The National Park Service has several sources of detailed written guidance to help managers make day-to-day decisions. The primary source of guidance is the 2001 edition of Management Policies. In the past, Management Policies have been supplemented by staff directives, special directives, and numbered guidelines.

The Service is currently revising and rewriting all of these supplemental materials so that they conform to the new NPS Directives System, which consists of Director's Orders, Handbooks, and Reference Manuals, in addition to Management Policies. When the policies are finalized, Director's Order (DO) 48A will provide additional guidance on the Concession Environmental Management Program (CoEMP).