„Fast
racts
U.S.Transportation Sector
Greenhouse Gas Emissions
1990-2019
United States
Environmental Protectior
M % Agency
Office of Transportation and Air Quaiity
EPA-420-F-21-076
December 2021

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Mobile Sources
Transportation
Non-Transportation Mobile
Highway Vehicles
Agricultural Equipment
Aircraft
Construction & Mining Equipment
Ships & Boats
Lawn & Garden Equipment
Rail
Logging Equipment
Lubricants
Recreational Equipment
Pipelines1

Transportation Emissions of the United States
The transportation sector is one of the largest contributors to anthropogenic greenhouse gas
(GHG) emissions in the United States. According to the Inventory of US. Greenhouse Gds Emis-
sions and Sinks 1990-2019 (the Inventory), the national inventory that the U.S. prepares annually
under the United Nations Framework Convention on Climate Change (UNFCCC), the transpor-
tation sector accounted for the largest portion (29%) of total U.S. GHG emissions in 2019. Cars,
trucks, commercial aircraft, and railroads, among other sources, all contribute to transportation
end-use sector emissions. Within the sector, light-duty vehicles (including passenger cars and
light-duty trucks) were by far the largest category, with 58% of GHG emissions, while medium* and
heavy-duty trucks made up the second largest category, with 24% of emissions. Between 1990 and
2019, GHG emissions in the transportation sector increased more in absolute terms than any
other sector (i.e. electricity generation, industry, agriculture, residential, commercial), due in large
part to increased demand for travel.
Greenhouse gas emissions from transportation sources include carbon dioxide (C02), methane
(CH4), nitrous oxide (N20), and various hydrofluorocarbons (HFCs). C02, CH4, and N20 are all
emitted via the combustion of fuels, while HFC emissions are the result of leaks and endof-life
disposal from air conditioners used to cool people and/or freight.2
When including emissions from non-trdnsportdtion mobile sources such as agricultural, lawn
and garden, and construction equipment, mobile sources constituted 32% of total U.S. GHG
emissions in 2019.
Transportation
29%
Share of U.S. Transportation Sector
GHG Emissions by Gas, 2C194
Note: Totals may not add to 100% due to rounding.
Share of U.S. GHG Emissions
by Sector, 20193'4
Note: Totals may not add to 100% due to rounding.
Share of U.S. Transportation Sector
GHG Emissions by Source, 2C194'5
Note: Totals may not add to 100% due to rounding.
Residential
6%
Commercial
7%
Electric Power
Industry
25%
griculture
10%
Industry
23%
Light-Duty
Vehicles
All Other
Transportation
Sources*
5%
Ships & Boats
2% v
Aircraft
10%
1	Pipeline emissions in the transportation sector include only C02 from the combustion of natural gas at compressor stations that power
natural gas pipelines, not emissions from electricity use, non-C02 gases, or other types of pipeline equipment. Not that natural gas pipeline
compressor stations are stationary equipment that are included in the transportation sector, but are not considered mobile sources.
2	C02 emissions from the combustion of biofuels are not directly included in the energy sector contribution (which includes the contribution
of transportation and non-transportation mobile sources) to U.S. totals in the Inventory; instead, net carbon fluxes from changes in biogenic
carbon reservoirs are accounted in the estimates for Land Use, Land-Use Change, and Forestry in the Inventory. See Page 4 for more
information on the Inventory.
3	For presentation purposes, emissions from territories which constitute less than 1% of the total U.S. GHG emissions, are not shown in
this chart, although they are included in the total emissions used to calculate the percentage share of emissions from each sector.
See Table ES-6 in the Executive Summary of the Inventory for official data. See page 4 for more information on the Inventory.
4	"Transportation" emissions in these pie charts include C02, N20, CH4, and HFCs from transportation sources like highway vehicles,
aircraft, ships and boats, rail, pipelines and lubricants. They do not include emissions from non-transportation mobile sources such as
agriculture and construction equipment.
5	"Other" sources include buses, motorcycles, pipelines, and lubricants.

