There is considerable interest in, and support for diesel scrappage schemes. The challenge is to target polluting vehicles making the biggest contribution to poor air quality. In my recent blog on air quality, I said that it would be hard to devise a scrappage scheme for the more polluting diesel vehicles. On reflection, I can see a way forward.

The Mayor of London has advocated a national diesel scrappage fund. Transport for London has developed detailed proposals that involve targeting small businesses, charities, schools, low-income households and the oldest taxis, at a total cost for London of some £500m. The recent Defra/DfT Technical Report on reducing NO2 levels considers a national diesel scrappage scheme aimed at all pre-Euro 6 diesel cars and vans, and also a scheme to replace non-compliant vehicles with battery electric vehicles. The former is extremely expensive, while the latter makes very limited impact.

I propose that a scrappage scheme could be integral to the  Ultra Low Emission Zone (ULEZ) proposed for London, which would naturally target the vehicles making the greatest contribution to poor air quality.

The ULEZ will generate net revenue that could be used to fund a scrappage scheme. The targeted vehicles would be those that pay the largest cumulative charges for entry into the zone, since these make the greatest impact on air quality. The formula might be a contribution of £X00 to scrappage for every £1000 of cumulative charges – a cash-back offer. The value of X could be adjusted in the light of experience of uptake.

Owners scrapping a car or van under the scheme would need to provide evidence that the vehicle had been scrapped. To discourage replacement by a further polluting vehicle, it might be a condition of the scrappage scheme that the owner would not be allowed in future to pay the standard charge for entry of a non-compliant vehicle into the ULEZ, and would therefore incur the penalty charge should this be done.

Over time, as non-compliant vehicles are scrapped, revenue from the ULEZ would fall, as would NO2 levels. Depending on how far the latter was from the statutory limit, the scope of the zone could be extended, whether to more recent vehicles or to a wider geographic area.

I suggest that TfL considers in detail how a scrappage scheme might work as part of a the ULEZ, and what incentives might be sought from the Government to adopt such arrangements.

The Government recently published its latest draft Air Quality Plan for reducing nitrogen dioxide (NO2) in towns and cities. This followed loss of a court case in which the previous Plan was found wanting, particularly by not fully recognising the poor on-the-road emission performance of diesel cars, despite their seeming compliance with regulatory requirements in laboratory tests. This latest Plan has been criticised as inadequate by many protagonists and press commentators.

Nevertheless, the new draft Plan and accompanying Technical Report represent a significant advance analytically, being based on systematic review of options, assessed using multi-criteria analysis and cost-benefit analysis. Impacts include health benefits, social and government costs, time savings from improved traffic flow, and change in greenhouse gas emissions.

The starting point is that road transport is by far the largest contributor to NO2 pollution in the 40 local authorities in England where the statutory limit values are exceeded. London has much the highest level – mean annual concentration in excess of 100 μg/m3, compared with the statutory limit of 40 μg/m3.

The most cost-effective – indeed the only worthwhile – approach to mitigation is through establishing Clean Air Zones (CAZs) where targeted action is taken. The 2015 Plan proposed CAZs in London and 5 other cities. This 2017 Plan extends coverage to 27 in all, reflecting updated assumptions about diesel emissions.

A key issue is whether a CAZ should require that the more polluting vehicles be charged for entry. For locations where NO2 levels are only modestly in excess of the legal limit, measures other than charging may suffice. Nevertheless, the Technical Report models the impact of charging in all 27 cities, which would involve set-up costs of £270m. For 12 of these, charging could be limited to public service and goods vehicles, but for 15 it would need to extend to cars not compliant with the latest Euro 6 diesel standard. The main impact of charging is assumed to be a two-thirds reduction of trips by non-compliant cars. A charging CAZ is projected to result in an 18% reduction in NO2 levels in the first year of impact.

