By Robbie Webber
The practice of developing highway projects sustainably by paying attention to the societal, environmental, and economic impact of projects has become increasingly common. States are using transportation sustainability rating systems (TSRSs) to assess the impacts of their planning, project development, operations, and maintenance decisions and actions. A recent Mountain-Plains Consortium report looks at which of the many available TSRSs would be appropriate in the four western states they studied.
Ten prominent systems were assessed: BE2ST-in-Highways, Envision, Green Guide for Roads, GreenLITES, GreenPave, Greenroads, I-LAST, INVEST, CEEQUAL, and STARS. Some of these rating systems are exclusively for transportation projects, while others can be used to rate a variety of infrastructure investments. The tools offer a wide variety of flexibility, with some rating only construction methods and materials, while others rate planning and project development as well.
Utah, Colorado, Wyoming, and South Dakota DOTs participated in the study. Each valued different capabilities in a TSRS, with most opting for one that did not require third-party verification and allowed for flexibility in rating different types of projects.
The study consisted of a literature review of existing TSRSs, interviews with state DOTs to gauge which capabilities were most important to them, the development of a secondary survey instrument based on the Analytic Hierarchy Process methodology to allow the assignment of weights to the desired capabilities, and an assessment of which TSRS was most appropriate for each state.
Although the authors admit that this research is preliminary, and the topic requires further investigation, the framework appears useful to determine which TSRS is appropriate for a state DOT based on the capabilities identified as important. INVEST was found to be the most appropriate system for Colorado and Wyoming and came in second in South Dakota, after STARS. The results of a portion of the study were inconclusive for Utah, but INVEST still came out as the preferred system.
The ability of an agency to select which criteria were most appropriate for a project before the rating was done was noted by the authors as a popular feature of INVEST. INVEST also features distinct modules for system planning, project development, and operations and maintenance, so different stages of agency work can be assessed separately or during the life of a project.
INVEST was developed by FHWA with CH2M Hill. SSTI has been partnering with FHWA and Resource Systems Group to test INVEST with interested states.