Determining a dosage threshold of drink-driving enforcement operations: A systematic review.

Issues: Policy enforcement is crucial to achieve impacts on alcohol-related harm. It is not clear what level of enforcement intensity or 'dosage' is necessary for addressing drink driving and related harms. Given competing enforcement demands and agencies' resource constraints, understanding how much enforcement is sufficient to deter drink driving is critical.

Approach: This systematic literature review followed Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA) guidelines to examine research about dosage effects of enforcement and related visibility on drink-driving outcomes, including motor vehicle crashes and fatalities. Risk of bias was assessed using the Cochrane Collaboration Effective Practice and Organization of Care tool and the JBI checklist.

Key Findings: The 21 studies that met the inclusion criteria for this review differed in measures of enforcement dosage and outcomes, making it difficult to synthesise results across studies and draw conclusions about a threshold or optimal level of enforcement. Although most included studies found that sustained enforcement was associated with reductions in drink driving or related harms, only two studies tested an optimal dosage. Due to study design limitations, a substantial percentage of these studies must be considered with caution.

Implications: Additional research with rigorous study designs with appropriate controls is needed to determine an optimal high visibility enforcement dosage level to help law enforcement agencies make realistic decisions about allocating enforcement resources to address drink driving.

Conclusion: Consistent evidence about a drink-driving enforcement dosage threshold is lacking, partly due to an insufficient number of well-designed studies. Addressing challenges of conducting rigorous studies in community settings is crucial.