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PennDOT Announces Start of Construction to Realign Route 320 (South Gulph Road) at Hanging Rock in Upper Merion Township


​King of Prussia, PA – The Pennsylvania Department of Transportation (PennDOT) today announced that construction will begin on Monday, January 18, to enhance travel and safety on Route 320 (South Gulph Road) by shifting the roadway alignment away from the historic Hanging Rock between Upper Gulph Road and Arden Road in Upper Merion Township, Montgomery County.

Beginning Monday, January 18, through November 2021, Route 320 (South Gulph Road) will be closed between Arden Road and Upper Gulph Road. During the 24/7 closure, northbound Route 320 (South Gulph Road) motorists will be directed to use Matsonford Road, Interstate 76 West to the Route 320/Gulph Mills Interchange and Balligomingo Road. Southbound Route 320 (South Gulph Road) motorists will be detoured over I-76 East to the Conshohocken Interchange to Matsonford Road and Old Gulph Road.

Work on this project will be in accordance with Centers for Disease Control and state Department of Health guidance as well as a project-specific COVID-19 safety plan, which will include protocols for social distancing, use of face coverings, personal and job-site cleaning protocols, management of entries to the jobsite, special signing, and relevant training.

The scope of this project includes reconstructing the cantilevered structure that carries Route 320 (South Gulph Road) over Gulph Creek; raising the profile of Route 320 (South Gulph Road) to meet the requirements for the 100-year flood elevation; and improving the intersection of Route 320 (South Gulph Road) and Upper Gulph Road by adding a southbound right-turn lane on Route 320 (South Gulph Road). Drainage improvements, ADA ramp installations and additional traffic signal improvements, specifically at the intersection of Route 320 (South Gulph Road) and Arden Road, will also be implemented under this project.

Allan Myers, LP, is the general contractor on the $8,180,888 project which is financed with 100 percent state funds. The entire project is expected to finish in fall 2021.

For a complete list of construction projects impacting state-owned highways in Bucks, Chester, Delaware, Montgomery and Philadelphia counties, visit

To help make decisions regarding winter travel, motorists are encouraged to "Know Before You Go" by checking conditions on more than 40,000 roadway miles, including color-coded winter conditions on 2,900 miles, by visiting 511PA, which is free and available 24 hours a day, provides traffic delay warnings, weather forecasts, traffic speed information and access to more than 1,000 traffic cameras. Users can also see plow truck statuses and travel alerts along a specific route using the "Check My Route" tool.

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MEDIA CONTACT: Chelsea Lacey-Mabe, 610-205-6798

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RT 320 South Gulph Rd Closure and Detour.jpg