An International Framework for Sustainable Roadway Rating Systems

Abstract

Increasing attention to greenhouse gas emissions, general environmental damage, human safety, and the general impact of transportation infrastructure on society has increased attention on designing and constructing infrastructure in a more sustainable manner. In recent years, a number of rating systems have been developed and are increasingly being used to measure and quantify the sustainability of infrastructure. However, there is no consistent framework for developing or analyzing these rating systems. Therefore, most rating systems consist of a piecemeal collection of sustainability best practices with little information on how they were developed or how they address the scope of sustainability. This can lead to significant issues in understanding the sustainability scope of these systems, what they implicitly prioritize, and how they can be transferred from one context to another. These issues come to the forefront with increasing international demand for these rating systems. Due to different rating system priorities, national contexts, and local circumstances, it is difficult, if not impossible, to apply one system universally. This research focuses on a subset of infrastructure, roadway projects, and proposes a framework that can be used to develop a sustainability rating system within the context of any country as well as evaluate and improve existing rating systems. The framework uses the Sustainable Society Index (SSI) categories and existing rating systems as a starting point to develop 49 roadway topics. Using this framework to evaluate eleven existing rating systems shows that most systems focus more on environmental aspects and lack consideration of social and economic aspects such as accessibility, safety, and local employment, which can be particularly inappropriate in developing countries whose priorities are basic needs (e.g., access, safety, employment). The framework presented here can be helpful in (1) evaluating and comparing the sustainability scope of existing roadway systems, and (2) developing or adapting rating systems for new contexts.