Vehicular movement on streets and highways is a 'system' with interacting components having the primary objective of moving people and goods from one place to another. The system requires a comprehensive management program, police traffic regulation and surveillance, and the coordination of police and engineering functions. Police functions in traffic supervision include the enforcement of traffic laws, the prevention of accidents, aid to the injured, the documentation of the particulars of individual accidents, and the supervision of accident cleanup and the restoration of safe and orderly traffic movement. The success of a police traffic supervision program will depend on the ability of police management to develop and maintain the cooperation of many other agencies, both official and unofficial. Guides to planning for traffic law enforcement range from recommended policies to detailed and proven procedures. The police administrator and the command supervisory personnel should see that traffic supervision and law enforcement work effort by patrol personnel will be planned and directed by management, as opposed to effort that is merely the product of occasional action by individual officers. Methods of enforcement include electronic devices, situational enforcement, and enforcement action. Issues to be considered include unnecessary tickets, civil versus criminal aspects of traffic law enforcement, selection and training of personnel, and traffic safety education. Other traffic law enforcement considerations involve vehicle collision reporting and investigation, alcohol-related traffic offenses, supervision of parking, bicycle traffic, traffic records and summaries, traffic laws and ordinances, and the decriminalization and administrative adjudication of traffic offenses. Thirty-eight footnotes are provided.