ECO-FRIENDLY TRAVEL

Emissions From the Different Modes of Passenger Transportation

In 2019, CO2 emissions from personal vehicles averaged 0.47 pounds per passenger mile.⁶ Average emissions from other modes of passenger transportation—heavy- and light-rail transit, passenger railroads, commercial air travel, and bus—were all lower per passenger mile. Emissions from bus transportation averaged 0.39 pounds of CO2 per passenger mile in 2019; that average encompasses several kinds of bus operations with varying emissions. Transit buses, for example, averaged 0.95 pounds per passenger mile, largely because they often operated at only a fraction of their capacity. (Emissions per passenger-mile decline as the number of occupants increases.) Emissions of CO2 from intercity buses (including charter buses and tour buses, which are sometimes referred to as motorcoaches) were much lower, averaging 0.15 pounds per passenger mile, slightly less than the average for rail transit.

Traffic congestion and travel speeds, which are influenced by travel growth, can affect the efficiency with which motor vehicles burn fuel and produce emissions. An extra 0.04 BMT of greenhouse gases—about 2 percent of all transportation-related emissions—were emitted in 2019 as a result of congestion.⁷