Car use

Car useEconomicsTransportTravel

My new book, titled ‘Travel Behaviour Reconsidered in an Era of Decarbonisation’, brings together arguments and evidence that I have discussed briefly in my commentary columns in Local Transport Today and in previous books intended for non-specialists. This book, aimed mainly at professionals and academics, is fully detailed, evidenced and referenced, yet concise and (I hope) cogent, the core of which is a critique of orthodox transport economic analysis and modelling, plus proposals for fresh approaches. It is published by the UCL Press, part of my own institution, an academic open access publisher launched in 2015, that makes copies of its books free to download as PDFs and claims more than 10 million downloads so far. In this blog post I will outline the main themes of the book, as a trailer to encourage readers to access the full text.

I argue that the need to reconsider travel behaviour and its analysis is two-fold. First, decarbonising travel could be achieved both by new technology and by altering behaviour so that we make less use of the car. The question for consideration is whether such behaviour change is feasible in practice on a scale that would make a useful contribution.

Second, I argue that there is a need to reconsider the economic analysis of transport investment so that this reflects the observed travel behaviour of real people in the real world, as opposed to assumed behaviour of utility-maximisers functioning within constrained analytical frameworks, the orthodox practice.

Behaviour change

To set the scene, the first chapter of the book outlines the pattern of travel on Britain, largely based on findings of the National Travel Survey prior to the pandemic. (UK data is particularly extensive, but I refer to other countries where possible.) The main feature, of course, is the dominance of car travel, which brings with it a variety of problems familiar the LTT readers. Yet the attractions of the car tend to be underestimated by those who hope for a shift to public transport and active travel. The car provides convenient door to door travel over short to medium distances where road traffic congestion does not cause excessive delays and parking is available at both ends of the trip. These conditions may not be satisfied in city centres, where public transport can be provided most economically and where catchment areas, whether for schools or supermarkets, are tighter, making active travel more feasible. But beyond city centres – in the suburbs, towns and rural areas – alternative to the car are much less attractive and mode shift much more difficult to achieve.

Yet the car is not attractive just for its utility; there are also ‘feel good’ factors that prompt car ownership and car-dependent lifestyles. Witness that cars are parked for 95% of the time, a good economic argument for car sharing, but conversely an indication of the value placed on private ownership. Witness also the growth ownership of SUVs, not least in urban areas where there is little practical need for a large 4×4 in place of a traditional smaller hatchback. The motor manufacturers are naturally focused on satisfying such feelings; and governments are supportive of auto industries for reasons of industrial and employment policies.

In the third chapter of my new book, I outline the important consequences of the coronavirus pandemic, a ‘natural experiment’ that showed how digital access could substitute for physical access under ‘lockdown’. Yet once the restrictions were lifted, car use returned quickly to pre-pandemic levels, consistent with the attractions of the car for gaining physical access to people and places, activities and services.

Chapter 6 discusses the routes to transport decarbonisation. For surface transport, electric propulsion is by far the most important means, though the equivalent in aviation is much more difficult. Some analysts and policy makers argue for a substantial reduction in car use as well, for instance by 20% as soon as 2030. But because of the attractions of the car, and given the built environment we have inherited within which trip origins and destinations very largely arise, any such reduction reflects much wishful thinking. The best prospects are in city centres where rail in all its forms provides speedy and reliable travel compared with cars, buses and taxis on congested roads. But urban rail is costly and takes a long time to build. Cycling infrastructure is much cheaper and quicker to implement, but largely attracts people from public transport, not from their cars.

So the prospects seem quite limited for changing travel behaviour and reducing car use on a scale that would make a useful contribution to decarbonisation objectives. How did we get to this state?

Changing travel trends

The historic trends in travel behaviour, the successive changes that have occurred, and their implication for future demand, are at the heart of what the new book explores. The evidence presented in the second chapter suggests four eras of travel: first, early man came out of Africa to populate the habitable earth, walking for 3-4 hours a day, covering around 3000-4000 miles on average, hunting and gathering. Then, starting 12,000 years ago, settled farming communities came into being, when average daily travel time fell to about an hour a day, covering about 1000 miles a year at walking speed (horse drawn vehicles on poor roads were not much faster).

The third era began in 1830 with the opening of the first passenger railway, between Manchester and Liverpool, utilising the energy of coal to travel faster than walking pace. Oil in the twentieth century permitted mass mobility through the internal combustion engine employed for road vehicle propulsion, as well as air travel. And the modern bicycle harnessed human power for local trips at faster than walking pace. According to the National Travel Survey, the average distance travelled in Britain increased to reach about 7000 miles per person per year by surface modes by the end of the twentieth century, with average travel time invariant at an hour a day. But then growth ceased, in part the result of exhausting the scope for faster travel through refinement of established technologies. This was the beginning of the fourth era of travel, that driven by the need for decarbonisation.

Each of these past innovations in transport technology based on fossil fuel energy led to a step-change increase in the speed of travel, and in turn to increased distance traversed in the long-run invariant hour a day of daily travel. Hence the benefits of faster travel were taken in the form of greater access to people and places, employment, services and activities, to family and friends, with the enhanced opportunities and choices that improve our quality of life.

In contrast, the new transport technologies seem unlikely to result in increases in speed of travel or of access. Electric propulsion is important for decarbonisation but does not increase the speed of travel. Digital platforms, exemplified by the access readily provided to car travel by the likes of Uber, and digital navigation, known in the road context as satnav, improve the quality of the journey without increasing speed. And automated vehicles on roads shared with conventional vehicles seem unlikely to permit faster trips. So these, the main new technologies, will not increase access benefits to users of transport networks.

A second reason why the growth of average daily distance travelled ceased to increase at the turn of the century, is evidence that those with the availability of a car in the household or good public transport services have arguably adequate levels of access, choices and opportunities, such that there is no need to travel further. Hence demand can be said to be saturated, a general feature of mature markets, and with no reason why travel should be an exception. However, travel to permit access has two distinct characteristics. First, improved access to any given class of destination is subject to diminishing returns, a standard economic concept. And second, access increases with (up to) the square of the speed of travel, reflecting elementary geometry. The combination implies that per capita travel demand for the purposes of access may be expected to saturate, consistent with the findings of the National Travel Survey and other sources.

While per capita travel has ceased to grow, the UK population is increasing, which requires consideration of how this may propel travel demand growth. Much would depend on where the growing population would be housed: new homes on greenfield sites would increase car use, whereas accommodating population growth within existing urban areas would point towards improvement of public transport services to meet the associated transport needs. The scale and location of new homes is currently a major issue of national policy, yet to be settled.

So the fourth era of travel is characterised both by the lack of new technologies to travel faster, and by substantial travel demand saturation, both helpful to implement transport decarbonisation. Yet population growth accommodated on greenfield sites is unhelpful. Overall, the scope for a significant reduction in travel demand seems quite limited.

Appraisal and modelling reconsidered

The second core theme of my book – decision-making processes for transport investment – leads to a fairly detailed critique of conventional transport economic appraisal which is based on the supposition that the saving of travel time is the main benefit of investment in new capacity. My conclusion is that it has not been possible to achieve a self-consistent methodology in this territory even after some sixty years of effort. One consequence is a mismatch between the policy objectives of many high-profile investments and the conventional estimation of economic benefits, which is therefore suitably massaged to align with the policy.

At the same time, there has been growing general recognition that the main benefit of investment that allows faster travel is increased access. However, attributing monetary value to access has proved difficult conceptually, and has not been successfully developed into a methodology for practical application. Besides, as noted above, travel demand for the purposes of gaining access is subject to saturation, quite unlike demand based on the supposition of time saving, which means that the latter cannot be a proxy for the former.

Identifying the benefits of investment as enhanced access creates problems for transport modelling, another issue I explore in some depth in the new book. Transport models to justify major investments typically comprise two parts: a variable demand multimodal traffic model, the outputs of which are inputs to an economic model that allows estimation of monetary benefits, comparing the with- and without-investment cases, and hence yielding the benefit-cost ratio, important for the decision to invest. Yet benefit in the form of increased access cannot be accommodated by the economic model as it exists, on account of the assumption of transport economists that time savings are the main benefit. This therefore requires the traffic modellers to constrain model outputs to a counterfactual case in which travel time is saved, rather than used to travel further for greater access, disregarding the increased vehicle-mile-related externalities and land use change that arise in reality. So transport modelling as currently practiced does not provide a secure basis for the estimation of investment benefits, nor of carbon and other externalities.

