Allegheny Mountain Realignment Project: How Studies During Preliminary Engineering Help the PA Turnpike Mitigate Impacts to Wildlife

Quick Summary

• The Allegheny Mountain Realignment (AMR) Project is in preliminary design, the first of three project phases, where environmental and wildlife data help guide roadway decisions. 
• This summer, the PA Turnpike is conducting two wildlife surveys along the corridor: mist-net surveys for bats and presence/absence surveys for the Allegheny woodrat. 
• Pennsylvania and federal law require major infrastructure projects to assess impacts to threatened and endangered species, such as the Indiana bat, before construction begins. 
• These studies are guided and approved by the Pennsylvania Game Commission (PGC)
• Survey findings provide information needed to refine the roadway alignments and time construction activities around sensitive seasons rather than stop the project. 

When Pennsylvania Turnpike Commission (Commission) construction projects take shape, teams of transportation engineers, environmental scientists and biologists first lead the charge in understanding how planned routes impact local ecological resources.

Construction projects move through three phases and the first, preliminary design, collects data to avoid, minimize and/or mitigate impacts of all types, including environmental and biological. Every wetland, stream, archaeological resource and wildlife habitat is measured and assessed, which is why this phase takes years—not months. Following Preliminary Design, the project advances to Final Design and then Construction

The Allegheny Mountain Realignment (AMR) Project is in preliminary design now and the PA Turnpike will continue building on its history of scientific, environmentally informed decision-making to move it forward.

Threatened and endangered species regulation in Pennsylvania involves various Federal and State Resource agencies. The US Fish and Wildlife Service is responsible for the enforcement and coordination of The Endangered Species Act of 1973. There are a variety of State statutes in Pennsylvania that are coordinated through the State’s Conservation Explorer Program. State agencies responsible for threatened and endangered species regulation include The Pennsylvania Game Commission, the Pennsylvania Fish and Boat Commission, and the Department of Conservation and Natural Resources.

Throughout the AMR’s three-decade history, the Commission has consistently updated strategies to safeguard the Commonwealth’s natural resources. In 2020-21, the U.S. Fish and Wildlife Service requested the Commission develop alternative routes south of the existing Allegheny Tunnel to avoid impacting the federally endangered Indiana bat's travel corridor. The change is one example of how environmental regulations, combined with the Commission’s sustainability commitments, helped it make choices that balanced safety, mobility and environmental responsibility.

Studying Wildlife Before Designing the Road

Pennsylvania law and federal environmental regulations require major infrastructure projects to assess potential impacts to threatened and endangered species before construction begins.

This summer, the Pennsylvania Turnpike Commission, in coordination with the PGC, is conducting two required wildlife surveys along the project corridor: mist-net surveys for bats and presence/absence surveys for the Allegheny woodrat. Both will provide information engineers can use to refine the design in ways that mitigate impacts to sensitive wildlife populations.

These are not checked boxes—they represent the Commission’s responsibility to understand the area’s ecological attributes and carry out projects in ways that mitigate impacts to Pennsylvania's native wildlife.

How are We Surveying Bats? 

The Allegheny Mountain corridor provides habitat for several protected bat species.

Mist-net surveys are a common bat study method; the PGC conducts them between May 15 and August 15, 30 minutes before dark. Fine-mesh nets resembling volleyball nets are strung along known bat flight paths. Licensed wildlife biologists temporarily capture bats in the nets, quickly collect species, age and health data, then release them unharmed.

From the information collected, scientists create models of how and when bat species use the area. PA Turnpike engineering teams use that information to determine where and when construction activities can occur, or if additional steps are needed to minimize effects on these protected species.

How are We Surveying the Allegheny Woodrat?

Crews are also surveying the project site for the Allegheny woodrat (Neotoma magister), a native Pennsylvania rodent that lives almost exclusively among rocky cliffs, loose-rock slopes, and boulder fields, and rarely ventures far from its rocky home. Not to be confused with the non-native Norway rat commonly found in cities, the Allegheny woodrat is listed as a threatened species in Pennsylvania due in part to the demise of its chief food source, the American chestnut.

Because precise data is essential, survey plans, including habitat assessments and photographic documentation, are reviewed by the Pennsylvania Game Commission before fieldwork begins.

Upon plan approval, camera traps are placed around the project area to determine whether Allegheny woodrats are present and how they use the landscape. As with bat populations, the rodents’ presence or absence gives engineers critical information on how to approach construction and design in that area.

What Happens If Wildlife Is Found? 

Finding protected wildlife doesn't automatically stop a project. Instead, engineers and biologists collaborate to refine the design. This could look like adjusting roadway alignments, timing construction activity to avoid sensitive seasons, protecting habitat features or developing mitigation strategies where necessary.

The goal is to build the safest roadway possible while responsibly protecting natural resources that make this region unique.

Environmental Stewardship Is Built into the Process

Bat and Allegheny woodrat studies are just two of the many taking place during the Allegheny Mountain Realignment’s preliminary design phase.

Responsible infrastructure project management begins with first understanding the landscape. Wildlife surveys provide critical environmental information that helps engineers balance safety, constructability and environmental stewardship.

For more information, visit Allegheny Mountain Realignment.

Frequently Asked Questions

What wildlife surveys is the PA Turnpike conducting for the AMR Project?

Currently, the Commission is conducting two surveys along the project corridor: mist-net surveys for bats and presence/absence surveys for the Allegheny woodrat. Both help engineers refine the design to mitigate impacts to sensitive wildlife populations.

What is a mist-net survey?

A mist-net survey is a common method for studying bats. Licensed biologists string fine-mesh nets that resemble volleyball nets along known bat flight paths, typically 30 minutes before dark between May 15 and August 15. Captured bats are quickly identified and assessed for species, age and health, then released unharmed.

Where does the Allegheny woodrat live?

The Allegheny woodrat (Neotoma magister) is a native Pennsylvania rodent that lives almost exclusively among rocky cliffs, loose-rock slopes and boulder fields, rarely venturing far from its rocky home. It is listed as a threatened species in Pennsylvania.

Does finding protected wildlife stop a construction project?

No. Finding protected wildlife does not automatically stop a project. Engineers and biologists collaborate to refine the design, which can include adjusting roadway alignments, timing construction to avoid sensitive seasons, protecting habitat features or developing mitigation strategies.

Why do infrastructure projects need wildlife surveys before construction?

Pennsylvania law and federal environmental regulations require major infrastructure projects to assess potential impacts to threatened and endangered species before construction begins. The surveys give engineers the environmental information they need to balance safety, constructability and environmental stewardship.

How long is the Allegheny Mountain Tunnel

At 6,070 ft, the Allegheny Mountain Tunnel is more than a mile long.