Perhaps no alcohol safety measure has attracted more research and public attention or shown more consistent evidence for its effectiveness than the federal minimum legal drinking age 21 (MLDA 21) law in the United States. The proposed study will make use of the NIAAA Alcohol Policy Information System (APIS) data set and will augment that information with data from the National Liquor Law Enforcement Association (NLLEA), the National Transportation Safety Board (NTSB), the Insurance Institute for Highway Safety (IIHS), and other sources that provide information on 14 underage drinking laws and regulations (e.g. possession, consumption, purchase, furnishing, age of servers, etc.) to construct a measure of the relative strength of each state's overall control program for underage drinking. This measure will then be related to underage 21 drinking drivers involved in fatal crashes in each state from the Fatality Analysis Reporting System (FARS) for the most recent 6 year period. In this analysis, structural equation modeling (SEM) will be used to identify the most important components of MLDA 21-related laws and the other factors affecting underage drinking drivers in fatal crashes. The SEM analysis will account for factors in each state such as the population of drivers younger than age 21, vehicle miles of travel, per capita alcohol consumption, geography, ethnicity, status of the state economy, overall state safety belt usage levels, arrest rates for driving under the influence (DUI), and the impact of other safety policies that could affect youth traffic fatalities. Discriminate function analysis will then be used to determine the state characteristics which are associated with a "strong" cluster of effective underage drinking laws and regulations. The results from this research can be used to recommend stronger and more effective laws to reduce underage drinking and underage drinking and driving. In summary, our proposed research has the following aims: (1) determine the relationship between the presence and strength of 14 state laws relating to underage drinking and to underage impaired driving to the involvement of drinking drivers under age 21 in fatal crashes; and (2) determine the state characteristics which are associated with strong underage drinking laws and regulations.