Planning for the segment of Highway 403 through Mississauga dates to the late 1950s when the Hamilton Expressway appeared on the Metropolitan Toronto's regional transportation plan. It was to be a continuation of the Richview Expressway, which was ultimately never built, continuing from Toronto to Hamilton. The plan featured the expressway's eastern terminus at the Highway 401 and Highway 427 interchange. As Toronto's anti-expressway movement gained momentum, provincial plans shifted the Hamilton Expressway to the west near Etobicoke Creek. In 1962, the right-of-way alongside the hydro corridor between Burlington and Etobicoke Creek was protected after traffic studies indicated the need for a future freeway.