Sustainability Rating Systems: Broad Based or Narrowly Focused?

Sustainability rating systemsA Guide To Help Transportation Infrastructure Owners Decide On The Best Approach

ce_news_logoAs published by CE News Magazine

By Sean Vargas and Kevin Thornton

Recently, a multitude of methodologies and rating systems have been developed to assess how sustainable, or “green,” infrastructure projects are. With so many systems, it is difficult for policy makers, elected officials, and their constituents to understand which approach is right for a project.

The following sustainability rating systems currently are in use for transportation infrastructure projects:

  • Envision, a rating system developed by the Institute for Sustainable Infrastructure, is a broad-based infrastructure rating system;
  • Greenroads Rating System, developed by the Greenroads Foundation, is a transportation-specific rating system; and
  • INVEST, the Infrastructure Voluntary Evaluation Sustainability Tool developed by the Federal Highway Administration (FHWA), also is a transportation-specific rating system.

A comparison of the three rating systems based on the following criteria can help project owners understand which tool might be most valuable in evaluating their infrastructure projects and increasing the projects’ sustainability:

  • applicability to various types of projects and project phases (pre-design, design, construction, operations, and maintenance);
  • project recognition requirements;
  • professional credentials required of the project team; and
  • benefits and limitations of each rating system.

While many owners may use sustainability rating systems for the purpose of gaining project recognition, others may wish to use a rating system in the project development or construction phase simply to improve the likelihood of selecting sustainable options. Even when there is no intention of seeking project recognition, rating systems can provide a framework for increased awareness of key sustainability issues as well as organizational improvement.

Applicability to Types of Projects

Envision is a broad-based rating system that can be used for any infrastructure project, not just transportation. Envision is excellent at evaluating projects with a combination of infrastructure improvements, for example roadways with major utility and flood control elements. Owners with broader mandates including transit, bicycle trails, or other types of infrastructure may find this broad-based rating system effective.

Greenroads can be used for all types of roadway projects, including new, reconstruction, rehabilitation/preservation, and bridge projects. It also may be applicable to paths and trails; contact Greenroads directly for a determination regarding these types of projects.

INVEST has six scorecards in the Project Development Module. They include Paving (pavement preservation and restoration), Basic Rural (small rural bridge replacement or road reconstruction projects), Basic Urban (small urban bridge replacement or road reconstruction projects), Extended Rural (new facilities or major rural reconstruction projects to add capacity), and Extended Urban (new facilities or major urban reconstruction of bridges and roadways to expand capacity). In addition, the custom scorecard allows users to select the criteria for projects that do not fit any of the predefined scorecards.

Applicability to Project Phases

The Envision rating system is currently most applicable to the pre-design and design phases of projects. There are plans to include construction, operations, and decommissioning in future releases.

The Greenroads rating system is focused on development and delivery of specific transportation projects. Planning phases and operations and maintenance are not included in this rating system.

INVEST has three modules. The first is the System Planning Module, which focuses on identifying projects that will benefit the system-wide network of an agency. The Project Development Module focuses on the planning, design, and construction of specific projects. Finally, the Operations and Maintenance Module looks at system-level operations and maintenance activities. The Project Development Module was reviewed for the purposes of this article.

Recognition Requirements

Envision recognizes four achievement levels (Platinum, Gold, Silver, and Bronze). Users self-evaluate their projects and there is no cost for this self-evaluation. If the agency or user wants a third-party verification of the scores and official recognition, the application cost is $1,000 with a minimum verification fee of $2,400 (ISI members) or $3,000 (non-members). There are 55 total credits, but the user may exclude from consideration credits that are not applicable to a project.

Greenroads has four certification levels (Evergreen, Gold, Silver, and Certified). Greenroads reviews and evaluates projects (there is no self-evaluation). The minimum certification cost is $4,995. Eleven required credits and 37 voluntary credits are evaluated.

Four achievement levels can be earned using the INVEST scorecard (Platinum, Gold, Silver, and Bronze). The projects are self-evaluated and there is no cost to the agency or user. There is no third-party validation process and, therefore, FHWA does not officially recognize achievement levels of projects. There are 29 credits that are evaluated for the most complex projects in the Project Development Module. Fewer credits are used for less complex or rural projects.

Professional Credentials Required

A member of the design team must be credentialed as an Envision Sustainability Professional (ENV SP) if submitting to ISI for verification and recognition. At the time of this writing there are approximately 500 ENV SP credentialed professionals.

A Greenroads Sustainable Transportation Professional (STP) is not required to manage a Greenroads project, however, points can be earned for having a team that includes one or more credentialed professionals. At the time of this writing there are approximately 76 STP credentialed professionals.

INVEST has no requirements or credentialing programs.

A further note: A project team may not be familiar with the documentation that all three rating systems require. In many cases, the work associated with a “credit” has been completed as part of the design effort, but additional documentation may be required, potentially resulting in added time commitment or cost. All three rating systems generally require the projects to go above and beyond current standard practices to achieve sustainability credits.

Benefits and Limitations of Each Rating System

Envision Greenroads INVEST
Benefits • Self-assessed
• No cost to self-assess, only to verify
• Excellent for complex, multi-faceted infrastructure projects
• A simple checklist is available as a quick review of a project’s sustainable features
• Scoring and documentation is web-based
• Complete third-party evaluation, so no significant agency/project team time commitment
• Good examples for scoring credits and extensive resources/references are included in manual
• No cost
• Self-assessed
• Funding is available to jurisdictions to implement the rating system and gather lessons learned
• Scoring and documentation is web-based
Limitations • May be too complex for smaller projects • The 11 required credits may make it difficult for some projects to be rated without significant additional effort • No official recognition
• No professional training or credentialing process


CASE STUDY: Rating Comparison

Houghton Road Design

Project Houghton Road, Irvington Road to Valencia Road, Tucson, AZ

Project Type Roadway capacity improvement from two-lanes to six-lanes

Length 3.5 miles

Cost $21 million

Features Rubberized asphalt top course, separated multi-use path, bike lanes and transit facilities (bus pullouts, shelters), native low-water-use vegetation, water harvesting, reclaimed water mainline, public art

The Houghton Road project was reviewed at 100 percent completion and developed without any specific sustainability goals. For the purposes of the comparison, the team generally assumed points were earned when the requirements were met and documentation could be produced with little effort. There were additional points that could have been achieved with a little added effort on all three rating systems. One of the easiest ways to increase the score for all three rating systems would be to review the requirements in advance and write construction specifications to meet specific requirements.

  • Envision – 36 percent of points; Silver achievement level
  • Greenroads – 32 percent of points; Certified achievement level (Note that all 11 project requirements were not met as required if pursuing certification
  • INVEST – 25 percent of points; no achievement level


While Envision was written for a broad range of infrastructure project types and stakeholder groups, infrastructure-specific systems such as Greenroads and INVEST have a roadway/transportation focus. The intent of this overview is not to find one rating systems superior to another, but rather to illustrate the merits of a broad-based vs. a more narrowly tailored system. Ultimately, the goal is to help readers gain an understanding of all the considerations involved.

Learn More

Consider taking the following steps to further your understanding of transportation infrastructure and sustainability issues:


Sean Vargas, PE, ENV SP, LEED AP BD+C, is a principal and Director of Sustainability for Psomas. Kevin Thornton, PE, ENV SP, STP, is a senior project manager in the Psomas Transportation and Public Works Group. Both authors are Envision credentialed and Thornton is a Greenroads Sustainable Transportation Professional.


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