Truck fuel consumption increased by 3.0 percent from 2009 to 2019 while truck
vehicle-miles traveled increased slightly more (4.1 percent). Fuel use in Class I freight railroads
increased by 7.1 percent, from about 3.2 billion gallons to 3.4 billion gallons for the same period.
Energy consumption by select freight transportation modes
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
Miles per gallon of single-unit trucks (based on total travel
and fuel consumption) increased
by 1.8 percent from 7.4 gallons to 7.5 gallons over the 2009 to 2019 period,
and total fuel consumption declined slightly as single-unit trucks traveled 20.9
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) remained relatively stable between 2009 and 2019. However, like single-unit trucks, combination truck fuel consumption increased slightly, as the average miles
traveled per vehicle declined by 6.7 percent.
Energy intensities of domestic freight transportation modes
Energy 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 2008, the energy intensity of trucking has decreased by 27.4 percent while rail has remained relatively stable.
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
In 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 28.7 percent of all greenhouse gases emitted in
the United States in 2019,
second only to the industrial sector, which produced the largest amount of GHG
emissions (29.7 percent).
U.S. transportation sector carbon dioxide (CO2) emissions from fossil fuel combustion by fuel type
The transportation sector is
responsible for 35.9 percent of total U.S. CO₂ emissions from fossil
fuel combustion in 2019. 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 58.6 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 2019,
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.
U.S. greenhouse gas emissions from domestic freight transportation
gas emissions from freight has increased, while passenger transportation sources increased until 2018 before decreasing in 2019. Freight emissions increased at a faster rate, (9.7 percent) than that
of passenger (2.5 percent).
Between 2015 and 2019, pipeline
emissions rose by 39.5 percent followed by water modes at 27.5, commercial aircraft emissions at 17.0 percent, and truck at 7.5 percent. An increase in the volume of freight
movements by the pipeline, air, and truck modes contributed to the rise in
their emissions between 2015 and 2019.
Greenhouse gas emissions from the rail declined by 7.2 percent over the same period.
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 2020 vessel-related spills
accounted for 40.3 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, 73.7 and 87.3 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