On Monday, the government unveiled its plan for a "third link" between Quebec City and Lévis — an 8.3-kilometre tunnel with three lanes in each direction stacked on top of each other.
The plan calls for one dedicated lane for electric buses on each level.
The project would link autoroutes 20 and 973 with an exit to the autoroute Dufferin-Montmorency.
Premier François Legault, Deputy Premier Geneviève Guilbault and Transport Minister François Bonnardel presented the tunnel as part of a broad transportation plan for the Quebec City area, a plan they dubbed the Réseau express de la Capitale (REC).
The REC also includes the much-anticipated Quebec City tramway.
The provincial government's preliminary estimate puts the cost of the tunnel between $6 billion and $7 billion.