By the way, here's proof that PennDOT has big plans for the Parkway West. Check out the width of the right of way under the Ridge Road overpass:
Notice how there's a little bit of grass near the eastbound exterior shoulder, and a whole lot of grass near the westbound exterior shoulder. That's no accident. PennDOT has left room under the overpass for eight travel lanes, an acceleration lane, a deceleration lane, two interior and exterior shoulders, and a median barrier. Per AASHTO requirements, all travel lanes and exterior shoulders on Interstates have to be 12' wide, and the interior shoulders also have to be 12' wide on Interstates with six or more lanes. Median barriers have to be at least 2' thick and reinforced. This gives us the following equation for eight lanes, one acceleration lane, one deceleration lane, two interior and exterior shoulders, and a median barrier:
12' + 12' + 12' + 12' + 12' + 12' +
12' +
2' +
12' + 12' + 12' + 12' + 12' +12' +
12' = 170'
Envision the shoulders as
BLUE and the median barrier as
RED in the equation above in order to see the cross-section of the planned highway. Now here's a distance measure from one overpass pier to the other:
As you can see, the distance measured is the exact amount of room needed for the setup that I described.
About half a mile west of the Ridge Road interchange is the U.S. 22/U.S. 30/PA 60 interchange. U.S. 22/U.S. 30 is a limited-access highway itself, but movement between it and the Parkway West involves an obsolete partial-cloverleaf interchange that does not meet AASHTO requirements for movement between two limited-access highways. More than likely, PennDOT will rebuild this as a stack interchange in the future, with acceleration and deceleration lanes extending for half a mile to the east, and under the Ridge Road overpass.
The only obstacles in the way of PennDOT widening the Parkway West right now are the following:
1. The design of the existing overpasses at the U.S. 22/U.S. 30/PA 60 and Green Tree/Mt. Lebanon interchanges are identical, with piers constricting the right of way underneath them. These overpasses were more than likely built in the 1960's, which means that they're at or near the end of their engineered lifespans.
2. The Wheeling & Lake Erie (W&LE) Railroad has two bridges that span the Parkway West with piers constricting the right of way underneath them. The bridge near the Carnegie interchange is about 1,000' long, and the bridge near the Fort Pitt Tunnel is about 500' long. Both would need to be rebuilt in order to create extra space.
3. The Fort Pitt Tunnel can only fit four lanes, and it needs to fit at least six lanes in order not to create a dangerous bottleneck if the rest of the Parkway West is widened to eight lanes.
If work is done on any of these things, especially the overpasses since they're the easiest to fix, then consider it another step toward widening the Parkway West.
