LAUSR

Statement of Purpose Sobriety checkpoints have strong empirical support as an intervention to reduce alcohol-related motor vehicle crashes. This study examined whether checkpoint size (number of police officers) and checkpoint duration (amount of time in operation) affect associations with alcohol-related crashes. Methods Queensland Police Service provided latitude-longitude coordinates and date and time data for all breath tests and alcohol-related motor vehicle crashes in the Australian city of Brisbane from January 2012 to June 2018. Hierarchical cluster analysis identified checkpoints as clusters of ≥ 25 breath tests conducted by ≥ 3 breath testing devices over a duration of 3 to 8 hours. Checkpoints and alcohol-related crashes were aggregated as counts per week. Generalized linear autoregressive moving average models related crashes to the number of checkpoints conducted within each week, as well as 1 week prior and 2 weeks prior. Models controlled for seasonality and other theoretically relevant covariates (e.g. precipitation, public holidays). Results A total of 3,420 alcohol-related crashes occurred and 2,069 checkpoints were conducted in Brisbane over the 6.5-year (339-week) study period. Checkpoints included a mean of 266.2 breath tests (SD=216.3), 16.4 devices (SD=13.7), and were 286.3 minutes duration (SD=104.2). Each 10 additional checkpoints were associated with a 5% decrease in crash incidence at a lag of 1 week (IRR= 0.95; 95%CI: 0.91, 1.00). We detected no differential effects according to checkpoint size or duration. Conclusions Sobriety checkpoints are associated with fewer alcohol-related motor vehicle crashes for around 1 week. Checkpoint size and duration do not appear to affect this association. Contribution to Injury and Violence Prevention Science Disadvantaged populations have greater incidence of alcohol-related motor vehicle crashes. Police departments can use the results of this study to maximize injury prevention and reduce health disparities while minimizing operational costs by conducting shorter checkpoints with fewer officers.