Lynn Sloman and colleagues of Transport for Quality of Life (TQL) issued a report about carbon emissions arising from the Department for Transport’s second Road Investment Strategy (RIS2). Their detailed analysis reaches the conclusion that the increase in CO2 from RIS2 would negate 80% of potential carbon savings from electric vehicles on the Strategic Road Network (SRN) between now and 2032.

This conclusion struck me as surprising. Although annual expenditure on new capital projects for the SRN has been running at over £2 billion a year, civil engineering is very costly and we don’t get much extra capacity for our money. The recent rate of addition of lane-miles to the SRN has been 0.5% a year, which is less than the rate of population growth. So how could such a low rate of addition of capacity have such a large adverse impact on carbon emissions? We need to question the TQL calculations.

TQL argues that the RIS2 road schemes will increase carbon emissions in a number of ways, particularly by increasing speeds and inducing more traffic, both of which they believe are underestimated in conventional scheme appraisal. They therefore estimate the additional cumulative carbon emissions from these sources, both put at around 6 Mt CO2 for the period 2020-2032. But I wonder if there is not some overstating here, given that more traffic would tend to reduce speeds. For instance, for a scheme to widen part of the M25, I found that outturn traffic flows were higher than forecast, such that there was no increase in traffic speed.

TQL estimate that RIS2 would increase carbon emissions by 20 Mt CO2 for the period 2020-2032, including carbon from construction. This is then compared with the difference in carbon emissions between two scenarios from the DfT Road Traffic Forecasts 2018, the Scenario 1 reference case and Scenario 7 high electric vehicle case, which amounts to a reduction of 25 Mt, hence the conclusion that the increased carbon emissions would negate 80% of the benefit of the shift to EVs.

There are, however, problems with this estimate of carbon reduction from EVs. Scenario 7 assumes no tax on EVs to replace fuel duty, so that the cost of motoring decreases substantially (by 60% by 2050), hence a projected large increase in traffic compared with Scenario 1 (50% increase by 2050 compared with 35% for the reference case). Whatever the realism of the assumption about tax, such a large increase in traffic is implausible as the consequence of electrification. Average travel time has remained constant at about an hour a day for the past 45 years at least, hence to travel further it would be necessary to travel faster, which will not happen through a change in propulsion. The problem is that the Road Traffic Forecasts derive from the National Transport Model, which does not recognise travel  time constraints.

An assumption that electrification has no effect on traffic volumes would substantially increase the scale of carbon reduction under Scenario 7, to which could be added the benefit of bringing forward the phase out of non-electric cars and vans earlier than 2040, as assumed in that Scenario. And if we reduce the additional carbon from the RIS2 programme to allow for some overstating, then we could arrive at a less pessimistic conclusion than the TQL authors about the carbon impact of this programme on future overall SRN emissions.

Nevertheless, despite these caveats, I agree with the conclusions of the TQL report that RIS2 is anachronistic, and that cancellation would free up substantial investment for better uses, not least fast broadband to lessen the need for travel, both for commuting and on business. The SRN is under greatest traffic stress in or near urban centres during the morning and late afternoon peaks, when car travel to and from work interferes with long distance road users. The economic case for road investment needs to be reconsidered in the light of changes in daily travel prompted by the pandemic.

I previously noted publication by the Department for Transport of its Second Road Investment Strategy (RIS2). DfT has now issued an economic analysis that concludes that the new programme represents high value for money. I had hope that this document would provide substantiation of the £27 billion, 5-year road investment programme but I was disappointed.

The summary states that overall RIS2 is High Value for Money, meaning £2 return for every £1 spent (Benefit-Cost Ratio of 2). Yet new commitments of major capital enhancement schemes yield a BCR of 1.5, which is unimpressive. The analysis is minimal, offering no breakdown into individual schemes, where some might be expected to have a BCR of 1 or less if the average is 1.5.

These estimates are based on the now rather dated Road Traffic Forecasts published in 2018, which included five distinct scenarios, yet no indication is given as to how the BCR would vary with scenario. The estimates are also derived from new but unpublished regional traffic models, asserted to be ‘world leading’.

