The City of Detroit, through the Detroit Street Railways (D.S.R.), began operating public transportation services during the early 1920's. During this period, service consisted of street railway cars and eventually bus services. In 1937, to increase the flexibility of transit services within the City, bus service was substituted for streetcars. Eventually, streetcar service was phased out in 1956. On November 19, 1962, trolley coach operation was discontinued. However, on September 20, 1976, four newly restored trolley cars from Lisbon, Portugal returned to operate on Detroit's Washington Boulevard as a transportation attraction. In later years, more trolleys were added to the fleet, giving a total of nine trolley cars. The downtown trolley service along with the trolleys were retired in 2003.
Today, under the restructured 1974 Detroit city charter, the Detroit Department of Transportation (DDOT), is the major bus transit carrier is Southeastern Michigan as well as the largest transit carrier in the entire State of Michigan. DDOT is responsible for operating transportation equipment (including scheduling of service, performing necessary maintenance and repairs to buses and service vehicles), and maintaining, repairing and replacing all DDOT properties, including buildings, structures, systems and bus shelters.