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U.S.Transportation GHG Emissions
(Tg C02 Equivalent)
Change from
1990 to 2019
U.S.Transportation GHG Emissions by Gas, 2019
(Tg C02 Equivalent)
Source	1990 2005 2015 2016 2017 2018 2019 Absolute Percent
On-Road Vehicles6
1,206.8
1,647.4
1,510.5
1,534.6
1,540.7
1,563.9
1,555.7
348.9
28.9
Passenger Cars
639.6
691.7
752.5
763.5
760.6
770.3
762.3
122.8
19.2
Light-Duty Trucks
326.7
537.7
320.9
330.2
324.3
325.7
323.1
-3.6
-1.1
Motorcycles
1.7
1.6
3.7
3.9
3.8
3.8
3,6
1.9
111.4
Buses
8.5
12.3
19.6
19.1
20.6
22.0
22.2
13.7
162
Medium- and Heavy-
Duty Trucks
230.3
404.1
413.9
417.9
431.4
442.1
444.4
214.1
92.9
Aircraft
189.2
193.6
160.5
169.0
174.8
175.5
181.1
-8.1
-4.3
Commercial Aviation
110.9
134.0
120.1
121.5
129.2
130.8
135.4
24.5
22.1
Military Aircraft
35.3
19.5
13.6
12.4
12.3
11.9
12.0
-23.3
-66.1
General Aviation
42.9
40.1
26.8
35.1
33.3
32.8
33.7
-9.3
-21.6
Ships and Boats
47.0
45.4
33.8
40.8
43.9
41.2
40.4
-6.6
-14.0
Rail
35.8
46.6
40.3
36.8
38.1
39.9
37.6
1.8
4.9
Pipelines7
36.0
32.4
38.5
39.2
41.3
49.9
53.7
17.7
49.2
Lubricants
11.8
10.2
11.0
10.4
9.6
9.2
8.9
-3.0
-24.9
Transportation Total
1,526.6
1,975.6
1,794.6
1,830.7
1,848.3
1,879.6
1,877.4
350.8
23.0
U.S. Non-Transportation Mobile GHG Emissions
Non-Transportation
Mobile8
167.3
224.9
192.4
195.4
201.9
207.6
211.5
44.2
26.4
Agricultural Equip.
44.8
52.6
42.4
41.4
41.0
41.0
40.8
-4.0
-8.9
Construction Equip.
50.3
78.5
58.7
61.8
67.0
70.2
72.3
22.0
43.7
Other
72.2
93.8
91.3
92.2
93.9
96.4
98.4
26.2
36.3
Non-Transportation +
Transportation Total
1,693.9
2,200.5
1,987.0
2,026.0
2,050.2
2,087.2
2,088.9
395.0
23.3
Source
o
o
ch4
n2o
HFCs
Total
Percent
On-Road Vehicles6
1,512.7
0.9
9.3
32.7
1,555.7
74.5
Passenger Cars
748.3
0.4
4.4
9.3
762.3
36.5
Light-Duty Trucks
304.3
0.2
1.7
16.9
323.1
15.5
Motorcycles
3.6
0.0
0.0
0.0
3.6
0.2
Buses
21.4
0.2
0.1
0.4
22.2
1.1
Medium- and Heavy-
Duty Trucks
435.2
0.1
3.0
6.1
444.4
21.1
Aircraft
179.4
0.0
1.6
0.0
181.1
8.7
Commercial Aviation
134.2
0.0
1.2
0.0
135.4
6.5
Military Aircraft
11.9
0.0
0.1
0.0
12.0
0.6
General Aviation
33.3
0.0
0.3
0.0
33.7
1.6
SW(5S3and Boats
35.9
0.4
0.2
3.9
40,4
1.9
Rail
37.1
0.1
0.3
0.1
37.6
1.8
Pipelines7
53.7
0.0
0.0
0.0
53.7
2.6
Lubricants
8.9
0.0
0.0
0.0
8.9
0.4
Transportation Total
1,827.8
1.4
11.5
36.7
1,877.4
89.9

Rail Electricity
3.07
0.00
0.06
0.00
3.14
NA
U.S. Non-Transportation Mobile GHG Emissions by Gas, 2019
Non-Transportation
Mobile8
204.1
0.9
6.5
0.0
211.5
10.1
Agricultural Equip.
39.7
0.1
1.1
0.0
40.8
2.0
Construction Equip.
70.3
0.2
1.9
0.0
72.3
3.5
Other
94.1
0.6
3.6
0.0
98.4
4.7
Non-Transportation +
Transportation Total
2,031.8
2.4
18.0
36.7
2,088.9
100.0
Change in GHG Emissions by Source: 1990-2019
I Light Duty Vehicles ¦ Medium-and Heavy-Duty Trucks BAircraft ¦ Rail ¦ Non Transportation Mobile Sources ¦ All Other Transportation Sources ¦ Ships and Boats
GHG emissions and vehicle miles traveled (VMT) estimates foron-road
vehicles presented in the Inventory are based on Federal Highway Admin
istration (FHWA) data. In 2011 FHWA changed its methods for estimated VMT
and related data, leading to a shift in emissions among on-road vehicle
classes. These methodological changes included how vehicles are classified,
moving some smaller trucks and sport utility vehicles from the light truck
category to the passenger vehicle category in this Inventory. These changes
in VMT data by vehicle class were first incorporated in the 1990 through 2008
Inventory and apply to the 2007 to 2019 time period.
Includes only C02 from natural gas used to power natural gas pipelines; does
not include emissions from electricity use or non-C02 gases.
Note: non-transportation C02 emissions estimates are presented here and
in Annex 3.2 of the Inventory for informational purposes, but these emissions
are officially accounted for in other energy sectors in the Inventory (i.e., indus
trial, residential, commercial sectors) using a different method. See Annex 3.2
of the Inventory for more information.	^
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