Fresh approaches

Pulling all these threads together, the final chapter of my book suggests some fresh approaches to travel analysis and transport policy, to respond to the methodological shortcomings of conventional appraisal and modelling that I identify, and to the need to make progress towards the Net Zero objective. I suggest a presumption that Britain has a mature transport system comprising the road and rail networks, consistent with travel demand saturation as discussed above. This is already the case for urban roads, where, in the last century, investment in increased capacity in the form of both new (often elevated) highways and enlarged carriageway for vehicles took place in response to growing car ownership; whereas more recently the trend has been to recover such capacity for active travel and prioritised bus routes. Demand for vehicle travel on urban roads must now be managed within constrained capacity.

There is a good argument for treating the interurban road network as mature, so not aiming to invest to increase capacity generally, hitherto justified by notional travel time savings. There may be benefits from particular investments associated with land use change; for instance, were a third runway at Heathrow airport to be built, investment in surface transport infrastructure would be needed to cope with increased passenger numbers, the resource implications of which should form part of the cost of the project as a whole.

More generally, location-specific road investment to make land accessible for development could be justified where the decision to develop is made jointly by planners, developers and transport authorities and where the developer contributes to the cost of the infrastructure. The case would be based more on commercial considerations than on orthodox welfare economics, although carbon emissions and other externalities should be taken into account.

Cessation of investment in a national road construction programme would be a big shift of policy politically, although this is what the Welsh government decided two years ago. But there is still widespread support for road investment among most politicians, national and local, the latter because the funds provided by central government are seen as ‘free money’. It is widely supposed that increasing road capacity reduces congestion, improves connectivity and boosts economic growth, although the basis for this supposition is tenuous. And of course, the construction industry and the consultancies that benefit from the funds that flow are also supportive. Nevertheless, there is a strong case for a switch in effort from costly investment in new civil engineering structures to making best use of the physical infrastructure we have. Economic analysis and modelling would then focus on the efficient management and use of the network, closely linked to the operational analysis of the road network in real time, a topic that has been neglected hitherto. To do this we now have the opportunity to take advantage of digital technologies that are already in wide use and are both scalable and relatively low cost.

Transport economic analysis has focussed on individual projects. In contrast, it has always been difficult to articulate an economically persuasive strategic case for a programme of transport investment. Regarding the transport system as substantially mature changes the main challenge from justifying a collection of investment projects to reconciling transport operations with the Net Zero objective.

The key elements of a strategy, whether of a particular sector or of transport provision as a whole, are:

  • the switch to zero-emission vehicles for surface transport;
  • employment of digital technologies to optimise network operations;
  • and financial support for public transport.

Alongside these, any investment in new capacity should now be specifically justified case by case to support economic development, such decisions being taken jointly with planners and developers, and schemes funded in part by the developers, as beneficiaries.

Active travel is not included in my key elements of strategy, although it is a good thing in many respects, including health and environmental benefits – I myself am a cyclist. But I see limited scope for getting people out of cars onto bikes. Copenhagen is a city famous for cycling, but car mode share is only slightly less than in London, while public transport is half that in London. So you can get people off buses onto bikes, but harder to get them out of cars, even in a small, flat city with excellent cycling infrastructure and a strong cycling culture.

One reason is that in Britain 80% of carbon emissions from car journeys arise from trip of more than 5 miles, and 95% from trips of more than 2 miles, so only limited opportunity to get switch to cycling and walking respectively. I don’t therefore see promotion of active travel as a central
element of a national transport strategy, although in cities with crowded public transport it may have more attractions, as in London, albeit with some loss of farebox revenue.

POSTSCRIPT

The new government’s policies: do they meet the need?

The manuscript of my book was completed before the General Election, which has led to a new focus on the basis of transport decision-making and the sources and allocation of funding. The new Labour Chancellor Rachel Reeves soon cancelled the proposed Arundel Bypass on the A27 and the tunnel adjacent to Stonehenge on the A303, as well as some minor rail schemes, laying the blame at the budget deficit.

Louise Haigh, the new Transport Secretary, has meanwhile been required to undertake a review of £800m of unfunded commitments in her department and a basis of prioritisation of projects, suggesting shortcomings in its system of controls. A new Office of Value for Money is to be established to identify areas where the government can reduce or stop such problems or improve the value of spending.

The government also intends to establish a National Infrastructure and Service Transformation Authority (NISTA), comprising the National Infrastructure Commission and the Infrastructure and Projects Authority, to drive more effective delivery of infrastructure across the country and support a 10-year infrastructure strategy. A seasoned transport and railway professional, Lord Hendy, has been given the rail policy brief, and a junior minister at the Department for Transport, Lilian Greenwood, the title ‘Minister for the Future of Roads’. All this suggests that there may be changes from past policies in the offing, in a direction that could be consistent with the arguments I have been making.

Such new approaches inevitably raise questions about the competence of the Department for Transport that cannot just be attributed to misjudgements by past Conservative ministers. A point of comparison is Transport for London, which is generally agreed to be a world leading planner and provider of regional public transport and major roads. TfL has a good vision of how London’s transport system needs to develop, aiming to implement the Mayor’s Transport Strategy and consistent with his responsibilities for housing, the environment and for London’s economy. This vision involves major investments in rail, low-cost investments in active travel, plus operational improvements across the board. Such a vision requires validation of individual investments – the ‘vision and validate’ approach.

But here it is important to recognise that decision makers do not simply bring an open mind to consider a portfolio of potential investments from which they might choose. Generally, those in charge – senior and experienced people – will have a pretty good idea of what investments they would like to make, and can justify. They seek validation from analysts – modellers, planners, economists, engineers. Validation includes securing good value for money and complying with all legal requirements. It is thus not often that major misjudgements occur in the choice of projects pursued. The popularity of the new Elizabeth Line, formerly known as Crossrail, is a good example of what has been achieved, despite overruns of construction time and budget. Other successful projects have been the introduction of the Congestion Charge and the upgrade of erstwhile ‘Cinderella’ rail lines into the London Overground.

In contrast to TfL, the Department for Transport has had neither a vision nor a strategy, nor has been a ‘driving force’ in the proposal/selection and delivery of the potential ‘best’ schemes, or the promulgation of effective ‘system management’ concepts. What it has had are problems with the major sectoral ‘wish list’ expenditure programmes for road and rail, the economic benefits of which it has found difficult to convincingly justify, both at programme level and for individual projects, but creating huge pre-emptive budget requirements. It has overseen serious cost overruns on HS2, had many setbacks and criticisms in the courts in the face of litigation by those objecting to road schemes. And it has struggled to reconcile the impacts of a large road investment programme with the Net Zero climate change objective, having its overall decarbonisation plans for transport twice rejected in the courts.

My book discusses many of the proposed investments supported by the Department as case studies in the application of a defective appraisal methodology, including the virtually impossible to justify Stonehenge A303 tunnel, questionable smart motorway schemes (a programme cancelled by the previous government as the result of public anxieties about safety, but falling well short of expectations economically), HS2 (now truncated), and the extended saga of a third runway at Heathrow. In some cases, the analysis was forced to comply with a prior policy decision, in others key strategic economic benefits were poorly treated or disregarded.

There is now surely a good case for an independent review of transport investment appraisal and modelling to identify a fit for purpose methodology for an era in which the high-level strategic priority is decarbonisation. I hope my book might provide useful evidence and argument were such a review to take place.

My new book is available at https://uclpress.co.uk/book/travel-behaviour-reconsidered-in-an-era-of-decarbonisation/ free to download as a PDF.

This blog post was the basis of an article in Local Transport Today of 5 September 2024.

Car useEconomicsTravel

Professor Glenn Lyons has been developing the concept of Triple Access Planning over the past decade and has now published, with 17 co-authors, a 130-page Handbook setting out the approach in some detail. The essential idea is that nowadays we seek access to other people and places by three means: spatial proximity, physical mobility and digital connectivity, each employed to different degrees to meet our needs. Accordingly, if transport planners consider only the transport system, they are ‘dangerously blinkered’ and invite uncertainty into decision making by ignoring the other two systems, it is contended.

The focus on access (or accessibility) as the real objective, rather than movement, is very welcome as an approach to planning. Access is what we seek – to people and places, activities, services and employment, friends and family, for the opportunities and choice that improve the quality of our lives. Over the past two centuries, physical access using mechanised transport systems based on fossil fuel energy arrived with the Industrial Revolution and was rapidly developed, indeed was economically and socially transformational – though not without damage. Next came telecommunication, latterly offering apparently limitless digital connectivity, again having a revolutionary impact. Meanwhile changes in how land is used and the locations of activities relative to one another has reshaped the world out of all recognition.

