Despite popular conceptions promoted by movies and television, many US police departments prefer not to maintain officers in non-patrol bureaus and divisions beyond a certain period of time, such as in the detective bureau, and instead maintain policies that limit service in such divisions to a specified period of time, after which officers must transfer out or return to patrol duties.[citation needed] This is done in part based upon the perception that the most important and essential police work is accomplished on patrol in which officers become acquainted with their beats, <answer>prevent crime by their presence</answer>, respond to crimes in progress, manage crises, and practice their skills.[citation needed]
How do patrol officers affect crime?
prevent crime by their presence