Using INVEST to Bridge Sustainability and Transportation Needs in the Denton Greenbelt

Long-range transportation plans recommend expansion of a North Texas roadway that crosses a conserved greenbelt and wildlife corridor in a state park. Recommendations call for the roadway to increase from 2 to 12 lanes. The roadway would connect two counties whose populations are expected to grow by as much as 77 percent by 2045.
The North Central Texas Council of Governments (NCTCOG) conducted a feasibility study to balance ecological and transportation needs in the Denton Greenbelt Corridor. The study was funded in part by a grant from the Federal Highway Administration (FHWA). Objectives of the feasibility study included:
- Using FHWA's Infrastructure Voluntary Evaluation Sustainability Tool (INVEST) as a decision-support tool to incorporate sustainability best practices early in project planning
- Engaging community and resource agency stakeholders to collaboratively identify potential impacts and solutions
NCTCOG staff modified existing INVEST sustainability best practices to make them more applicable to corridor-scale planning. These modified best practices were included in the feasibility study. The project team also promoted dialogue with stakeholders preceding and following development of the draft feasibility study. Stakeholders included community members, transportation partners, federally recognized tribal nations, and resource agencies. NCTCOG conducted nine meetings from June 2017 to January 2019.
The INVEST-based sustainability best practices resulted in new content in the feasibility study to address wildlife connectivity, impacts to tree canopy, facilities sensitive to light pollution, quantification of animal-vehicle collisions, and collaboration with external "champions" who recognized a need to balance transportation and ecological needs. The feasibility study identified next steps addressing stakeholder support for a wildlife crossing, stormwater management infrastructure, the use of trees as sound mitigation, and the ecological health of the greenbelt.
The success demonstrated by the Denton Greenbelt Corridor Feasibility Study is applicable nationally. The US Forest Service's "Forests on the Edge" reports document increasing development burdens faced by private forests and national forests and grasslands. The INVEST-based sustainability best practices developed and tested by NCTCOG can be used to address environmental sustainability in roadway corridor planning.
Despite these successes, the project faced challenges in creating a balance for ecology and transportation. Some stakeholders requested the roadway include more lanes to better serve expected population growth. Some recommended acquiring land in the conservation easement to increase the roadway right-of-way. Some emphasized the recreational benefits of the greenbelt over its ecological benefits. NCTCOG has identified funding to continue addressing the planning challenges in this corridor.