Energy Intensity of Transit Motor Buses (Metric)

KEY: KWH = Kilowatt hour; N = data do not exist.

^a Before 2002, Other major fuels includes liquefied petroleum gas, methanol, ethanol, and bunker fuel. From 2002 - 13, Other major fuels includes liquefied petroleum gas, methanol, ethanol, bunker fuel, kerosene, and grain additive. After 2013, other major fuels includes liquefied petroleum gas, ethanol and hydrogen.

^bPower includes electric propulsion and electric battery.

Average Fuel Efficiency of U.S. Light Duty Vehicles (metric)

KEY: CAFE = Corporate Average Fuel Economy; GVWR = gross vehicle weight rating; kmpl = kilometers per liter; R = revised; U = data are not available.

^a Data from 2007 were calculated using a new methodology developed by FHWA. Data for these years are based on new categories and are not comparable to previous years. The new category Light duty vehicle, short wheel base replaces the old category Passenger car and includes passenger cars, light trucks, vans and sport utility vehicles with a wheelbase (WB) equal to or less than 121 inches. The...

Energy Intensity of Light Duty Vehicles and Motorcycles

KEY: Btu = British thermal unit; N = data do not exist; U = data are not available.

a Motorcycle was included in Light duty vehicle, short wheel base (previously Passenger car) in 1960 and 1965.
b 1960-99 data are for Passenger car and Other 2-axle, 4-tire vehicles, respectively. The data from 1960-2006 are not comparable to the data from 2007-15.
c Energy Intensity (Btu/passenger-mile) is calculated by converting the fuel consumption in gallons to the energy equivalent Btu units and dividing by the passenger-miles. The heat equivalent factor used for Btu...

Energy Intensity of Certificated Air Carriers, All Services (Metric)

KEY:  R = revised.

^a U.S. owned carriers only. Operations of foreign-owned carriers in or out of the United States not included.

Petroleum Oil Spills Impacting Navigable U.S. Waterways

KEY: N = data do not exist; R = revised.

^a Other vessels include commercial vessels, fishing boats, freight barges, freight ships, industrial vessels, oil recovery vessels, passenger vessels, unclassified public vessels, recreational boats, research vessels, school ships, tow and tug boats, mobile offshore drilling units, offshore supply vessels, publicly owned tank and freight ships, as well as vessels not fitting any particular class (unclassified).

^bOther nonvessel sources include deepwater ports, designated...

U.S. Carbon Dioxide Emissions from Energy Use by Sector

KEY:  CO2 = carbon dioxide; R = revised; Z = a value of zero, or value too small to report.

^a  Hydrocarbon Gas Liquids (HGL) includes ethane, propane, normal butane, isobutane, and natural gasoline, and their associated olefins. Excludes Liquified Natural Gas (LNG). 

Air Pollution Trends in Selected Metropolitan Statistical Areas

KEY:  AQI = Air Quality Index; R = revised.

Estimated U.S. Emissions of Sulfur Dioxide

KEY: R = revised.

^aIndustrial processes consists of chemical and allied product manufacturing, metals processing, petroleum and related industries, and other industrial processes; solvent utilization; and storage and transport. 

Estimated U.S. Emissions of Carbon Monoxide

KEY: R = revised. 

^aIndustrial processes consists of chemical and allied product manufacturing, metals processing, petroleum and related industries, other industrial processes; and solvent utilization, storage, and transport.

Estimated National Average Vehicle Emissions Rates per Vehicle by Vehicle Type Using Reformulated Gasoline and Diesel

KEY:  CO = carbon monoxide; HC = hydrocarbon; NOx = nitrogen oxide; RFG = reformulated gasoline; R = revised.