t ask the people of Chiswick where they were proposing to stick the tunnel portal for the long tunnel options!
I don’t think much stock can be placed in the survey results given how much sugar-coating of the scheme was done by LBH&F. As you mention, only about half of the traffic on the A4 west of the gyratory would use the tunnel and there was no explanation of what would happen to the other half.
I think public opinion may have been different if the public had been told that the scheme would involve spending billions and would “reconnect Hammersmith to the river” by reducing the A4 from 6 lanes….to 4 lanes.
Its RSI.
Not so much a
Repetitive Strain Injury
as a
Really Stupid Idea
Reynolds 953: I think you are referring to the Hammersmith diveunder, rather than the (existing) Hammersmith flyover.
@Anomnibus 16:28 – there are ways to address demand other than firing up the TBMs. One is demand management, such as more comprehensive and sophisticated road pricing. Think of the equivalent of Oystercard for motor vehicles where every journey has the potential to be charged based upon vehicle type, time and zone.
A Evening Standard editorial this week was calling on the mayoral candidates to come up with proposals for road pricing so the concept appears to be entering the mainstream.
@ PoP – we should always be extremely wary of any scheme that is presented as being “all things to all men”. They don’t exist and therefore you have to seriously question just what is going on. The last thing London needs is yet more roads. It needs vastly more public transport as I hope everyone who posts or writes here would accept.
I also find it strange that TfL appears to be sending mixed messages. It is normally pretty good at presenting one clear line but I fear that it is getting distracted in its internal thinking because of the pressure from City Hall (and from declining finances) to become a form of development agency as well as the City’s main transport planner / co-ordinator / supplier. We must hope that TfL can keep the transport aspect running properly despite the frantic pressure to “build more houses” on each square inch of “spare” land TfL apparently owns and to grab every penny of private sector money it can find. I do fear for what will happen after May with a new Mayor (regardless of which party) given some of the common themes that exist. Past experience suggests that it takes TfL 8-10 months to “adjust” to the new constraints, pressures and opportunities of a new Mayoralty (and presumably to “educate” (ahem) the new Mayor).
@WW
“be extremely wary of any scheme that is presented as being “all things to all men”.”
I read in the paper a few days ago that Boris’s enthusiasm for Crossrail 2 is tempered by the realisation that it would pass directly under his house (just as HS2 works will affect his father’s house in Primrose Hill)
@Rational Plan
Sadly a tunnel starting at Hangar Lane, even with a junction at White City, wouldn’t clear enough traffic from the existing A40 to allow it to be turned into anything much different from its current form. Too much of the traffic wants to make journeys which don’t extend beyond Hangar Lane and White City at each end.
@Reynolds 953, WW
I think your suggestion of demand management starts to get to the nub of the problem. This is the preferred course for TfL, if left to themselves, but the current Mayor is adamantly opposed. The most that he could be persuaded to say was that if all else fails, at some stage in the future, there might be a need to consider demand management. The corollary of that is that, given the level of growth in London, he either accepts growing congestion – not gridlock, but a large area covered by persistent congestion over a greater part of the day – or is seen to be ‘doing something’ about it. The fact that he won’t be Mayor by the time anything is actually done makes this a cheap option politically.
If you want my guess, therefore, the proposal comes out of City Hall rather than TfL.
IIRC both the current main candidates are of the opinion that there’s too much traffic in the inner London areas.
What they propose to do about it is a n other question.
But by the time it’s built it won’t need ventilation because all our cars will be scaled-up Scalextric ones. Really.
I did wonder whether it was significant that the press release was from the Mayor rather than from TfL. I don’t remember much else transport related not coming from TfL
@Reynolds 953:
“there are ways to address demand other than firing up the TBMs. One is demand management, such as more comprehensive and sophisticated road pricing.”
Ah yes, the “demand management” excuse. Because that single crossing over the Thames between Kent and Essex at Dartford has so many great alternatives. (Oh, wait…) [Snip]
Sometimes, building new infrastructure isn’t just the right answer, it’s the only answer. And it’s not just my pet hobby-horse of SE London and an adjacent county either: Central London itself is effectively saturated with road traffic.
[Snip]
While I don’t think the two proposed tunnels are actually likely to happen, it is at least interesting that people at this level are seriously considering such bold options. Until now, the usual approach has been the “Do Nothing” option, which helps nobody.