There can be little dispute that the ‘three option’ thinking is very useful in putting transport provision itself in its proper place. Yet the Triple Access Planning approach, as set out in the new Handbook, has its limitations.

Triple Access Planning is stated to be a way of thinking that marks a change for transport planning from the ‘predict and provide’ paradigm to ‘decide and provide’. This is a fashionable shift of perspective, described as a ‘vision-led’ philosophy, for which there are good arguments in respect of addressing emergent issues such as sustainability. Yet the question avoided is whose vision, and who decides? The answer presumably is that of planners, and of the politicians they serve, both national and local, but who must nevertheless take account of the views of those whose taxes pay their salaries and who elect them into office. The democratic process often impedes the deployment of measures that planners would see as beneficial to the community, but which many members of the public may see as detrimental to their personal well-being, particularly if less car use is proposed. For instance, the Handbook cites as sound thinking the Scottish Government’s Climate Change Plan of 2020 that made a commitment to a 20% reduction in car kilometres travelled by 2030 compared to pre-pandemic levels –  an example of decide and provide, but one for which measures to implement such a substantial change have not been articulated. Generally, the Triple Access approach seems designed for planners and has comparatively little to say about the practicalities of gaining general public support for its proposals.

A second, and more substantial limitation of Triple Access Planning is the lack of economic content. Resources are always constrained, so that planners and politicians have to be concerned with the relative cost-effectiveness of different approaches to meeting access needs and their wider consequences.

There is quite a lot that can be said about cost-effectiveness of measures to enhance the three components of Triple Access Planning. Spatial proximity is very largely determined by the built environment we have inherited, whether the low densities of sprawling US cities such as Los Angeles, or the high densities of admired inner areas of European cities like Paris or Barcelona. Generally, UK cities are relatively low density, reflecting a preference for single family homes with gardens. While there is scope for what is called ‘gentle densification’ of existing communities, we could not afford, nor would we wish, to attempt large scale redevelopment of suburbs to higher density. The historic development of British cities therefore limits the opportunity to enhance spatial proximity.

On the other hand, enhanced spatial proximity is an option for some types of new build, for instance based on high rise apartments on urban brownfield sites. However, for new greenfield housing at low density, built to sell by developers, lack of spatial proximity seems not to be seen by purchasers as a disadvantage, although campaigners remonstrate at the lack of alternatives to the car. Occasionally, wholly new settlements might be created, as exemplified by Britain’s Post-War New Towns, the last of which, Milton Keynes, was designed to accommodate the growing car ownership of that era. Subsequently, Poundbury, an urban extension on the western outskirts of Dorchester masterminded by the Duchy of Cornwall (led by the then Prince of Wales), was designed as a walkable community, giving priority to people rather than to cars. Nevertheless, because Poundbury is small – 5,000 homes are planned – the mismatch between homes and jobs means that residents are likely to travel further afield for work, such that car ownership is higher than in Dorchester and the surrounding region, with 55% of residents using a car or van to get to work.

New built homes increase the national housing stock by only about one per cent a year, so it is the existing built environment, homes and facilities, within which almost all trip origins and destinations occur, that places a limit on improving spatial proximity, with little scope for cost-effective change.

Physical mobility meanwhile depends on the historic transport infrastructure already in place that accommodates all trips. There is much debate about adding capacity to the road and rail networks, and considerable public resources have been allocated for this purpose by successive governments. Yet adding capacity is costly, whether shifting earth, pouring concrete and rolling tarmac for new roads, or constructing track, tunnels, power supplies and signalling for new rail routes, so that the net addition to capacity is quite small. For the strategic road network, annual additional lane-miles barely keeps up with population growth. And for rail, the prospect of escalating construction costs may lead to truncation of plans, as with HS2, or to an unwillingness of decision makers to commit public money in the first place.

So the possibilities for cost-effectively increasing the physical capacity of transport infrastructure to enhance mobility are quite constrained. However, there is scope for making better use of existing networks by means of digital technologies, thereby increasing access, particularly on the railways where modern signalling and control technologies allow higher train frequencies to be achieved while maintaining safety standards. Digital technologies to increase effective road capacity are more difficult to implement, given the diversity of traffic, but warrant more attention than they are receiving, particularly to exploit the very general use by drivers of digital navigation, known as satnav in the road context. But in any event, higher speeds of travel are unlikely to be achievable by digital or other new mobility technologies, which limits increased access by physical mobility, given the constraints on the time available for travel within the 24-hour day.

Enhancing access by improved digital connectivity seems a more promising approach, given the scalability of the relevant rapidly advancing technologies and the resulting cost reduction, hence the ubiquity of digital connectivity, driven by Wi-Fi and Broadband that have facilitated a variety of telecom innovations and apps for online interaction, such as Zoom or Teams, and services such as Skype and FaceTime, as well as social media sharing and conversational networks, all at an affordable cost.

So enhanced access through the new digital technologies is a persuasive approach in theory, but what about the practice?

There has been a long-running but inconclusive debate about whether digital communications technologies can and will actually substitute for physical mobility, or instead mainly complement it, for instance by allowing people to cultivate wider social and business networks, with whom face to face contact from time to time would be important to sustain relationships, and the parallel desire to undertake ‘experiential’ activity through leisure travel. The forced cessation of travel during the coronavirus pandemic showed that we could make much more use of digital communications than we had previously. Although travel behaviour has not yet returned to pre-pandemic levels for all modes, it has come fairly close, and indeed sometimes exceeding prior levels, particularly car use and air travel. In respect of the journey to work, the tensions between desires of employees to work from home for part of the week, and the wish of their managers to have them in the workplace, seem not to have yet fully played out. But in any event, it would be hard to conclude that the desire for face-to-face access has changed substantially, let alone being in decline, despite the availability of cost-effective digital technologies that make remote personal interactions possible.

The pandemic also led to a boost to online retail, but subsequently growth returned to the prior trend. Much shopping is a social and hands-on activity, so a new balance will emerge between the physical and the virtual – perhaps in the quite near future. Yet public policy is focused on sustaining the vibrancy of town centres, not promoting digital connectivity as an alternative to bricks-and-mortar retail. More generally, digital technologies may be comparatively low cost compared to physical structures, yet cost-effectiveness requires the utility of digital technologies for access purposes to be assessed in comparison with physical mobility – with the outcome still to be determined. The comparative carbon footprint of electricity-driven digital activity compared with physical mobility, and its own shift to electric power, is similarly far from yet clear.

The Triple Access concept is welcome in that it encourages wide ranging thinking about the possibilities for meeting people’s needs for access. Yet when an assessment of the cost-effectiveness of measures that might be adopted is superimposed, the scope for implementing innovative measures becomes quite constrained.

A third limitation of the Triple Access approach is the lack of consideration of the basic characteristic of access, which is that it is subject to diminishing returns – the more access you have to any kind of service, the less the value of a further increment. The Competition Commission, as it then was, some years ago investigated competition between the main supermarket brands. This involved relating where people lived from census data to where the large supermarkets with car parking were located, finding that 80% of the urban population had three or more supermarkets within 15 minutes’ drive, and 60% had four or more – arguably offering good levels of choice. You could ask yourself whether you would need to drive further to have more choice in the weekly shop – if not, your demand for travel to supermarkets would be said to have ‘saturated’. This has come about over the years through growing household car ownership and investment by the supermarket chains in more large stores, both trends now largely played out.

For those who don’t run a car and rely on local food stores, similar developments have been widely seen, with the main chains opening small local branches and many thriving independent minimarkets staying open for conveniently long hours. In my own neighbourhood, for instance, in an inner London borough, there are branches of two chains and some four independents, all within ten minutes’ walk. However, there remain ‘food deserts’ in areas of low income where choice of outlets is limited.

How much shopping choice we need depends on the nature of the goods or services we seek. For standard products at fixed price, such as newspapers, the nearest shop suffices. For fashion goods, a trip to the city centre may be justified, plus a search of online outlets. Many services are routinely purchased online, insurance in all its forms, for instance, and much travel booking.

