Expected behaviour and actual behaviour – is there a difference?

Abstract

Daniel Kahneman, the Nobel Prize winning psychologist, made the following observation. ‘Economists think about what people ought to do. Psychologists watch what they actually do’. This apparently simple and obvious theory could be equally applied to other fields and in particular the behaviour of road users in urban streets. This paper considers when and why road user behaviour may not conform to the designer's expectations and how this affects road safety. Drawing on the experiences of 16 years of undertaking more than 500 road safety audits and nearly 40 years of managing the design and delivery of urban highway design, with recent particular emphasis on alternative design thinking such as ‘shared space’, this paper argues that priority and regulation, and routine application of highway engineering standards may not automatically provide the resulting safe streets that would be expected.