Left on the Side of the Road? A Review of Deterrence-Based Theoretical Developments in Road Safety

Deterrence-based initiatives form a cornerstone of many road safety countermeasures. This approach is informed by Classical Deterrence Theory, which proposes that individuals will be deterred from committing offences if they fear the perceived consequences of the act, especially the perceived certainty, severity and swiftness of sanctions. While deterrence-based countermeasures have proven effective in reducing a range of illegal driving behaviours known to cause crashes such as speeding and drink driving, the exact level of exposure, and how the process works, remains unknown. As a result the current study involved a systematic review of the literature to identify theoretical advancements within deterrence theory that has informed evidence-based practice. Studies that reported on perceptual deterrence between 1950 and June 2015 were searched in electronic databases including PsychINFO and ScienceDirect, both within road safety and non-road safety fields. This review indicated that scientific efforts to understand deterrence processes for road safety were most intense during the 1970s and 1980s. This era produced competing theories that postulated both legal and non-legal factors can influence offending behaviours. Since this time, little theoretical progression has been made in the road safety arena, apart from Stafford and Warr's (1993) reconceptualisation of deterrence that illuminated the important issue of punishment avoidance. In contrast, the broader field of criminology has continued to advance theoretical knowledge by investigating a range of individual difference-based factors proposed to influence deterrent processes, including: moral inhibition, social bonding, self-control, tendencies to discount the future, etc. However, this scientific knowledge has not been directed towards identifying how to best utilise deterrence mechanisms to improve road safety. This paper will highlight the implications of this lack of progression and provide direction for future research. Introduction The significance of improving road safety continues to be reflected in the range of countermeasures and interventions that are currently being implemented to reduce traffic violations (e.g., law enforcement initiatives). The majority of these countermeasures utilise (or are founded upon) deterrence theory, which is central to criminal justice policy (Piquero et al., 2011). In regards to deterrence, the Classical Deterrence theory remains the mostly widely cited model, and it proposes that individuals will avoid offending behaviour(s) if they fear the perceived consequences of the act (Homel, 1988; Von Hirsch et al., 1999). The model was originally developed by two 18 century utilitarian philosophers named Bentham and Beccaria and proposes that offending behaviours are inversely related to the certainty, severity and swiftness of punishment (Taxman & Piquero, 1998). That is, the threat of legal sanctions are most effective when individuals perceive a high likelihood of apprehension when committing an illegal act, and believe that the impending punishment will be both severe and swift (Homel, 1988). This is known as general deterrence. In contrast, specific deterrence is the process whereby an individual who has been apprehended and punished for a criminal act refrains from further offending behaviour for fear of incurring additional punishment (Homel, 1988). The primary focus of this review is on general deterrence, although specific deterrence is still of relevance (and difficult to Peer review stream Freeman Proceedings of the 2015 Australasian Road Safety Conference 14 16 October, Gold Coast, Australia ignore) when examining the impact of different road safety countermeasures. Given the increasing utilisation of deterrence-based approaches in road safety (e.g., the expansion of random drug testing initiatives and speed cameras) it is timely to consider evidence regarding the effectiveness of the approach. It is also timely to consider whether theoretical progression of deterrence-based theory has kept pace with its corresponding application. Method The systematic review incorporated core principles of the “Preferred Reporting Items for Systematic reviews and Meta-Analyses” (PRISMA) statement checklist, including defining: (a) eligibility criteria e.g., studies between 1960 and 2015, (b) information sources e.g., electronic databases, reference lists, (c) study selection approach e.g., peer reviewed publications, and (e) study characteristics. However, given a primary aim of the study was to focus on the existence of theoretical progression (rather than effect sizes) the review focused on identifying (rather than quantifying the impact of) deterrence-based road safety research. Studies that reported on perceptual deterrence between 1960 and June 2015 were searched in electronic databases including PsychINFO and ScienceDirect.