A second characteristic of access is that it increases, approximately, with the square of the speed of travel: what is accessible is proportional to the area of a circle whose radius is proportional to the speed of travel (recalling elementary geometry). A constraint is the density of the road network, highest in urban areas, lower in rural. But in any event, access increased markedly as car use replaced slower modes. It is the combination of access increasing with up to the square of the speed of travel while being subject to diminishing returns implies an expectation of the saturation of travel demand to achieve access to frequently used activities.

In practice, those who have available use of a car and/or good public transport provision, plus fast broadband, arguably have sufficient access to sources of most goods and services to meet their needs, implying that their demand for access has saturated. Demand saturation is a phenomenon that arises generally once uptake of some new innovation is widespread, washing machines for instance where the market now depends on replacement of worn-out models plus population growth. There is no reason to suppose that demand saturation would not apply to travel, although it is a topic neglected by investigators and theorists.

In conclusion, while Triple Access Planning encourages fresh thinking, the constraints on practical measures, and the circumstances in which these might be applied, seem thus far to have been underestimated. Limiting factors are insufficient consideration of public aversion to change, the cost-effectiveness of measures that might be adopted, and the fundamental characteristics of access benefits. Nevertheless, the aim of meeting the human need for access by means other than investment in transport infrastructure is a welcome extension to conventional transport planning and analysis that deserves further development.

This blog post is the basis for an article published in Local Transport Today 2 July 2024.

Car useEconomics

The recent publication of the Full Business Case (FBC) for the A428 Black Cat to Caxton Gibbet Improvements Scheme highlights the policy inconsistencies and misleading supporting analysis that typify road investments. We have the Introduction by the Roads Minister explaining that A428 has long been seen an important section of the strategic road network that required upgrade due to its problems of congestion, poor journey time reliability and resilience, and how accordingly the Scheme will enhance journey times, support local and regional economic growth, create jobs, and improve employment and the environment.

To justify these high level objectives, the 270 page FBC grinds through all possible aspects of the case for constructing ten miles of dual carriageway. This is impressive in its way, but is the effort ‘proportionate’, to use a favourite DfT term, I wonder? Perhaps the intent is to ensure the proposal is crash-proof in the event of any further legal challenge; or perhaps to deter potential challengers from initiating such challenge. Then again, the economics of the investment look pretty marginal, based on opaque reported analysis, so perhaps extensive quantity is seen as a counterbalance to thin quality in making the case for the Scheme.

Journey time savings for all classes of vehicles, of £633m, are claimed as the main benefit, as is usual (although in 2010 prices discounted to 2010, implying some antiquity to the modelling). But this is not split between business users (cars and road freight) and non-business (commuters and others), as must have been modelled, since each class has a different value of time. In other cases I have examined, the split between business and non-business has been shown, with time savings to non-business users almost entirely offset by increased vehicle operating costs, the result of local users diverting to take advantage of faster travel provided by the improved route. The economic case for a scheme depends on the scale of such diversion, since local users pre-empt capacity intended for longer distance business users. This failure to split the journey time savings looks like intentional obfuscation.

The time saving benefits are in any case offset by quite substantial carbon disbenefits worth -£182m. My impression is these are much more than in previous road schemes, reflecting updated carbon values promulgated by the former Department of Business, Energy and Industrial Strategy. So no longer are increased carbon emissions dismissed as de minimis, at least in economic terms. Nevertheless, if, as I expect, the long run benefits of the scheme mainly take the form of enhanced access, rather than time savings, the increased vehicle-miles-travelled (known as ‘induced traffic’), would increase externalities. So carbon disbenefits are likely to have been underestimated.

Whatever the magnitude, new road capacity must generate more carbon emissions. What needs to be spelled out is the total increase in carbon from the whole road investment programme, to see to what extent this impedes delivery of transport’s contribution to Net Zero. Regrettably, the new 114 page National Networks National Policy Statement, recently published, fails to prescribe programme level estimation of carbon emissions. If neither at programme level nor at scheme level, where is this significant and unwanted damaging impact to lie?

While the cost data in the FBC are redacted, presumably to protect National Highways position in other road scheme projects out to tender, the initial benefit-cost ratio (BCR) is estimated as 0.92. To make the investment at all viable, ‘wider impacts’ of £282m have been adduced to yield an adjusted BCR of 1.63. This scale of wider impacts seems very high for a non-urban scheme, based as it is on an elaborate, yet in reality, not much more than a back-of-the-envelope calculation. It may be that it is this tenuous boost to benefits, to put the Scheme in the DfT’s medium VfM category, that has necessitated the supporting assessment and sign off by the two accounting officers, the DfT permanent secretary and National Highway’s chief executive.

For my part, I suspect that optimism bias is at work to generate even an initial BCR of 0.92, requiring yet more optimism to get to 1.63. So I would not regard the figures in the FBC as robust, even though the analysis is presented as exceptionally extensive. Yet I have some sympathy for the highways engineers at National Highways, who see this scheme as necessary to create continuous dual carriageway between the M1 at Milton Keynes and the M11 at Cambridge, with onward travel to the ports of Felixstowe and Harwich. A stretch of single carriageway in what is otherwise a dual carriageway route is, to them, offensive. Naturally they seek to add capacity to reduce congestion and achieve a free-flowing network. This approach would also seem logical and persuasive to most local politicians and business leaders not versed in the principles of transport planning and the observed road user responses to additional capacity provision, let alone the minutiae of scheme appraisal and Benefit Cost Ratio calculation.

However, congestion on roads in well-populated parts of the country typically displays morning and evening peaks, indicating use by commuters, who have choices of route. Travel patterns are not fixed and are certainly influenced by network changes. So new free-flowing routes tend to attract additional traffic, whether by diversion in the short run to achieve the saving of journey time, or in the longer run through permitting longer trips within the travel time available. Both of these are beneficial but are not the benefits conventionally modelled, nor are they allocated to the categories of traffic that underpin the original justification for the scheme. Generally, where commuters and longer distance business users share road space, free flow is difficult to achieve, particularly at peak hours.

There is a gulf between the simplistic but erroneous headline justification for this and similar road investments, and the complex, opaque and misleading quantified supporting analysis. It would be good to find a common language to bridge this gap, based on a behaviourally realistic account of what is going on, what options there are to improve matters, and what is most likely to happen in practice if changes are made. Applying the concept of Heuristics is one possible solution.

Heuristics are simple rules – rules-of-thumb – for making decisions, coming to judgement, solving problems or shaping intuitions, that work well enough in most circumstances. I want to suggest that transport planners and practitioners would benefit from relatively simple heuristics in offering advice to decision makers about addressing perceived issues of system inadequacy and the justification for providing additional capacity in a range of circumstances.

This would mean distilling the evidence from research by academics and others to yield rules-of-thumb that are intuitively credible to both practitioners and decision-makers. One problem is that research findings are often based on case studies, specific to place and time, and are path-dependent, so generalisation may be difficult. Besides, the research literature in the area of transport studies has burgeoned in recent years, not necessarily to overall professional benefit, in part the consequence of the proliferation of open access journals that charge researchers for the cost of publication, rather than rely on library subscriptions; this creates an incentive for the journal to downplay rigorous peer review and editorial oversight in the interest of increasing income, and the consequence is a proliferation of case studies that may gain academic credit but are of limited general applicability.

Moreover, the research literature may overlook the authoritative information available in official publications, including statistical series, as well as in the unofficial ‘grey literature’ publications from think-tanks and others. Hence formal reviews of the ‘research literature’ may therefore be both unwieldy and incomplete, making it hard to see the wood for the trees and so difficult to draw useful conclusions. Government departments accordingly now seem often to commission ‘rapid evidence reviews’, which give consideration to a manageable number of selected papers to save time and effort, but selection may be biased, consciously or otherwise, to support the expectations of the commissioning department, and the most important recently revealed insight and understanding may not yet be included.

In these circumstances, I believe helpful Heuristics would need to be based on a deep and wide knowledge of both publications, practice and observed data, to establish a cogent and concise framework for analysis and decisions, in accessible language, not set in stone but subject to review in the light of new evidence and experience.

One area where rules-of-thumb may be particularly useful for transport planners and decision makers is in the tackling of road traffic congestion, central to the contemporary travel experience and to transport investment, such as the A428 Scheme, but for which repeated interventions have demonstrated little impact in practice. To the extent that relief may be achieved, this is more short term than long term. Yet huge amounts of public expenditure are justified by the objective of relieving congestion and boosting connectivity, with little evidence of success at outturn.

So, let me suggest some rules-of-thumb for thinking about road traffic congestion. I will not cite chapter and verse of the evidence in support, for which see my recent book.

