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Health and climate impacts of future United States land freight modelled with global-to-urban models


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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Fig. 1: System of systems approach.
Fig. 2: Effect of urban spatial structure on trends in short-haul freight delivery and impacts from 2010 to 2050.
Fig. 3: Spatial distribution of PM2.5 concentrations resulting from freight truck and rail transport in 2010 and 2050 under the baseline scenario.
Fig. 4: Total mortalities from inhalation of PM2.5.
Fig. 5: Assessment of annual mortalities, integrated short-lived forcing, and long-lived forcing for all US truck and rail freight.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.


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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.

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Authors and Affiliations



T.C.B. conceived and managed the project; T.H. and Y.O. developed the freight demand forecasting models and produced the freight shipment flows over the truck and rail network; S.L. and B.L. developed the urban development scenarios; S.J.S. produced the macroeconomic scenarios; K.D. supplied the Phoenix model data; C.W.T. and J.D.M. developed InMAP and helped with the model analysis; F.Y. developed the SPEW-Trend model. L.L. integrated all model results, estimated the emissions and impacts, and wrote the first draft of the manuscript; all authors provided feedback on the manuscript.

Corresponding author

Correspondence to Tami C. Bond.

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Supplementary Notes 1–6, Supplementary Tables 1–7, Supplementary Figures 1–4, Supplementary Discussion, Supplementary References 1–48

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Liu, L., Hwang, T., Lee, S. et al. Health and climate impacts of future United States land freight modelled with global-to-urban models. Nat Sustain 2, 105–112 (2019).

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