As the modern transportation facilities, freeway has become an important traffic mode that adapts to the development of the modern industries with large traffic flow, quick speed, well facilities and comfortable journey.

• 高速公路作为现代化的交通运输基础设施，以其交通流量大、行车速度快、设备完善、运行舒适等特点，已成为适合现代产业结构发展需求的重要运输方式。 随着当前国内社会经济的飞速发展，高速公路路网通行能力已逐渐不能满足交通量增长的需要，交通拥挤和堵塞现象日益严重，交通事故和污染问题正引起社会的普遍关注。