Trends and correlates of spatially aggregated alcohol-involved crashes among Whites and Hispanics in California.

Aims: This paper examines trends and correlates of alcohol-involved motor vehicle crashes (AMVCs) in California between 2005 and 2016 among Hispanic and non-Hispanic Whites (Whites hereafter). Together these two groups comprise 76% of the state population. The paper also examines whether alcohol outlet density, percentage of Hispanics in census tract populations, and distance to the U.S./Mexico border are related to greater risks for AMVCs. The border is of interest given the greater availability of alcohol in the area.

Methods: Crash data come from Statewide Integrated Traffic Records System maintained by the California Highway Patrol. Sociodemographic and community characteristics data from the U.S. Census and alcohol outlet density were aggregated to census tracts. Total motor vehicle crashes and AMVCs were related to these characteristics using hierarchical Bayesian Poisson space-time models.

Results: There were over two million injury and fatality crashes during the period of analysis, of which 11% were AMVCs. About 1.7% of these crashes had fatalities. The rate of AMVCs increased among both Whites and Hispanics until 2008. After 2008, the rate among Whites declined through 2016 while the rate among Hispanics declined for 2 years (2009 and 2010) and increased thereafter. Crash distance from the border (RR = 1.016, 95% CI = 1.010 to 1.022) and percent Hispanic population (RR = 1.006; 95% CI = 1.003 to 1.009) were well-supported results with 95% credible intervals that did not include 1. The percentages of the following: bars/pubs, males, individuals aged 18 to 29 and 40 to 49 years, U.S. born population, individuals below the 150% poverty level, unemployed, housing vacant, and housing owner-occupied were all positively associated with AMVCs and well supported.

Conclusions: Between 2005 and 2016 the rate of AMVCs in California declined among Whites but not among Hispanics. Population-level indicators of percent Hispanic population, distance to the U.S. Mexico border, gender, age distribution, and socioeconomic stability were positively associated with crash rates, indicating that important contextual characteristics help determine the level of AMVC rates in communities.