Extending the theory of planned behaviour: The role of personal norm

Abstract

This study assesses the sufficiency of Ajzen's (1985) theory of planned behaviour in predicting intentions to commit each of three driving violations involving poor lane discipline: cutting across traffic to leave a motorway; weaving in and out of two lanes of slow‐moving traffic; and overtaking on the inside. Behavioural intention was predicted reasonably well by the three main constructs of the theory of planned behaviour. However, the addition of measures of anticipated regret and moral norm substantially improved prediction in each case, suggesting that personal normative influence is an important factor in shaping intentions to perform behaviours that are antisocial or socially controversial. The development of a belief‐based measure of perceived behavioural control is also considered.