From the Summary: "Trusted traveler programs expedite the inspection of preapproved, low-risk travelers to the United States. Trusted traveler programs help the Transportation Security Administration (TSA) and U.S. Customs and Border Protection (CBP) achieve their goals of facilitating the lawful flow of people and goods while preventing the entry of unauthorized individuals, criminals, terrorists, and contraband. Trusted traveler programs operate at various combinations of air, land, and sea ports of entry. They all screen individuals arriving at a U.S. port of entry, and some programs screen those departing the United States, those traveling within the United States, or those embarking on U.S.-bound travel (i.e., at international preclearance locations). [...] This report discusses the five major U.S. trusted traveler programs: PreCheck, Global Entry, NEXUS (not an acronym), Secure Electronic Network for Travelers Rapid Inspection (SENTRI), and Free and Secure Trade (FAST). PreCheck is an expedited security screening process at U.S. airports. Global Entry allows for expedited clearance for preapproved, low-risk travelers when they enter the United States by air. NEXUS allows prescreened travelers expedited processing when entering the United States or Canada by air, land, or sea. SENTRI allows for expedited clearance for preapproved, low-risk travelers at certain land ports of entry along the U.S.-Mexico border. FAST is a commercial truck clearance program that provides expedited processing for known, low-risk shipments entering the United States from Canada and Mexico."
CRS Report for Congress, R46783
Congressional Research Service: https://crsreports.congress.gov/