PNNL

Abstract

This work develops an integrated model approach to project emissions from long-haul freight truck and rail transport in the U.S. between 2010 and 2050. We connect models of macroeconomic activity, freight demand, and emission technology to represent the different factors affecting freight emissions and its spatial distribution. Future uncertainties are represented by four macroeconomic scenarios with different economic growth rates and climate policy. Our estimates show that while freight activities are more than doubled or tripled in the four scenarios by 2050, freight fuel use increases at a slower rate because of improved fuel efficiency; freight emissions of all pollutants decrease significantly by 2030 due to the retirement of older vehicles built under less stringent emission standards. Climate policy causes a modal shift from truck to rail because of higher fuel prices, resulting in a 30% reduction in fuel use and 10% to 28% reductions for particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), and total hydrocarbon (THC) emissions in 2050. Alternative mitigation policy to expand highway capacity eases congestion, improves fuel efficiency, and reduces emissions. The elimination of superemitters stands out as achieving the most emission reduction for PM, CO and THC, reducing emissions by 65%, 30%, and 25% in 2050, respectively.