Alcohol outlet density and motor vehicle crashes in Los Angeles County cities

The extent to which the availability of alcohol encourages alcohol consumption resulting in alcohol-related problems remains controversial. In order to address this issue we used 1990 data from 72 cities within Los Angeles County to estimate the relation between densities of four types of alcohol outlets (restaurants, bars, liquor stores, mini-markets) and rates of two types of alcohol-related motor vehicle crashes reported by police (injury, property damage). After logarithmic transformation of variables, crash rates were repressed on outlet densities and possible demographic confounders. The demographic covariates accounted for 25% of the variance in injury crashes; adding the combined outlet density to the model yielded a significant elasticity estimate (β ± SE) (β = 0.55 ± 0.13). Separate models for types of outlets yielded significant elasticities for restaurants (β = 0.22 ± 0.07), liquor stores (β = 0.46 ± 0.17) and mini-markets (β = 0.34 ± 0.13), but not for bars (β = 0.08 ± 0.07). Alcohol-related crashes resulting in property damage also showed positive associations with outlet densities, but these associations were smaller and reached statistical significance for restaurants (β = 0.19 ± 0.11) and bars (β = 0.21 ± 0.10). Direction of influence cannot be inferred from these cross-sectional findings, but they do indicate that increased alcohol availability is geographically associated with increased alcohol-related motor vehicle crashes and that this association is independent of measured confounders.