Abstract
Transportation supports ease of movement, access, and economic health for communities, but transportation also has indisputable impacts on air, water, and natural ecosystems. Although state departments of transportation (DOTs) are increasingly harmonized in their approaches to performance measurement for areas such as infrastructure preservation and congestion, there has been little consensus or direction on approaches for measuring environmental performance. This paper describes the identification and testing of a suite of core environmental performance measures designed to help state DOTs better understand and communicate the impacts of transportation on the environment and ultimately to support more informed business decisions. The measures reflect five major focus areas: air quality, energy and climate, materials recycling, stormwater, and wildlife and ecosystems. The measures discussed in this paper were subject to proof of concept testing with available data gathered from state DOTs. Twenty-seven states participated in the testing to some degree. The performance measures recommended in this paper should be considered a sound starting point for continued efforts in assessing the impacts of DOTs on the environment and not perfect or permanent metrics.