Introduction

The context of transport policy development after the initial recovery and reconstruction period at the end of the Second World War was dominated by two main issues. The first was the ownership, regulation and service delivery of the transport industries, and the second was coping with rising road traffic by the development of what was seen as a modern road system. It was how the second of these tasks evolved and transformed over the next three quarters of a century which is the main topic of this chapter, and especially how this interacted with the technical methods of forecasting how much traffic there would be, the gradual death of ‘predict and provide’ as an intellectually respectable planning theory, its long after-life as planning practice, tensions in its policy consequences, the growth of alternatives grounded in an acceptance of uncertainty, and a recognition of fundamental changes to social life.

The interaction of technical appraisal and policy development affected everything in the sector, in ways which were an uncomfortable interweaving of feelings that road appraisal was either the jewel in the crown of formal strategic thinking, or a biased and distorted barrier to it. It is also a story reflecting my whole professional career, having worked as a young researcher with the people who had themselves previously started traffic forecasting in the UK, and then met, and sometimes worked with, the authors of nearly all of the reports acknowledged in the reference list. I should state that I have often been a protagonist in arguments I comment on in this text, which may colour my account.

Road Research Laboratory traffic forecasts 1958–75 and the ACTRA Review 1976–7

Technical work by Glanville and Smeed (1958) of the government's Road Research Laboratory (RRL) calculating likely future traffic levels can be regarded as the beginnings of modern traffic forecasting in the UK. The phrase ‘predict and provide’, whose origin is unknown, had not yet been used in a transport context, but essentially it was taken as given that the role of such forecasts was to guide how much road space would be needed, notably in the construction of what became the motorway network.