A variety of other measures to reduce NO2 levels are considered in the Report. One approach that has attracted much support is for a scheme to offer payments to owners to scrap older polluting vehicles. The Report states that a national scheme to scrap all pre-Euro 6 diesel cars and vans could cost £60 billion. A scheme limited to replacement by battery electric vehicles assumes that only 15,000 vehicles would be scrapped.

The Report does not consider targeting by area, for which London would have a strong case for funding given the high NO2 levels, although this would be politically contentious. High mileage polluting vehicles would be the target. However, the difficulty is that the oldest vehicles tend to be both most polluting per distance travelled but least used, and owned by low-income households for whom the cash incentive would need to be high. So a well-targeted scrappage scheme seems hard to devise.

Transport for London is consulting on an Ultra Low Emission Zone (ULEZ) – effectively a charging CAZ – to cover the same area as the Congestion Charge. Non-compliant cars and vans will be charged £12.50 a day, which will apply 24/7 from April 2019. This is in addition to an emissions surcharge on top of the congestion charge for pre-Euro 4 cars and vans of £10 from October 2017. There is also a London-wide Low Emissions Zone in operation since 2008 that charges polluting heavy diesel vehicles.

On introduction, the ULEZ is projected to reduce the proportion of road kilometres exceeding limit NO2 values in Central London from 82% to 70% – a moderate air quality benefit but far from sufficient. This suggests that the charge and/or scope may need to be increased in future.

Introducing the ULEZ is relatively easy in London, given the existing of the Congestion Charge arrangements for payment and enforcement. Other cities needing to adopt a charging CAZ could adopt the technology used by London, in which case it would be natural to use it for congestion charging, both to manage peak demand and to raise revenue for investment in local transport. If 27 cities have such arrangements, this constitutes the nucleus of a national road user charging framework, which could be used to raise revenue for the road system as electric vehicles gradually take over, given that these do not pay fuel duty. The Government’s ambition is for all new cars and vans to be zero emission by 2040, and for nearly every car and van to be zero emission by 2050.

Seeing charging CAZs as a precursor to general road pricing would be contentious. This may be why the Government wished to delay publishing its draft Air Quality Plan until after the election, and why in the published consultation document the Government has been coy about charging, stating: ‘The Government believes that charging zones should only be used where local authorities fail to identify equally effective alternatives.’ The analysis presented suggests that the alternatives are unlikely to be sufficient.

The present objective is to reduce NO2 emissions to below the statutory limits specified in the EU air quality directive. However, Britain is to leave the EU, which may open other possible approaches, for instance setting policy targets expected to be achievable with available technologies and resources, balancing benefits against costs. In the long run, the problem of transport NO2 emissions will be solved by switching to electric vehicles – which arguably should be the policy priority.

This blog is the basis for a Viewpoint article in Local Transport Today of 26 May 2017.

 

 

 

 

 

 

 

 

 

The current main method of adding capacity to UK motorways is known as Smart Motorway All Lane Running. This involves allowing traffic to use the hard shoulder (previously reserved for breakdowns), with speed controls to respond to accidents and congested conditions. This approach has been applied to a section of the M25, London’s orbital motorway, increasing running lanes from 3 to 4. A monitoring report after two years of operation has been published. The main findings, compared with before the scheme was introduced: traffic flows up by as much as 17%, well above the regional trend (5%); some journey times increased by up to 8%; and only a slight improvement in reliability. Significantly, the biggest increases in traffic occurred at weekends (as much as 26%).

Assessment

The intention of investment to increase the capacity of the Strategic Road Network, of which the M25 forms an important part, is to improve connectivity between cities and reduce congestion. However, roads like the M25, that are located in densely populated areas, are also used by local users for their daily travel. Any increase in capacity offers opportunities for more or longer local trips.The resulting extra traffic restore congestion to that it had been prior the the investment in capacity. The findings of the present study are consistent with this general experience. Regrettably, there is no data on the composition of the traffic, by journey purpose or distance travelled. However, the finding of a big increase in weekend traffic is consistent with leisure users taking advantage of initially faster travel to reach more distant destinations.

