Between 1958 and 1971, studies were conducted for a bypass of the segment of US 13 through Dover along with a connector between Dover and Frederica. The proposed routing began at US 113 and DE 12 north of Frederica and continued northwest to Woodside, where it was planned to cross US 13. From here, the bypass was to run to the west of Dover and head north to its terminus at US 13 north of Cheswold. As part of planning of the Dover Bypass, an archaeological survey had to be conducted along part of the proposed route between 1972 and 1975. By 1976, construction of the Dover Bypass was postponed indefinitely. From 1971 to 1978, a north–south extension of the Delaware Turnpike between Wilmington and Dover was studied. In 1983, studies began for a "Relief Route" of US 13 between Dover and Wilmington. The new highway was proposed in order to relieve US 13 of traffic heading to the Delaware Beaches in the summer. Prior to the beginning of construction, an archaeological survey was conducted along the proposed route of the freeway in 1986. The same year, plans were unveiled for the route, which would begin at US 113 south of Dover and head north to US 13 in Tybouts Corner. The Relief Route would cross US 13 several times, passing to the east of Dover and Smyrna and to the west of Odessa. The US 13 Relief Route would be designated DE 1 in 1988, keeping US 13 on its original alignment. DE 1 was extended north from Milford to Tybouts Corner in 1988, following US 13 between Dover and Tybouts Corner.