I previously pointed out a major discrepancy between traffic forecasts and post-opening outturn for the smart motorway widening of the M25 between Junctions 23 and 27. These forecasts were generated by a regional model of the kind now in general use by Highways England, based on SATURN software that originated in the 1980s. The purpose of these models is to estimate travel time savings that arise from adding carriageway, which feed into an economic model. Yet in the M25 case, no time savings were observed beyond year 1 after opening, putting the validity of such models  in doubt.

The new DfT analysis frequently asserts that its analysis is robust (15 times, in fact), which is usually a sign of intellectual insecurity. In fact, the analysis is pretty thin and seems intended to justify a road construction programme developed in earlier era, before we have had a chance to assess the impact of the coronavirus pandemic and what this might mean for travel demand and for public expenditure priorities, urban vs. inter-urban transport vs. broadband.

An on-line meeting organised by Local Transport Today on 19 June was concerned with the future of car travel after the coronavirus pandemic. I contributed the following thoughts.

The average distance travelled by car in the UK per person ceased to grow at turn of century, following strong growth in the last century. This phenomenon has been called ‘Peak Car’, but ‘Plateau Car’ would be a better term, given the 20-year flat trend. But with the coronavirus pandemic, we have three new influences that could affect the trend of car use in the longer run.

First, a natural preference for the car in place of public transport during the pandemic, which will add to road traffic congestion. Second, less road space for cars in urban areas to allow more room for active travel, both as response to the pandemic and to promote longer term reduction in carbon emissions and improve urban air quality; this also will tend to increase congestion, unless car users could be persuaded to switch to active modes. Third, less car travel due to more working at home, more video-conferencing, and more on-line shopping, accentuating recent trends; this would relieve congestion. We can’t yet estimate the likely magnitude of these influences, so can only speculate in broad terms how they may play out.

Might active travel substitute for some car use? The London Mayor aims to increase cycling 10-fold. That would take mode share to 30%, as Copenhagen, a city with comprehensive cycling infrastructure. Yet car use in Copenhagen only slightly less than in London, while public transport use half that in London – 18% mode share vs 37% in London.

It seems that people can be attracted off buses onto bikes, which are cheaper, healthier, environmentally better, and no slower in congested traffic. Yet this would reduce fare income to public transport and likely the level of service. In contrast, it seems harder to get people out of cars onto bikes, even in Copenhagen where most motorists have bikes at home.

The fundamental problem in getting people to travel by slower modes is the consequent reduction in access. The key historic transport innovations all increased access. Railways, the modern bicycle, motor car, motorised two-wheelers, each offered a step change increase in speed of travel and hence in access to people, places, opportunities and choices. Access increases with the square of the speed of travel. Comparing walking at 3 mph with urban car travel at say 20mph, a 7-fold increase in speed, yielding a 50-fold increase in access to desired destinations. Comparing cycling at 10mph with car travel – twice the speed giving four times the access. People have become used to the access offered by the car and most would be reluctant to settle for less by opting for slower modes.

To reduce car use, we need to offer a mode that is faster and more reliable than the car on congested roads, which is rail – interurban between cities, commuting into cities, and rail in all its forms within cities. Investment in rail in London has been important in reducing car mode share from 50% in early 1990s to the current 36%. But continuation of that shift depends not only on successfully tacking the coronavirus pandemic, but also continuing to invest in urban rail, which is very costly and so limits expansion of rail travel.

The other way of reducing car use is to lessen the need to travel for work. The pandemic has shown us how we can manage to travel much less, but this is undoubtedly suboptimal. The magnitude of the rebound remains to be seen. Investment in broadband could facilitate remote working and could be much more cost-effective than new road capacity.

 All in all, I do not expect to see a substantial change in per capita car use nationally, once the pandemic is behind us, but we could be at the start of a downward trend, reflecting less need to travel and some switching to other modes. It may turn out that we are now at the peak of car travel on a per capita basis, which should prompt review of all those ‘shovel ready’ schemes in the road construction programme.

As a means to decarbonise the transport system, the contribution of behavioural change is problematic to rely on because of the uncertainties of responses to both the easing of lockdown restrictions and policy interventions aimed at changing travel behaviour. This means that we need a strong commitment to technology in the form of electrification, both to cut transport carbon emissions and improve urban air quality.

The other new technology – automation – is not a solution to the problems we face. It will be difficult to deploy autonomous vehicles on the existing road network. The technology is expensive and the benefits limited, so that the appetite of consumers is uncertain. The car manufacturers will give priority of electric vehicles, leaving automation to be developed in the slow lane.