The findings of this report confirm the phenomenon of ‘induced traffic’ – the traffic that results from additional road capacity – as I discussed recently in connection with the CPRE study. Such traffic adds to congestion and so reduces the time savings expected from such investment, time savings that constitute the main economic benefits presumed to justify the investment.

 

Bruce Schaller, an expert on urban transportation, has published an informative and insightful report on the impact in New York City of what he calls ‘Transportation Network Companies’ (TNCs) such as Uber and Lyft. Use of these providers of app-based ride services has grown rapidly, more than doubling in each of the past four years. This reflects the popularity of the services offered, which reduce anxiety, uncertainty and stress, not least by providing assurance of a vehicle in situations where hailing the traditional yellow cab may be problematic.

The contribution of the TNCs to congestion has been a matter of controversy. The present report confirms a previous study carried out by the NYC authorities which found that worsening congestion was driven primarily by increased freight movement, construction activity, pedestrian volumes and record levels of tourism, all of which put growing demands on the streets’ limited capacity. However, use of TNCs continue to grow, raising the question of their future impact on congestion.

A key question is whether TNC growth is making more efficient use of scarce street space by putting more passengers in each vehicle, as with UberPool which offers low fares for trips shared with others? Or does it add to traffic by diverting people from high capacity services such as rail and bus, for which evidence of a recent decline in ridership is suggestive? The available evidence as a whole is insufficient for a definitive answer, but the report suggests that diversion is likely to be more important, implying  that TNC’s add to congestion.

The report is concerned that TNCs are fundamentally undoing the cost incentives to use public transport. NYC taxi fares were traditionally set at about 4.5 times the subway fare to encourage the use of transit (public transport). However, as they cut fares, the TNCs are beginning the erase these disincentives to road vehicle use. These fares do not reflect the costs of time delays arising from congestion, hence there would be a case for some kind of congestion charging.

Assessment

Congestion is self-limiting in that as traffic builds up, for instance from more TNC vehicles, speeds drop, trips take longer, and some road users make alternative decisions, for instance to travel at a less busy time, or to go to a different destination, or to use the subway. So it is not to be expected that growth of TNCs would worsen congestion in already congested parts of NYC. The switch of people from the subway to TNC services would be limited for the same reason.

 

My new book, Travel Fast or Smart?, is one in a series of short books on policy and economics topics described as ‘essays on big ideas by leading writers’. My contribution is a critique of the inconsistencies of transport policy in recent decades, which I attribute to the shortcomings of conventional transport economic appraisal in identifying the benefits that arise from investment.  This book is available both in print and as an ebook from Amazon Books


There is much current interest worldwide in the concept of Mobility-as-a-Service (MaaS), the aim of which is to provide seamless journeys using the most appropriate travel modes, routed and ticketed by means of a smart phone app. The MaaS provider ‘aggregates’ the services provided by transport operators (in the way that Amazon acts for retail product providers). MaaS is intended to be an attractive alternative to private car ownership. The Transport Catapult has recently published a report on the opportunities for MaaS in the UK. And the New Cities Foundation has addressed the role of public transport operators in its development.

There are many recognised technical and policy issues that need to be tackled, including managing the large amounts of data, and coordinating ticketing and payments on behalf of a multiplicity of operarors. However, there are two aspects that deserve particular consideration. The first is the ability of MaaS to cope with peak travel demand.

Peak demand

Daily travel demand is characterised by morning and evening peaks, and there are also seasonal variations. Peaks result in road congestion and crowding on railways. One approach would be to charge higher prices at times of greatest demand, with the aim of spreading the peak. This model has been adopted in the aviation sector, led by the low-cost carriers, and by Uber for urban taxis (and also in other sectors such as hotels). The railways offer off-peak discounted fares, but do not flex fares upwards to reflect actual peak demand.

