Truck fuel consumption increased by 16.5 percent from 2011 to 2021 while truck vehicle-miles traveled increased significantly more (22.4 percent). Fuel use in Class I freight railroads decreased by 16.4 percent, from about 3.7 billion gallons to 3.1 billion gallons for the same period.
Energy consumption by select freight transportation modes
In 2021, freight trucks accounted for the lion’s share of freight transportation energy consumption, followed by pipeline, a distant second.
Single-unit truck fuel consumption and travel
per gallon of single-unit trucks (based on total travel and fuel consumption)
increased by about 3.3 percent from 7.3 gallons to 7.5 gallons over the 2011 to 2021
period, and total fuel consumption increased slightly despite single-unit
trucks traveling 7.3 percent fewer miles per vehicle.
Combination truck fuel consumption and travel
Miles per gallon for combination trucks (based on average
miles traveled and fuel consumption) increased by 5.0 percent between 2011
and 2021. However, like single-unit trucks, combination truck fuel consumption
increased by 13.2 percent, despite the average miles traveled per vehicle declining by 6.9
Energy intensities of domestic freight transportation modes
intensity is the amount of energy used to produce a given level of output or activity,
which is measured by vehicle-miles, freight-car-miles, or ton-miles. Since 2010,
the energy intensity of trucking has decreased by 3.2 percent while Btu per freight car-mile increased by 5.2 percent and Btu per ton-mile increased by 3.1 percent.
Air quality is affected by freight
vehicle emissions. Compared with gasoline-fueled cars and trucks, diesel-fueled
heavy trucks emit a smaller
amount of carbon monoxide (CO) but larger amounts of nitrogen oxides (NOx).
However, since 2000, the rate of NOx emissions from diesel-fueled
heavy trucks declined by 79.5
Estimated nitrogen oxides (NOx) and particulate matter (PM-10) emissions
from single-unit and combination trucks
The U.S. Environmental Protection Agency (EPA) estimates that
trucks will produce nearly
1.7 million tons of NOₓ in 2020. Substantial reductions in freight-related NOₓ emissions
have been made since the EPA required the use of ultra-low sulfur diesel fuel
in heavy-duty trucks and other diesel-powered highway vehicles beginning in
2006. Between 2000 and 2019,
NOₓ emissions from gasoline- and diesel-powered single-unit and combination
trucks decreased by 71.5
percent, and PM-10 emissions declined by 66.8 percent. By 2030 truck-related NOₓ and PM-10
emissions are projected to decline by 84.6 and 78.2 percent, respectively, from 2000 levels.
U.S. greenhouse gas emissions by economic end-use sector
addition to carbon monoxide, nitrogen oxide, and particulate matter emissions,
the transportation sector releases large quantities of greenhouse gases (GHGs),
such as carbon dioxide, methane, nitrous oxide, and hydrofluorocarbons. When emissions from electricity are
distributed among end-use sectors, transportation was responsible for about 28.5 percent of all greenhouse gases emitted in the United States in 2021.
U.S. transportation sector carbon dioxide (CO₂) emissions from fossil fuel combustion by fuel type
transportation sector is responsible for 37 percent of total U.S. CO₂ emissions
from fossil fuel combustion in 2022. Carbon dioxide (CO₂) accounts for nearly
all of the transportation sector’s greenhouse gas emissions. Almost all of the
energy consumed by the sector is petroleum based and includes motor gasoline,
diesel fuel, jet fuel, and residual oil. Gasoline-fueled passenger cars and
light-duty trucks are responsible for about 55.5 percent of transportation
sector CO₂ emissions, while the combustion of diesel fuel in medium- and
heavy-duty trucks and jet fuel in aircraft produced much of the rest.
The overall trend, from 1990 to 2022, shows that transportation CO₂ emissions rose in large part to an increase in travel demand that was fueled by population and economic growth, urban sprawl, and periods of low fuel prices. From 2021 to 2022, transportation CO₂ emissions increased 1.5 percent.
U.S. greenhouse gas emissions from domestic freight transportation
Between 1990 and 2021, the percentage growth of greenhouse gas emissions from freight sources was 60 percent. Emissions from passenger sources shrank by about 2 percent from 1990 to 2020, followed by an increase of 11 percent from 2020 to 2021, an overall increase of 8.8 percent from 1990 to 2021. This difference in growth is due largely to the rapid increase in emissions associated with medium- and heavy-duty trucks.
Oil spills in and around U.S. waterways
Water quality is affected by oil spills from vessels and
pipelines transporting crude oil and petroleum products and by facilities, such
as offshore drilling units and platforms. In 2021 vessel-related spills
accounted for 68.6 percent of total gallons spilled. Since 2000 significant
reductions were reported in the number of all oil-spill incidents and in the
total gallons of oil spilled, 75.8 and 93.1 percent, respectively.
U.S. Department of Transportation, Bureau of Transportation Statistics, Freight Facts and Figures (Washington, DC: 2019).
Freight Facts and Figures, developed by the Bureau of
Transportation Statistics, is a collection of charts and statistical
tables about freight transportation in the United States. These
interactive visualizations and tables provide a snapshot of freight
movement; the extent, condition, and performance of the freight
transportation system; the economic implications of freight movement;
and the safety, energy, and environmental impacts of freight