It was originally envisioned that Autoroute 20 would extend from the Turcot Interchange, along the route of the 720, to the Louis Hippolyte Lafontaine Bridge-Tunnel.

The right-of-way has existed since the original layout of the A-720, and buildings along the extension were demolished at that time, even though the 720 was not completed due to cost constraints.

The government of Montreal instead converted the portion of Rue Notre Dame east of the Jacques Cartier Bridge into a six-lane urban boulevard, rather than continue a sunken limited-access expressway.

In 2007, working crews for Transports Québec discovered major cracks in a support pillar and closed several lanes of the expressway.

Transports Quebec announced on August 10, 2007, major repair projects for a large section of the Expressway west of the Ville-Marie tunnel.