[The snips are things which were valid comment when first said, but this contributor has a tendency to repeat himself, then repeat the repetitions. We prefer to encourage new thoughts. Malcolm]
People complain about living under the Heathrow flightpath, despite the fact that the airport is older than they are. Likewise, the Thames has always been there, so it is not a strong argument for a lower crossing of the Thames to say simply that Barking is twenty miles from Thamesmead by road – it always was. You wouldn’t expect to get from Barking to Hammersmith, or Southend, in five minutes. (Would you build a tunnel from Hammersmith to Hackney withgout any intermediate interchanges?)
The need, or otherwise, for a new road must depend on the numbers of people already making the journey, or who you want to enable to do so, and the adequacy of the existing links. The volume of traffic crossing the river at Dartford and Blackwall is ample evidence that more capacity is needed. The mere presence of a natural barrier is not.
@Anomnibus
“Central London itself is effectively saturated with road traffic.”
— Yes but don’t you see, if you build more capacity it will just end up EVEN MORE saturated with road traffic. If You Build It They Will Come. Of course some of the traffic (private motorists) shouldn’t be allowed in central London in the first place. At the very least, the congestion charge needs to be increased and the charging zone expanded. Cities are for people, not for tin boxes on wheels.
@Anomnibus
The argument that you must ‘do something’ is frequently rolled out, but I can’t see how that justifies spending billions of pounds on something that won’t actually help. It’s a good message from politicians who know they won’t be around to see just what a waste of money their proposal was but not a good answer for London. After all, did any politician have to answer for the West Cross Route or the northern M23 spur?
See also
THIS maybe?
[Driverless cars: London wants Google vehicle trials. LBM]
@PZT
” if you build more capacity it will just end up EVEN MORE saturated with road traffic. If You Build It They Will Come.”
Depends whether you see the objective moving people around faster (which an increase in capacity will not help), or simply moving more people (which it will).
Of course, whether we are talking about trains or cars, an increase in capacity on the arterial routes is no use if the terminal facilities are not also augmented – on the trains, platforms not being able to be cleared between services – on the roads, all the extra capacity occupied by people driving round in circles looking for somewhere to park – on the buses, the extra dwell time of a double decker compared with two single deckers (or a bendybus).
@peezedtee:
“Yes but don’t you see, if you build more capacity it will just end up EVEN MORE saturated with road traffic.”
Capacity of roads is finite; once they’re saturated then, by definition, you cannot physically squeeze in any more traffic, so they cannot become “even more saturated”. They are either saturated, or not. Adding more capacity — whether to roads, rail, air, or any other mode — adds more capacity and allows more people to travel. The speed isn’t an issue; 10 mph. is still quicker than walking.
When that capacity is filled, then it is time to add more capacity. Not to throw one’s collective hands up and demand all that extra demand goes elsewhere, while still permitting construction of even more high-density office blocks and the like.
In a rational world, you’d plan for capacity enhancements to be done sufficiently before that saturation point so the disruption of the work doesn’t cause problems. As it is, the saturation of inner London’s roads means that it’s almost impossible to justify digging them up to lay down tracks for trams, so an entire intermediate layer of transit is now effectively priced out of the realms of possibility.
That doesn’t leave a lot of conventional alternatives.
This is one of the reasons I mention LEV/ZEVs and self-driving vehicles. They will tip the balance back in favour of road-building again: Tunnels can be a lot smaller and cheaper if you don’t need to worry about venting fumes and the fire hazards inherent in internal combustion engines. If the vehicles are driving themselves, you can also reduce the tolerances for lane widths and the like, thus reducing the size of the junctions too. A tunnelled South Circular starts to make a lot more sense now.
We’ve been here before: the railways struggled to fight the electric tram, then the latter succumbed to the motor bus. Lorries ate the railways’ wagon-load lunch too. Disruptive technology is nothing new, but its effects on existing technologies can be hard to predict. I do, however, suspect that the railways may yet see a second axe.
I went along to the exhibition at New London Architecture and took this photo , which shows a number of intermediate junctions along both corridors.
