Lynn Basford, a veteran of transport planning and a fellow of CIHT, and transport consultant, Aoife Dudley, speak about the move away from forecasting towards Decide and Provide (D&P) scenario planning.

Decide and Provide (D&P) is a forward-looking approach to strategic planning that is cognisant of the many uncertainties of the 21st century. It replaces the forecast-led approach of Predict and Provide (P&P) that reflected the car-centric planning policy of the time.

“We've got a huge paradigm shift to D&P, to meet net zero targets,” explains Lynn Basford, co-founder of BasfordPowers. “We need the strategies to decarbonize in our transport plans, along with mitigation measures set for development proposals. If we carry on as we are in transport planning, we’re simply not going to meet those net zero targets.”

“The other reason why D&P is significant now is because we’re dealing with huge levels of post-pandemic uncertainty, including the behavioural trends that we see with travel and transportation,” Basford adds. “D&P, with its scenario planning approach, allows you to reference that uncertainty – in the transport sector and in travel behaviour – in the assumptions.”

Aoife Dudley, a transport consultant at City Science is blunt in her assessment of the need to move to D&P, saying: “What we're doing currently doesn't work. You can see that outcomes are not ideal, not just in terms of climate change, but also in producing transport deserts and disadvantaging people who don't have access to a car or can't drive.”

New paradigm, new TRICS

D&P can still benefit from P&P’s most important resource, the TRICS database of observed, multi-modal trip rates associated with different types and scales of development. In 2021, Basford wrote a Guidance Note on the use of TRICS data in the practical application of D&P, helping transport planners transition and use the data when scenario planning.

The guidance includes six worked examples, showing how the D&P approach is applicable at every level of development, providing practitioners with a workflow or pathway for the process of applying D&P in their transport assessments.

Dudley is currently using TRICS on a project with Herefordshire County Council to develop a transport evidence base for its new spatial plan. “We identified different potential types of development in Herefordshire over the life of the spatial plan,” she says. “We used the different typologies and population thresholds in TRICS to build up a picture of personal and vehicle trip rates, and mode share, in five-year time slices, from the early 2000s to today.

“That gave us a picture of similar developments, so we could see what’s changed over time, what the mode share’s like now, what proportion of people use public transport, walk, and rely solely on the car.”

“We’re using the TRICS D&P guidance throughout – and a document called Net Zero Transport: the role of spatial planning and place-based solutions.”

Creating better places

Ultimately, D&P will help answer questions about the places we create, the types of activities we’ll be taking part in and what our mobility needs will be.

Basford sums it up, saying: “We need to be creating better places, sustainable places for communities. And we need to be creating the types of environments that support and contribute to net zero.”

Read Lynn Basford’s guidance for TRICS from 2021 and click through to the report to see the presentations provided by Lynn Basford with Glenn Lyons, Mott McDonald professor of future mobility and member of the CIHT’s Route to Net Zero Advisory Group and Nick Rabbets, managing director of TRICS.

See also Net Zero Transport: the role of spatial planning and place-based solutions produced by the RTPI and supported by CIHT. Lynn Basford also represented CIHT on the report’s expert steering group.