Transport planners: we need to get our act together on decarbonisation

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Transport Knowledge Hub logo Published on: 24th September 2020 by Stephen Bennett.

Transport planners, we have failed. In the past decade, there has been little to no progress in reducing greenhouse gas emissions from surface transport in the UK. Due to reductions in emissions from other sectors, it is now the highest-emitting sector in our economy.

Okay, that may be a bit harsh. Transport planners have actually achieved some great outcomes in that past decade. In particular we have seen significant progress in active travel, with a number of cities reallocating roadspace for walking and cycling, creating better places for people and supporting public health and wellbeing. This has been amplified during the current pandemic, with the DfT’s guidance on reallocating road space in response to Covid-19 enabling local authorities to quickly and easily improve conditions for walking and cycling. I am hoping that will create lasting positive change in areas that have embraced it.

But we are still struggling with emissions. Car traffic is now returning to pre-Covid levels, higher in some cases as people are deterred from using public transport. Trends in the private car market aren’t helping, as people are choosing larger and heavier cars over lighter or electric models. A lot of this is beyond our control in the transport planning profession. But there are areas where can have an influence.

A core area of work for transport planners is in the assessment and appraisal of projects, providing our expertise to help clients and decision-makers make the right choice on which projects to deliver. A recent report by Transport for Quality of Life has highlighted some of the flaws in our assessment of schemes, which could have a significant impact in terms of emissions.

In their report on The Carbon Impact of the Roads Programme, there is a fascinating section on the current approach to assessing carbon impacts of road schemes. This shows how, at present, the impact of the programme is considered at the level of individual schemes. While most schemes are expected to result in carbon emission increases, the conclusion for virtually every scheme is that any change in emissions resulting from the scheme is small and insignificant, relative to the total carbon emissions of the economy. I advise you to take a look at this section of the report, it’s staggering to see so many major road schemes with the conclusion of every one that impacts are insignificant.

In an article about the report, Professor Phil Goodwin points out that this problem largely arises because the scheme assessments divide the estimated additional carbon resulting from the road scheme by the total carbon emissions in the economy, which clearly results in a very small number. He concludes that we should “formally retire this unique denominator, which so restricts the scope of decarbonisation discussions”.

This led to an interesting debate on social media, where one contributor suggested assessing carbon impacts of transport schemes against local budgets (i.e. carbon budgets per person aggregated to the users of the scheme or to the local area), rather than the total emissions in the whole economy. This seems to make sense and has significantly different outcomes, demonstrating that schemes do have an impact when considered in the context of local carbon budgets.

So what does this all mean for transport planners? It means we need to get our act together on decarbonisation. We need to understand the flaws in our current appraisal methods, and work with the profession, with academia and with the Department for Transport to evolve and improve them. We need to understand carbon budgets, both at a national level and what they might mean in local areas, and for users (and non-users) of proposed schemes. And we need to do this assessment up-front, at the beginning of projects, so they drive the choice of solutions rather than being an afterthought for mitigation.

If we can do this, and be more honest in our assessment of impacts of schemes, and be bolder in our advice and influence, maybe we can change the trajectory for greenhouse gas emissions for surface transport in the UK. And that would be not only success for transport planners, but for everyone.

About the Author

This post was written by Stephen Bennett. Stephen is the chair of the Transport Planning Society