The Department for Transport recently issued a report concluding that the Second Road Investment Strategy (RIS2) represents high value for money. One might have thought that this 29-page RIS2 Analysis Overview would porvide substantiation of the £27 billion, 5-year road investment programme announced earlier. We are disappointed.

The summary states that overall RIS2 is High Value for Money, meaning £2 return for every £1 spent (Benefit-Cost Ratio of 2). Yet new commitments of major capital enhancement schemes yield a BCR of 1.5, which is unimpressive. The analysis is minimal, offering no breakdown into individual schemes, where some might be expected to have a BCR of 1 or less if the average is 1.5.

These estimates are based on the now rather dated Road Traffic Forecasts published in 2018, which included five distinct scenarios, yet no indication is given as to how the BCR would vary with scenario. The estimates are also derived from new but unpublished regional traffic models, asserted to be ‘world leading’.

I previously drew attention to a major discrepancy between traffic forecasts and post-opening outturn for the smart motorway widening of the M25 between Junctions 23 and 27. These forecasts were generated by a regional model of the kind now in general use by Highways England, based on SATURN software that originated in the 1980s. The purpose of these models is to estimate travel time savings that arise from adding carriageway, which feed into an economic model. Yet in the M25 case, no time savings were observed beyond year 1 after opening, putting the validity of such models  in doubt.

The DfT report frequently asserts that its analysis is robust (15 times, in fact), which is usually a sign of intellectual insecurity. In fact, the analysis is pretty thin and seems intended to justify a road construction programme developed in earlier era, before we have had a chance to assess the impact of the coronavirus pandemic and what this might mean for travel demand and for public expenditure priorities, urban vs. inter-urban transport vs. broadband.

The Department for Transport has initiated an exercise to assess how the transport system could be decarbonised, in line with the Government’s commitment to a net zero carbon target for the whole economy by 2050.

I have submitted some thoughts on behavioural aspects, including the scope for increasing active travel, decreasing motorised road travel and air travel, and the need to improve modelling to accomodate such behavioural changes.

The Department for Transport’s (DfT) second Road Investment Strategy (RIS2) was published at the time of the recent Budget, committing to spend £27.4bn over the next five years on the strategic road network (SRN). The stated main priority is to maintain the existing roads. Only where existing roads are ‘simply not up to the job’ is the Government asking Highways England to develop wider, realigned or, in a few cases, wholly new roads to keep people and goods moving. Yet expenditure on maintenance is expected to be £12bn, whereas capital enhancements are worth £14bn.

Investment

Prioritising investment is based on the 2018 Road Traffic Forecasts, projecting growth on the SRN in the range of 29% to 59% by 2050. This suites the civil engineers of Highways England who see their main purpose as building roads. However, as I have argued previously, the DfT traffic forecasts are very problematic and have generally proved to overestimate outturn traffic levels. Moreover, as I noted in chapter 2 of my recent book, the rate of addition of lane-km to the SRN in recent years has been less than the rate of population growth, despite the high levels of spend.

It is therefore not surprising that average delays on the SRN have worsened during the RIS1 period, growing from 8.9 seconds per vehicle mile to 9.5 seconds per vehicle mile. The DfT’s ambition for performance at the end of RP2 is to be no worse than at the end of RP1. This is a very modest aspiration, and contrasts with the aim of the previous road investment strategy (RIS1) of a free-flow core network with mile a minute speeds increasingly typical.

The new ambition is consistent with the document’s recognition that it is ‘widely accepted that it is not possible to outbuild congestion across the whole of the road network’. Accordingly, investment is to be focused on congestion hotspots, so that average network performance will be at least as good in 2025 as it is in 2020. Yet, as I have pointed out, adding capacity induces more traffic, so tackling congestion hotspots has little impact beyond perhaps shifting congestion to another part of the network.

Optimisation

One odd feature of this and similar publications of Highways England, is the disregard of digital route guidance (Google Maps, Waze and others) that is in very wide use by drivers, because they find it of benefit in optimising routes under congested conditions and in estimating journey times. Roadside variable message signs are an outmoded technology, providing too little information, too late to be of much use.