  • Congestion arises in or near areas of high population density where car ownership is also high. More car trips might seek to be made at times of peak demand than the road network can accommodate. Delays ensue, which motivate some road users to make other choices, including adopting alternative routes or times of departures, alternative modes of travel where available, different destinations where there are choices (such as for shopping trips), or not to travel at all (such as ordering good online). Congestion therefore is generally self-regulating in that if demand increases, delays increase and more potential trips are suppressed. Daily gridlock or long tailbacks are uncommon and arise where there are unanticipated obstructions to movement.
  • Increasing road capacity has the effect reducing delays in the short term, but thereafter attracting previously diverted and suppressed trips, as well as permitting new and longer trips, consistent with the maxim that we can’t build our way out of congestion, known from experience to be generally true. The result is additional traffic, known as ‘induced traffic’, which in the short term is the consequences of diversion of commuters and other local users on to the new capacity to save time; and, in the longer term, of road users taking advantage of faster travel to make longer trips to increase access to desired destinations, as well as changing trip origins by moving homes.
  • Interventions that reduce vehicle use initially reduce delays, but this attracts back onto the network previously suppressed trips, thus restoring congestion to what it had been. Interventions conceived as intended to reduce vehicle road use include the promotion of active travel and public transport, congestion charging and road pricing, and consolidation of freight deliveries into fewer goods vehicles.
  • Reduction in urban carriageway available to general traffic can make more space available for bus lanes, cyclists and pedestrians. This initially can increase congestion delays, which leads to drivers making alternative choices. In the longer term the intensity of congestion is difficult to reduce, but the absolute amount of congested traffic would be lessened and could be better managed to benefit the whole population.
  • Induced traffic results in more vehicle operating costs and in additional externalities, including carbon and air pollutant emissions, which public policy is seeking to reduce.
  • The orthodox economic case for road investment relies mainly on the saving of travel time. Yet the evidence is that average travel time is a long term invariant, implying that people take the benefit of faster travel in the form of improved access – to people, places, employment, services and activities, with ensuing enhanced opportunities and choices.
  • Transport models that project travel times savings, comparing the with- and without investment cases, do not reflect the reality that improved access is actually the main beneficial outcome. Access is subject to diminishing returns, implying declining returns to road investment as the road network matures.
  • The car is very popular for its utility in door-to-door travel over short to medium distances, as well as over longer distances when alternatives are less attractive, provided  congestion delays are acceptable and parking is available at both ends of the journey. These conditions may not apply in city centres, where public transport, particularly rail-based in all its forms, provides a speedy and reliable alternative to cars and buses on congested roads. But beyond city centres, in suburbs, towns and rural areas, the popularity of the car as a mode of travel against available alternatives is difficult to challenge.
  • Promotion of active travel has limited impact on car use. The evidence is that improved cycling facilities mainly attracts people from buses, which reduces farebox income and leads to reduced service levels or a requirement for more subsidy. It is difficult to be pro-active to successfully increase walking, which is the slowest mode of travel, permitting the least access to desired destinations for most people.
  • The built environment, within which are located nearly all the homes, facilities and services that are trip origins and destinations, is largely a given, with limited opportunity to increase density through brownfield or infill development. Creation of new communities on greenfield sites with choice of travel modes has proved difficult. Accordingly, there is limited scope for the creation ’15-minute cities’, an aspiration of many urban planners, aimed at reducing car use, congestion, pollution and carbon emissions.
  • As well as being popular for getting from A to B, for many people ownership of a car is attractive for a variety of lifestyle reasons. The fact that cars are generally parked for 95% of the time is a seemingly persuasive economic argument for car sharing in its various forms. But conversely, the desire to own a resource that is so little used is an indication of the value attached to ownership and convenience. This is in part why it proves difficult to shift car owners to other modes. Cars parked at the kerbside reduce carriageway available for vehicles on the move, contributing to congestion delays and deterring some road users.
  • The wide use of digital navigation (known in the roads context as satnav) has the effect of redistributing traffic. Commuters and other local users divert from existing routes to new capacity on major roads, to save time, pre-empting capacity intended for longer distance business users, including freight, so detracting from the projected economic benefits of the new capacity. In addition, traffic diverts from congested major roads to minor roads that offer a less congested alternative route, such minor roads previously used only by those with local knowledge, making them ‘rat runs’ less suited for active travel and detracting from quiet residential environments.
  • The most advanced forms of digital navigation predict journey times, so reducing uncertainty about time of arrival, which is what bothers road users most about the impact of congestion. Digital navigation is thus arguably the best means available for mitigating the perceived impact of road traffic congestion, as well as being vastly cheaper than providing new road capacity.

These rules-of-thumb about observed realities are proposed as ‘good enough’ ways of recognising and addressing the problem of congestion that we face on road networks and identifying effect means of mitigation. I suggest three questions to structure shared thinking about this and the other problems we face, amongst transport planners, politicians, other decision makes and influencers:

Q1 What’s going on here?

Q2 What options do we have to do better, that are both cost-effective and affordable?

Q3 What choices to make?

Responding to the first two questions is the task of analysts, including transport planners, economists and policy advisers, approaching problems with an open mind. Responding to the third question, with the benefits of the answers to the first two, is the task of decision makers in the public and private sectors, as well as advocates of all kinds. Better decisions would be made if those involved are clear about their roles, tasks and expectations. Heuristics, of the kind outlined above, could help them acquire good intuitions of the cost-effective options available, and give others greater insight into the basis on which decisions are made.

Nevertheless, some may argue that such heuristics serve to over-simplify what is bound to be a complex analysis of what’s going on. Albert Einstein said: ‘Make things as simple as possible, but no simpler’. Are these heuristics for understanding and reacting to congestion good enough or are they too simple? Do we still need the full panoply of the Department for Transport’s Transport Analysis Guidance to present to a small coterie of people a theoretical analysis based on problematic behavioural assumptions as to what should be done? Or, as some may believe, to justify, through virtually impossible to decipher analytical complexity (as represented by the likes of A428 business case), someone’s original hunch, then bought into tenaciously by the scheme’s promoting bodies. My own view is that narrative and dialogue based on heuristics would offer an alternative approach, well worth trying, to answer the three questions above in a generally understandable way.

This blog was the basis of an article in Local Transport Today of 21 March 2024.

Car useTravel

The coronavirus pandemic caused major dislocation in society, not least to the amount and modes of travel, with many similarities across countries, albeit differing in detail depending on local constraints imposed on work and travel. This amounted to a ‘natural experiment’ in that an exogenous event led to large changes in travel behaviour over a two-year period, 2020-2021, before the cause faded away and normal life largely resumed, yet with some possible permanent long-term consequences. The findings of the National Travel Survey for 2022 are ambiguous as to whether we are on the path to pre-pandemic normality, or whether some permanent changes have arisen. Transport for London has recently published its annual Travel in London report for 2023 that includes relevant data for the capital. So it is worth considering the evidence for pointers to the future.

The pandemic led to two main changes in how we live and in the related demand for travel: more working from home and more shopping online.

Working from home

While some of those who do not need face-to-face contact with customers, clients or colleagues have always worked from home, the pandemic resulted in a step-change in the numbers adopting this practice. In some cases, this was a sub-optimal response to an emergency, for instance in the education sector. In other cases, this reflected advantages of not travelling to a workplace for at least part of the week, avoiding both the time and discomfort of commuting, flexibility of when to work, and perhaps benefiting from the avoidance of interruptions in the privacy of the home environment.  

For some organisations, it has been found that the workplace office could be dispensed with entirely. For many others, some form of hybrid working has emerged, with employees spending part of the week in the office, although the long-term stability of this outcome is yet to be seen. The extent of hybrid working reflects a balance between the preference of many employees for working at home and the preference of many of their managers for having people in the office – for oversight, to stimulate creative interactions and to induct new staff into the culture and practices of the organisation. This balance is affected by the state of the employment market – the demand and supply of employees with appropriate skills. The market was tight following the pandemic, with low levels of unemployment as many older workers decided not to return. But over time, this balance could shift, particularly if the benefits of agglomeration are as significant as had previously been supposed, so that businesses that have more staff on site prove to be more successful and profitable. On the other hand, businesses that commit to hybrid working may be able to attract staff from a wider area, as well as reducing the expense of maintaining office space for the full complement of staff.

