Understanding Material Stocks in Roads at the City and Multinational Scale

Abstract

Improving resource efficiency is critical to reduce the environmental impacts of constructing and maintaining the built environment. Construction materials represent a growing share of global greenhouse gas emissions, but limited knowledge concerning the quantity and distribution of materials making up infrastructure is an obstacle to designing robust policies and tracking progress towards greater resource efficiency. This thesis investigates material stocks in roads at the city and multinational scale through case studies of the road networks of Toronto and six high-income countries. Modelling material stocks at the city scale using simplified archetypes is shown to introduce significant uncertainty that is not well addressed in existing studies. Multinational road stocks are estimated using a method that better captures the inherent variability in pavement design. Considerable differences in the material intensities of different countries’ road networks are observed, suggestive of opportunities to build roads with lower environmental impact.