目前，我国公路交通事业已得到了飞速的发展，并进入了向高等级公路发展的新阶段。一方面，公路建设、特别是高等级公路建设的加快，公路里程的快速增长，根据最近公布最新统计数字，截止到１９９９年年底，我国公路通车里程已达１３３．６万ｋｍ；另一方面，交通流量大幅度提 At present, China’s road transport industry has witnessed rapid development and has entered a new phase of development to high-grade highways. On the one hand, highway construction, especially the construction of high-grade highways and the rapid growth of highway mileage, have reached 1.336 million km by the end of 1999, according to the latest statistics released. On the other hand, Traffic flow significantly raised