高速公路具有行车速度快,科技含量高,服务功能完善,安全可靠等特点,因此世界各国都非常重视高速公路的建设,并投入大量资金建设高速公路。各国政府对高速公路建设的大量投资,保证了高速公路建设的迅速发展,基本满足了各国国民经济飞速发展的需要。就目前而言,美国用于高速公路建设的投资占国内生产总值的2.4%,日本 Expressway has the characteristics of fast driving speed, high technology content, perfect service function and safe and reliable. Therefore, all countries in the world attach great importance to the construction of expressway and invest a lot of money in the construction of expressway. The massive investment made by the governments in the expressway construction has ensured the rapid development of expressway construction and basically met the needs of the rapid economic development of various countries. For now, U.S. investment in highway construction accounts for 2.4% of GDP, with Japan