Surveys by the Office for National Statistics of working adults in Britain found that while 50% reported working from home at some point in the previous seven days in the first half of 2020, early in the pandemic, this had fallen to 40% in early 2023; throughout 2022, when the restrictions of the pandemic had been lifted, the percentage of working adults reporting having worked from home varied between 25% and 40%, without a clear upward or downward trend, indicating that homeworking was resilient to the end of travel restrictions. Professionals and those in higher income bands were more likely to work from home, whereas those who require face to face contact with clients or personal engagement with facilities resumed travelling to their workplace – in education, healthcare, hospitality, retail, manufacturing and laboratories.

The emergence of a new normal involving both fully remote and hybrid working raises a question about the value of agglomeration benefits from learning, sharing, and matching in city centres. Estimation of the economic value of agglomeration has been based on econometric analysis addressing the change in productivity in relation to the change in effective economic density, with the biggest benefits accruing to knowledge-focussed businesses, despite remote or hybrid working being most feasible for such businesses. The observed movement of businesses to central locations in recent decades reflects net agglomeration benefits, the positive benefits being offset by the negative, the balance being affected by technological developments. But this may be changing.

Fleet Street, for instance, was once the physical location of the national newspapers in central London, with printing presses in the basements, print workers on floors above and editorial staff on the upper floors. This was a classic cluster, with benefits from shared facilities and staff, allowing news to travel faster and gossip to flourish. But there were offsetting disbenefits: newsprint had to be brought into central London, from where newspapers were distributed across the country overnight, and there were restrictive labour practices reflecting trade union power when the product had to be made anew each day. But then the advent of digital typesetting allowed newspapers to be printed at remote printworks with better access to transport networks, so that the editorial offices could disperse to scattered locations around London. Nowadays, ‘Fleet Steet’ is a metaphor for the newspaper industry, no longer the actual location. With hindsight, the agglomeration benefits and disbenefits were more finely balanced than had been supposed, so that new technology could tilt the balance in favour of dispersion of the cluster.

A question, then, is whether something similar may be happening more generally to knowledge-based businesses that had been benefiting from clustering in city centres. It has long been suggested that modern information and telecommunications would lead to the ‘death of distance’, yet the benefits of agglomeration seemed to trump those associated with dispersal. But then the shock of the pandemic both enforced working from home where possible and brought forward technologies to facilitate online meetings and collaboration based on broadband telecommunications that had steadily been improving. The disbenefits of agglomeration to employees in the form of the time, cost and discomfort of commuting became immediately apparent, with a consequential reluctance to return full time to the workplace. The balance of benefits and disbenefits may have shifted in favour of dispersal, although it may take time to reach a settled outcome.

For employers, increased working from home could lead to a decrease in demand for office space in the centres of cities, although this would depend on how workspace is managed to accommodate staff who are there for only part of the week. Shrinkage of space to save rental costs could make the office a less attractive destination. High quality premises with good facilities within and nearby would be preferred, to attract high quality staff. Older, lower quality buildings are becoming redundant, particularly on account of regulatory requirements to improve the energy efficiency of rented buildings. This presents opportunities to repurpose such redundant workplaces, as has long been the case by creating loft apartments from historic warehouses. The scope for repurposing more recent office accommodation can be limited by the depth of floor plan, since windows would be expected by residents of flats, and by the core location of services. Creation of laboratory space, hotels and student accommodation are being considered. Perhaps the simplest repurposing would be a reversion to residential use of inner city eighteenth and nineteenth century houses built for families with servants but subsequently converted to offices. Such repurposing would fit the concept of the 15-minute city or 20-minute neighbourhood where most needs can be met by active travel within a short distance. However, with many tenants and landlords bound by long term leases, it will take time for the extent of the full changes to occupancy to emerge

While reduced use of public transport for commuting means less crowding at peak times, it also results in less revenue for the operators and so either more subsidy is required, or the outcome is poorer service and/or higher fares. This raise the question of the role of bus and rail travel in sustaining the economic and social vibrancy of towns and cities, particularly those whose density is such the general use of the car is not viable. The scope for raising fares is limited by use made by those who cannot afford a car, which means that some external source of funding support is required. Support from government was increased substantially during the pandemic as an emergency measure, but the longer-term position remains to be seen. Transport for London (TfL) has been more dependent on operating income from passenger revenue than other major cities, hence it was hit harder by the loss of fare income during the pandemic so that tortuous negotiations with central government were required to avoid serious loss of services. The case for increased external subsidy to sustain high quality public transport fits well with the need to decarbonise the transport sector by offering alternatives to car use, given that internal combustion engine vehicles will be dominant for some years to come.

It is possible that the time saved by commuting less will be used for other travel, given the long run invariant hour a day of average travel time. If this other travel is local active travel, cycling or walking, that would be helpful for reducing the environmental impact; if by car, less so, particularly if commuting had been by public transport. Working from home also allows living more remotely from the workplace if travel to work is less frequent; this leads to changes in residential property prices as between urban and rural locations, and new construction where land with planning consent is available for development, with consequential changes for travel behaviour, particularly increased car use.

Online shopping

The other shift prompted by the pandemic was to online retail, growth of which was accentuated markedly. Yet shopping is also a social activity, and the suitability of many goods are best judged first hand, whether the feel and look of fashion items or the bulk of furnishings. Data for internet sales as a proportion of total retail sales had been on a steadily increasing trend before the pandemic, rising from around 3% in 2007 to 19% immediately before the pandemic. It spiked to reach 38% in early 2021 before falling back to 25% in mid-2022, broadly returning to trend, although for how long the upward trend will continue is as yet unclear.

The main impact of this shift to online shopping has been to reduce the attractiveness of city centre department stores, some chains of which have closed entirely while others have shut some branches and repurposed floor space in continuing locations. Stronger city centres that relied on a wide catchment area were most affected by the pandemic, while highstreets in economically weaker cities and towns were less affected, although many were already experiencing difficulty in attracting shoppers and shops on account both of general economic conditions in towns that had lost major industries and the shift to online retail. Over time, rents will adjust to a lower demand for retail floor space, either allowing new entrants or repurposing for other uses.

Implications for travel demand

Department for Transport monitoring data showed that, by April 2022, motor vehicle use nationally had returned to just over 100% of pre-pandemic levels. Public transport use grew back at slower rates and some components have tended to remain below pre-pandemic levels: by late 2023, national rail use was 85% of that observed in the same period in 2019, London Underground use a little higher, and bus use was about 90%, although there have been significant fluctuations due to school holidays, weather events, tourist flows and industrial action. Use of the Underground to central destinations bounced back more quickly at weekends than in the week.

There was a burst of recreational cycling during the first lockdown, reaching a peak of 63% above a 2013 baseline in mid-2021, falling back to a 24% increase above 2013 in late 2022, consistent with a modest rate of long-term growth. Although there were many adaptations to urban roads at the outset of the pandemic to facilitate cycling as an alternative to crowded public transport, the ultimate impact of this will not be clear until the extent of return to the office becomes evident.

The findings for 2022 as a whole, from the National Travel Survey, show only partial return to pre-pandemic levels, which may reflect the emergence of the Omicron variant in late 2021, even though travel restrictions were lifted by February 2022. Thus, average travel time prior to the pandemic was close to 60 minutes a day; during 2020 and 2021 it fell to about 45 minutes, but rose in 2022 to 53 minutes. It would not be surprising if average travel time returned to an hour a day in 2023, although it remains too early to rule out some longer term change in travel behaviour, for instance from increased working from home. Thus, the average number of commuting trips in 2022 was 85% of that in 2019, whereas the average number of education trips (including escorting) was 94% of the earlier year, indicating the greater opportunity for working from home in contrast to studying at home. Average car mileage in 2022 was 89% of that in 2019.

Data published by Transport for London provide a more granular account of the position as of late 2023 (see Figure). Overall public transport demand reached 90% of the pre-pandemic baseline. There has been a consolidation of weekday travel on Tuesdays to Thursdays, where demand is typically higher than on Mondays and Fridays (particularly on rail modes), although only 26 per cent of all London residents have the option to work from home, reflecting a ‘blue collar’ versus ‘white collar’ difference. There is also more travel on weekends than on some weekdays, and slightly longer average journey lengths, all of which appear to be becoming established features of post-pandemic demand.

Conclusions

A key question is whether the travel changes triggered by the pandemic will have long term impacts that will help achieve transport decarbonisation. The evidence is that car use rebounded towards pre-pandemic levels faster than public transport use, where full recovery has yet to occur, and may not do so if working from home persists as an alternative to the full week in the workplace. Active travel at best shows a slow growth trend.

