—though not all the way to the-then Highway 2 (Kingston Road),—where a cloverleaf interchange was constructed in anticipation of it developing into a freeway around the eastern side of Lake Simcoe; Highway 404 was constructed for this purpose, but along or parallel to Woodbine Avenue instead. In 1962, the highway was extended to Highway 46 at Bolsover via a concurrency with Highway 12 north from Beaverton. This routing would last until November 4, 1966, when the Beaverton Bypass opened, routing Highway 12 to the east. A new road was opened connecting Highway 48 south of Port Bolster with the bypass on the same day, and both Highway 12 and Highway 48 were rerouted. Portions of the former route of Highway 48 and Highway 12 were renumbered as Highway 48B. However, the segment between Port Bolster and what is now Brock Sideline 17 was decommissioned entirely. The original route of Highway 48, prior to 1954, is now part of Durham Regional Road 23.