The thousands of police agencies vary widely in size, officer assignments, and responsibilities. Many of the roots of modern policing in the United States are found in the model established by Sir Robert Peel in London, England in 1929. Boston and New York City established the first police departments in the United States. The first assignment for almost all police officers graduating from police academies is with the patrol division. Patrol duties include routine patrol and observation, dealing with noncrime calls for service, attendance at public gatherings, community services, preliminary investigations, arrests, traffic direction and control, and court testimony. Police agencies' traffic responsibilities include traffic control, accident investigation, and traffic law enforcement. Police work in rural areas differs in some respect from that in urban areas. The role of campus police has evolved from an emphasis on rule enforcement and property protection to professional law enforcement. Among the responsibilities of police detectives are evidence collection and case screening and assignment. The development of computerized criminal information has significantly improved the efficiency and effectiveness of police operations. Recent developments in policing include community policing and problem-oriented policing. Photographs, table, case examples, discussion and review questions, notes, and 25 references