Written evidence submitted by Mr Sam Eyre (SRI0008)

Introduction & Summary:

1. Two main questions from the call for evidence that this submission of evidence seeks to provide aid with are the following:

•        “Whether the Government’s current and forthcoming roads investment programme is meeting the current and future needs of consumers and businesses.

•        Whether the Government’s roads investment programme aligns with other policy priorities, such as decarbonisation, levelling up, productivity and growth.”[1]

2. Furthermore, this submission also seeks to ask the Government the following:

•         Could the money being used particularly on adding capacity to the strategic road network be used elsewhere on other projects such as rail?

•         With the Government’s commitment to net zero by 2050. Do the Government see a future where mass private passenger vehicle ownership is still the case in our society?

3. Overall, the main point of this submission of evidence is to highlight the phenomenon of ‘induced demand’ and the possible consequences of capacity upgrades to Britain’s Strategic Road Network. This evidence comes from an individual studying politics at the University of Sheffield who has a general interest in transport planning, particularly what the future of travel should look like concerning reducing carbon emissions and creating a society less reliant on cars.

4. Salient points:

• ‘Induced demand’ must be considered when proposing road capacity upgrades
• Increasing the number of smart motorways may cause ‘induced demand.’
• The demand that is induced by new road capacity will likely cause greater greenhouse emissions
• Thus, increased usage of Britain’s Strategic Road Network runs in direct contradiction with the Government’s priority of decarbonisation
• Money may be better spent on public transport capacity upgrades such as on our InterCity rail and rail freight networks
• In a less car-reliant future, consumers and businesses will rely less on the strategic road network; thus, it possibly does not deliver on the future needs of consumers and businesses

What is ‘Induced Demand’?:

5. ‘Induced demand’ is an idea in economics that effectively means ‘if you build it, they will come’ but is put into academic terms and tested repeatedly. When linked to road-building projects or projects that expand the capacity of existing road infrastructure, it predicts that the amount of road users will go up to fill the new capacity.[2] Consequently, this means that improving the capacity of the strategic road network to reduce congestion and improve the system’s efficiency will cause the re-emergence of issues they seek to solve.

6. The term Vehicle Miles Travelled (or VMT) is often used to quantify the effects of induced demand. The theory is also almost exclusively studied and applied to road networks in the United States; thus, studies or data referenced in this evidence will be from American sources. However, despite this, the theory is, of course, applicable worldwide. It is merely the case that it mainly captures the imagination of American academics due to their pervasive Car Culture. The most definitive study that proves ‘induced demand’ comes from two American scholars, Matthew Turner and Gillies Duranton. They studied multiple American regions and found a one-to-one ratio between the increase in road capacity and the VMT on those roads.[3] They found that between 1990 and 2000, if an area’s road network increased its capacity by 10%, the VMT on that network would increase by 10% and that if road capacity was improved by 11%, then VMT would go up by 11% etc.[4]

7. Furthermore, a study done in California found that a 10% increase in VMT could be associated with a 1/3rd expansion of the region’s road lane capacity.[5] Their study used data recorded over 22 years.

8. The theory can also work in reverse. In Paris, there was a reduction in overall road capacity within the city and surrounding region. This led to a 20% increase in public transportation usage.[6] Thus, demand went down because the supply of road capacity decreased, meaning it made more sense for many trips to be made on public transport. Clearly, this road capacity reduction must be matched by an equal or more significant increase in public transport capacity and reliability. While this is possibly less useful in the direct application of induced demand to improvements on our Strategic Road Network as, a decrease in capacity is not a realistic scenario. It further proves the theory of induced demand and how it can be applied to road networks and broader transport infrastructure.

9. In essence, this shows us that increasing the capacity of the strategic road network will likely lead to more traffic on these roads overall.

Consequences of ‘induced demand’ for Road Investment Strategies:

10. Fundamentally, the evidence above suggests that the number of vehicles using those roads increases when roads see improvements such as extra lanes, etc.

11. It seems clear that the Smart Motorways stocktake will suggest that smart motorways are safe enough.[7] Thus, it is likely that the capacity upgrades will go ahead at some point, either in RSI2 or RSI3.

