>The National Academies of Sciences, Engineering, and Medicine reports that 28 percent of energy used in the United States is for transportation, moving people and goods. Transport vehicles in this context include automobiles, motorcycles, trucks (light, medium, and heavy‐duty), buses, trains, aircraft, and watergoing vessels. Of these vehicles, approximately 58 percent of the related energy use is from cars, light‐duty trucks, and motorcycles, with the remaining shares being other trucks (23 percent), aircraft (8 percent), boats and ships (4 percent), and trains and buses (3 percent). Pipelines account for 4 percent of transportation energy use, transporting liquids and gases across the United States. It is worth noting that greenhouse gas (GHG) emissions reported by the US Environmental Protection Agency (EPA) are greatest in the transportation sector (29 percent), followed by electricity (28 percent), industry (22 percent), commercial and residential (22 percent), and agriculture (9 percent), as illustrated in Figure 1. This suggests, as many know, that any serious effort to reduce GHG emissions—as many states and municipalities and businesses and consumers have pledged—requires reducing energy use and, therefore, GHG emissions in the transportation sector. 展开▼
