In the case of the Big Dig, it did.

-- just look at those pictures someone linked, and they don’t actually do it justice. Before, you might have to cross under a six lane elevated highway with surface streets. Now getting from one part of the city to another is a literal walk in the park. Reconnecting parts of the city to be walkable was one of the main goals, and it achieved

-- part of the mitigation was required transit improvements. Of course, some of that was delayed by politics, but I believe it did happen.