设想与选题的由来人们经常可以看到城市中交通堵塞的现象,引起交通堵塞的原因之一是交通要道上有很多车辆需要交叉通行,例如:在交叉路口,交通信号灯定时地只允许某一条道路上的车辆通行,不允许其它道路上的车辆同时通行;引起交通堵塞的原因之二是在道路上进行敷设管道、整修道路等施工作业,所以车辆一般都得绕道通行,一直要等到施工结束后才能恢复通车;引起交通堵塞的原因之三是发生了交通事故等意 One of the causes of traffic congestion is that many vehicles in the traffic routes need to cross traffic. For example, traffic lights can only allow one traffic at a time Vehicles on roads do not allow vehicles on other roads to pass at the same time. The second reason for causing traffic congestion is construction work such as laying pipelines and renovating roads on roads. Therefore, vehicles generally have to bypass and wait until the construction is completed After that, the traffic jam was caused by traffic accident