The present study is an evaluation of a road safety intervention programme dealing with alcohol in traffic. The intervention was based on a programme developed by the Swedish Road Administration using three different messages. The aim of the study was to evaluate which message (emotional, factual or a combination of both messages) had the largest effect on the variables included in the theory of planned behaviour (TPB).
Of the 930 Senior High School Students who took part in the study 265 received an emotional message, 251 received a factual message, 254 received a combination of both messages and 160 were assigned to a control group who did not receive any message. Two scenarios were used describing situations where the participants would receive a lift from someone who had drunk two 'strong' beers and was either someone they did not know very well or their best friend.
The results showed that the intervention combining the emotional and the factual message had the largest effect on the variables included in the theory of planned behaviour (TPB). Attitude was affected the most by the interventions while further activities need to be taken in order to better target perceived behavioural control and especially subjective norm and thereby also intention.