The New Carrollton–Silver Spring Line, designated as Route F4, is a daily bus route operated by the Washington Metropolitan Area Transit Authority between New Carrollton station of the Orange Line of the Washington Metro and Silver Spring station of the Red Line of the Washington Metro. The line operates every 12 minutes between 7AM and 9PM, and 30-60 minutes after 9PM. F4 trips are roughly 62 minutes. The line mainly provides service on the East-West Highway corridor from the eastern portion of Prince George's County to Montgomery County.