Patrol A patrol is commonly a group of personnel , such as police officers or soldiers , that are assigned to monitor a specific geographic area . Military . In military tactics , a patrol is a small tactical unit sent out from a larger unit by land , sea or air for the purpose of combat , reconnaissance , or a combination of both . The basic task of a patrol is to follow a known route at which sent to investigate some feature of interest , or to fighting patrols ( US combat patrol ) , sent to find and engage the enemy . A patrol can also mean a small cavalry or armoured unit , subordinate to a troop or platoon . A patrol usually comprises a section or squad of mounted trooper s , or two AFVs ( often tank s ) . Law enforcement . In non - military law enforcement , patrol officers are uniformed police officers assigned to monitor specified geographic areas — that is , to move through their areas at regular intervals looking out for any signs of problems of any kind . They are the officers most commonly encountered by the public , as their duties include responding to calls for service , making arrests , resolving disputes , taking crime reports , and conducting traffic enforcement , and other crime prevention measures . A patrol officer is often the first to arrive on the scene of any incident ; what such an officer does or fails to do at the scene can greatly influence the outcome of any subsequent investigation . The patrol officer , as the person who is in the field daily , is often closest to potential crime and may have developed contacts who can provide information . The Philadelphia Foot Patrol Experiment , a randomized control trial conducted by Temple University , has shown that foot patrols reduce crime . With the resources to patrol 60 locations , researchers identified the highest violent crime corners in the city , using data from 2006 to 2008 . Police commanders designed 120 foot patrol areas around these corners , and stratified randomization was used to assign pairs of foot patrols with similar crime rates as either a comparison or a target area . Officers generally patrolled in pairs with two pairs assigned to each foot patrol . After three months , relative to the comparison areas , violent crime decreased 23 % . Official records of police activities during the intervention period reveal the following in the target areas : An emerging trend within patrol is the supplement of basic police patrol with that of private security agencies . The privatization of police is explored in James Pastor ' s book " The Privatization of Police in America : An Analysis and Case Study " . Etymology . From French " patrouiller " from Old French " patouiller " ( “ to paddle , paw about , patrol ” ) from " patte " ( “ a paw ” ) . Non - law enforcement patrols . Schools . Some elementary schools use the term " patrol " to refer to students who are selected to monitor safety in the classroom or to those students who assist crossing guard s with safety of children crossing busy streets . Another common term for this use of patrol is " hall monitor " . Scouting . In Scouting , a patrol is six to eight youth under the leadership of one Patrol leader and an Assistant Patrol Leader . This is the basic unit of a Scout troop . The " Patrol method " is an essential characteristic of Scouting by which it differs from all other organizations , using the natural dynamics of the " gang " for an educational purpose .