一、引言随着经济的迅速增长,我国高速公路建设正处于一个蓬勃发展期。特别是1998年以来,国家实施积极的财政政策,高速公路得到快速发展,年均通车里程超过了4000公里,到2004年底,中国高速公路通车里程已超过3.4万公里,继续保持世界第二。随着全国通车总里迅速增长,运网日益通畅,公路出行成为越来越普遍的方式,高 I. Introduction With the rapid economic growth, China’s expressway construction is in a period of vigorous development. Especially since 1998, when the state implemented a proactive fiscal policy, the expressway developed rapidly with an average annual mileage of more than 4,000 kilometers. By the end of 2004, the mileage of the expressway in China had exceeded 34,000 kilometers and remained the second in the world. With the rapid growth of the whole country and the opening up of the whole country and the smooth growth of the transportation network, highway travel has become an increasingly common way with high