This map from 1966 showing proposed expressways in Philadelphia will blow you away
There was supposed to be an I - 695, connecting the Airport to the Schuylkill Expressway, via Cobbs Creek. It was supposed to keep going east on what was going to be the Crosstown Expressway across South Philly, where Bainbridge Ave is. Route 1's southbound interchange with the Schuylkill was not supposed to be routed along City Line Ave. It was supposed to keep going as a full expressway across the Schuylkill River, plow right through Chamounix Mansion, connect with what would've been called the Main Line Expressway (Route 30) and keep going due south, connect with the aforementioned Cobbs Creek I -695 road, and then head due west along what is now U.S. 13. In Northeast Philadelphia, Route 1 North would again be a full expressway, the entire length of the Inner Drive of Roosevelt Boulevard would be dug under and grade-separated from any crossing street. Girard Avenue was also supposed to be an expressway, which would have taken the load off of the existing I -676 Vine Street Expressway. And the existing PA Route 309 expressway southbound wasn't supposed to abruptly terminate at Ogontz Ave and Cheltenham Ave. It was supposed to keep going, following Tacony Creek, and connect with the Betsy Ross Bridge, NJ Route 90. This was supposed to be called the Pulaski Expressway. You can see where it was almost started, if you look at Aramingo Ave on Google Earth.
Instead, this is what Roosevelt Blvd looks like today
And this is what the Schuylkill Expressway looks like today.