Until fairly recently, the main driver of growth of travel demand in developed economies was growth of personal incomes. This is no longer the case, a key change that is an important contributor to the Peak Car phenomenon. For the future, demographic change is the main driver of demand growth. There are four aspects: population growth, population ageing, the young deferring maturity, and the spatial consequences of these developments.

I have a chapter summarising changing demographics in a new Handbook on Transport and Urban Planning in the Developed World. A copy of the manuscript is available Changing Demographics chap 23-1-15

Transport accounts for over 60 per cent of global oil consumption and about a quarter of energy-related carbon emissions. Typical forecasts of future world vehicle ownership project substantial increases, particularly in the developing economies. The transport sector relies largely on oil for motive power and has been seen as more problematic than other parts of the economy when it comes to reducing greenhouse gas emissions.

The problem of transport greenhouse gases may be less than generally supposed, however. There is emerging evidence that individual car use, as measured by the average annual distance travelled, has ceased to grow in most of the developed economies, starting well before the recent recession, and it may be declining in some countries – a phenomenon known as ‘Peak Car’. A number of explanations have been proposed, which are not mutually exclusive and include a decline in younger people holding drivers licences, changes to company car taxation, saturation of demand for daily travel, technological constraints on faster travel, and a shift away from car use in urban areas.


The shift away from car use in cities is particularly important in a world in which future population growth will be mainly urban and the economic attractions of population density are increasingly recognised – agglomeration economics. London illustrates these developments. Over the past twenty years the population has been growing and incomes rising, but car use has held steady at about 10m trips a day. This is mainly because the city has not increased road capacity but instead has invested in public transport, particularly rail which offers speedy and reliable travel for work journeys, compared with the car on congested roads.

A growing population but no growth of car use has resulted in a marked decline in the share of journeys by car in London, from 50 per cent of all trips in 1990 to 37 per cent currently. With continued population growth projected and more investment in rail planned, the share of trips by car could fall to 27 per cent by mid-century. There is every reason to suppose that London will continue to thrive as car use declines – perhaps because car use declines.

This decline in car use from 1990 was preceded by a 40 year period of growth from 1950, the result of growing incomes, growing car ownership and at the same time a falling population as people left an overcrowded damaged city for new towns, garden cities and greener surroundings. So we see a marked peak on car use around 1990, the time when the population of London was at a minimum, when attitudes to city living began to changes.

Peak Car in the Big City

This phenomenon of ‘Peak Car in the Big City’ is not unique to London although this is the city for which we have the best data. There is evidence for something similar happening in Birmingham, Manchester and other British cities as well as those in other developed countries. The shift in economies from manufacturing to services is an important driver, as is the growth of higher education located in city centres, attracting young people for whom the car is not part of the life style.

The Peak Car phenomenon is helpful for mitigating transport greenhouse gas emissions – both the cessation of per capita car use nationally and the decline in the share of trips by car in cities. I have estimated that these changes in behavior, taken together with expected developments on low- and zero-emission technologies, could reduce UK surface transport greenhouse gas emissions in 2050 by 60 per cent compared with a 1990 baseline. This fall short of the overall target of 80 per cent reduction, but is a good deal better than conventional projections.

Peak Car is not just an emerging phenomenon to be investigated. It is a helpful trend to be encouraged to achieve both successful, sustainable cities and national reduction of transport greenhouse gas emissions.


This article is based on a recent paper of mine published in the journal Case Studies on Transport Policy, also available as a final draft Metz CaseStudies 1-5-15 pdf.

The Department for Transport has published its Road Investment Strategy with details of £15bn expenditure on the Strategic Road Network. I have a critique of this programme published in Local Transport Today. I argue that, as ever, you can’t build your way out of congestion, but you can use the digital technologies to help drivers use the network more efficiently under congested conditions. The Highways Agency places far too much emphasis on the civil engineering technologies, and too little of the digital technologies.

Metz LTT Roads pdf 18-12-14


NNNPS stands for National Networks National Policy Statement. The UK government has issued a draft for consultation. This covers national perspectives for future road and rail developments and is intended to be approved by Parliament and provide a settled input to local planning enquiries into specific schemes.

There is quite a lot wrong with the consultation draft. I have submitted a response  Metz NNNPS response 26-2-14. My main concerns are the following.

There are good reasons to suppose that the National Transport Model substantially overestimates future demand on the Strategic Road Network. The traffic projections do not therefore provide a sound basis for the scale of investment planned by the Government. The Model needs to be made public and available for independent audit.

A major shortcoming of the NTM is its inability to model the consequences of a strategic choice between greenfield and urban housing to accommodate the growing population.

There is a good case for investment in the network where this can make land accessible for development, consistent with planning policy. However, constructing additional carriageway is not an effective means of reducing congestion.

The main problem with congestion is the uncertainty of journey time. This is tackled most cost-effectively by provision of reliable predictive journey time information.

A strategic issue for national Government is where to accommodate the UK’s growing population since this will determine the kind of investment needed in the transport system. In London, transport investment can be planned to respond to population growth. Nationally, there is no such coherence.

I presented a paper (Metz ETC 15-9-13) at the recent European Transport Conference held in Frankfurt. This shows how car use in London rose from about 5% of all journeys in 1950 to 50% by 1990 – no surprise there. But then it started falling, to 38% currently, and projected to fall further to 30% before 2040. This is surprising since car use has always risen with growing incomes. However, in London we have not built new road capacity, which has constrained car use to a steady 10m trips a day for each of the past 20 years. But because the population has been growing, these car trips represent a declining share of all travel. This is the clearest illustration of the phenomenon of Peak Car.

I also suggest that growing cities in developing countries, where car use is still low, may be able to avoid this peak and move directly to a more sustainable level of around 30% for a city of 10m. The key policies to achieve this are to provide rail travel for work journeys since this can get business and professional people out of their cars, and limit parking in the city centre to keep buses, taxis, good delivery and emergency vehicles moving.

I have a new paper published in the Journal of Transport and Land Use, title ‘Mobility, access and choice: a new source of evidence’. The new source is the UK Department for Transport’s accessibility statistics, which relate where people live (census data) to where are located services and facilities such as doctors, hospitals, schools etc. My analysis allows estimates of how much choice people have, dependent on their mode of travel. I find that for those with use of a car or good public transport, levels of choice are quite high, consistent with the proposition that demand for travel has ceased to grow because we have enough choice to meet our needs.

This Journal is unusual in that it is available free of charge online without charging authors for the costs of publication. Commendable.

These are my key papers published since 2008 in peer-reviewed journals, and also my book published in that year.

There is also a review paper on Mobility and Access Needs, Expectations and Costs, published by the International Transport Forum of the OECD (2011) http://www.internationaltransportforum.org/jtrc/DiscussionPapers/DP201107.pdf