Depending on the city, parking enforcement officers may be sworn officers. In some major cities, like Los Angeles and New York City, parking enforcement is the responsibility of the police, while in cities such as San Francisco, parking enforcement is maintained under separate municipal departments. On the other hand, the city of Detroit contracts third party institutions to handle all parking enforcement. Many medical facilities and schools, as well as other buildings that are considered private property, commonly hire private security contractors to regulate their parking lots and structures.