Gauthier went into labour right around the time the St-Jean-Baptiste Day fireworks wrapped up in Vaudreuil.
Because they live right next to the site of the festivities, she said they had no choice but to take the main road to try to get to the Lakeshore Hospital.
Gauthier's labour was no match for the gridlock that greeted them.
A good Samaritan noticed the couple was in distress and tried to clear the way, to no avail. Prud'homme pulled over onto the side of the busy road.
"We ended up stopping on the service road near St-Charles Boulevard on the 40 and they baby had to come out," Gauthier said.
Gauthier and Prud'homme say their newborn daughter is doing well.