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2019 Fuel Consumption

Volume
(billion gallons unless
otherwise specified)
Energy (Tbtu)
C02 (Tg)
MOTOR GASOLINE
129.5
16,079.1
1,136.0
Transportation9
Passenger Cars
84.5
10,505.5
742.3
Light-Duty Trucks
32.9
4,091.7
289.1
Medium- and Heavy-Duty Trucks
4.6
567.4
40.1
Motorcycles
0.4
50.6
3.6
Buses
0.1
14.2
1.0
Recreational Boats
1.2
151.7
10.7
Non-Transportation Mobile10
Agricultural Equipment
0.1
15.6
1.1
Construction Equipment
0.4
46.5
3.3
Other Non-Transportation Mobile
5.3
635.9
44.8
DISTILLATE FUEL
60.1
8,335.4
618.0
Transportation9
Passenger Cars
0.4
61.6
4.6
Light-Duty Trucks
1.4
200.7
14.9
Buses
1.9
260.3
19.3
Medium- and Heavy-Duty Trucks
38.4
5,324.6
394.8
Recreational Boats
0.3
39.2
2.9
Ships and Boats
0.7
101.9
7.6
Rail
3.6
500.2
37.1
Non-Transportation Mobile10
Agricultural Equipment
3.7
519.0
38.5
Construction Equipment
6.5
896.5
66.5
Other Non-Transportation Mobile
3.1
431.4
32.0
RESIDUAL FUEL OIL
1.3
196.0
14.7
Ships and Boats
1.3
196.0
14.7
JET FUEL
18.2
2,461.9
177.8
Commercial Aircraft
14.1
1907.8
134.2
General Aviation Aircraft
3.0
403.2
31.7
Military Aircraft
1.1
150.9
11.9
AVIATION GASOLINE
0.2
23.4
1.6
General Aviation Aircraft
0.2
23.4
1.6
ELECTRICITY (Billion Kilowatt hours)
11.7
39.8
4.7
Transportation
Passenger Cars
3.5
11.9
1.4
Light-Duty Trucks
0.5
1.8
0.2
Buses
0.1
0.2
0.0
Agricultural Equipment
7.6
25.8
3.1

Volume
(billion gallons unless
otherwise specified)
Energy (Tbtu)
C02 (Tg)
NATURAL GAS (billion cubic feet)
1,046.6
1,086.4
57.5
Transportation
Passenger Cars
0.1
0.1
0.0
Light-Duty Trucks
0.2
0.2
0.0
Medium- and Heavy-Duty Trucks
0.8
0.8
0.0
Buses
17.6
18.3
1.0
Pipelines
978.6
1,015.8
53.7
Non-Transportation Mobile10
Agricultural Equipment
1.5
1.6
0.1
Construction Equipment
6.3
6.6
0.3
Other Non-Transportation Mobile
41.5
43.0
2.3
LPG
2.7
249.3
15.7
Transportation
Passenger Cars
0.0
0.0
0.0
Light-Duty Trucks
0.0
1.2
0.1
Medium- and Heavy-Duty Trucks
0.1
4.8
0.3
Buses
0.0
1.6
0.1
Non-Transportation Mobile10
Agricultural Equipment
0.0
0.0
0.0
Construction Equipment
0.0
2.5
0.2
Other Non-Transportation Mobile
2.6
239.3
15.0
LUBRICANTS
0.0
1.0
8.9
Total11
220.8
28,472.3
2,034.9