However, unless peak pricing is part of the public transport provision (which at present it is not), the scope for coping with peak demand for multi-modal journeys is quite limited. This means that unreliability of travel time for each stage of a journey would present a scheduling problem.

While MaaS comprises a minority of all trips, congestion would be a given, and scheduling would need to allow for expected journey stage times plus a margin for uncertainty, with rerouting in the event of unexpected congestion. On railways, consideration would need to be given to offering alternatives to overcrowded trains. Such dynamic scheduling could be technologically challenging.

Were MaaS to grow to encompass a substantial part of travel demand, there may be scope for routing travellers to spread demand across the network in a way that optimises overall efficiency, simplest for routes that involve stages with assured reliability – rail, bus rapid transit, walking and cycling. There would also be scope to consolidate car trips by means of shared taxis, as with UberPOOL. However, such sharing, incentivised by lower fares, could attract passenger from buses, which could add to congestion.

If MaaS were to be a major intermediary in meeting travel demand, a significant operational issue would be whether to respond to peak demand for door-to-door travel by mobilising more taxis through surge pricing, as does Uber. Surge pricing to deter demand and increase supply is sensible in the absence of congestion, but may not be optimal under congested conditions. In the absence of surge pricing, demand would exceed supply and would be rationed by waiting in a virtual queue until a taxi becomes available. With surge pricing, there is a greater supply of taxis and so less waiting time, but journey times might be slower on account of increased congestion. Which approach would be optimal would require modelling.

Surge pricing works well for aviation, a closed system where an aircraft can only fly if it has airport slots allocated at trip origin and destination. But roads are an open system and hence prone to congestion at peak times in populated areas. MaaS would be more straightforward to implement in lower density areas, less so in urban centres, unless private cars were entirely replaced by a fleet of shared use self-driving vehicles, as has been suggested.

Who owns the platform?

The question of how MaaS can best cope with peak demand is linked to the second problem – the nature of the platform by means of which demand and supply are matched, prices set and revenues allocated. The central issue is familiar: benefits of competitive supply versus benefits of an integrated network. Experience is varied. In the case of buses, Mrs Thatcher’s government opened the bus services outside London to competition with minimal regulation, hoping to benefit users by on-the-road competition between private sector operators. This largely failed to materialise since such competition resulted in unattractive profit margins. In consequence, the present Government has introduced legislation that would allow other cities to adopt the successful London model, whereby an integrated public transport network is operated by a politically controlled public body, Transport for London.

For MaaS, the question is whether an open source public platform would naturally evolve on account of the superior benefits, as envisaged by the TravelSpirit collaboration. Or whether competition in the market between competing platforms would be the main driver, with perhaps a dominant platform emerging through economies of scale and scope.

A dominant private sector platform might need to be regulated to avoid market failure that allowed economic rents to be extracted at the expense of users. The MaaS provider would have access to all the data arising from use of the system. Fair sharing of this data with transport providers would help meet the needs of users. On the other hand, discriminatory sharing could increase returns to the provider.

Assessment

Traffic congestion is the main problem of the road system. A key question is whether MaaS has the potential to lessen traffic congestion. If it does, then promoting MaaS could be a sensible transport policy, in which case a view would need to be taken of the relative attractions of competing platforms versus a single public platform.

In the longer run, developments in shared use driverless urban vehicles might achieve substantial mitigation of urban traffic congestion. Sharing of taxis would increase vehicle occupancy and hence efficiency of the road system; demand management could limit use of single occupancy vehicles under congested conditions; and the development of vehicle-to-infrastructure communications could permit flow management, analogous to air traffic control. In such circumstances, MaaS would be likely to be an integral part of an urban transport management system. However, development of such a system would be challenging in respect of technology, business models, institutions and public acceptability – hence the feasibility and timing is uncertain. In the meantime, development of MaaS in urban areas would need to cope with traffic congestion.

