as a concrete road from Sparrows Point Road in Edgemere to Trappe Road at the hamlet of North Point in what is now Dundalk by 1921. The concrete road was extended from North Point to Baltimore in 1922 and 1923; those same years, a macadam road was built from Sparrows Point Road to the interurban tracks near Bay Shore Park. MD 20 was widened and resurfaced with bituminous concrete north of Edgemere by 1926. By 1934, MD 20 was proposed to be expanded from a width of to from Baltimore to MD 151 in Edgemere to serve the Sparrows Point industrial complex. In addition, MD 20 from MD 151 to the interurban near Bay Shore Park was proposed to be widened from to . The Edgemere portion of MD 20 was bypassed when a new four-lane divided highway—Sparrows Point Boulevard and North Point Boulevard—was completed from Sparrows Point to Wise Avenue in Dundalk in 1940 and 1941. Between 1942 and 1944, the remainder of North Point Boulevard was constructed from Wise Avenue to Baltimore as a wartime access project, including a cloverleaf interchange at MD 150. In addition, Erdman Avenue was extended as a four-lane divided highway to connect with North Point Boulevard, bypassing the segment of North Point Road between the boulevard and US 40 in the city of Baltimore. By 1946, MD 151 was applied to the four-lane divided highway connecting Baltimore with Sparrows Point, and MD 20 was assigned to four mainline segments and a spur of the old North Point Road: MD 20A was the designation for the section of North Point Road from the ramp from southbound MD 151 to westbound MD 150 northwest to a dead end at the Canton Railroad near the Baltimore city limit. MD 20B was the designation for the section of North Point Road from MD 151 and Cove Road in Dundalk northwest to a right-in/right-out interchange with eastbound MD 150 at the MD 150–MD 151 cloverleaf. MD 20C was the designation for the section of North Point Road from MD 151 near Wise Avenue north to MD 151 near Cove Road in Dundalk. MD 20D was the designation for the section of North Point Road from the former interurban track intersection at Penwood Avenue near Fort Howard north to MD 151 north of Edgemere. The portion of MD 20 from near Fort Howard to Sparrows Point Road in Edgemere