Introduction

A well-functioning traffic and transport system is a necessity for an industrialised and complex society. At the same time, the way our traffic and transport system is shaped and functions also causes major societal problems. Emissions of pollutants from vehicles worsen the quality of the air, causing health hazards to humans and other living species. Emissions of CO2 in particular contribute to global warming. The continuously increasing number of vehicles makes it ever more difficult for traffic to proceed smoothly, causing congestion, limiting the accessibility of many destinations, and threatening the livability of cities and other living areas.

These problems have been on the agendas of public authorities since the 1960s. In general, these problems have been split into behavioural and technological problems. Emissions are regarded as a technical problem because the engine technologies and the fuels used discharge hazardous substances. Congestion is primarily a behavioural problem caused by people travelling (too) much and/or choosing an inefficient means of travel.

These problem definitions strongly determine the search for solutions. Emissions are primarily made the problem of the vehicle industry which is requested, or forced by means of legislation, to develop cleaner engines. Congestion is primarily tackled by making an appeal to people's sense of responsibility to society via awareness campaigns that request them to travel less or to make greater use of public transport.

Over the past decade, though, policymakers as well as many others have become increasingly skeptical about the possibilities of influencing people's mobility. At the same time, interest has grown in technical options to tackle congestion problems. There appears to be a shift from the behavioural approach to the technological approach. However, this shift has not remained uncontested. A variety of actors, especially those concerned with the environment and the livability of cities, continue to emphasise that only a change of behaviour on the part of travellers can lead to fundamental (or sustainable) solutions for traffic and transport problems.

From an STS perspective, this distinction between technical and behavioural problems and approaches is not only strange but also counter-productive. STS research has extensively shown that technical change and societal or behavioural change typically go hand in hand. New technologies rarely just replace existing ones.