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美国高速公路网为世界第一大网络。全国拥有高速公路里程为68000公里,多数为双向六车道的州际高速公路(ＩｎｔｅｒｓｔａｔｅＨｉｇｈｗａｙ)。速度限制基本为75英里(120公里)/每小时。在这样的道路系统中,重型卡车自然而然地成为全美货物运输的支柱。重型卡车的年更换量在1998
The U.S. highway network is the largest network in the world. The country has 68,000 kilometers of highway mileage, most of which are two-way six-lane interstate highways. The speed limit is basically 75 miles (120 km) / hour. In such a road system, heavy-duty trucks naturally become the backbone of the nation’s cargo transport. The annual replacement of heavy trucks in 1998