Special access programs (SAPs) in the U.S. federal government are security protocols that provide highly classified information with safeguards and access restrictions that exceed those for regular (collateral) classified information. SAPs can range from black projects to routine but especially-sensitive operations, such as COMSEC maintenance or presidential transportation support. In addition to collateral controls, a SAP may impose more stringent investigative or adjudicative requirements, specialized nondisclosure agreements, special terminology or markings, exclusion from standard contract investigations (carve-outs), and centralized billet systems. Within the Department of Defense, SAP is better known as "SAR" by the mandatory Special Access Required (SAR) markings.