大城市交通拥挤探因(The Causes of Traffic CongesUon in Big Ci

1．大城市普遍交通拥挤；
2．导致大城市交通拥挤的原因。
[写作导航]第一段可作为介绍段，讲交通拥挤很普遍，人们很关心并时有抱怨，因为给工作和生活带来了不便；第二段可写成转折段，承上启下，引起第三段讲原因；三段集中讲原因，可从私车增加、路况较差、管理水平不高、人们对交通法规意识淡薄等方面入手；第四段收尾。
[范文]
    Traffic congestion has long been a problem of great concern and complaint in big cities. It has caused a lot of inconvenience to people's life and work. For example, people have to set off well in advance to get to work on time and come back very late when their work is over.
    There are many causes for this problem, but the following may be the most important ones.
    The first cause is the great increase in the number of private cars. Cars take up more space but they carry fewer people. Some private car drivers, ignoring traffic regulations, drive only for the sake of their own convenience, blocking the way of other public transportation vehicles. The second cause is the slow and inefficient construction and improvement of the roads and streets. With a large population and numbers of automobiles increasing, some roads still remain unimproved, which will surely lead to problems. The last cause is the insufficient management of the traffic system and the people's lack of awareness of traffic regulations. Many pedestrians cross the streets even when the traffic lights are against them, which is an obstacle to the flow of traffic.
    The problem of traffic congestion is an urgent one because it concerns the safety allofus. Wewillnot resolve it if we only rely on the government. Let all of us act now to solve it.