一、大、中城市进出口公路的形成公路穿过大、中城市,过境车辆和以城区内为起讫点的车辆,都要进出城市,则靠近城市的一段公路即形成了城市进出口公路。这样,过境交通和以城区内为起讫点的车辆,就会同市内交通相互干扰,降低行车速度,甚至会产生拥挤、阻塞,而且还会增多交通事故和运输成本,降低 First, the formation of large and medium-sized cities import and export of highways Road through the large, medium-sized cities, transit vehicles and to start and end of the urban area of ​​the vehicle, must enter and exit the city, the road close to the city that formed the city import and export highway. In this way, cross-boundary traffic and vehicles starting from and within the urban areas will interfere with the traffic in the city, reducing the speed of traffic and even causing congestion and congestion. Traffic accidents and transportation costs will also be increased and the costs will be reduced.