ObjectivesResearch on the deterrent effects of driving-under-the-influence (DUI) laws has been limited in China, which has criminalized drunk driving since May 2011 yet the effectiveness of this legislation remains unclear. Primary studies are needed to confirm whether government reports of reductions in DUI rates since then can indeed match changes in driver perceptions of DUI risk, and if so, be attributed to what specific components of the DUI legal environments. Based on the classical theory of deterrence and recent advances in differential deterrence, this study adopted a conjoint experiment from a previous US study that simulated the decision-making process of potential drinking drivers, and evaluated how DUI sanctions and enforcement practices contributed differentially to the three components of deterrence (i.e., certainty, swiftness, and severity of punishment). Key individual characteristics and nonlegal factors, as suggested by differential deterrence research to moderate the impact of DUI laws, were also considered. MethodsA Web-based conjoint experiment was conducted on a sample of 109 college students from two major universities in Shenzhen, China. Participants were randomly assigned to blocks of hypothetical scenarios composed of different levels of DUI enforcement and penalties, and asked to choose from a pair of scenarios each time, in which they were more likely to drink and drive. They also answered questions adapted from previous studies that measured key individual factors in relation to differential deterrence, such as informal sanction threat, moral inhibition, and personal and vicarious experiences with punishment. Such individual differences were accounted for in both a conventional two-level mixed logit aggregate model and a Hierarchical Bayes model. ResultsConsistent with prior findings in Western countries, DUI enforcement intensity, was found to be the strongest deterrent to potential drinking drivers in China. License suspension, as an administrative punishment that can be swiftly implemented, was also effective in deterring the Chinese drivers, who however were much more likely to fear the revocation of their licenses rather than a 6-month suspension only. Meanwhile, they were notably deterred by the possibility of being in jail for 1–3 days, let alone for 1–2 months. Altogether, enforcement, license suspension and jail penalties accounted for more than 75 percent of attribute impact on drivers’ decision to drink and drive, whereas fine penalty and license points had almost no effect. On the other hand, nonlegal factors such as informal sanction threat and vicarious experiences were found to have significantly moderated the deterrent effects of DUI laws. ConclusionsOverall, this study quantified the unique effects of perceived certainty, swiftness, and severity of DUI punishment in the Chinese context, and supported the usefulness of conjoint experiments for examining risk perceptions and DUI decisions in different legal environments. It also provided new empirical evidence on differential deterrence and pointed out the need of determining for which subsets of individuals and under what conditions can legal sanctions successfully deter potential offenders. Such research will help researchers and policy makers better understand the role of deterrence, for more effective policy development related to DUI as well as other important traffic safety issues.