Usually they build half of the new bridge first - usually what will eventually be the lanes for one direction. Then, they shift traffic to the new bridge (traffic both ways in the interim) and then tear down the old bridge and build the second half of the new bridge in its place. Now the new bridge is technically two new bridges, one in each direction.

Maybe start with whether it will take place and who will pay for it.

Are you familiar with the Tappan Zee? It will probably be like that.

Does anyone understand exactly how the construction will take place? The news articles claim it will be a brand new bridge (with more lanes) standing in the same place as the existing bridge. But how is that possible without decommissioning the existing bridge for 5+ years, which is obviously a no-go?