The solutions to impaired driving lie mainly at the State and community levels. That is where the laws are applied and enforced, where programs are implemented, and where changes can be made. State and community leaders need countermeasure strategies that can increase the perceived risk of drivers being stopped and arrested by law enforcement if driving while impaired. Among the most successful strategies is the coupling of intense and highly visible enforcement with publicity about the enforcement campaign. The focus of this enforcement strategy is to deter driving after drinking in the first place by increasing the public's perception of being caught, arrested, and prosecuted for impaired driving (a general deterrent strategy). Details of 17 highly visible impaired-driving enforcement programs were compiled and submitted to the NHTSA for review. After a thorough review of numerous potential program sites, NHTSA selected seven programs for case studies. These case studies provide descriptions of innovative strategies to increase enforcement visibility, such as: visibly marked trailers and patrol cars ("DUI Enforcement"); large warning signs at the entrances to checkpoints or saturation patrol areas; enforcement at key locations and events (e.g., large sporting events); happy-hour checkpoints or other enforcement conducted between 4 p.m. and 7 p.m.; phantom checkpoints set up to resemble an active checkpoint; visible use of preliminary breath testers; and safety vests marked with "DUI Enforcement." Tables, appendixes, and references