SR 0070-W31 3.3 Mile Interstate Reconstruction Project

Interstate 70 is the primary east-west highway in extreme southwestern Pennsylvania. In recognition of the age of the highway (dating back to the 1950s and 1960s), PennDOT District 12-0 has been investing significantly in geometric, operational, and safety improvements to the corridor. The Gibson-Thomas team was selected to design the 3.3 mile SR 0070-W31 section between the I-70/I-79 South Junction Interchange and the I-70/SR 0519 Interchange in South Strabane Township, Washington County.

The design of the project entailed a full reconstruction of the interstate to modern design criteria and included the following key features:

  • Full-depth reconstruction of the existing roadway, including the widening of the 4 foot median to 10 feet and the widening of the 10 foot outside shoulders to 12 feet.
  • Acceleration and deceleration lane upgrades
  • Realignment of T-574 (Wilson Road)
  • Relocation of approximately 2,650 feet of a tributary to Little Chartiers Creek
  • Mitigation for a Pennsylvania Threatened/Endangered Plant and Phase III Archaeological Data Recovery.

Due to the high traffic volumes and the regional importance of this interstate, two lanes of traffic in each direction were maintained throughout the construction phase.

The SR 0070-W31 project was joined with the adjacent SR 0070-T10 section (encompassing portions of the I-70/I-79 South Junction interchange) as a combined let with construction cost of $120 million – the largest project by cost ever let by PennDOT District 12-0. The project was let in August 2016 and construction was completed in the fall of 2020.

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Gibson-Thomas is a multi-discipline consulting engineering firm established in 1916 in Latrobe, Pennsylvania. Our past experience, key staff and commitment to total client satisfaction are the major factors that our clients consider when contracting with Gibson-Thomas.

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