今天，道路运输已成为最重 要的地面运输方式之一。进入 ９０年代以来，世界各国交通拥堵、交通事故、环境污染越来越影响着社会经济的发展，虽然道路运输增长需求可以靠提供更多的道路设施来满足，但是，在资源、环境矛盾越来越突出的今天，道路设施的增长将受到限制，这就需 Today, road transport has become one of the most important ground transportation modes. Since the 90s of the 20th century, traffic congestion, traffic accidents and environmental pollution have increasingly affected the development of the society and economy in all countries in the world. Although the demand for road transport growth can be met by providing more road facilities, more and more resources and environmental conflicts have arisen The more prominent today, the growth of road facilities will be limited, which is required