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We’re all ears – DfT’s consultation on priorities for developing our appraisal and modelling guidance (WebTAG)

The Department for Transport

16 August 2018/Categories: PTRC News

Last month, DfT published a consultation on priorities for developing our appraisal and modelling guidance (WebTAG). Our appraisal framework aims to provide as full a view as possible about the wide range of impacts transport has on the economy, environment and society. 

The consultation sets out an ambitious vision for developing robust, flexible and easy to use appraisal and modelling tools relevant to the policy and investment decisions that will be made over the next five years. Consulting on the strategy will allow us to better understand the evidence needs of our stakeholders and draw out areas of best practice across the industry. An important element of the strategy will be exploring how we can support the application of WebTAG and make it more user friendly. 


Over the next few months, DfT will be actively engaging with a wide range of stakeholders to hear their views. We will be holding regional events in the Midlands, South West, South East and the North, alongside more focused workshops to discuss priorities for each of the themes in the strategy. Please get in touch at if you would like to find out more. 

Themes for the strategy

We have developed five key themes and priorities for developing the evidence base and supporting users of our guidance (WebTAG). These have been formed through discussions with a wide range of stakeholders, including the Joint Analysis Development Panel  which we established in 2015 to provide strategic level comment and advice on our modelling and appraisal priorities. 

The themes are: 

People and place: capturing the range of impacts relevant for transport policy – cities and devolution are increasingly important dimensions of transport policy which require a fresh focus for certain aspects of our guidance. Physical infrastructure helps to define the built environment, with wide ranging implications for wellbeing. Well-connected communities are essential for a healthy society and transport has an integral role to play in this. Improvements to the urban realm, often considered alongside transport schemes, can also generate value for affected communities which we need to better capture in appraisal. There is a case for advancing analytical methods to value improved journey experiences including (but not limited to) journey time reliability, quantifying the value individuals place on a variety of aspects of ‘customer experience’ and understanding the impact of technology (for example autonomous vehicles) on values of time.

Reflecting uncertainty over the future of travel
– the future of travel is highly uncertain, largely due to a combination of technological and behavioural uncertainties. We need to develop our understanding of emerging and future technologies that could fundamentally change the transport market. These include the impact of autonomous vehicles, ‘mobility as a service’ and electric vehicles. On the behavioural side, we need to better understand trends including young people’s travel behaviour, the impact of an ageing population, flexible working and online shopping. We also need better tools to capture and communicate uncertainty to decision makers, including the development and use of scenarios.

Modelling and appraising transformational investments and housing
– a number of potentially transformational schemes and programmes are being assessed and/or delivered, including East-West Rail, Oxford to Cambridge Express Way, Northern Powerhouse Rail, Crossrail 2 and the Trans-Pennine Tunnel. Their strategic objectives extend well beyond ‘traditional’ transport outcomes. Recent guidance has taken big steps forward in capturing many of these impacts but we need to build on this to support the ambitions of DfT's Transport Investment Strategy, for example, understanding transport's impact on housing growth along a corridor and a consideration of productivity benefits beyond those generated by agglomeration effects.

Supporting the application of WebTAG and making it more user friendly
– we recognise that continually developing and improving our appraisal guidance can present challenges for those using and applying it. We would like to explore options for building capability including: developing case studies showing how the guidance can be applied in different situations; organising workshops to raise awareness of aspects of the guidance and share best practice and better signposting of the guidance. We would also like to investigate options to streamline and simplify the guidance to make it more user friendly while maintaining its robustness.
Developing and maintaining modelling and appraisal tools to meet user needs – given the challenges we are facing, different sources of evidence and modelling approaches may be needed to represent the transport market and undertake policy analysis in the future. We need to investigate the use of ‘big data’ in transport models and get a better grasp of any inherent opportunities or shortcomings in its use. We also need to strengthen the link with evaluation so that appraisal learns from and helps build better evaluation evidence. And we need to ensure our national modelling capability is fit for purpose.




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