Currently, traffic jams are a common phenomenon in a growing number of cities. While, People living in these cities still continue using private cars rather than public transport facilities . In this essay, I will investigate the reasons contributing to these problems. Firstly, with the rapid development of economy and society, more and more people have bought private cars, even some family have more than one private car. Secondly, there is a trend that a lot of people don’t obey traffic rules, illegal parking in public places can be seen everywhere. Lastly, the public transport facilities aren’t pretty perfect. When we want to go some places, existing public transport can’t make it. Certainly, private cars have many merits. This is the factors why people go on using private cars even if traffic is very terrible.