Although there is not much information in the public domain about these proposals at the moment, there are a number of factors at play:
– The growth in certain types of vehicles – especially servicing, goods and freight
– The desire for better urban realm at the surface, eg. along Euston Road, Vauxhall and Tower Hill, where currently there is an unsteady balance between “movement” and “place” priorities
– The need to accommodate more housing on public land: such as where the Westway currently sits
– The experience of cities such as Stockholm, Tokyo, Madrid and Seoul, which have successfully buried major roads
– New methods of constructing tunnel portals to avoid the severance usually associated with them
People who spend much time in central London will have observed the balance of vehicles on the roads during the working week: overwhelmingly vans, taxis, PHVs and buses. The private motorist is virtually an extinct species in the CC zone – but in the outer suburbs the car remains the majority mode of travel.
I would also like to question the assertion that it is a bad thing that “building new roads generates new traffic”. Building Crossrail (1 and 2) is going to generate so many new trips that Crossrail will probably be full within a couple of years. Does that make it a bad investment? Similarly with all public infrastructure: we want it to be used by the public.
If these proposals were taken forward as a “replacement” of road capacity (ie. along with demolishing the Westway, removing gyratories around the Inner Ring Road, providing more space for buses, cycling and pedestrians at surface level) and also would help to accommodate the city’s growth, it seems remiss not to at least study them seriously.
Chris H: Some interesting points there, and thanks for the picture.
I know you said there is not much information in the public domain, but I wonder if you might be able to expand on your comment that there are “new methods of constructing tunnel portals to avoid the severance usually associated with them“. Might that be a relaxation of maximum gradient restrictions? If as many access points are planned as the maps suggest, and the tunnels are intended to provide a net decrease in surface land-take by roads, then a fairly drastic redesign of portals would seem to be necessary.
@Malcolm – indeed: it doesn’t usually seem that the portals are the issue in themselves but the elaborate cloverleaves and slips that accompany them; it’s not easy to envisage how these can be dispensed with, without limiting access to the tunnels from a number of directions.
It is possible to build over a tunnel approach ramp, provided you do not need to use the ground floor. The southern approach ramp to City Thameslink provides an example* – so do most Tube stations, where there are buildings over the escalator shafts.
*From platform level at City up to ground level anyway – the ramp continues on a viaduct from ground level up to first-floor level@ at Blackfriars.
@in the British-English sense.
@timbeau
What is “@in the British-English sense”? ‘at’?
@Malcolm
I imagine that there might be a range of options regarding maximum gradients for portals. The first step in any design would be to use the Design Manual for Roads and Bridges but this can be relaxed in stages depending on the location and project requirements.
My thoughts around minimising the severance of portals is to pair them with existing severance. For instance, where an elevated railway crosses a major road (for example the East Coast Mainline at Holloway Road), a 200m long portal could be built adjacent to the railway with no increase in severance to the local area. Similarly with large buildings like cinemas, markets, or any “blank frontages” as they are now known in urban planning. And as timbeau says, a building could be put on top to further ameliorate the situation.
The volume of traffic that enters and exits the tunnels via the local street network would be the bigger challenge. I can think of several inner London boroughs with dots on that map who might have something to say about that…!
Long Branch Mike,
timbeau was referring to “first floor”. British English has ground floor which is marked as “G” or “0” in a lift*. First floor is the next level up. American’s do it differently and, if I recall correctly, go from 1 (ground) to -1 (basement) without an intervening 0.
*elevator in American English
So the “@” in “level@” was a typo?
You are correct in your North American numbering of floors.
Thx
I was using @ to point to a second footnote as I had already used * for the first one. Sorry if that led to confusion.
The Blackfroars / city Thameslink situation is further confused by the fact that the ground level slopes upwards as the railway descends.
https://www.google.co.uk/maps/@51.5120844,-0.1032845,3a,15y,349.92h,92.16t/data=!3m6!1e1!3m4!1sfRICB6XMBSFgM09yBgYz6g!2e0!7i13312!8i6656!6m1!1e1
(the train is emerging from the tunnel and climbing at about 1 in 35 – the gradient of the street can be judged from the coursework in the wall on the left).
Another space-saving tunnel portal
http://dewi.ca/trains/conduit/subway3.jpg
Road tunnels can be good news for a neighbourhood if they simply shift an existing flow underground and restrict themselves to plain in-out ramps at each end (ie no grade separated junctions). However, there will never be many of these opportunities where a serious gain can be made in terms of the ground released up top. I really don’t believe that a long tunnel makes any sense. Much more likely that several shortish tunnels could make life better for everyone. I haven’t read the original article again, but my hazy memory tells me that the original TfL proposals contained a list of these short ‘urban realm’ schemes as well as the long ‘pie in the sky’ ones.
