Tools for addressing the environmental, social and economic sustainability of transport systems in a metropolitan area, and their application to two road case studies in Biscay

The challenges of the environmental, social and economic sustainability of transport systems become frequently more acute in metropolitan areas –where the amount of people potentially affected is high-, than elsewhere. Indeed, these areas usually suffer more diverse challenges as daily congestion, time losses, pollutant emissions, land scarcity or climate change effects. Namely, when addressing transport system projects, often agents as decision makers, designers and operators have to face the referred challenges, owing to social demands, to requests from environmental agencies, and recently, when seeking financial support, also from lending institutions, growingly committed to social and environmental sustainability. In this paper a literature review of current Sustainability assessment (SA) methods will be presented, outlining their framework and desirable features. Then the mentioned challenges will also be reviewed. Several tools used by the authors will be presented which permit the named agents to address the challenges in metropolitan areas. These tools comprise modern transport and traffic multimodal models, environmental impact assessment of projects, public participation processes, urban planning and the said requests from environmental agencies and lending institutions; how these tools fit within the framework and desirable features of SA methods will be discussed. Two road case studies in Bilbao Metropolitan Area (Spain) of two projects promoted by Biscay Territorial Council will be presented, in which environmental, social and economic sustainability challenges were addressed with the aid of the referred tools, which were useful for the authors to tackle those challenges in the study phases of each project. Selected results of the cases will be discussed and compared. Finally conclusions will be drawn.