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Criterion Details

PD-09 Ecological Connectivity

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Project Development Scorecard

  • Rural Basic
  • Rural Extended
  • Urban Extended


Avoid, minimize, or enhance wildlife, amphibian, and aquatic species passage access, and mobility, and reduce vehicle-wildlife collisions and related accidents.

Sustainability Linkage

Triple Bottom Line

Improving ecological connectivity supports all of the triple bottom line sustainability principles by improving habitat for species while reducing accidents, therefore preventing the impacts associated with personal and public property damage, injury, and the loss of life.

Background & Scoring Requirements


For the purpose of this criterion, the key terms are defined as follows:

  • “Traditional Alternative” – The traditional alternative is the alternative that would most likely be approached without consideration of impacts to habitat. For new alignments, this is typically the alignment that is most geometrically fitting given the beginning and end points. For reconstruction, this is typically the alignment option that widens the cross-section in-place without shifting alignments. In no case, should the traditional alternative be exaggerated beyond alignments that would be considered appropriate for the context in order to inflate the perceived reduction in impacts to habitats for this criterion.

Credit for enhancement can be obtained for this criterion through project-specific mitigation or through the use of mitigation banking.

Scoring Requirements

In order to achieve points for this criterion, the following prerequisite must be met.

Prerequisite PD-09.1P

0 points. Conduct Ecological Assessment

Conduct a site-specific ecological assessment of the roadway project using GIS data or regional expertise. Report the resulting impacts that the roadway has on the major ecosystems, according to the best scientific knowledge available. A project or resource agency biologist should be involved with the assessment. The ecological assessment should be consistent with the State-approved wildlife action plans, if available.

Requirement PD-09.1

1-3 points. Avoid or Minimize Impacts to Ecological Connectivity or Enhance Features

Points shall be achieved per Table PD-09.1.A on the following page. Points are not cumulative; rather the highest point value earned should be used. Note that more points are available for enhancing features on new alignments than existing alignments because more opportunities typically exist to improve ecological connectivity on new alignments.


Dedicated wildlife crossings are structural features of the roadway that are not used by motorized vehicles. Where deemed appropriate by an ecologist, crossings may be shared by non-motorized modes of transport. No points will be awarded in the following conditions:

  1. For projects that maintain or rehabilitate existing ecological connections to out-of-date or current standards (i.e., routine maintenance of drainage culverts does not qualify).
  2. Pre-existing ecological connectivity features: all new features or upgrades must be due to and completed as part of the roadway project.
  3. Projects that add wildlife connectivity features where such features are clearly outside of the project context.
  4. Projects located in a network that is systematically inadequate. However, points could be awarded for such projects where it is demonstrated that a program is in place at the owner agency for systematic improvements on that network, and that this project fits this program.

Requirement PD-09.2

1 point. Advanced Consultation and Integration with Broader Ecological Plans

The project team went above and beyond current consultant requirements by engaging natural resource and regulatory agencies throughout the planning process and by ensuring consistency with broader (metropolitan or statewide) planning goals and objectives.


None referenced.

Case Studies & Criterion Examples

Arizona DOT - Roundabouts and Local Partnerships: The Arizona Department of Transportation (ADOT) used all three INVEST modules to validate strategic directions, increase knowledge across core functions, and advance a decision-making framework around sustainability best practices. This case study focuses on ADOT’s use of the Project Development module to score and improve the sustainability of twenty roundabout construction projects as well as ADOT’s use of INVEST training workshops to facilitate collaboration internally and with local governments. Roundabouts have seen increased application across the United States and in Arizona due to their safety and congestion reduction benefits. Using INVEST, ADOT scored twenty planned or under construction roundabouts. ADOT found the scoring process helpful both in improving the sustainability of the individual roundabout projects and in understanding the sustainability of the state’s roundabout program as a whole.

Central Federal Lands - Knowledge Sharing and Lessons Learned Help to Institutionalize INVEST: The Central Federal Lands Highway Division (CFL) within Federal Lands Highway (FLH) is using INVEST as a knowledge transfer tool to better inform staff of sustainable highway practices and as a mechanism to share lessons learned to help identify improvements for future projects. In 2013, CFL used the Project Development (PD) module to carry out INVEST evaluations for three separate under-construction or recently constructed projects. These included Halstead Meadow Bridge, Taylor River Road, and Marshlands Road and La Riviere Bridge. For two of the three projects, Halstead Meadow Bridge and Taylor River Road, CFL created scoring teams consisting of staff members and partner agency representatives. Scoring team members were selected due to the wealth of knowledge and experience they had with each project (from project development through construction).

Arizona DOT - Using INVEST to Integrate Sustainability: The Arizona Department of Transportation (ADOT) decided to use all three modules of INVEST – System Planning, Project Development, and Operations and Maintenance – to help the agency meet its sustainability goals across the transportation life cycle.  ADOT used INVEST to integrate and advance existing sustainability efforts and to push forward new efforts.  INVEST’s comprehensive sustainability framework and criteria helped ADOT institutionalize sustainability across the agency and with local partners through inclusion in manuals, trainings, and awards.  This case study focuses on ADOT’s use of the Project Development module.

Arizona DOT - State Route 30 Sustainable Project Development: This case study describes the use of the INVEST PD module to analyze and score the ADOT State Route (SR) 30 project—an approximately 13-mile section of new freeway in the Phoenix metropolitan area. The new freeway would be built five (5) miles south of Interstate 10 and would run from Sarival Road in Goodyear east to Loop 202 (South Mountain Freeway) in the western section of Phoenix in Maricopa County, Arizona. SR 30 is a proposed new freeway managed by the ADOT that would eventually link with the proposed ADOT Interstate 11 project in western Maricopa County near Tonopah at its western terminus and with the existing Interstate 17 at the Durango Curve in Phoenix at its eastern terminus. The section of SR 30 analyzed and scored using INVEST is currently in the preliminary design and environmental assessment evaluation phase pursuant to the National Environmental Policy Act.

Scoring Sources

The project is considered to have met this criterion if the requirements above can be reasonably substantiated through the existence of one of the following documentation sources (or equal where not available):

  1. Ecological study performed for the project provided in NEPA documentation. State permitting documentation that includes an ecological connectivity element.
  2. Contract documents showing wildlife crossing improvements.
  3. Technical report that describes minimization that occurred throughout the project development process.