The pandemic has shown that we could make major changes to lifestyle and travel behaviour under the impetus of concerns about personal health. Coming out of the pandemic, some analysts saw indications of a long-term shift to travelling less, notably those working from home making less use of the car. It is possible that working from home will prove to be a long term feature for those for whom it is practicable and where employers are amenable, resulting in more agreeable and less crowded and congested commuting. Yet this leaves open whether and how the saving in commuting time might be used, whether for nontravel activities or for other kinds of journey purpose, and by what mode.

The full impact of the pandemic on travel behaviour therefore remains to be seen, yet the emerging evidence suggests that we largely reverted to pre-pandemic travel behaviour, particularly by car, once the threat to health had receded. The impetus of the climate emergency is less immediately pressing, and so we persist in travel behaviour that meets our needs for access to people, places, activities and services, with the opportunities that ensue, hoping that advances in technology would avoid having to make hard choices about travelling less. Those seeking substantial reductions in car use to mitigate climate change can take but little comfort from the pandemic experience.

This blog was the basis for an article in Local Transport Today 23 January 2024.

Car useTransportTravel

The National Infrastructure Commission published its Second National Infrastructure Assessment on 18 October. The Commission’s objectives, set by the Government when it was established in 2015, are to support sustainable economic growth across all regions of the UK, improve competitiveness, improve quality of life, support climate resilience and transition to net zero carbon emissions by 2050, all within a specified long-term funding envelope for its recommendations.

The NIC’s remit is to issue a comprehensive analysis of the UK’s infrastructure requirements once every five years. This covers all economic infrastructure sectors, setting out recommendations for transport, energy, water and wastewater, flood resilience, digital connectivity and solid waste. The Assessment takes a 30-year view of the infrastructure needs within UK government competence and identifies the policies and funding to meet them.

First, I will look at some of the key conclusions and recommendations concerning transport from the NIC’s analysis, which should be fairly uncontentious, at least for transport planners and practitioners:

  • The public transport networks of England’s largest cities under-perform relative to comparable European cities. Initial priorities for investment should be in Birmingham, Bristol, Leeds and Manchester and their wider city regions, to prevent growth being constrained. The scale of capacity increases required justifies investment in rail- or tram-based projects. The government should make financial support conditional on cities committing to introduce demand management measures to reduce car journeys in city centres, and cities should provide a contribution of at least 15-25% to the funding of large projects, whether from fiscal devolution or transport user charging.
  • Transport budgets should be devolved to all local authorities responsible for strategic transport so that all places are able to maintain existing infrastructure – for example improving the condition of road surfaces – and invest for local growth. This will also help places develop locally led infrastructure strategies through which transport investment can be considered against long term goals and planned alongside housing and land use development.
  • For the national road and rail networks, the government’s first priority should be to maintain existing networks by investing adequately in maintenance and renewal, including ensuring resilience to climate change impacts.
  • In order to align the processes of road and rail capital investment, the government should set a long-term investment pipeline across road and rail around an indicative total budget envelope and with clear common strategic objectives. This should incorporate a strategic vision for the main transport corridors that includes both road and rail, ensuring that they are considered together and not separately.

The NIC goes on to say that the cancellation of HS2 beyond Birmingham, which happened only at the beginning of October, after the Assessment had been completed, leaves a major gap in the UK’s rail strategy around which a number of cities have based their economic growth plans. A new comprehensive, long term and fully costed plan is needed, says the Commission, to set out how rail improvements will address the capacity and connectivity challenges facing city regions in the North and Midlands. Who could argue with that?

More problematic, in my view, is the NIC ‘s proposition that the government should plan and invest in enhancements to the road network, targeting under-performing sections that can facilitate trade in goods, and provide better connections between cities to facilitate trade in services, observing that it is not clear that this happens at present. Accordingly, the NIC has developed a portfolio of road enhancement options, based on a connectivity metric developed by consultants, that gives each place in Britain a score to denote how well connected it is to other places, calculated by taking the average travel time between a given place and other places in Britain, and weighting them by population and distance, which are useful indicators of likely demand for travel between places. This approach is used to identify the worst performing routes on the network with substantial demand potential between key cities and towns (see map in illustration). The portfolio has been developed within a proposed budget for road investment to cover the next 20 to 30 years.

In support of its proposals for road investments, the Commission states that better connectivity will help improve trade efficiency, making it easier for businesses to move freight and trade goods and services. However, the evidence for this is problematical. For instance, one source cited by the NIC concludes that for an inter-regional transport investment, economic activity may shift either to the lower productivity region (the periphery) or to the higher productivity region (the core), the outcome depending on the underlying economic conditions and the type and scope of the investment. This is known as the Two-way Road Effect.

The emphasis of the NIC ‘s analysis is on trade in goods and services, only indirectly on non-business travel. Yet adding capacity to road and rail routes accommodates and generates more use of all kinds. On motorways, for instance, there is evidence that the increased capacity arising from converting the hard shoulder to a running lane results in local users, commuters and others, diverting to take advantage of a faster journey, pre-empting capacity intended for longer distance business users. A low connectivity metric score may well arise from delays due to morning and evening traffic congestion, indicating the existence of substantial car-based commuting. This suggests that enhancement of capacity could be expected to further increase in use by commuters, with little benefit to trade in goods and services. So, I would contend, the NIC’s approach to connectivity is too simplistic.

A further problem with the NIC’s analysis is that although it recognises that road investment will need to be compatible with plans to decarbonise transport, it concludes that the additional emissions from its proposals will not themselves substantially alter the scale of the challenge (which must therefore be borne by the plan to achieve widespread vehicle electrification by 2035). This conclusion is based on embracing the Department for Transport’s projections of road traffic demand growth of 10-28% by 2035 (as indicated in the DfT Decarbonisation Plan), while a road enhancement programme over that period would be expected to increase demand by only around 0.6 to 1.3% (based on historic evidence from a number of studies).

However, the rule of thumb, based on general experience, is that we cannot build our way out of congestion, so any increase in capacity will result in more journeys (good for trade), it will also mean more traffic, resulting in more carbon emissions – at least until fossil fuels are eliminated from road transport – and restoring congestion to what it had been (not good for trade). The Commission’s analysis, suggesting that the additional carbon emissions from its road investment proposals are relatively small, is unconvincing. What is missing is an estimate of the total additional carbon emissions from its programme of road investment, to be compared with the DfT Decarbonisation Plan projection of 620-850 MtCO2 savings from vehicle electrification between 2020 and 2050. If the total additional carbon emissions from the proposed road investments turns out to be relatively small, this implies relatively little benefits to trade; if they are large relative to the impact of vehicle electrification, then the pathway to net zero is put at risk.

A lacuna in the Commission’s analysis of transport infrastructure investment more generally is the failure to consider the application of digital technologies, both to the highway network and the vehicles using it, to enhance the performance of the system overall. The exemplar for this is the application of digital signalling on the railways that allows shorter headways between trains at peak times, thus increasing the capacity of existing track.

Conclusion

I had high hopes for the NIC as an alternative source of policy advice and appraisal methodology when it was set up in 2015. Its analysis of rail investments for the Midlands and North of England offered fresh thinking and was influential in shaping the Government’s plans published in 2021. But the Commission’s proposals for road investment are disappointing, both as regards methodology and conclusions. I suspect at least part of the problem is that its efforts are spread across the whole range of infrastructure investment it is required to cover, so that there is too little capability for deep thinking about how the road network functions and how additional capacity impacts on performance. The NIC needs to develop better models, methodologies and data sources if it to offer fresh thinking for road investment and challenge conventional wisdom and assumptions. If not to provide fresh thinking to that hitherto applied by the DfT, what is the purpose and benefit of the Commission?

Moreover, the Commission was badly unsighted by the Prime Minister’s announcement of the truncation of HS2. The failure of the Government to engage with it on such a major decision prompts a question about the purpose and status of the Commission. The politically-driven redistribution of the funds allocated to HS2 to local transport schemes is quite contradictory to the long term analytically-driven approach that is the remit of the NIC. So, while in principle, analysis of long term requirements for infrastructure investment must be right, in practice short term budgetary constraints and political priorities can render the long view nugatory. One has to ask whether there is a future for the NIC.

