Changes in the environment surrounding these encounters make police oriented toward accomplishing organizational goals, using tested theories of the cause and effect relationships related to those goals. The most significant change, and greatest source of increased rationality in police conduct, is the federally-funded police research and development sector. The "soft" academic research will guide the adaptation of new "hard" communications and data processing technologies. Other important changes include the increasing dominance of the political environment by special interest groups and the legal restrictions placed on police discretion. Less important changes relate to the demographic characteristics of police personnel and the citizens they serve. (Author abstract modified)