Closed elementary schools allow entry through only one door, fence in play areas, and lock buildings that abut the street so strangers cannot get on campus.
In a 2009 Public Health Advocacy Institute report on open campuses, a study of areas around secondary schools in three North Carolina counties found a higher risk of car accidents during open campus lunch periods when students were allowed off campus compared to any other time of the day or to closed campuses.
Students on closed campuses do not have the opportunity to get involved with gangs during school hours, lessening the situational possibility of school violence.
Parents wanting closed campuses are concerned with students obtaining illegal substances, such as cigarettes, drugs or alcohol, from outsiders who come on campus.
At closed schools, visitors must sign in at one place and wear identification. Administrative staff can monitor them to make sure they leave the building instead of staying to prey on children after school.