Energy used by cars, trucks, buses, planes, ships, trains, and pipelines accounted for 27.6% of total U.S. energy use in 2021, making transportation the second largest user of energy in the economy, behind only electricity generation (Figure 6-1).China and the Russian Federation are the only two countries that consumed more energy for transportation. Specifically, the U.S. transportation system used 26.9 quadrillion Btu of energy to generate five trillion passenger-miles of travel and five trillion ton-miles of freight. From a global perspective, the U.S. accounts for about 17% of world energy use and 15% of global greenhouse gas (GHG) emissions.

“Automated vehicle development is advancing across all transportation modes. There are 39 state-level jurisdictions actively engaged in permitting testing or full deployment of driverless highway vehicles in 2022, more widespread autonomous port systems and ships, and the use of Positive Train Control in railroads, BTS said.