The diversion of the route necessitated the construction of a divided highway between the site of US 29's current interchange with MD 650 in White Oak and an intersection with MD 198 in Burtonsville, and a two-lane highway between Burtonsville, across the Patuxent River at the site of the future Rocky Gorge Reservoir, through Scaggsville and Columbia (then a small village east of today's US 29/MD 108 interchange) to a point south of Ellicott City, where the new route merged with the original route near the site of the US 29/MD 103 interchange and continued as normal. It is unclear if the new route was immediately signed as US 29 or as an extension of MD 196, but an undated GULF map of the state of Maryland shows no highway designation for the route between White Oak and Columbia. The first new segment of the current route of US 29 opened on November 30, 1959, and by 1964 MD 196 had been retracted to Burtonsville and US 29 had been rerouted to its current route.