@Fandroid
“Road tunnels can be good news for a neighbourhood if they simply shift an existing flow underground and restrict themselves to plain in-out ramps at each end”
But where would the BCR be in doing that, given that autos move far fewer people than public transport, and even short tunnels will require ventilation of exhaust gases?
@anomnibus:
Tunnels can be a lot smaller and cheaper if you don’t need to worry about venting fumes and the fire hazards inherent in internal combustion engines
What about the fire hazards inherent in large lithium batteries? If you can’t legally put a spare camera battery in checked luggage on a plane, what chance of being allowed to drive a car with a much bigger one into a tunnel with no smoke ventilation system? And what about the cargo on board goods vehicles? Wasn’t the Channel Tunnel fire caused by a lorryful of cornflakes?
while still permitting construction of even more high-density office blocks and the like
Are you really suggesting that roads should be built to enable people to drive to work in high-density office blocks in London? Why can’t they just get the train or bus to work like most London office workers? That way they could average more than 10mph on their way to work (incidentally, Reuben Smeed in 1949 posited that average traffic speeds in central London would always be around 9mph because that was the minimum speed people would tolerate. His prediction has been extraordinarily accurate (page 17)).
@Chris H: The volume of traffic that enters and exits the tunnels via the local street network would be the bigger challenge
That feels like the Achilles heel of the proposals – you would need many smaller exits to spread the traffic if you weren’t going to completely gum up the local streets. But each local exit will require compulsory purchase and demolition.
@ Anomnibus – you completely fail to mention that you simply cannot build enough road capacity to cater for the demand and then all the generated demand that will follow. You just seem to favour building things for the sake of “doing stuff”. You do not seem to recognise that it is actually possible to reduce demand or to shift demand to less polluting / less intrusive modes. London’s air quality is abysmal and building new river crossing, tunnels and all the associated link roads will do nothing to help. If you build new road infrastructure all you do is generate more road based development – retail parks, hotels you can only reach by car etc. Just look at what happens to ring roads in most UK towns. All the assumptions about demand go out of the window once development springs up and yet more travel happens to those new developments. Sometimes you just *don’t* have to build a road, you have to adopt different and difficult policies to get people to change their ways through a mix of persuasion and compulsion.
@ Chris H – the fundamental difference between vast new roads and Crossrail is that Crossrail doesn’t come with externalities like pollution and congestion inflicted on those people who live near the route. There *may* be some noise but Crossrail are taking a range of steps in different locations to keep noise and vibration to a minimum. You are also pretty unlikely to get unacceptable severance as a result of a new railway. When the Overground was linked up near Surrey Canal Road footpath access was maintained, a new park created and pedestrian links provided under the line. I am not aware of anyone vehemently complaining about that new bit of railway. I suspect there are plenty of people who don’t like living with the A12 through Leytonstone or the reconstructed and widening North Circular through vast tranches on North and East London.
There are plenty of cities that can demonstrate that a heavy reliance on public transport, cycling and walking can create places that are vastly move liveable than the worst examples of UK and American car addiction policies from the 60s and 70s.
One way to limit the severance caused by ramps is to make the tunnel only high enough for a car. If you halve the height of the tunnel, you halve the length of the ramp.
But then you end up confining HGV juggernauts with their noise and diesel fumes to the streets above! Hardly an improvement, I imagine…..
@Fandroid: my hazy memory tells me that the original TfL proposals contained a list of these short ‘urban realm’ schemes
According to the Mayor’s press release:
A number of smaller tunnels and ‘flyunders’ across London have also been identified that would see roads moved underground, unlocking land at the surface for thousands of new homes and open space. As an example, two locations – the A13 in Barking and the A3 at Tolworth would have the potential to release land for up to 6,000 homes combined
The Streets Ahead catalogue has a drawing on page 38 of what the Tolworth scheme would entail – basically building high rise flats on the waste land between the A3 and the station, and decking over the road itself with parkland. Since the road itself is not decked over and the large roundabout remains in place, I’m not sure you can really say that the road tunnel has freed up any space for housing, although it would improve the marketability of the flats. But a clue to the main driver behind the scheme is the big purple roundel on the station next to the flats – this would be a Crossrail 2 development more than a road project.
