THE PANEL, WHICH CONSISTED OF EXPERTS IN THE FIELD OF DRUGS AND DRUG RESEARCH, IDENTIFIED FOUR MAJOR CATEGORIES OF ISSUES: EPIDEMIOLOGY, LABORATORY STUDIES, ASSAY DEVELOPMENT, AND LEGAL QUESTIONS. CURRENT EPIDEMIOLOGICAL STUDIES OF DRUGS AND DRIVING FREQUENTLY ARE CHARACTERIZED BY POOR SAMPLING PROCEDURES, THE ABSENCE OF AN APPROPRIATE CONTROL GROUP, INAPPROPRIATE DATA-COLLECTING PROCEDURES, AND THE FAILURE TO INCLUDE APPROPRIATE QUALIFICATIONS IN THE ANALYSES OF STUDY RESULTS. RELIABLE EVIDENCE OF THE EFFECTS OF DRUG AND ALCOHOL USE ON HUMAN PERFORMANCE IS NOT PRESENTLY AVAILABLE FROM LABORATORY STUDIES DUE TO METHODOLOGICAL INADEQUACIES. THERE ARE MAJOR DIFFERENCES IN THE METHODS REQUIRED TO DETECT AND MEASURE THE PRESENCE OF ALCOHOL AND DRUGS IN THE BODY, AND THERE IS A STRONG NEED FOR THE DEVELOPMENT OF IMPROVED DETECTION TECHNIQUES. INCREASED STUDY IS NEEDED OF THRESHOLD EFFECTS, CONTROLLED FOR BODY WEIGHT AND DRUG CONCENTRATION. EFFORTS SHOULD CONCENTRATE ON DETERMINING THE EFFECTS OF EACH DRUG'S USE ON PERFORMANCE AND THE ROLE OF VARIOUS INTERVENING VARIABLES SUCH AS BODY WEIGHT, SEX, AGE, DOSAGE, TIME SINCE INGESTION, ETC., RATHER THAN ON ADDRESSING LEGAL ISSUES WITH RESPECT TO THE EFFECTS OF DRUGS ON PERFORMANCE, PARTICULARLY DRIVING. WHILE THE EFFECTS OF VARIOUS DRUGS ON DRIVING PERFORMANCE UNDER A VARIETY OF CIRCUMSTANCES HAVE NOT BEEN DETERMINED SUFFICIENTLY TO FRAME PROSCRIPTIVE LAWS, THE MEDICAL PROFESSION SHOULD BE ENCOURAGED TO DEVELOP EFFECTIVE STANDARDS FOR PRESCRIBING DRUGS AND INCREASE PUBLIC AWARENESS OF THE POSSIBLE DETRIMENTAL EFFECTS OF DRUGS ON DRIVING PERFORMANCE. RECOMMENDATIONS ARE OFFERED FOR PRIORITY DRUG CATEGORIES TO BE STUDIED (ALCOHOL AND MARIHUANA), METHODOLOGICAL ISSUES, AND PREVENTION STRATEGIES. (RCB)