The initial sketch for the bridge-tunnel spared the Saint-François-d’Assise Church as well as parts of Longue-Pointe. However, engineers quickly realized that such a configuration would be impossible due to the inclination of the tunnel relative to the Boucherville Islands, as it would encroach on the Saint-Jean-de-Dieu property. A slight curve had to be designed in order to achieve a perfectly straight line.
https://www.communitystories.ca/v2/pont-tunnel-louis-hippolyte-lafontaine_bridge/gallery/76-2/