Loss of life and non-fatal serious injuries are among the public health costs associated with alcohol related rashes. In order to develop successful public policies for reducing alcohol related crashes, it is necessary that we understand the causes of these crashes and how effective alternative public policies are in reducing the incidence and severity of these crashes among various at-risk groups. Because of their increasing proportion on the nation's highways, older drivers are at greater risk. This raises two questions. What are the underlying determinants of alcohol related crashes among older drivers? And what public policies are most effective in reducing alcohol related crashes among this group of drivers? The purpose of this project is to analyze each of these questions using California as a case study and based upon data over a 16 year period, 1981 through 1996. The focus of the analysis will be upon four specific areas of public policy interest: the per se BAC level for driving under the influence of alcohol; alcohol availability; traffic enforcement; and speed limits. The analysis will comparative analyze the extent to which each of these public policies affects the incidence and severity of alcohol related crashes among older drivers relative to the other-age population. Further, in order to better our understanding of older driver crashes and regulatory policy, three different methodological approaches will be used: aggregate time series analysis using monthly data over a 16 year period; time series-cross section analysis based upon county-wide observations over the 16 year period, and ordered probit analysis using a sample of individual crash data from 1996.