The Transit Profiles: 2015 Top 50 Agencies Summary is one of three profiles provided in the National Transit Database (NTD) Annual Report. This volume provides an aggregate profile of the Top 50 reporting agencies filing an NTD Annual Report for 2015 as well as individual profiles for the Top 50 reporting agencies filing an NTD Annual Report for 2015.. The Top 50 agencies were determined from total unlinked passenger trips.