The U.S., widely considered to have the most developed highway system in the world, has already discovered that the amount of energy required to get a given amount of goods or a given number of people from one place to another requires the investment of ever more resources.
被認為公路運輸系統最發達的美國，也已發現：美國人為了將同等量的貨物與旅客從一地運到另一地，必需輸入的能量愈來愈多。