 

 

 

 

 

 

 

My new book published on 1 September is one in a series of short books on policy and economics topics described as ‘essays on big ideas by leading writers’. My contribution is a critique of the inconsistencies of transport policy in recent decades, which I attribute to the shortcomings of conventional transport economic appraisal in identifying the benefits that arise from investment.  This book, Travel Fast or Smart?, is available both in print and as an ebook from Amazon Books


The House of Commons Transport Committee is carrying out an inquiry into urban traffic congestion. I submitted evidence and appeared at an oral evidence session along with other experts.

Traffic congestion occurs in densely populated areas where car ownership is high. There is too little road space to meet all potential demand for car travel while maintaining reasonable flow. Accordingly, many possible car trips do not take place. People are deterred by the prospect of uncertain delays in congested traffic, so they change the timing of their trip, or the destination (alternative shops, for example), or the mode of travel (rail often faster than a car on congested roads), or decide not to travel at all (by working at home, for instance).

The implication of such suppressed demand for car travel is that measures to lessen congestion may have little impact. A congestion charge, as in Central London, would deter some drivers, but they would be replaced by others able to bear the cost who previously would have been dissuaded by the congestion delay. Increasing road capacity, while generally not feasible in urban areas, is seen by many as a solution beyond. However, this permits more and/or longer car trips, the extra traffic thereby restoring congestion to what it had been – hence the maxim that you can’t build your way out of congestion.

Congestion is self-regulating in the long run. As traffic builds up, speed drops and journey times increase. Some drivers opt for alternatives of the kind mentioned above, and congestion stabilises. Urban Traffic Management systems, which operate through adjusting the timing of traffic signals, help to prevent gridlock. However, congestion can be exacerbated in the short run by temporary blockages such as street works or major construction, and also while adaptation takes place to new permanent structures such as cycle lanes.

Assessment

There is little that can usefully be done to mitigate urban traffic congestion. On the other hand, the growth of urban car traffic can be contained by not increasing road capacity for cars, and indeed can be reversed by subtracting from such capacity. This is the experience of London Congestion Charging, which returned congestion to past levels and yet traffic volumes are lower than they were – because the Mayors took the opportunity offered by the Congestion Charge to take road capacity away from conventional traffic in favour of pedestrians, cyclists and other uses.

 

 

 

The Independent Transport Commission (ITC) has updated its earlier report on trends in road and rail travel, On the Move, to 2014. This is based on detailed analysis of National Travel Survey data by Peter Headicar and Gordon Stokes.

A key finding is that per capita distance traveled has been decreasing significantly over the past decade and is now 10% lower than in the mid-2000s. As author of a book (and this blog) entitled ‘Peak Car’, I was gratified to read that individual car driving mileage per adult has declined significantly over the period 1995-2014 (see Figure).

The main purpose of the analysis was to identify trends rather than the causes behind them, but the authors believe that attitudinal factors are becoming increasingly significant as drivers of travel. The ITC’s 2015 attitudinal research indicated that cars are increasingly viewed as ‘appliances not aspirations’, especially by young people, while public transport is being seen more favourably.
 Assessment
This report of the ITC provides valuable analysis of the Department for Transport’s National Travel Survey, well worth reading by those who follow the debate about the future of car use. This detailed consideration contrasts with the rather limited account provided by the Department itself.
The present study is consistent with the proposition that travel behaviour changed significantly as we transitioned from the twentieth century to the twenty-first.

My new book published on 1 September is one in a series of short books on policy and economics topics described as ‘essays on big ideas by leading writers’. My contribution is a critique of the inconsistencies of transport policy in recent decades, which I attribute to the shortcomings of conventional transport economic appraisal in identifying the benefits that arise from investment.  This book, Travel Fast or Smart?, is available both in print and as an ebook from Amazon Books.


