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Reductions in the greenhouse gas (GHG) intensity of passenger and freight transportation are possible through adoption of fuel-saving technologies, demand switching between modes, and large-scale electrification of fleets, in addition to other actions. In this study, future scenarios to 2030 and 2050 are the basis for assessment of GHG reduction potentials for major passenger and freight modes (automobiles, buses, trains, aircraft, and oceangoing vessels) across eight regions of the world. New fuel-saving technologies can significantly reduce the life-cycle GHG footprint of both passenger and freight vehicles, but not uniformly worldwide. Countries outside of the Organization for Economic Cooperation and Development (OECD) lag behind OECD countries in GHG reduction potentials for all modes but oceangoing vessels owing to a combination of slower adoption of fuel-saving technologies and a slower decarbonization of electricity generation and other processes. The reduction of GHG intensity will occur more slowly for freight modes than for passenger modes. However, improved fuel efficiency has negative feedbacks to the effectiveness of mode-switching and alternative fuel adoption policies through 2050 because improvements in the fuel efficiency of vehicles alone may cause the marginal benefits of GHG abatement policies to diminish over time. This trend may be reversed if alternative fuel pathways decarbonize at faster rates than conventional transportation fuels. The largest opportunities for GHG reductions occur in non-OECD countries. Given the many factors that distinguish transportation systems between developed and developing nations (e.g., availability of new technologies, the financial ability to acquire them, and policies to incentivize their adoption), many benefits could be gained through interregional cooperation. [ABSTRACT FROM AUTHOR]

The freight infrastructure network (e.g., roads, railways, waterways, etc.) is the backbone of nearly all trade partnerships in the United States and abroad. The manner in which the individual portions of its constituent parts are interrelated or arranged plays an important role for determining the environmental footprint of goods moved within the network. Herein, we compare the spatial distribution of potential consumer-producer exchanges (i.e., accessibility) under varying greenhouse gas (GHG) budgets or preferences for minimal transportation-related GHG emissions. We conduct case studies using two freight modes (truck and intermodal rail) for two representative commodities: meat/seafood and paper articles. Results across all counties in the United States indicate that the geographic area in which trade is possible, given a GHG budget, varies by transportation mode, location, and commodity. Our results suggest that intermodal terminal availability is an important determinant of low-GHG accessibility. Since only a fraction of road-to-rail terminals accommodate meat/seafood (4.9%) and paper (0.7%), the United States could increase its expected GHG savings associated with truck-to-rail mode-switching policies by 70% (+20 kg CO2,e/ton for meat/seafood) and 310% (+30 kg CO2,e/ton for paper) by upgrading current terminals to allow the exchange of all types of goods. [ABSTRACT FROM AUTHOR]

The formation of effective policies to reduce emissions from goods movement should consider local and remote life cycle effects as well as barriers for mode shifting. Using uni- and multimodal freight movements by truck, rail, and ocean-going vessel (OGV) associated with California, a life cycle assessment (LCA) is developed to estimate the local and remote emissions that occur from freight activity inside and associated with the state. Long-run average per tonne-kilometer results show that OGVs emit the fewest emissions, followed by rail, then trucks, and that the inclusion of life cycle processes can increase impacts by up to 32% for energy and greenhouse gas (GHG) emissions and 4,200% for conventional air pollutants. Efforts to reduce emissions through mode shifting should recognize that infrastructure and market configurations may be inimical to mode substitution. A uni- and multimodal shipping emissions assessment is developed for intrastate and California-associated freight movements to illustrate the life cycle impacts of typical trips for certain types of goods. When targeting GHG reductions in California, it should be recognized that heavy-duty trucks are responsible for 99% of intrastate goods movement emissions. An assessment of future freight truck technology improvements is performed to estimate the effectiveness of strategies to meet 2050 GHG reduction goals. Whereas aggressive improvements in fuel economy coupled with alternative vehicles and fuels can significantly reduce GHG emissions, to meet 2050 goals will likely require zero carbon emission vehicle technology. The value of using LCA in GHG reduction policy for transportation systems is explored. [ABSTRACT FROM AUTHOR]