12. Although much of the evidence discussed has been synthesised with a focus on traffic congestion, it is implicit that more road usage means more greenhouse emissions and possibly even more car ownership. This is because it sets the precedent that one should drive if money is being invested in the road network. Thus, capacity upgrades such as the creation of more ‘smart’ 4-lane motorways are in direct conflict with the Government’s priority to decarbonise.

13. Even if we see a total change to electric vehicles, the production of batteries, tyres etc. is still not as green as the use of electric trains powered by overhead line equipment (as opposed to battery-powered trains). When electric cars output 180g of CO2 per passenger when only one passenger is in the vehicle. If that individual had taken an electric train, they would have output 80g of CO2.

14. Furthermore, road upgrades will increase the efficiency of journeys. Thus, the per-mile cost of a car journey is reduced. Causing a rise in vehicle usage and an increase in carbon emissions despite the overall increase in journey efficiency. This is known as the ‘rebound effect’.[8]

15. Suppose the Government is serious about its priority to decarbonise. Further road capacity expansion should not be considered especially when money may be best used elsewhere, such as investing in the InterCity rail network. A network that, in many cases, can facilitate the same journeys as the Strategic Road network but at far less cost to the environment. This is why the Government must be questioned on this line of spending and tested on whether this is the best use of the money allocated.

16. The case of South Wales is a blatant example of where investment in rail infrastructure makes far more sense than improving road capacity. In this case, the Government proposed spending £1.4bn on a new road link. This was rejected by the Welsh Government, which believed that the same capacity could be generated on their public transport and rail freight network through an investment of £600-800 Million.[9] Thus, saving the taxpayer and the environment.

17. Furthermore, if we are to move to a more car-less society (as we ultimately should) then the capacity upgrades to our Strategic Road Network will not meet the future needs of consumers and businesses. Consumers and businesses will instead want better public transport capacity and connectivity that is cheaper to use (here, we can exploit economies of scale).

Concluding Remarks:

18. While the argument of this submission is not to scrap the Strategic Road Investment projects altogether. Maintenance and minor improvements, such as replacing concrete road surfaces with tarmac, are clearly needed. However, in a world where we must decarbonise, when considering road capacity upgrades such as creating more ‘smart motorways’ with added lanes, we must consider the effects of phenomena such as ‘induced demand’ and associated phenomena. Transport is one of our most significant greenhouse gas emitters.[10] Thus any new road-building project should take steps to reduce the emissions from transport. Capacity upgrades to our Strategic Road Network could contradict these government priorities and run the risk of not delivering what our society requires over the next 50 years if we move to a less car-reliant society.

19. “A developed country is not a place where the poor have cars. It’s where the rich use public transportation.” ― Gustavo Petro

Bibliography:

1.     Burroughs, David, ‘Road vs Rail: The Route to Decongestion’, International Railway Journal, 61.5 (2021), 30–32

2.     ‘Call for Evidence - Committees - UK Parliament’ <https://committees.parliament.uk/call-for-evidence/3003/> [accessed 24 January 2023]

3.     Cervero, Robert, and Mark Hansen, ‘Induced Travel Demand and Induced Road Investment: A Simultaneous Equation Analysis’, Journal of Transport Economics and Policy, 36 (2001)

4.     Downs, Anthony, Still Stuck in Traffic: Coping with Peak-Hour Traffic Congestion (Washington DC, UNITED STATES: Brookings Institution Press, 2004) <http://ebookcentral.proquest.com/lib/sheffield/detail.action?docID=273540> [accessed 17 January 2023]

5.     Greening, Lorna A, David L Greene, and Carmen Di, ‘Energy Efficiency and Consumption * the Rebound Effect * a Survey’, Energy Policy, 2000

6.     Mann, Adam, ‘What’s Up With That: Building Bigger Roads Actually Makes Traffic Worse’, Wired <https://www.wired.com/2014/06/wuwt-traffic-induced-demand/> [accessed 21 January 2023]

7.     Smart Motorways Stocktake, First Year Progress Report 2021

8.     ‘Transport and Environment Statistics 2022’, GOV.UK <https://www.gov.uk/government/statistics/transport-and-environment-statistics-2022/transport-and-environment-statistics-2022> [accessed 25 January 2023]

January 2023

Endnotes