Conspicious from its absence in the smaller schemes mentioned is Hammersmith.
The major problem with the argument that tunnels can just replace surface road capacity is that it fails to take into account journey lengths and capacities. Most car trips are still quite short, less than 5km, and journey origins and destinations don’t always follow the same line. So even if the tunnels have very frequent junctions (which would increase the cost and the severance) they would be of no use to substantial volumes of traffic. This volume would continue to need to use the surface roads. In the case of the Hammersmith ‘long’ tunnels, more than 50% of the current A4 traffic would continue to use the surface roads.
While any reduction can be seen as a gain, the ability to eliminate to eliminate the severance disappears. And, if Anomnibus’ argument is to be accepted, we should welcome the fact that the surface roads would just fill up again with generated traffic.
@ quintet – indeed. Even with the Hammersmith “short” tunnel proposal which would be a straight replacement of the current flyover, I think about 40% or so of current A4 traffic would continue to use the surface roads. A tunnel would only move severance around and may even have increased it given the length of tunnel portal ramps. When I looked at the plans for this scheme, most of the redevelopment was just a grab of the existing eastern end of King St with little land released by the road scheme.
A lot of the growth of traffic in central London has been Uber cars driving around waiting for fares and as has been discussed in a previous LR article, black cab and private hire regulation is ripe for reform and can be managed rather than assuming that more capacity is needed for even more private hire cabs.
Re Quinlet and Reynolds 953,
Part of the Hammersmith issue is how to sort out the different traffic flows as the Hammersmith problems are at junctions (as usual) rather than actual road capacity in between various junctions on the network, hence replacing flyover with tunnel isn’t going to do much and neither are 1 way systems that great either as the create capacity restrictions similar to junctions. If they really wanted to solve the traffic issues they would leave the flyover in place and add some additional tunnels to remove large conflicting junction flows.
1 very simple /cheap solution would be to open up the roads/ parking under the flyover between Fulham Palace Road and Hammersmith Bridge Road would should help improve the traffic through one way system. It is exactly the opposite of what H&F actually want.
@ ngh – the current consultation for the cycle route around part of Hammersmith gyratory says “Removal of the gyratory is part of TfL and H&F Council’s long term vision for Hammersmith Town Centre and options for removal are being assessed. However, such a removal will require major changes to the bus network, operation of the bus station and to traffic movement through Hammersmith Town Centre.”
So watch this space but for how long, I don’t know…
@Walthamstow Writer:
“You do not seem to recognise that it is actually possible to reduce demand or to shift demand to less polluting / less intrusive modes.” (and other valid criticisms.)
Actually, I do recognise that it is possible to shift demand to other, better, modes. Unfortunately, I’m not allowed to mention the said modes, which rather ties my hands.
I’m not sure how I can answer your points without getting snipped into oblivion.
Re Reynolds 953,
One does get the feeling that the idea will be placed into the “too difficult” drawer for a while!
@Anomnibus
“I do recognise that it is possible to shift demand to other, better, modes”
But what tends to happen in practice is that however many people you shift to other modes, be they new railways or magic carpets, the space they leave behind will get filled up by new users until you are back where you started. The only way to actually reduce the number of vehicles using the road space is to reduce the road space. Whether you provide an alternative (jet packs, triple decker Piccadilly Line trains or whatever) or simply accept that the number of people able to travel will be reduced is another question.
Actually reducing demand for travel can only be achieved by making it possible for more people to live over, or at least closer to, the shop. Which means making city centre living more affordable and/or more pleasant.
timbeau says “reducing demand for travel can only be achieved by making it possible for more people to live over, or at least closer to, the shop. Which means making city centre living more affordable and/or more pleasant.”
That is not even the only way to reduce demand for commuting travel. Demand can also be reduced by raising the price, or dispersing workplaces, or encouraging teleworking, to name three other possibilities. But reducing demand for leisure travel, travel to school, within-work travel, and shopping travel are each a different problem, with a different set of solutions.
Having said all that, I agree that improving city centre living would be a Good Thing.
@Malcolm:
I’ve pointed out before that London will need a lot more Lewishams before the eye-watering cost of living anywhere near your place of work falls to reasonable levels.
