The growing number of treatment programs for people who drink and drive requires that these programs be clearly understood. The judicial mandate for treatment creates not only a significant opportunity to modify behavior and improve personal and interpersonal functioning, but also brings with it an obligation to implement programs which reflect sound clinical practices. Yet little investigative attention has been devoted to these programs, the clients they serve, and the programs' impact. An 18-month study of the counseling component of the Philadelphia Alcohol Highway Safety Program assessed clients at intake to treatment, monitored their participation during treatment, and assessed them again at termination of treatment. The 369 clients involved in the study represented a broad range of ages, income levels, living situations, driving histories, and employment characteristics. Counselor ratings of clients' reasons for termination and their goal attainment were examined in an attempt to identify relationships between client characteristics and global outcome status. The results of analyses of variance identified six variables having significant relationships with positive treatment outcomes: age, marital status, drinking quantity, drinking frequency, valid driver's licenses and insurance coverage, and drinking-driving histories. Clients who terminated treatment in non-compliance accounted for 20 percent of all terminations. (NRB)