Analyzing the economic and environmental impacts of urban infrastructure{\textemdash}whether its contribution to productivity or its generation of greenhouse gas emissions{\textemdash}is very challenging because urban or metropolitan infrastructure is seldom self-contained. Cities almost always import infrastructure services (e.g., power and water) from outside their boundaries, and allocating the costs and benefits of intercity transportation to specific cities is a difficult accounting problem. Accounting for emissions from industrial production and household consumption raises the issue of how to assign the carbon emissions of intermediate inputs and final production goods that originate outside the city.

Promising approaches that address this problem specify a boundary around the city or metropolitan area and carefully analyze all transboundary flows of goods and services to analyze both infrastructure and all other movements, as noted by Anu Ramaswami in this paper. Results indicate that improvements in energy efficiency and reductions in greenhouse gas emissions will be achieved more readily for buildings (responsible for nearly half of urban greenhouse gas emissions) than for transportation (responsible for nearly a quarter of greenhouse gas emissions).

This paper was presented at the Lincoln Institute{\textquoteright}s annual Land Policy Conference in 2012 and is Chapter 11 of the book Infrastructure and Land Policies.