Southern Maryland Boulevard was marked as MD 416 by 1933 .
The new highway was constructed as an 18 - foot ( 5.5 m ) wide concrete road from MD 4 at Waysons Corner south to MD 2 at Sunderland in 1929 and 1930 .
Southern Maryland Boulevard was marked as MD 4   by 1933 .
The new highway was constructed as an 18 - foot ( 5.5 m ) wide concrete road from MD 4 at Waysons Corner south to MD 2 at Sunderland in 1929 and 1930 .