Impact of an enhanced sobriety checkpoints programme and publicity campaign on motor vehicle collisions, injuries and deaths in Leon, MX: a synthetic control study.

Objective: Drunk driving is a major cause of road traffic injuries and deaths in Latin America. We evaluated the impact of a drunk driving intervention in Leon, Mexico on road traffic safety.

Methods: The intervention included increased drunk driving penalties, enhanced sobriety checkpoints and a young adult-focused mass media campaign, beginning 19 December 2018. We created a synthetic control Leon from 12 Mexican municipalities from a pool of 87 based on similarity to Leon using key predictors from 2015 to 2019. We assessed the effect of the intervention on road traffic collisions overall and collisions with injuries, deaths and involving alcohol, using data from police, insurance claims and vital registration.

Results: As compared with the synthetic control, Leon experienced significant postintervention lower police-reported total collision rate (17%) and injury collisions (33%). Alcohol-involved collisions were 38% lower than the synthetic control. Fatal collisions reported by police were 28% lower while vital registration road traffic deaths were 12% lower, though these declines were not statistically significant. We found no impact on insurance collision claims. There was heterogeneity in these changes over the evaluation year, with stronger initial effects and weaker effects by the end of the year.

Conclusions: Drunk driving policies in Leon led to fewer traffic collisions and injuries during the first year of implementation, with a weakening of this effect over time, similar to interventions in high-income settings and other Latin American countries. Supporting the expansion of similar policies to other cities in the region could improve road safety.