The DRP is a standardized, systematic method of examining a person suspected of impaired driving or another alcohol and/or drug-related offense. The examination determines whether the suspect is impaired; if impaired, whether the impairment is drug-related; and if the impairment is drug-related, the broad category (or combination of categories) of drugs that has caused the impairment. The DRP is a postarrest investigative procedure, not a field test procedure, since it requires a carefully controlled environment. This monograph describes seven categories of drugs that impair driving and also notes various drug combinations that can affect driving. The 12 major components of the DPR are outlined. Validation studies (laboratory evaluation and field study) are described as to procedures and results. The discussion of training requirements focuses on preliminary training, the 7-day drug recognition school, certification training, and instructor training. The site selection criteria for the pilot programs feature demographics, policy, legislation, law enforcement agency operations, and laboratory resources. Aspects of implementing a pilot DRP are discussed. Technical citations, list of governors' highway safety representatives and coordinators.