Three studies of prospective road investments in the North of England have been published recently. These illustrate some of the questions that arise when the aim is to boost economic growth by increasing road connectivity between cities.

M60: Manchester North-West Quadrant

The NW section of the M60 orbital motorway within Manchester is one of the busiest roads in the country, on account of the mix of local and strategic traffic. Traffic congestion, local air quality and noise are considered to inhibit economic growth.

A number of road schemes are proposed to improve matters: new outer orbital roads to divert strategic traffic from the inner orbital M60, plus improvements to enhance capacity of the M60 itself. The benefits have been assessed, according to standard practice, on the basis of the value of journey time savings, which typically are quite small – up to 5-12 min for strategic long distance users and up to 3-5 min for local users. The capital costs are estimated at around £14 billion.

A public transport only scheme has also been considered but rejected since it offered no journey time savings for road users.

Northern Trans-Pennine Routes

This study addresses the most northerly major east-west road routes in England, currently underused on account of poor journey time reliability, high collision rates, high proportion of Heavy Goods Vehicles and lack of alternative routes if diversion is needed due to poor weather or road works. Parts of these routes are still single carriageway. Capital costs are estimated at about £5 billion. No quantitative estimation of benefits has yet been made.

Trans-Pennine Tunnel

This scheme involves a ‘bold concept’ – building a tunnel under the Peak District National Park to improve road connectivity between Manchester and Sheffield, with journey time saving of up to 30 min. Depending on the precise route, the length of tunnel would be 12-20 miles, longer than most road tunnels in Europe, costing £8-12 billion. No quantitative estimation of benefits has yet been made.

Assessment

The total cost of these three schemes is put at up to about £30 billion, which is twice the total investment planned under the current five year Road Investment Strategy. It is very hard to see how the economic benefits could justify such expenditure, not least because the evidence for benefits from improving the connectivity of cities around 50 miles apart in thin (see my discussion of Glasgow and Edinburgh, two well connected cities).

Moreover, standard economic analysis does not distinguish between benefits to commuters and to long distance users. As I have argued, in situations like the urban M60, where car commuters comprise 40% of morning peak traffic, it would be commuters that would take advantage of any increased capacity, leaving long distance users no better off – consistent with the maxim that you can’t build your way out of congestion.

Standard economic appraisal, based on time savings to road users, takes no account of the way transport investment makes land accessible for development and so contributes to economic growth. Such development results from investment in urban public transport, as for example at MediaCity in Greater Manchester. The rejection of public transport investment as a means of mitigating congestion on the M60 reflects this disregard of development in standard appraisal.

The construction costs estimated at this stage are not to be relied upon. Very likely ‘optimism bias’ is at work, underestimating costs and overstating benefits at an early stage, to ensure the project remains under consideration, consistent with a ‘bias to action’ on the part of promoters and their agents when there is an opportunity to spend other peoples money.

On the other hand, the estimates of fairly small time savings are consistent with the outcomes of previous road investments, raising a question about the nature and value of incremental investment in a mature road system that generally provides dual-carriageway or better connectivity to all major cities.

What is entirely missing from these studies of road investment is any consideration of how digital technologies might help meet the needs of users, technologies that can be far more cost-effective that the very expensive civil engineering technologies that have dominated thinking about the road system. This is in marked contrast to the railways where the virtues of the ‘digital railway’ are increasingly recognised.

There is too much wishful thinking about the economic benefits of investment in road infrastructure, particularly in the context of the ‘Northern Powerhouse’, the North of England seen as a region with unrealised economic potential. More rigorous analysis is needed, otherwise outcomes will be disappointing.

 

 

My new book published on 1 September is one in a series of short books on policy and economics topics described as ‘essays on big ideas by leading writers’. My contribution is a critique of the inconsistencies of transport policy in recent decades, which I attribute to the shortcomings of conventional transport economic appraisal in identifying the benefits that arise from investment. A column in The Spectator magazine of 26 September described my book as ‘excellent throughout’. My book, Travel Fast or Smart?, is available both in print and as an ebook from Amazon Books.


