A1 dualling + 1.4m tonnes CO2e

Two pictures. First picture has a two lane traffic jam and a driver saying 'can't wait for the road to be widened'. Second picture has a three lane traffic jam and a driver, still not moving, saying 'finally!'.

“Can’t wait for the road to be widened!” The effects of Induced Demand.

In what may have been his last act, Conservative transport minister Mark Harper has approved the Development Consent Order to dual the A1 between Morpeth and Ellingham. With an estimated cost of £290m in 2014 (£390m in 2024 prices) this could be one of the single most expensive transport projects in the North East. 

We don’t yet know what will be included in political manifestos, so this may still not go ahead, but in the last few months both Government and opposition Labour shadow ministers have supported the scheme. In this blog we present evidence on emissions, road safety and the economy that suggests there would be far better uses for this money.

Our key concern is that, according to National Highways’ own estimate, A1 dualling will lead to an additional 1,437,282 tonnes CO2e at exactly the same time as we are all being told we should be rapidly reducing emissions.

Most, if not all, of the evidence we present below applies to all major road expansion projects. 

1. The UK cannot achieve legal carbon budgets if it continues to expand road capacity

We know that:

If the Government had a lawful climate strategy that robustly demonstrated that it was possible to dual the A1 and still meet carbon budgets then that would be different, but currently it does not. This strategy would have to show what other emissions will be reduced to offset the increase due to A1 dualling.

Instead the Government use what Transport Action Network describe as a ‘bonkers test‘, comparing the extra emissions from the scheme to the total UK emissions from all sources. Using the same logic we could all justify driving everywhere, burning coal on an open fire and flying long-haul six times a year on the grounds that each makes only a small percentage difference to total UK emissions.

The leader of Northumberland County Council, Councillor Sanderson has said there were “different” ways to address environmental concerns and that “the Northumberland Line project would help to take cars off the road by providing a reliable rail link between south east Northumberland and Newcastle.” If this is true then for transparency’s sake this plan and associated modelling should be released immediately.

Timing will also be an important part of the strategy. If built in 2035 or 2040 the impact would be less than if built in 2025, because a greater proportion of vehicles would be EVs. If a new Government restored the ban of new petrol and diesel cars to 2030, that would help also bring forward the date when this scheme could be built.

The other consideration would be what other road schemes will be built. Just dualling the A1 would be far less impact than a large programme of work expanding roads across the country, as is currently planned.

2. There are much better options to improve road safety

Perhaps the best reason given to support the A1 dualling project is to improve road safety. SPACE for Gosforth supports Vision Zero – the target of having zero deaths or serious injuries from road traffic collisions.  

Between 2006 and 2024 there were 785 deaths or injuries recorded in total across all single carriageway sections of the A1 in Northumberland, from Morpeth to Berwick-upon-Tweed. These included 26 fatalities, 133 serious injuries and 626 slight injuries. In the same time period, across Northumberland as a whole, there were 3054 people killed or seriously injured on the roads.

However, we know schemes to increase road capacity have the potential to increase deaths, injury and poor health in a number of ways including:

  • From air pollution.
  • By contributing to climate change.
  • From physical inactivity because they encourage more driving and driving is a sedentary activity.
  • From increased road traffic collisions in surrounding areas due to higher volumes of traffic caused by the scheme, including on the remaining single carriageway between Ellingham and Berwick-upon-Tweed.
  • Due to the opportunity cost of not using the same budget on more cost-effective road safety measures.

It is also not clear from the injury statistics that dualling will reduce the number of people killed or injured. On the ~10 mile dualled section of the A1 between the A19 and A167, there have been about 9 fatalities and 53 serious injuries since 2006, a similar rate per mile as the single carriageway section. So even if individual journeys are made safer, the totals remain similar because of the much higher volume of traffic.

The paper Traffic volume and crashes and how crash and road characteristics affect their relationship – A meta-analysis explains this, setting out that “Crashes increase with increasing volumes [of traffic] but mostly at a lower rate. The relationship is strongest for multi vehicle crashes, at high volumes, and on freeways.” This means that additional traffic caused by this scheme is likely to lead to additional collisions, especially on surrounding roads that won’t have benefited from the safety improvements.

Looking at the NE England Road User Casualty Dashboard, it is easy to see the opportunity cost of focusing on one section of dual carriageway rather than a more comprehensive safety plan. The map below shows deaths (in red) and serious injuries (dark blue) from road traffic collisions in Northumberland between 2014 and 2024 (to date). This includes 141 fatalities and 1,550 serious injuries spread across both rural and urban areas.