A Labour government might well be more sympathetic to the NIC’s role, given that the party in opposition in 2012 established a review of infrastructure planning under Sir John Armitt, now chair of the NIC. That review indeed proposed a National Infrastructure Commission be established. Labour has plans for major capital investment to support the transition to net zero, so having a source of independent advice on such expenditure may be continue to be attractive.

Indeed, there may be a case for merging the NIC with the Climate Change Committee, given the overlap of functions and their cross-departmental approach to future demand and supply. Yet as long as individual departments and their ministers retain responsibility for their budgets and spending plans, with the associated tendency to take a short term view, the strategic may continue to be subordinate to the politically pragmatic.

This blog post was the basis for an article in Local Transport Today of 28 November 2023

Car use

The planning system for adding significant capacity to national rail and rail networks includes a national policy statement that obviates the need for discussion of national policy at local planning enquiries. The existing statement dates from 2015, and the Department for Transport has been consulting on a updated version that takes account, in particular, of the development of policy on transport decarbonisation. The House of Commons Transport Committee has published a critical report that highlights shortcoming in the DfT draft. I submitted evidence.

The DfT draft fails to reconcile the wish to continue investment in additional road capacity with the need to achieve Net Zero objectives. We await with interest the final text of the policy statement, to see if the Department can do better, so lessening the risk successful challenges in the courts.

Car useEconomics

I previously mentioned my analysis of the widening of the M1 motorway between junctions 10 and 13. My paper has now been published in a peer-reviewed journal: Transportation Research Part A, 174, 103749. The abstract is below. Access to the article may be available free of charge for a limited period here

Abstract

Cost-benefit analysis of road investments involves models that generate travel time savings as the main economic benefit. Evaluation five years after opening of a scheme to widen a section of England’s M1 motorway between junctions 10 and 13 found that the traffic moved more slowly than before the scheme opened. Comparison was made with forecast flows generated by SATURN variable demand modelling and an associated economic model. Substantial net benefits to business users were forecast, whereas for non-business users time saving benefits were more than offset by increased vehicle operation costs, consistent with diversion of local trips to take advantage of the increase in capacity. There is reason to suppose that such diversion is facilitated by the wide adoption of Digital Navigation (known generally as satnav), which makes evident the fastest route choices, even at the expense of increased fuel costs. Diversion of local trips to utilise new strategic road capacity seems likely to be a general phenomenon, which detracts from the economic case for road investment. There is therefore a good case to treat the strategic road network as mature, focussing on improving operational efficiency and exploiting vehicle-to-infrastructure connectivity in the form of Digital Navigation.

Car useEconomics

The National Infrastructure Commission has published an Advice Note, directed to the government, on roads policy, to help inform plans for the Third Road Investment Strategy (a five year investment programme for strategic interurban roads). I found this rather disappointing in its analysis of the problem.

The need to decarbonise road transport is obligatory, yet investment in new road capacity is counterproductive, whatever is achievable through the switch to electric propulsion. The Department for Transport’s draft National Networks National Policy Statement, recently issued, persists in addressing carbon emissions at scheme level, where they can continue to be treated as de minimis. There should be a requirement to estimate carbon emissions for the whole future programme (RIS3), when announced.

Given the conflict between road building and achieving decarbonisation, a critical look is needed at the econometric analysis of the relationship between interurban road investment and GDP growth, which is less than convincing. Likewise, scepticism is justified as regards projections of the growth of future traffic growth based on demographic and economic factors; per capita car use did not increase for twenty years prior to the pandemic. The main factors determining car use per capita are speed of travel, time available for travel and household car ownership, none of which seem likely to increase in the future.

The benefits of road construction are subject to diminishing returns. Arguably, the UK has a largely mature road network. For instance, cities such as Stoke-on-Trent and Wakefield, which would see themselves as lagging economically, are well located in relation to the Strategic Road Network. For devolved regional governments able to decide priorities for infrastructure investment, new road capacity may not be high, except where it is required to permit major site-specific development.

The Advice Note argues that effective prioritisation of road projects requires a focus on the links that will be most significant for trade between major regional cities. However, interurban roads are used by commuters travelling into cities. It is a common situation for traffic on interurban routes in or near populated areas to show pronounced morning and evening peaks, the consequence of commuting. If capacity is increased to alleviate congestion at these times, this will attract commuters from local roads on account of the faster travel made possible – one type of induced traffic, and one reason why we cannot build our way out of congestion. This diversion of commuters on to new major road capacity is facilitated by the wide use of Digital Navigation (generally known as satnav), which makes fastest options clear. The increased local commuting pre-empts the additional capacity intended for longer distance business users.

The proposal for a systematic analysis of the road network to see which routes are slow or unreliable is reminiscent of the approach of US highway engineers to categorising levels of service as the basis for proposals to increase capacity, thus justifying multilane freeways that attract more traffic. Yet there is a conflict between accepting the need for further road construction and demand management measures to reduce carbon emissions from the sector.

We no longer add to urban road capacity to accommodate growth of demand for road traffic; indeed, the trend is to subtract carriageway available for general traffic in favour of more space for buses, cyclists and pedestrians, plus investment in urban rail, traffic management and demand management measures. Yet the focus of interurban roads policy continues to be on investment in new capacity (although the Welsh Government has taken a different view). Given the demands of decarbonisation, a reconsideration of this traditional focus is desirable.

The prospects for autonomous vehicles as a source of economic benefit are unclear. Yet Digital Navigation is widely use and is changing travel behaviour. Road freight operators take advantage of similar digital technologies to manage their fleets effectively. There are opportunities to exploit digital technologies to improve the operational efficiency of the mature road network, which would be far more cost effective than civil engineering technologies employed to increase capacity.

Car use

The Department for Transport has scrapped plans for new smart motorways, citing current lack of confidence felt by drivers and cost pressures. It also reflects a pledge by the Prime Minister when he was campaigning last year for election as leader of the Conservative Party. However, the possibility of resuming build seems not to be ruled out since cancellation is said to ‘allow more time to track public confidence in smart motorways over a longer period’.

This cancellation is no great surprise, given the existing pause on construction until five years of safety data is available, a response of the DfT to a critical report from the House of Commons Transport Committee. There has also been a succession of reports from coroner’s inquests into deaths from fatal crashes when a broken-down vehicle on the innermost lane, previously the hard shoulder, had been impacted by a moving vehicle. It always seemed unlikely that the safety case could be made sufficiently persuasive to road users for the programme of smart motorway constriction to resume.

The attraction of so-called smart motorways was that an additional lane could be added to a motorway without further land take and without the cost and disturbance of rebuilding the bridges crossing the carriageway. The greater reliability of modern cars provided some justification. Yet the public was not convinced. The reliability of variable message signs used to close the inner lane in the event of a breakdown has been criticised. And while in the past new road construction could credibly be presented as offering safety improvement compared with historic roads, this was not evidently the case for smart motorways.

Cancellation of the current batch of proposed smart motorways raised a major question about the value for money of future road construction. This economic benefits of the forthcoming plans for the third Road Investment Strategy (RIS3) will need thorough scrutiny.

Car usePublished papers

I was invited to contribute to a special issue of the journal Urban Planning on the topic ‘Car Dependence and Urban Form’. The aim of the editors was to explore the scope for developments of urban form to reduce car use. I agreed to contribute a review of the evidence of drivers’ perspectives, because I sensed there is a mismatch between the general popularity of the car and the concerns about its adverse impacts held by many transport planners and academics, such that they would wish to see a reduction in ownership and use. The paper is here. The abstract is below.

Abstract:  The concept of car dependence includes both travel to destinations for which other modes than the car are not practical and preference for car travel even when other modes are available. While the concept has been a focus for transport analysts for some time, car ownership and use have continued to grow. This reflects the utility of the car for travel on roads where drivers do not experience excessive congestion and where there is parking at both ends of the journey. Local public transport and active travel only become generally attractive alternatives to the car in dense city centres where road space for car use is limited. Reduced car dependence is facilitated by city planning that encourages increased density, opportunities for which are constrained by the stability of the built environment. As well as utility for travel to achieve access to desired destinations, car ownership is also attractive on account of positive feelings, including pride, reflecting both self-esteem and social status. The positive feelings of the population at large towards car ownership are not consistent with the critical view of many analysts, a divergence in point of view that contrasts with the general acceptance of the need to respond to climate change, for which the purchase of electric vehicles is seen as an appropriate action. Rather than advocating measures explicitly aimed at reducing car dependence, a more effective policy approach would be to increase the availability of alternative modes while mitigating the detriments of car use.

The issue of the open access journal that includes my paper is published.