The National Infrastructure Commission has issued a report on the corridor connecting Cambridge to Oxford via Milton Keynes, in response to a request from the Government for proposals to optimise the potential of this knowledge intensive cluster that competes on a global stage.

The Commission’s national remit does not extend to housing. Nevertheless, its central finding in the present study is that a lack of sufficient and suitable housing presents a fundamental risk to the success of the area. Investment in infrastructure, including enhanced east-west transport links, can help to address the challenges, but it must be properly aligned with a strategy for new homes and communities, not developed in isolation. This means local authorities working in partnership, and with national government, to plan places, homes and transport together.

The Commission recommends that planning for the East West Rail route and the Oxford-Cambridge Expressway should be taken forward urgently, as investments that will deliver substantial national benefits and, if designed properly, can provide the foundations for the corridor’s long-term prosperity: unlocking housing sites, improving land supply, and supporting well-connected and sensitively designed new communities, whilst bringing productive towns and cities closer together.

Assessment

The Commission’s recognition of the importance of planning transport investment to unlock land for housing and to facilitate access to employment is very welcome. However, the orthodox approach to transport economic appraisal focuses on time savings to travellers, which is unhelpful in making decisions about best value for money in this context. A new approach to appraisal is needed.

The Commission’s recommendations for strengthening rails links within the corridor are more persuasive than those concerning road improvements. Increased road capacity in an area of housing development would result in roads filling up with commuter traffic, consistent with the maxim that we can’t build our way out of congestion. Conventional economic appraisal of road investments does not distinguish between benefits to different classes of road users – commuters, long distance business, freight etc. Yet such understanding is important if road investment is not to disappoint.

 

I have a new book published on 1 September, one in a series of short books on policy and economics topics described as ‘essays on big ideas by leading writers’. My contribution is a critique of the inconsistencies of transport policy in recent decades, which I attribute to the shortcomings of conventional transport economic appraisal in identifying the benefits that arise from investment. A column in The Spectator magazine of 26 September described my book as ‘excellent throughout’. My book, Travel Fast or Smart?, is available both in print and as an ebook from Amazon Books.


Nottingham is a city unique in Britain in that it has taken advantage of national legislation, the Transport Act 2000, to introduce a Workplace Parking Levy. The consequences have been outlined in a helpful brief prepared by the Campaign for Better Transport.

Nottingham is a medium sized city with two universities and a tram system. The Levy was implemented in 2012 and applies to employers providing 11 or more parking places for employees, who must pay £375 per place per year. There are 42,000 workplace parking spaces in the city, of which 25,000 are chargeable. Operation of the levy is quite low cost.

The direct impact of the levy is to reduce car commuting, reinforcing the declining trend in car traffic shown in the Figure. The revenue of £25m raised in the first three years is ring-fenced for transport improvements, the indirect impact, for instance to help fund doubling to coverage of the tram network.

Assessment

Big cities like London, with dynamic economies and growing populations, are experiencing a declining share of journeys by car, as they invest in rail for speedy and reliable travel for commuters. A declining share for the car is associated with increasing prosperity, at least in big cities. But what of smaller cities? Do they do best by attempting to accommodate the car, the traditional approach? Or should they push back the cars, which impede economic, cultural and social interactions that make cities good places to live?

Nottingham’s experience suggests that bearing down on car commuting may make a useful contribution, even though it requires brave politicians to push through a Workplace Parking Levy against the inevitable initial opposition. The Levy has particular virtues: it impacts only on residents, not on visitors from out of town, who may have available competing  destinations for shopping and leisure activities; and because it reduces car commuting, it makes more road space available for buses at peak times.

Encouragingly, Nottingham ranked top in 2016 in the National Highways & Transport Network Satisfaction Survey carried out in 106 local authority areas by Ipsos MORI.