This study used randomized field trial conditions to test the impact of police using the principles of procedural justice during routine encounters with citizens on attitudes towards drunk-driving, perceptions of compliance, and their satisfaction with the police.
The first randomized field trial—the ‘Queensland Community Engagement Trial’ (QCET)— was conducted to test the impact of police engaging with citizens by operationalizing the key characteristics of procedural justice (neutrality, citizen participation, respect, and trustworthy motives) in a short, high-volume police–citizen encounter. The study randomly allocated 60 roadside Random Breath Testing (RBT) operations to control (business-as-usual) and experimental (procedural justice) conditions. Driver surveys were used to measure the key outcomes, i.e., attitudes towards drinking and driving, satisfaction with police, and perceptions of compliance. Citizen perceptions of the encounter revealed that the experimental treatment was delivered as planned. The study also found significant differences between the experimental and control groups on all key outcome measures. Drivers who received the experimental RBT encounter were 1.24 times more likely than the control group to report that their views on drinking and driving had changed; experimental respondents reported small but higher levels of compliance (d = .07) and satisfaction (d = .18) with police during the encounter than did their control group counterparts. The results indicate that the way citizens perceive the police can be influenced by the way in which police interact with citizens during routine encounters, and they demonstrate the positive benefits of police using the principles of procedural justice. The study was limited by the use of paper-only surveys and low response rate. Also, the study setting (RBT road-blocks) was limiting and non-reflective of the wider set of routine police–citizen encounters. Future research should use experimental methods to replicate the field operationalization of procedural justice for different types of police–citizen encounters. (publisher abstract modified)