BIOFUELS12
15.4
1,381.3
95.8
Transportation
Biodiesel
1.8
231.3
17.1
Ethanol
13.6
1,150.2
78.7
9	Excludes contributions from biofuels.
10	Non-transportation mobile fuel consumption, energy, and C02 are estimated based in part on the MOVES-Nonroad model
(see www.epa.gov/moves). Because the fuel consumption in MOVES-Nonroad is intended to reflect real-world usage, these estimates
may include low-level ethanol blends. Note that these estimates are presented here and in Annex 3.2 of the Inventory for informational
purposes, but that non-transportation mobile source C02 emissions are officially accounted for in other energy sectors in the Inventory
(e.g., the industrial sector) using a different method and do not include emissions from biofuels.
11	Total Volume is the sum of physical (billion) gallons of fuel; because natural gas volumes are reported as million cubic feet, natural gas
volumes are converted to billion gallons of gasoline equivalent for the Total Volume (billion gallons) sum in this table.
12	Biofuels are presented as line items below the total for informational purposes only, in line with IPCC methodological guidance and
UNFCCC reporting obligations. Biofuel estimates only reflect transportation sources and do not include biofuels used in non-transportation
mobile sources, e.g., ethanol used in commercial or industrial applications. C02 emissions from the combustion of biofuels are not directly
included in the energy sector contribution (which includes the contribution of transportation sources) to U.S. totals in the Inventory; instead,
net carbon fluxes from changes in biogenic carbon reservoirs are accounted in the estimates for Land Use, Land-Use Change, and
Forestry in the Inventory. See page 4 for more information on the Inventory.

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Additional Information
Data Sources for This Document
The source for all data in this document is the Inventory of U.S. Greenhouse Gds Emissions and
Sinks 1990-2019 (EPA 2021). The U.S. Environmental Protection Agency prepares the inven-
tory annually to fulfill the U.S. commitment under the United Nations Framework Convention
on Climate Change (UNFCCC), using calculation methods that are consistent with guidelines
from the Intergovernmental Panel on Climate Change (IPCC). Complete information on the
inventory is available at: www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-
sinks. The inventory methods and assumptions related to transportation and non*transportation
mobile sources are available in the main body of the Inventory as well as Annex 3.2 of the
Inventory.
Inventory Definitions of Selected Transportation Categories13
Passenger Cars:14 automobiles used primarily to transport 12 people or less. In
2019, passenger cars traveled a total of 2,254,309 million vehicle miles.
Light-Duty Trucks:14 vehicles used primarily for transporting light-weight cargo
or which are equipped with special features such as four-wheel drive for off-road
operation. In the U.S., this category also includes many vehicles that primarily
transport passengers such as sport utility vehicles (SUVs) and minivans. The
gross vehicle weight rating (GVWR) normally ranges around 8,500 pounds or
less. GVWR is the maximum weight a vehicle is designed to carry when pas-
sengers, fuel, cargo, and any other additions to the vehicle are accounted for. In
2019, light-duty trucks traveled a total of 669,744 million vehicle miles.
Medium- and Heavy-Duty Trucks:14 vehicles with GVWR of more than around
8,500 pounds. In the Inventory, single unit trucks and combination trucks rep-
resent the medium- and heavy-duty truck category, including tractor-trailers and
box trucks used for freight transportation. In addition, this category includes
some vehicles that are not typically used for freight movement such as service
and utility trucks. In 2019, medium- and heavy-duty trucks traveled a of 318,030
million vehicle miles.
Pipelines: systems that transport liquids, gases, or slurries through either
above or below ground pipes. In the Inventory, the pipelines category includes
emissions from the combustion of natural gas used to power pumps and other
distribution equipment, while leaks and other emissionsources from pipelines
are assigned to the natural gas systems category.
Emissions Metrics
A teragram (Tg) is equal to 1 million metric tons.
Greenhouse gas (GHG) emissions are measured in this document in terms of teragrams of
"carbon dioxide equivalent" (C02 Eq); an "equivalent" refers to the Global Warming Potential
(GWP) of a greenhouse gas. GWP values are determined based on the chosen time horizon and
properties of the gas, such as its ability to absorb radiation and its atmospheric lifetime. C02 has
a GWP of "1"; all other greenhouse gases have GWP values relative to that of C02. For example,
methane (CH4) has a radiative forcing value or GWP of 25, which means that releasing one ton
of (CH4 is equivalent to releasing 25 tons of C02.
The data in this document is based on the 100-year time horizon GWP values from the IPCC's
Fourth Assessment Report 15, in accordance with UNFCCC reporting guidelines for national
GHG inventories. More information on greenhouse gases and GWP is available at:
www.epa.gov/ghgemissions/overview-greenhouse-gases.
13	The data used to estimate emissions for specific transportation categories may not directly align with the
Inventory's definition of the categories; both the data and Inventory definitions may also differ from EPA's
regulatory definitions for the same categories.
14	GHG emissions and vehicle miles traveled (VMT) estimates for on-road vehicles presented in the Inventory
are based on Federal Highway Administration (FHWA) data. In 2011 FHWA changed its methods for estimated
VMT and related data, leading to a shift in emissions among on-road vehicle classes. These methodological
changes included how vehicles are classified, moving some smaller trucks and sport utility vehicles from the light
truck category to the passenger vehicle category in this Inventory. These changes in VMT data by vehicle class
were first incorporated in the 1990 through 2008 Inventory and apply to the 2007 to 2019 time period.
15	See www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf.
4

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