A combination of factors: government subsidization of roads and highways more than public transportation, powerful auto, oil and tire corporations, and a culture that glamorized the automobile.

• 可以说这是几方面原因的综合结果：政府对高速公路的财政补贴政策远多于对公共交通的补贴政策,汽车、汽油和轮胎企业的强大力量以及使得汽车更加诱人的美国“汽车文化”。