There is picture of a route guidance app on page 38 of the RIS2 document, but no mention of its relevance. There is a statement that ‘During RP2 Highways England will work with Transport Focus [a consumer body] to investigate future opportunities to make more granular information about delay on the SRN publicly available. We anticipate that this might include reporting on a regional basis, journeys between conurbations, and maps showing delay across the network on a link-by-link basis.’ Highways England seems totally out of touch with the real world.

Non-investments

The RIS2 mentions the outcome of a number of earlier ‘strategic studies’ that now seem unlikely to lead to much. For the M60 Manchester NW Quadrant, it is concluded that the transformational options identified by the study would have significant adverse impacts on local people and communities, and overall would not provide value for money. The proposed Trans-Pennine Tunnel, improving the route between Manchester and Sheffield, seems unlikely to proceed. The Oxford to Cambridge Expressway project has been paused to look at other options.

In contrast, the A303 Stonehenge Tunnel is to go ahead. Yet the National Audit Office found that transport and economic benefits accounted for only 27% of total benefits; the value of cultural heritage, based on a survey asking people what they would be willing to pay to remove the road altogether, was put by the DfT at 73%, and yet this yielded a benefit-cost ratio of only 1.15 , which in the event is likely to be worse because cost overruns. The NAO noted that the DfT has no plan for the corridor as a whole, and that all the other projects on the route offered poor value for money.

This critique of the A303 route can be generalised to the RIS2 as a whole. Although it is entitled a ‘strategy’, in reality it is a construction programme that is deficient in both economic justification overall and indication of spatial impact of economic benefits. What benefits might we expect, and where? We are not provided with more than vague aspirations.

 

 

 

 

 

 

 

 

 

The Office of Rail and Road (ORR) is responsible for overseeing the performance of Highways England (HE), a publicly owned company responsible for England’s strategic road network. ORR is consulting on how it should perform its role. I have responded as below:

HE is responsible for a substantial programme of investment in new and improved road infrastructure, each element of which is supported by cost-benefit analysis consistent with the Department for Transport’s Transport Analysis Guidance. The main economic benefit is assumed to be the value of the time saved as a result of investments which increase capacity and are intended to reduce road traffic congestion.

However, there are questions about the estimation of prospective travel time savings derived from the standard models used for traffic forecasts. For example, monitoring of the outcome of widening of the M25 between junctions 23 and 27 concluded that ‘increases in capacity have been achieved, moving more goods, people and services, while maintaining journey times at pre-scheme levels and slightly improving reliability.’[1] No travel time savings were observed beyond the first year after opening, in part at least due to increased traffic, notably an increase of 23% at weekends. These outturns were inconsistent with the forecasts of traffic volumes that were significantly less than observed, and with speeds that were projected to be higher with the road widening than without.[2] The higher speeds were the basis for estimates of travel time savings, leading to the DfT’s estimate of the Benefit-to-Cost ratio of 2.3, which justified the investment.

This example shows that there may be a substantial discrepancy between forecast and outturn traffic flows and speeds. That this is a general problem is indicated by the observed invariance of average travel time over the past 45 years, as found in the National Travel Survey.[3] This implies that the benefits of road investment have been taken, not as time savings, but as increased access to desired destinations, which results in more traffic. This additional traffic is known as ‘induced traffic’, the consequence of increasing capacity, which results in increased externalities related to vehicle-miles travelled, including congestion, carbon emissions, air pollutants, and death and injuries. While HE routinely monitors outcomes of schemes 5 years after opening, this may not be sufficiently long to observe the full extent of induced traffic.[4]

There is therefore reason to suppose that in general the outcome of road investment as experienced by users does not correspond to the rationale for the investment, which is principally to increase welfare and economic growth by reducing congestion and improving connectivity. This discrepancy should be of concern to the ORR.

[1] Smart Motorway All Lane Running M25 J23-27 Monitoring Third Year Report. Highways England. 2108.

[2] https://www.gov.uk/government/publications/vdm-used-to-estimate-traffic-volumes-and-travel-time-saved

[3] Table nts-0101-2018

[4] Sloman L, Hopkinson L and Taylor I (2017) The Impact of Road Projects in England, Report for Campaign to Protect Rural England

 

 

Transport for London has recently published its latest report on Travel in London. At 279 pages, this latest in an annual series is almost certainly the most detailed account of travel behaviour in any city in the world. All credit to TfL.

