Effects of a Community-Level Intervention on Alcohol-Related Motor Vehicle Crashes in California Cities: A Randomized Trial

Optimizing sobriety checkpoints to maximize public health benefits and minimize operational costs

BACKGROUND

Sobriety checkpoints are a highly effective strategy to reduce alcohol-impaired driving, but they are used infrequently in the USA. Recent evidence from observational studies suggests that using optimized sobriety checkpoints-operating for shorter duration with fewer officers-can minimize operational costs without reducing public health benefits. The aim of this research was to conduct a pilot study to test whether police can feasibly implement optimized sobriety checkpoints and whether researchers can examine optimized sobriety checkpoints compared to usual practice within a non-randomized controlled trial study design.

METHODS

The study site was the Town of Apex, NC. We worked with Apex Police Department to develop a schedule of sobriety checkpoints during calendar year 2021 that comprised 2 control checkpoints (conducted according to routine practice) and 4 optimized checkpoints staffed by fewer officers. Our primary operations aim was to test whether police can feasibly implement optimized sobriety checkpoints. Our primary research aim was to identify barriers and facilitators for conducting an intervention study of optimized sobriety checkpoints compared to usual practice. A secondary aim was to assess motorist support for sobriety checkpoints and momentary stress while passing through checkpoints.

RESULTS

Apex PD conducted 5 of the 6 checkpoints and reported similar operational capabilities and results during the optimized checkpoints compared to control checkpoints. For example, a mean of 4 drivers were investigated for possibly driving while impaired at the optimized checkpoints, compared to 2 drivers at control checkpoints. The field team conducted intercept surveys among 112 motorists at 4 of the 6 checkpoints in the trial schedule. The survey response rate was 11% from among 1,045 motorists who passed through these checkpoints. Over 90% of respondents supported sobriety checkpoints, and momentary stress during checkpoints was greater for motorists who reported consuming any alcohol in the last 90 days compared to nondrinkers (OR = 6.7, 95%CI: 1.6, 27.1).

CONCLUSIONS

Results of this study indicate the sobriety checkpoints can feasibly be optimized by municipal police departments, but it will be very difficult to assess the impacts of optimized checkpoints compared to usual practice using an experimental study design.

Place of last drink enforcement: Effects on alcohol-related traffic crashes

BACKGROUND

Binge drinking can result in various types of harms including traffic crashes. Bars and restaurants that serve alcohol to patrons who are obviously intoxicated (i.e., overservice) contribute to these crashes. One strategy to address overservice is place of last drink (POLD) where law enforcement officers responding to alcohol-related incidents inquire about where the individuals last drank alcohol. This information may then be used to identify bars and restaurants that frequently overserve alcohol. There is limited evaluation of the effectiveness of POLD in reducing overservice, traffic crashes, and other harms.

METHODS

We evaluated the effects of a POLD initiative, developed by some law enforcement agencies in Minnesota (USA), on alcohol-related traffic crashes from 2010 to 2019. Among 89 intervention (POLD) vs. comparison communities, we fit regression models with participation in POLD as the predictor. As secondary analyses, we fit models with POLD implementation level as the predictor (implementation levels were assessed via a survey of law enforcement agencies). We controlled for relevant community and agency characteristics.

RESULTS

In the model with participation in POLD as a predictor, there was little difference in the rate of total alcohol-related crashes (rate ratio [RR] = 1.07, 95% CI: 0.85-1.34). In the model with level of implementation as a predictor, the rate of total alcohol-related crashes was comparable between communities with high implementation and those with no implementation (RR = 0.89; 95% CI: 0.71-1.10). Similar results were seen for alcohol-related crashes with nonfatal injury and property damage outcomes.

CONCLUSIONS

This study found little evidence that the POLD initiative, as currently implemented, was associated with reductions in traffic crashes across communities in Minnesota. Further research could explore whether specific characteristics of POLD are particularly important and whether POLD could be combined with other strategies to reduce traffic crashes and other alcohol-related harms.