Map of road user casualties in Northumberland from 2014 to 2024 (to date)

Map of road user casualties in Northumberland from 2014 to 2024 (to date)

Councillor Sanderson, leader of Northumberland Council has said “the safety factor of dualling the road was the most important part”, but if there was a £390m budget to improve road safety there is no way, given the distribution of injuries shown above, that anyone would reasonably decide to spend the entire amount on just one thirteen-mile section of road.

For the same price as the A1 dualling project, more cost-effective measures could be introduced right across Northumberland’s rural roads, achieving a much greater safety benefit overall.

More cost-effective options for improving road safety include:

  • Introducing average speed cameras. When these were introduced on the A9 in Scotland, there was a reduction of about 40% in fatal and serious injuries.
  • Lower speed limits by junctions or where visibility is limited.
  • Reducing speed limits on minor rural roads that are not part of the main road network.
  • Traffic-free walking and cycling routes and safer pedestrian and cycling crossings.
  • Specific junction improvements.  

We should also remember that carbon emissions from the scheme will contribute to climate change and extreme weather events. Scientists have sought to understand the likely impact of additional carbon emissions on death rates due to climate change through the calculation of a “mortality cost of carbon (MCC)”, which estimates the number of deaths caused by the emission of one additional metric ton of CO2. According to Nature, “adding 4,434 metric tons of carbon dioxide in 2020—equivalent to the lifetime emissions of 3.5 average Americans—causes one excess death globally in expectation between 2020-2100.” Dividing 1,437,282 tonnes by 4,434 suggests the climate impact of the A1 dualling project will be in the region of 324 additional deaths.

3. Economics

The economic case for new roads is generally based on the idea that if capacity is increased people will be able to travel more quickly. However, this does not always work out in practice, and other costs also need to be taken into account.


  • Additional traffic induced by the increased road capacity means journey times don’t reduce as planned.
  • Road works while schemes are built cause delays. 
  • Economic damage from climate change.
  • Like with road safety, there is an opportunity cost from not investing in other projects that would yield a greater economic benefit.

In the example below relating to the M25, journey times improved in the first year after a new lane was installed but then returned to what they were prior to the extra lane being installed. The article doesn’t say whether one year of improved journey times was sufficient to offset multiple years of delays due to roadworks.

In 2019, the BBC reported that Traffic was ‘worse’ at Newport M4 junction in Wales after £13m upgrade.

In 2021 the Welsh Government announced new road building would be put on hold while a review was undertaken. In 2023, following that review, Wales cancelled its road building programme concluding that “approach of the last 70 years was not working” aiming instead to put the money into projects that “reduce carbon emissions and support a shift to public transport, walking and cycling, improve safety through small-scale change and help the Welsh government adapt to the effects of climate change”.

Wales is not alone in coming to this conclusion, as we set out in our blog How much less will we use our cars in future?

A recently released paper estimates the likely economic damage due to climate change to be about £840 per tonne CO2e emitted. Multiplying that by the 1.4m additional tonnes that will be emitted due to A1 dualling gives an expected economic impact of negative £1.2bn.

By comparison, walking and cycling schemes have none of these disadvantages. In 2014 the Government reviewed the evidence relating to walking and cycling schemes and concluded “The typical benefit-cost ratios [for walking/cycling schemes] are considerably greater than the threshold of 4:1 which is considered by the Department for Transport as ‘very high’ value for money.” Investing the £390m budget that would be required for A1 dualling in walking and cycling schemes could lead to an economic benefit of >£1.6bn.


The A1 dualling business case now will be worse than ever as a result of inflation and the need to consider the impact of emissions which, as above, could amount to £1.2bn economic damage and 324 deaths just due to this one project.

Our view is that the budget should be reallocated (while there is still a budget) to cheaper, more effective changes that will lead to greater economic and safety benefits without the negative impact on climate and the environment. For example:

  • Average speed cameras to improve safety – with a 40% reduction in KSIs achieved on the A9 in Scotland.
  • Cleaner engines and more EV chargers to reduce emissions and air pollution.
  • Alternatives to driving to reduce the need to drive on the A1.
  • Tourist services to allow people to visit Northumberland without needing to own a car.
  • Service roads for farm vehicles so they don’t need to use the A1 itself.
  • Safe walking and cycling routes.

Of course, the future Government could choose to ignore the emissions and go ahead anyway. 

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