一、高速道路的作用及特点高速道路分为高速公路和城市高速道路两类。高速道路的优越性是多方面的。首先,它具有高速、舒适的行驶条件。一般日交通量可达5万Pcu/d(当量小汽车/每日),行驶速度达到120公里/小时。城市高速道路,一般为80公里/小时,对加快运输周转起到很好作用。第二,高速道路的交通事故比一般道路少。为保证高速行驶,高速道路只允许快速机动车行驶,禁止慢车及人畜等通行。为避免对 First, the role and characteristics of highways Highways are divided into two types of highways and urban highways. The advantages of highways are manifold. First of all, it has high speed and comfortable driving conditions. The daily traffic volume can reach up to 50,000 Pcu/d (equivalent car/daily) and the speed can reach 120 km/h. Urban highways, typically 80 km/h, play a good role in accelerating transport turnover. Second, there are fewer traffic accidents on highways than on ordinary roads. In order to ensure high-speed driving, high-speed roads only allow fast motorized vehicles, prohibiting slow vehicles, humans and livestock. To avoid