Behavioural economics is a topic that has come into public prominence in recent months, having been a recognised sub-discipline for some years.   As an editorial in The Guardian newspaper of 1 September explained: ‘The new insight is that the right way to build up an understanding of how markets work is to watch how real people go about buying and selling. That may seem trivially obvious, but economists have traditionally started off instead by making assumptions – that people are rational and essentially selfish…..’

This is a message that transport economists could usefully hear.   A central assumption of standard transport analysis is that people take the benefit of investment in transport infrastructure in the form of time saving.   Because time has value, travel time saving is supposed to constitute the bulk of the benefit as arising from public investment in roads and railways.  This approach has made tractable the estimation of monetary benefits as an input to cost-benefit analysis.  However, in the real world, people can be observed to behave in a way inconsistent with this core assumption.   Average travel time has not changed significantly over the years.   What has altered is the average distance travelled, which has grown as people take advantage of investment in vehicles and infrastructure to move faster, so getting more access to desired destinations and choice of services on offer, in the time they have for travel.

It’s time for the transport economists to wake up to the wider developments in the discipline of economics and take account of progress in behavioural economics in particular.