DDP was established to promote highway safety by providing motorists convicted of alcohol-related or drug-related traffic offenses with an opportunity for rehabilitation. The department of motor vehicles (DMV) implemented a standardized education/rehabilitation program on October 1, 1975. By December 1978 over 60,000 motorists had taken part in the program. Studies of other drinking driver programs have produced inconclusive results regarding the programs' effects, because study designs have not been rigorous. Motorists participating in the New York program include social drinkers, preproblem drinkers and problem drinkers. In addition to providing information on alcohol use and abuse and highway safety, the DDP is an intervention mechanism to identify, refer, and treat persons with drinking problems. The referral rate for evaluation and possible treatment has nearly doubled between the first and third years of the DDP. Some motorists who were eligible for the DDP declined to enroll because of personal reasons, DMV procedures, court restrictions, or lawyers advice. In many cases the fines imposed were less than the charges to take the course and many offenders found that a 60-day license suspension was an inconsequential punishment. Also, some persons did not follow court requirements regarding program enrollment or completion, but were not resentenced. Although the DMV evaluation of the program concluded that it had a positive impact on highway safety in that driving accidents decreased dramatically after motorists were exposed to DDP, further analysis of the DMV report suggests that this conclusion is an overstatement. DDP may, however, be contributing to improved highway safety. Absence of a suitable control group and other methodological problems suggest that the observed decline in accident and traffic violation convictions after program participation may be due to other factors. Tables and footnotes which contain references are provided. Appendixes list persons contacted, and include blood alcohol concentration tests, approved drinking driver programs as of February 1979, and present agency responses to the draft report. (Author abstract modified)