The interchange at the 401 evolved over time to a complex 26 bridge interchange, the most-complex in Ontario to that time. The Spadina was envisioned at first to provide access to the Yorkdale development from the 401, with a four-lane road. While the Spadina was being planned, the 401 highway was being developed into the present-day 12-lane highway and the Spadina was being revised to a six-lane highway to downtown, with a subway line in the middle. It cost in 1960s dollars to build, after being initially estimated to cost $1million.