 In 1985, the highway was widened into a four-lane road through Seaford, with a parallel bridge built over Conrail's Delmarva Secondary (now the Delmarva Central Railroad's Delmarva Subdivision).The route was extended east to DE 1 in Fenwick Island by 1994, following its current alignment between Millsboro and DE 54 before overlapping with DE 54 (Lighthouse Road) for the easternmost portion of the route.In 2005, DE 20 was removed from the DE 54 concurrency after it was determined unnecessary for there to be two route numbers for that stretch of road.