In 1930, US 13 along Division Street north of downtown Salisbury was placed on an overpass over the New York, Philadelphia and Norfolk Railroad (now the Delmarva Central Railroad's Delmarva Subdivision) US 13 was relocated between Princess Anne and Fruitland in 1933 to bypass the circuitous route via Loretto Road and Allen Road and to eliminate two railroad crossings, running parallel to the Pennsylvania Railroad (now the Delmarva Central Railroad's Delmarva Subdivision) on a straight alignment. The former alignment became MD 529 in 1939. US 13 was relocated between Princess Anne and Westover in 1935, bypassing what is now known as Old Princess Anne Road. This former alignment became MD 598 in 1939, and was removed from the state highway system by 1961. The first portion of the first Salisbury Bypass, now named Salisbury Boulevard, was completed in 1938 between College Avenue and Main Street in Salisbury. The second segment, between the present intersection of US 13 Bus. and Camden Avenue south of Fruitland and College Avenue, was completed in 1939. Upon completion of the first two sections, US 13 was moved to the bypass and Camden Avenue was designated MD 663. The third and final section, from Main Street to Zion Road on the north side of Salisbury, was completed by 1942. After US 13 moved to the new highway, Division Street north of Main Street was designated MD 475. By 1946, US 13 was realigned to a straighter alignment to the south of Pocomoke City, with the former alignment along Old Virginia Road becoming MD 250. In 1949, US 13 was rerouted to bypass Costen on a straight alignment to the southwest, with the former route through Costen becoming MD 673.