Route D8 operates daily between Washington Union Station and MedStar Washington Hospital Center connecting the hospital centers and Metrorail stations.

Passengers that are wishing to go southbound from Washington Hospital Center would get on a northbound bus, which will turn into a southbound bus to Union Station at the 1st Street terminal, and proceed directly on 1st Street to Michigan Avenue.

Route D8 was created as a new route on June 4, 1977 to operate between Washington Hospital Center and Sibley Hospital alongside route D6, via the Hospital Complex, Trinity University, Glenwood Cemetery, the Edgewood Terrace Apartments, the Rhode Island Avenue Shopping Center, the Rhode Island Avenue–Brentwood station, Washington Union Station, Judiciary Square, Metro Center, and Dupont Circle stations.

[3] In 2014, WMATA proposed to shorten the D8 to Rhode Island Avenue station and to have a new Route D7 to operate between Rhode Island Avenue and the hospital campus in order to Improve reliability of service by operating shorter routes, Reduce the number of buses operating on the congested hospital roadways, and Create a better balance of capacity and demand throughout the line.

[4] During the COVID-19 pandemic, the route was reduced to operate on its Saturday supplemental schedule during the weekdays beginning on March 16, 2020.