Call for less uncertainty in predictions of future transport demand

Transport forecasters need to pinpoint drivers of travel demand that are less prone to change and those that can be changed by policies we choose today, Dr Greg Marsden has urged as the Commission on Travel Demand he chairs calls for evidence.

Marsden, noting in his blog that attempts to identify plausible sets of alternative futures has alighted on variations in traffic volumes of between -62% and +10%, comments: "We need to ask... whether the relatively near future of 2040 is so uncertain that we have to present decision makers with a range of outcomes which are this wide?"

Highlighting that DfT low and high forecasts vary by 100 billion miles, Marsden says that while there will always be some demand uncertainties, "some are not somehow 'out there' waiting to happen but will be created by policy pathways we choose," with some behaviour more amenable to change. He hopes the Commission can identify alternative approaches to forecasting demand. The call for evidence is here.