Local communities have begun using policy to affect the drinking environment itself as an approach to reducing alcohol involved trauma. That is, policy is used to produce structural changes in the drinking environment. In turn, changes in the environment effect changes in drinking behavior. This paper describes an effort in three communities in two states to reduce alcohol problems at the community level, "Preventing Alcohol Trauma: A Community Trial." This trial was a 5-year research project with a goal to reduce local alcohol-involved injuries and deaths in three experimental communities with populations of approximately 100,000 each (one in northern California, one in southern California, and one in South Carolina). The communities contained racial and ethnic diversity as well as a mix of urban, suburban, and rural settings. Each of these three communities had a control community that did not receive the prevention interventions. The project used an environmental policy approach to prevention and five mutually reinforcing components were implemented: (1) community mobilization to develop community organization and support, (2) responsible beverage service to establish standards for servers and owners/managers of on-premise alcohol outlets to reduce their risk of having intoxicated and/or underage customers in bars and restaurants. (3) a drinking and driving component to increase local drunk-driving enforcement efficiency and to increase the actual and perceived risk that drinking drivers would be detected, (4) an underage drinking component to reduce retail availability of alcohol to minors, and (5) an alcohol access component to use local zoning powers and other municipal controls of outlet numbers and density to reduce availability of alcohol. Results show that the project reduced alcohol-involved crashes, lowered sales to minors, increased the responsible alcohol serving practices of bars and restaurants, and increased community support and awareness of alcohol problems.