Driven by economic growth, globalization and e-commerce, freight per capita in the United States has been consistently increasing in recent decades. Projecting to 2050, we explore the emissions, and health and climate impacts of US freight truck and rail transport under various policy scenarios. We predict that, overall, air pollutant emissions and health impacts from the freight-truck-rail system will be greatly reduced from 2010 to 2030, while long-term climate forcing will continue to increase if petroleum is the fuel source. A carbon tax could shift freight shipments from trucking to energy-efficient rail, providing the greatest reduction in long-term forcing among all policies (24%), whereas a policy enforcing truck fleet maintenance would cause the largest reduction in air pollutant emissions, offering the largest reduction in mortalities (36%). Increasing urban compactness could reduce freight activity but increase population exposure per unit emission, offering slight health benefits over the current urban sprawl trend (13%).
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This publication was supported by assistance agreement nos. EPA RD-83428001 and R835873 (Center for Clean Air Climate Solutions) awarded by the EPA. It has not been formally reviewed by the EPA. The views expressed in this document are solely those of the authors and do not necessarily reflect those of the Agency. The EPA does not endorse any products or commercial services mentioned in this publication. C. Barkan shared the observation about mode-shifting in response to fuel price increase that inspired the long-haul freight modelling. Additional support was provided by the PNNL Global Technology Strategy Program for S.J.S. We thank R. Minjares of the International Council for Clean Transportation for critical feedback on the work, and Y. Cui and C. Roney for their helpful comments.
Supplementary Notes 1–6, Supplementary Tables 1–7, Supplementary Figures 1–4, Supplementary Discussion, Supplementary References 1–48
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Nature Sustainability (2019)