采用快速、大运量的拖挂车辆，是提高运输效率、降低运输费用的重要和必要的途径。美国的高速公路全部是立体空间交会，没有停车等候问题，也很少有途中发生故障的停车维修，无论是双车道，还是四车道，所有大小车辆，都是前后成串，以90～110km/h的速度高速行驶，形成滚滚车流 The use of fast, high-volume trailers, is to improve transport efficiency and reduce transport costs, an important and necessary way. The U.S. highways are all three-dimensional space rendezvous, there is no parking waiting problem, and there are few parking maintenance problems on the way, whether it is two-lane or four-lane. All the vehicles of all sizes are in a series of 90-110km / h speed of high-speed driving, the formation of rolling traffic