Table 2.3 shows trip-based mode share. Private transport (very largely car) was responsible for 48% of trips in 2000, declining to 37% in 2015, but thereafter stabilising. Public transport has been stable at 35-36% of trips since 2012, and walking at 24-25% since 2000. Cycling grew from 1.2% in 2000 to reach 2.5% 2018. So the declining trend of car use has ceased in recent years, but it may resume as new rail capacity is opened, particularly Crossrail (the Elizabeth Line). Nevertheless, the target reduction of private transport to 20% by 2041, a feature of the Mayor’s Transport Strategy, looks difficult to achieve.

Section 9.7 discusses the role of licenced taxis and private hire vehicles (PHVs), a topic of much current interest. Taxis (black cabs) have been in slight decline while PHVs have grown substantially in recent years, largely reflecting the entry of Uber into the market. A survey of PHV users in London found that the two main trip purposes were for a night out and to/from airports, but only 28% of PHV trips were for both outward and return legs. App-based PHV users were attracted by specific features: estimate of fare, time for driver to arrive, knowing details of car booked, and estimate of journey time. 30% of PHV users said they had not needed to buy, replace or own a car, which facilitates a shift from individual car ownership.

Assessment

While a long-term target for reduction in car use has merit in that it shapes shorter term decisions, no Mayor is likely to hold office for anything like the time to reach the 2041 target date. A shorter-term target would allow performance to be held to account. And while the recent experience of London is that a steady reduction in the share of trips by car is compatible with the economic, cultural and social success of the city, sustaining this in the longer term would depend on substantial investment in the rail system that provides a fast and reliable alternative to buses, cars and taxis on congested roads. The biggest challenge for TfL and the Mayor is to find means of financing this investment.

BMW and Daimler recently announced that they were withdrawing their joint car-sharing service from the North America and the UK, although it will continue in some European cities. This business, known as ShareNow, which was the successor to BMW’s DriveNow and Daimler’s Car2Go brands, offered app-based short term car rentals, with pick-up and return anywhere withing large urban areas. The reasons given for withdrawal were rising costs and insufficient customer interest. The rationale for entering this shared use market was in case this were to develop into a significant alternative to the private ownership and fleet markets.

The implication of the BMW/Daimler decisions is that shared use seems less promising than many had supposed, not least CoMoUK, the association for the promotion of shared vehicle use in Britain. They see car sharing as a way of providing socially inclusive, low emission mobility which helps break dependency on private car ownership. Pay-as-you-go cars offer affordable, occasional access to cars to benefit individuals. At the same time, they help policy makers meet targets for emissions reduction, improvements to air quality and encouraging use of sustainable modes. However, CoMoUK’s concept of car sharing does not extend to the chauffeur-driven version, Uber and similar, the existence of which is likely to be a reason for the lack of commercial success of ShareNow.

Many observers believe that shared vehicle use is the solution to traffic congestion: if  occupancy could be increased, fewer vehicles would be needed. However, in urban areas there is substantial suppressed demand for car travel, the consequence of the deterrent effect of prospective delays due to congestion. Measures to reduce congestion initially reduce delays, which make car trips more attractive to those previously deterred, generating more traffic. So the limited levels of vehicle sharing that seem likely are probably not going to make much difference to road traffic congestion.

Last month, James Dyson announced the abandonment of his electric car project, worth £2bn of planned investment involving 500 staff. One factor in this commercial decision was the difficulty of developing a solid state lithium ion battery, seen as the next step in the evolution of lithium ion batteries. Getting the battery technology right is crucial for achieving commercial advantage in the electric vehicle market. A new entrant needs to offer a significant improvement in performance if it to grow market share, exemplified by Tesla.

Another likely factor prompting the Dyson decision, though not mentioned in press coverage, is the expectation that the car of the future will have autonomous driving options as well as electric propulsion. Autonomy involves either prolonged costly development or buying in someone else’s technology – both involving considerable risk.

As I have argued previously, the benefits to users of the new auto technologies will be incremental, not transformative. Yet the new technologies will be transformative for the manufacturing industry. There is a risk that returns from incremental improvement in performance will be insufficient to reward the large investment in technology development. Dyson may have made a shrewd judgement in cancelling his EV project.