Long-Term Effects of a Multi-Component Community-Level Intervention to Reduce Single-Vehicle Nighttime Crashes - Follow-Up Findings From a 24-Community Randomized Trial

Q: What was the main objective of the follow-up study?

To determine whether the multi-component, high-visibility alcohol enforcement intervention had long-term effects on alcohol-related single-vehicle nighttime (SVN) crashes beyond the original study period.

Q: How was the intervention implemented and which cities were involved?

A randomized trial used 24 California cities; 12 cities were assigned to the intervention and implemented high-visibility alcohol enforcement operations and related components from April 2013 to March 2016.

Q: What did the regression analyses show about long-term crash outcomes?

Monthly SVN crash levels among ages 15–30 were significantly lower in intervention cities through 2021 compared with control cities, with an incidence rate ratio of 0.88 (95% CI 0.79–0.98) after key controls.

Sep 28, 2026

Uploaded by Finn

Follow-up findings evaluate whether a multi-component, high-visibility alcohol enforcement intervention in 12 California cities produced long-term reductions in alcohol-related single-vehicle nighttime (SVN) crashes beyond the original study period. A randomized trial selected 24 California cities (2012–2017); 12 implemented enforcement operations and other components (Apr 2013–Mar 2016). Multi-level negative binomial regression used crash data (2010–2021), controlling for community sociodemographics, time trends, COVID-19, and pre-intervention SVN crash levels. Post-intervention monthly SVN crashes among 15–30-year-olds were lower in intervention cities through 2021 versus controls (IRR 0.88, 95% CI 0.79–0.98). Results suggest sustained intervention effects on crashes and related injuries and fatalities.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Abstract

Objective and design

Method and statistical approach

Results

Conclusions

Background and context

Intervention description

Challenges for post-intervention evaluation

Outcome measures

Long-Term Effects of a Multi-Component CommunityLevel Intervention to Reduce Single-Vehicle Nighttime Crashes: Follow-Up Findings From a 24-Community Randomized Trial ROBERT SALTZ,a,* & MALLIE J. PASCHALLa aPrevention Research Center, Paciﬁc Institute for Research & Evaluation, Berkeley, California ABSTRACT. Objective: This follow-up study examines whether a multi-component, high-visibility alcohol enforcement intervention implemented in 12 California cities had long-term effects on alcoholrelated motor vehicle crashes beyond the period of the original study. Previous results indicated a signiﬁcant reduction in single-vehicle nighttime (SVN) crashes among 15- to 30-year-olds in intervention cities relative to controls. Method: A randomized trial was conducted with 24 randomly chosen California cities from 2012 to 2017 to evaluate a multi-component intervention to reduce excessive drinking and driving while impaired among adolescents and young adults. Twelve of the cities were randomly assigned to the intervention condition and implemented high-visibility alcohol enforcement operations and other components from April 2013 to March 2016. Multi-level negative binomial regression analyses were conducted with motor vehicle crash data from 2010 to 2021 to examine whether SVN crashes among 15-to 30-year-olds decreased in intervention cities relative to controls after the multi-component intervention was implemented. Analyses controlled for community sociodemographic characteristics, the overall time trend, the COVID pandemic, and pre-intervention levels of SVN crashes and adjusted for correlation of repeated observations within cities over time. Results: Regression analyses indicated a signiﬁcantly lower level of monthly SVN crashes among 15- to 30-year-olds in intervention cities during post-intervention months through 2021 relative to control cities (incidence rate ratio [95% CI] = 0.88 [0.79, 0.98],p < .05) when controlling for community sociodemographic characteristics, the overall time trend, COVID, and pre-intervention levels of SVN crashes. Conclusions: Study ﬁndings suggest that a multi-component, high-visibility alcohol enforcement intervention can have long-term effects on alcohol-related motor vehicle crashes and related injuries and fatalities among adolescent and young adult drivers. (J. Stud. Alcohol Drugs, 86, 136–139, 2025) STARTING WITH A tion approach, Saltz COMMUNITY-LEVEL prevenand colleagues (2021), working in collaboration with the California Department of Health Care Services and funded by the federal Substance Abuse and Mental Health Services Administration (SAMHSA), designed a group-randomized trial involving 24 California cities with an intervention to reduce alcohol-related harm among 12- to 25-year-olds (as speciﬁed by the grant) . Of note, the cities were selected at random, paired by demographic characteristics, and then assigned to treatment or control conditions at random as well. The multi-component intervention included enhanced and highly visible enforcement of driving-under-the-inﬂuence (DUI) laws and alcohol sales to minors, along with training in responsible beverage service. The study found an estimated 310 fewer alcohol- This research was supported by National Institute on Alcohol Abuse and Alcoholism Grants R01-AA028772 and P60-AA006282 . *Correspondence may be sent to Dr. Robert Saltz, Senior Scientist, Prevention Research Center, Paciﬁc Institute for Research & Evaluation, 2030 Addison St., Ste. 410, Berkeley, CA 94704-2642, or via email at: saltz@ [prev.org. Robert Saltz was](prev.org. Robert Saltz was) responsible for conceptualization, methodology, validation, investigation, writing (original draft), visualization, supervision, and funding acquisition. Mallie J. Paschall was responsible for conceptualization, funding acquisition, methodology, analysis, writing, review, and editing. doi:10.15288/jsad.24-00103 involved crashes in the intervention cities relative to c

FAQs

What was the main objective of the follow-up study?

To determine whether the multi-component, high-visibility alcohol enforcement intervention had long-term effects on alcohol-related single-vehicle nighttime (SVN) crashes beyond the original study period.

How was the intervention implemented and which cities were involved?

A randomized trial used 24 California cities; 12 cities were assigned to the intervention and implemented high-visibility alcohol enforcement operations and related components from April 2013 to March 2016.

What did the regression analyses show about long-term crash outcomes?

Monthly SVN crash levels among ages 15–30 were significantly lower in intervention cities through 2021 compared with control cities, with an incidence rate ratio of 0.88 (95% CI 0.79–0.98) after key controls.

Sep 28, 2026

Uploaded by Finn