BACKGROUND: Health communications often present graphic, threat-based representations of the potential consequences of health-risk behaviours. These 'threat appeals' feature prominently in public health campaigns, but their use is controversial, with studies investigating their efficacy reporting inconsistent, and often negative, findings. This research examined the impact of a threat-based road safety advertisement on the driving behaviour of young male drivers. METHODS: To address limitations of previous research, we first identified a road safety advertisement that objectively and subjectively elicited fear using physiological and subjective measures. Study 1 (n = 62) examined the effect of this advertisement, combined with a manipulation designed to increase perceived efficacy, on speed choice. Study 2 (n = 81) investigated whether a state emotion, anger, impacts on the effectiveness of the advertisement in changing four distinct driving behaviours. Both studies examined short-term effects only. RESULTS: Study 1 findings indicated that a high threat message, when combined with high perceived efficacy, can lead to a decrease in speed choice. Study 2 results suggested that increased levels of state anger may counteract the potential value of combining fear-arousing threats and efficacy-building messages. CONCLUSIONS: Findings suggest that threat-based road safety communications that target affective (fear) and cognitive (perceived efficacy) mechanisms can positively affect driving behaviours. State emotions, such as anger, may negatively impact on the effectiveness of the message. Taken together, these findings provide additional support for the use of efficacy-building messages in threat-based communications, but highlight the need for further research into the complex array of affective influences on driving
