Our Technical Director Graham James has provided expert commentary on how scenarios around possible futures can support transport scheme decisions and case-making.
His article, in the latest issue of Local Transport Today (LTT), highlights that assumptions about the future – such as behavioural trends, electric vehicle take-up, travel costs, or the potential impact of self-driving vehicles – are not just a technical issue for analysts, but have an important role in decision-making. Scenarios allow decision-makers to explore the uncertainties and ‘what-ifs’, to see if a particular option still makes sense under a range of potential futures. Graham explains how the UK Department for Transport’s (DfT’s) Transport Analysis Guidance (TAG) has evolved to bring in greater use of scenarios, through the Uncertainty Toolkit and the Common Analytical Scenarios – and how this guidance is now in flux. He takes readers through the key points of a recently-published report into how scenarios are used in transport modelling and appraisal both here and overseas. He also provides his own perspectives and expertise on critical questions such as:
- How to bring uncertainty and scenarios into the initial stages of problem definition and optioneering
- How to measure a project’s robustness against a range of scenarios, and judge which option is best if it’s not clear-cut
- Whether there should continue to be a central ‘core scenario’
LTT is the leading journal covering the UK’s transport policy, planning and delivery. Graham’s article appears in the 29 July 2026 issue. It is available at https://lttmagazine.co.uk/edition/ for LTT subscribers or to purchase the individual edition.