The Pennsylvania Department of Transportation is continuing to develop plans for reconstructing the Parkway West/Interstate 376 interchange with Route 22/30 beginning next year, but one thing is clear: The project will cost substantially more than originally anticipated.
At a late January public meeting, PennDOT project manager Anthony Annett said the anticipated cost of the work is expected to fall between $30 million and $35 million because of an increase in the length of two new bridges and higher costs for materials. In December 2021, the projected cost was $22 million to $26 million.
Despite the increase, Annett said the department expects to have the money to begin construction next year.
The department is using the need to replace the Route 22 bridge above the parkway, which has a “fair” rating due to structural and deterioration problems, as an opportunity to upgrade the interchange. The other goals of the new interchange are to reduce congestion rated among the worst in the country and high crash rates between exits 59 and 61 near the interchange that often are blamed on stopped traffic.
The revamped interchange will have a completely new design. The traditional cloverleaf that dates to the 1950s will be replaced with a relatively new design called a diverging diamond, where traffic travels on the left side of the road rather than the right to eliminate left turns across traffic.
The project also will replace the existing ramps and install a new ramp to allow direct access to Route 60 toward Crafton, which isn’t available now.
As part of the design, the existing bridge above the parkway will be replaced by two bridges, one of which will be built on each side of the current bridge. That will allow the current structure to remain open during construction, reducing traffic delays.
With the diverging diamond, traffic on Route 60 approaching the Parkway West interchange from the east will cross to the left side to go around, and traffic approaching from the west on Route 22/30 will cross to the right side. Traffic lights at the crossover points and driving on what seems like the wrong side of the road will allow vehicles to exit to the left without crossing traffic, eliminating potential collision points.
After vehicles go through the diamond, they will cross back to the right side of the road at another traffic signal.
The diamond design is fairly new in Western Pennsylvania, with the only active one at the Interstate 70-Route 19 interchange in Washington County. Another is under construction at the I-70-Route 51 interchange in Westmoreland County, but the Parkway West diamond interchange would be the first in PennDOT District 11, which includes Allegheny, Beaver and Lawrence counties.
The new bridges that will be part of the project will be 171 feet long. That’s longer than the existing bridges, to allow space under them for additional lanes on the parkway in the future, although there are no active plans for that right now.
Additionally, instead of two phases anticipated previously, the project will be built in four phases.
In the first phase, crews will begin building the new bridges and set up temporary roads to move traffic.
Phase 2 will continue building the bridges and starting construction on ramps to the northwest and southeast. In the third phase, those new ramps will be open and work will begin on the northeast and southwest ramps.
The last phase will have traffic using the new bridges and all of the new ramps, but crews will remove the current bridge and complete road work to join the interchange with the existing roads.
Traffic engineer Dan Fritz said the project is designed for most construction to take place overnight. The biggest traffic problems will be several weekend closures during bridge construction and removal, when traffic will be detoured using Interstate 79, Route 60, Beaver Grade Road and Montour Run Road.
There also could be intermittent closures or delays on the parkway and Steubenville Pike throughout the project. The only property that the department needs for the project is a small parcel from Diehl Auto Collision Center to build a support wall or dump fill to support one of the ramps.
The department expects to have another public meeting before the project begins.
Ed covers transportation at the Pittsburgh Post-Gazette, but he's currently on strike. Email him at eblazina@unionprogress.com.