Like that’ll ever happen.
@ Reynolds 953 – such a shame there’s an inconvenient tube station, 2 bus stations and a shopping centre in the way that makes changing the roads difficult!!!! Talk about the wrong way round. They’ll be complaining that there are too many roads from surrounding areas all meeting up at Hammersmith next.
TfL seem to be a mission to remove every single gyratory in London with the main result being even worse traffic jams, slow grinding traffic, slower and less efficient buses and big contracts for highway construction companies. I know some locations are hideous now and require improvement but I’ve yet to see a scheme implemented efficiently and deliver any obvious results.
@ Anomnibus – don’t worry then. I can guess what you would say and am extremely unlikely to agree it. I agree we should not be causing the LR scissors department any undue excitement.
@Walthamstow Writer – I think Hammersmith definitely qualifies as “hideous”. At peak times large numbers of people are queued up trying to cross the roads between the D&P and H&C tube stations while a comparitively tiny number of motor vehicles drive past and I think one of the objectives of removing the gyratory is to pedestrianise that crossing.
I have used the Hammersmith gyratory for forty years, in the car, on foot, and as a bus and tube passenger and I do not recognise Reynolds 953’s description. It is probably better than it has ever been and the bus station extension, the last major improvement, made a big difference. Yes it is busy with pedestrians in the rush hours but wait periods are relatively short and congestion in the shopping centre/station entrance is probably more of a problem. Closing the south end of Hammersmith Grove would help the long suffering 266 but other works are not a priority except possibly for cyclists (though as previously pointed out the bus and Underground stations and shopping centre are an obstacle……..).
@Malcolm
“timbeau says “reducing demand for travel can only be achieved by making it possible for more people to live over, or at least closer to, the shop..”
Demand can also be reduced by raising the price, or dispersing workplaces, or encouraging teleworking, ”
two of those are ways of making it possible to live over the shop, the other makes it (realtively) more economic to do so. .
“But reducing demand for leisure travel, travel to school, within-work travel, and shopping travel are each a different problem, with a different set of solutions.”
Indeed, but on the whole it is not these travel patterns which determine peak demand for capacity. (Except travel to school, which is just as much commuting as any other travel to work)
@ Westville13 – you should take a look at http://www.collisionmap.london. Over the last 5 years someone got injured at Hammersmith gyratory about every 3 weeks, on average.
Now it is a busy place and I don’t know if that constitutes an acceptable level of casualties amongst the public but I find it difficult to believe that it can’t be made safer and more pleasant.
Cycles are the biggest injury group making up about a third of the number.
@Anomnibus
“I’ve pointed out before that London will need a lot more Lewishams before the eye-watering cost of living anywhere near your place of work falls to reasonable levels.
Like that’ll ever happen.”
But that is exactly what is happening and what is likely to happen more in the future with densification of residential developments around public transport nodes now the official policy.
@quinlet:
If there’s one thing London hasn’t been any good at, it’s creating policies and applying them consistently over many, many years.
I’ll believe it when I see it.
@reynolds953 – maybe I’m misreading the map but I don’t see that many accidents on the gyratory itself – more on the roads approaching it. I’m sure it could be improved (I did mention cyclists as a group of particular concern) but I still dispute hideous. Of course we could reinstate the subways…….
In terms of dropping roads down into tunnels and putting ‘something on top’, an example where this was very successful is on the North Circular where there used to be a junction with the A504. Now, there isn’t and although not much has been done with the ‘on top’ bit it could be easily extended over the cuttings each side.
https://www.google.co.uk/maps/@51.5940698,-0.1835423,18.95z
@Alison W
However –
The removal of the junction with the A504 has undoubtedly led to more traffic on roads leading to the remaining nearby junctions than would otherwise have used them; and
Had they wanted to put a junction in with the A504 both the land take and the intrusion would have been very significant – not to mention the costs.
Covering over existing major roads where there are neither junctions or frontages is often a good idea, but it is expensive and there are no transport benefits that will acrue.
@Alison W
I agree that it’s worked very well for the residents around that former junction. Walking along the A504 it was surprisingly pleasant, and the A406 is well camouflaged.
It has the added advantage that when the A406 is gridlocked, which it often is, all of the roads that have junctions with it become gridlocked too, and the A504 becomes the only way to cross the A406 in a reasonable time..