Evaluation of the national sobriety checkpoints program in Mexico: a difference-in-difference approach with variation in timing of program adoption.

BACKGROUND: Up to a third of global road traffic deaths, and one in five in Mexico, are attributable to alcohol. In 2013, Mexico launched a national sobriety checkpoints program designed to reduce drink-driving in municipalities with high rates of alcohol-related collisions. Our study measured the association between the sobriety checkpoints program and road traffic mortality rates in 106 urban municipalities. METHODS: We leveraged data from the Salud Urbana en America Latina (SALURBAL), which compiles health and environmental data from cities with over 100,000 residents. Death data from 2005 to 2019 (i.e., outcome) were from official vital statistics. Among 106 Mexican municipalities defined as priority areas for intervention, 54 adopted the program (i.e., treatment) in 2013, 16 municipalities did so in 2014, 16 in 2015, 10 in 2016, 7 in 2017, and 2 in 2019. We used a difference-in-difference approach with inverse probability weighting adapted to a context where program adoption is staggered over time. RESULTS: There was a 12.3% reduction in road traffic fatalities per 10,000 passenger vehicles in the post-treatment period compared to the pre-treatment period (95% Confidence Interval, - 17.8; - 6,5). There was a clear trend of decline in mortality in municipalities that adopted the program (vs. comparison) particularly after year 2 of the program. CONCLUSIONS: In this study of 106 municipalities in Mexico, we found a 12.3% reduction in traffic fatalities associated with the adoption of sobriety checkpoints. There was a clear trend indicating that this association increased over time, which is consistent with sustained changes in drink-driving behavior. These findings provide support and insight for efforts to implement and evaluate the impact of sobriety checkpoint policies across Latin America.

Drink driving and speeding in Sao Paulo, Brazil: empirical cross-sectional study (2015-2018).

OBJECTIVES: To evaluate the prevalence of drink driving and speeding during 2015-2018 in Sao Paulo, Brazil. DESIGN: Cross-sectional observational study. SETTING: Roads representing the five main regions of the city of Sao Paulo in Brazil, one of the world's largest urban areas. PARTICIPANTS: Drivers (N=10 294) stopped at routine roadside breath testing checkpoints and those driving in selected roads for speeding measurement (N=414 664). PRIMARY AND SECONDARY OUTCOME MEASURES: Microwave radar guns were used to measure the speed of vehicles, while the prevalence of drivers under the influence of alcohol was observed in police checkpoints. Data were collected during three consecutive years (2016-2018) following a baseline study established in 2015 using a city-level representative sample of observational data representing all days of the week. RESULTS: Alcohol-related fatalities kept at a constantly high percentage, with 39% of road traffic deaths involving alcohol in 2016. Drivers testing above the legal breath alcohol concentration limit showed a decreasing trend, from 4.1% (95% CI 2.9% to 5.5%) at baseline to 0.6% (95% CI 0.2% to 1.2%) in the end of 2018 (p<0.001); however, more than half of drivers refused breath tests at checkpoints despite steep legal penalties. The prevalence of speeding among all vehicles decreased from 8.1% (95% CI 7.9% to 8.2%) to 4.9% (95% CI 4.7% to 5.1%) by the end of 2016 (p<0.001), but then increased again to 13.5% (95% CI 13.2% to 13.9%) at the end of the study period (p<0.001). CONCLUSIONS: Drink driving rates have reduced, likely due to an increase in drivers refusing breath alcohol tests, while speeding rates have increased significantly by the end of the study period, particularly among motorcycles. Future strategies aiming at reducing road traffic injuries in the major Brazilian city should tailor drink driving and speeding enforcement based on the new evidence provided here.

Challenges associated with drunk driving measurement: combining police and self-reported data to estimate an accurate prevalence in Brazil.

BACKGROUND: Drunk driving is an important risk factor for road traffic crashes, injuries and deaths. After June 2008, all drivers in Brazil were subject to a "Zero Tolerance Law" with a set breath alcohol concentration of 0.1 mg/L of air. However, a loophole in this law enabled drivers to refuse breath or blood alcohol testing as it may self-incriminate. The reported prevalence of drunk driving is therefore likely a gross underestimate in many cities. OBJECTIVE: To compare the prevalence of drunk driving gathered from police reports to the prevalence gathered from self-reported questionnaires administered at police sobriety roadblocks in two Brazilian capital cities, and to estimate a more accurate prevalence of drunk driving utilizing three correction techniques based upon information from those questionnaires. METHODS: In August 2011 and January-February 2012, researchers from the Centre for Drug and Alcohol Research at the Universidade Federal do Rio Grande do Sul administered a roadside interview on drunk driving practices to 805 voluntary participants in the Brazilian capital cities of Palmas and Teresina. Three techniques which include measures such as the number of persons reporting alcohol consumption in the last six hours but who had refused breath testing were used to estimate the prevalence of drunk driving. RESULTS: The prevalence of persons testing positive for alcohol on their breath was 8.8% and 5.0% in Palmas and Teresina respectively. Utilizing a correction technique we calculated that a more accurate prevalence in these sites may be as high as 28.2% and 28.7%. In both cities, about 60% of drivers who self-reported having drank within six hours of being stopped by the police either refused to perform breathalyser testing; fled the sobriety roadblock; or were not offered the test, compared to about 30% of drivers that said they had not been drinking. DISCUSSION: Despite the reduction of the legal limit for drunk driving stipulated by the "Zero Tolerance Law," loopholes in the legislation permit many drivers under the influence of alcohol to act with impunity. In this context the police/traffic officers are often powerless to enforce the law and thus drunk driving continues to go unchecked. CONCLUSION: Strong legislation and effective enforcement are necessary to reduce the prevalence of this dangerous behaviour. Correction techniques allow calculation of a truer prevalence of drunk driving, which can assist police and policymakers alike to redirect resources and align strategies.