How scenario planning can aid transport decision-making

The past offers an unreliable guide to the future in transport, where new technologies, environmental pressures and changes in demand have the potential to blow the best laid plans off course, reports business motoring writer Jonathan Manning

The practice of gazing into the rear view mirror to determine the future direction of travel policy is facing fundamental challenges from some of the UK’s leading transport planners.

In an era of disruptive change, both in transport and wider society, experts are increasingly adopting scenario planning techniques to assess different potential futures and engage communities in alternative visions of transport decades ahead.

Advocated by the Government Office of Science, scenario planning explores possible and preferable futures, typically by identifying areas of uncertainty and underlying drivers.

The objective is to deliver policies that are more resilient in the face of a variety of uncertainties.

Armed with a clear vision of the most desirable future, planners can wrestle with the ‘what if’ questions, testing current strategies and potential interventions against trends that develop at different paces and intensities.

The arrival of autonomous vehicles provides a prime example of how a long anticipated development might be positive or negative, or both, dependent on the ultimate vision of transport planners.

On the plus side, autonomous vehicles could dramatically reduce road traffic accidents (helping planners achieve their goals of safer travel), cut traffic volumes and increase road capacity as fewer vehicles will be required. They will also provide travel solutions to people who can’t access transport today.

Alternatively, self-driving cars could compete with public transport, luring passengers away from trams, tube, trains and buses, increasing traffic volumes.

There’s no crystal ball to reveal how trends will advance, but it is possible to take a view on which developments would blow transport ambitions off course, and which might accelerate progress towards the stated objective.

“We suggest future demand policy should be led by asking ‘What sort of places do we want to live in and what sorts of actions need to be taken to bring that about?’,” says the Commission on Travel Demand in its report All Change.

“The solutions will be quite different indifferent places, but the question seems equally important everywhere.”

Accepting a wide range of possibilities

Naturally, transport scenarios range widely dependent on the criteria that lie behind them and the level at which they apply, whether national, regional, city or citizen.

Plausibility can help scenarios capture the attention of both policymakers and the public but, importantly, for scenario planning to work, no potential outcome should take precedence over another for being more likely.

“The current practice of operating with a ‘core’ or ‘preferred’ scenario is not defensible,” says the Commission on TravelDemand. “With this comes a disproportionate depth of analysis and focus on the benefit-cost ratio of a scheme under one imagined future. A more pluralistic and feasible set of futures should be developed. It should be established that schemes make sense in a broader range of futures than is currently the case.”

In effect, policies and investment decisions should be tested against a wide range of potential scenarios to sift out vulnerable ideas from the more resilient and robust.

Glenn Lyons, Mott MacDonald professor of future mobility at UWE Bristol, is one of the ‘godfathers’ of transport scenario planning, having worked in the field for the past 20 years. He sees scenario planning gaining momentum as planners and policymakers grapple with how to handle mounting levels of uncertainty.

“Instead of reactive policymaking that is vulnerable to policy failure due to unanticipated change (predict and provide), we need proactive policymaking that helps guard against policy failure through adaptability to unanticipated change (decide and provide),” he says.

Lyons accepts that this puts decision makers in the uncomfortable position of having to judge the full extent of uncertainty as well as distinguish between subjective opinions of probable (likely to happen), plausible (could happen) and possible (might happen) futures. But, making decisions on the basis of a clear, well-defined future is seriously flawed.

To find out how Highways England and England's Economic Heartland are using scenario planning, read the full article, How scenario planning embraces uncertainty in transport planning (PDF), taken from the Smart Transport Journal.