Share link

Southern Beltway

Southern Beltway

Southern Beltway Wetlands

Southern Beltway Wetlands



Services Involved

  • Environmental Planning
  • NEPA + Environmental Documentation
  • Geographical Information System (GIS)
  • Water Resource
  • Hazardous Waste
  • Bridge Design + Inspection
  • Highway, Roadways + Interstate Design
  • Traffic Engineering + Planning

Southern Beltway

The Southern Beltway Project (U.S. 22 to I-79) is a significant element of a major transportation improvement plan for the southwestern Pennsylvania region being administered through the Pennsylvania Turnpike Commission (PTC). A project of massive proportions, ms has been working alongside PTC and many other consultants on this project for more than 10 years. This project creates a toll road system around Pittsburgh to the south and west, connecting the Pittsburgh International Airport with the Monongahela Valley and West Virginia to the south.


ms consultants provided preliminary design and comprehensive environmental documentation for a 116-square-mile project study area for the development of a new toll road expressway, which was to be a four-lane limited access highway with an anticipated four interchanges.


Preliminary environmental considerations included:

  • Special population groups
  • Socioeconomic characteristics
  • Land use
  • Community facilities and services
  • Hazardous waste and materials
  • Vegetation and wildlife
  • Wetlands
  • Farmlands
  • Surface water resources
  • Drainage and floodplains
  • Cultural resources
  • Noise and air quality
  • Threatened and endangered species investigations



Five new toll road alternatives were evaluated by ms consultants in an Environmental Impact Statement. Evaluation was based upon the alternative’s ability to meet the project need, environmental and socioeconomic impacts, as well as sound engineering practices. Based on this analysis, ms consultants was able to eliminate two alternatives from further investigation. The report documents the findings of these investigations, preferred alternatives, as well as the public and agency involvement. The report was submitted and approved by the Federal Highway Administration.


Key environmental considerations in the development of the evaluation of the project alternatives included:

  • Socioeconomics
  • Natural resources
  • Vegetation and wildlife habitat
  • Threatened/endangered species, energy, surface waters and aquatic resources with complete physical, biological, chemical analyses and characterizations
  • Floodplains
  • Wetlands
  • Air quality
  • Noise
  • Municipal, industrial, and hazardous waste studies
  • Section 106 Cultural Resource Investigations
  • Section 4(f) Resources and Evaluation
  • Construction impacts
  • Public Involvement




Geographic Information Systems (GIS) were used to inventory resources, evaluate and compare impacts among alternatives, and to prepare graphics for presentations to agencies, the public, as well as the Transportation Executive Committee that participated in the project development process.

POST-NEPA Services

ms consultants was retained under a Post-NEPA services contract to coordinate environmental and design commitments with the PTC design manager, section designers, and environmental agencies.


This included:

  • Re-evaluation of environmental resources
  • Asbestos and lead paint inspections on acquired properties.
  • Coordination of design section resource impacts and mitigation strategy.
  • Mitigation tracking.
  • Preparation of Chapter 105 permits to PADEP.
  • Design, permitting and construction consultation of 55-W wetland mitigate site.
  • Phased EIS Re-Evaluation approach coordinated so that as design sections completed design, those sections could be environmentally cleared and released for construction bids.
  • Three EIS Re-evaluations were completed.


After issuance of the Record of Decision on the Final Environmental Impact Statement, the project was advanced into Final Design with five design sections. PTC engaged ms to develop final design for the fifth subproject, 55C2, located in Cecil Township and South Fayette Township, Pennsylvania.


When complete, the first component of 55C2 will be a new, four-lane highway with a 60-foot median along the Southern Beltway mainline, state Route 0576.


It will include:

  • Approximately 9 million cubic yards of total earthwork excavation
  • 71,000 feet of concrete pavement
  • 10 ramp alignments
  • 6 box culverts
  • 4 bridge structures
  • 1 interchange exit
  • Stream relocations

The design also includes widening a three-mile stretch of I-79, from four lanes to six lanes. The widening will occur in the interstate’s existing median, both northbound and southbound. The bifurcated roadway will require moment slabs with toe walls to support the extra 24 feet of proposed pavement in both directions.


The team will implement a multiple-phase, traffic-control plan to maintain two lanes of traffic at all times. The plan will protect the traveling public while the construction team widens the two existing mainline structures and builds two new multi-span structures, allowing state Route 0576 to pass underneath I-79.


A second component, currently under construction, includes the relocating of 6,500 feet of Morganza Road and relocating 4,800 feet of Morgan Road.


The team designed a roundabout at the intersection of Morganza and Morgan Roads. The roundabout provides efficient traffic operations with a smaller footprint—less pavement, less maintenance, less operation costs—and ultimately a safer intersection.


When complete, the project will reduce congestion, provide safer travel, and increase development opportunities in the area.

Get in touch

Love our projects? Interested in starting something exceptional?

Contact us and we would be happy to help.