The theory of planned behaviour: The role of descriptive norms and past behaviour in the prediction of drivers’ intentions to violate

Road crashes are largely attributed to driving violations, a behaviour which is committed willingly. The most commonly used theoretical model to predict this behaviour has been the theory of planned behaviour (TPB) and its predecessor, the theory of reasoned action. This study includes a sample of 275 people of the general public holding a current driving licence. Its general aim is to predict the intention to commit two different driving violations: speeding in an urban area and dangerous overtaking by an expanded version of the TPB containing separate measures of descriptive norms and past behaviour. The results show that both past behaviour and descriptive norm make a unique contribution towards the prediction of intention to violate. Furthermore, it also found that the effect of descriptive norms is greater in a situation described as ‘risky’. The effect of age and annual mileage were significant with regard to speeding indicating that young drivers and those who use the car regularly are more likely to speed. Implications of the current findings for the development of intervention programmes are discussed.