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.

The geography of sobriety checkpoints and alcohol-impaired driving

BACKGROUND AND AIMS

Sobriety checkpoints are an effective strategy to reduce alcohol-impaired driving, motor vehicle crashes, injuries and fatalities. The aim of this study was to identify the geographic extent over which individual sobriety checkpoints affect alcohol-impaired driving.

DESIGN, SETTING, PARTICIPANTS

Spatial ecological panel analysis using geolocated breath test data from the Queensland Police Service, Australia, for January 2012 to June 2018. Data were aggregated over 338 weeks within 528 Statistical Area level 2 (SA2) units (n = 178 464 SA2-weeks) and 84 Statistical Area level 3 (SA3) units (n = 28 392 SA3-weeks). SA2 units in Queensland contain a mean population of 8883.5 (SD = 55 018.3) and encompass 468.9 roadway kilometers (SD = 1490.0); SA3 units contain a mean population of 57 201.6 (SD = 29521.6) and encompass 2936.0 roadway kilometers (SD = 7025.0).

MEASUREMENTS

Independent measures were the density of sobriety checkpoints conducted per 500 roadway kilometers within local and spatially adjacent space-time units. The dependent measure was the rate of tests that detected breath alcohol concentration (a proxy for blood alcohol concentration [BAC]) greater than the legal maximum value of 0.05% for fully licensed drivers in Queensland. Bayesian hierarchical spatial negative binomial models-related sobriety checkpoints to the rate of breath tests with BAC ≥ 0.05% within and between space-time units.

FINDINGS

One additional sobriety checkpoint conducted per 500 roadway kilometers was associated with 2.5% reduction in the rate of breath tests with BAC ≥ 0.05% within local SA2 units (incidence rate ratio [IRR] = 0.975; 95% credibility interval (CrI): 0.973-0.978), and with 5.5% reduction in the rate of breath tests with BAC ≥ 0.05% within local SA3 units (IRR = 0.945; 95%CrI: 0.937-0.953). Associations were attenuated towards null in spatially adjacent units and in temporally lagged units (e.g. SA3-weeks; adjacent lagged 1 week: IRR = 0.969; 95%CrI: 0.937-1.003).

CONCLUSIONS

Individual sobriety checkpoints appear to be associated with reductions in nearby alcohol-impaired driving. Relationships decay after approximately 1 week and beyond local areas containing approximately 60 000 residents and 3000 kilometers of roadway.

Alcohol-involved motor vehicle crashes and the size and duration of random breath testing checkpoints

OBJECTIVE

Sobriety checkpoints have strong empirical and theoretical support as an intervention to reduce alcohol-involved motor vehicle crashes. The purpose of this study was to examine whether checkpoint size (the number of police officers) and checkpoint duration (the amount of time in operation) affect associations between individual checkpoints and subsequent alcohol-related crash incidence.

METHOD

Queensland Police Service provided latitude-longitude coordinates and date and time data for all breath tests that occurred in Brisbane, Australia, from January 2012 to June 2018. We applied hierarchical cluster analysis to the latitude-longitude coordinates for breath tests, identifying checkpoints as clusters of ≥25 breath tests conducted by ≥3 breath testing devices over a duration of 3 to 8 hours. Generalized linear autoregressive moving average (GLARMA) models related counts of alcohol-involved motor vehicle crashes to the number of checkpoints conducted per week, as well as 1 week prior and 2 weeks prior.

RESULTS

A total of 3420 alcohol-related crashes occurred and 2069 checkpoints were conducted in Brisbane over the 6.5-year (339-week) study period. On average, checkpoints included a mean of 266.0 breath tests (SD = 216.3), 16.4 devices (SD = 13.7), and were 286.3 minutes in duration (SD = 104.2). Each 10 additional checkpoints were associated with a 12% decrease in crash incidence at a lag of 1 week (IRR = 0.88; 95%CI: 0.80, 0.97). We detected no differential associations 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 relationship.