In central city like Jakarta, there are some reasons why traffic jam occurs. First, population of vehicle increases. Population of vehicle in Indonesia reached 50,824,128 units or sixth largest in the world. Indonesia’s population reached 234.69 million people in 2010. So, the ratio of Indonesia’s population to the population of vehicle is one unit of vehicle versus 4.6 persons. It means every 4.6 people in Indonesia have a vehicle, either car or motorcycle. Next, indicipline people. For example, public transport drivers often stop at any part of street for a long time. They sometimes cut their way, break the law of traffic regulation, and drive with high speed that can endanger other road users. Last, unadequate infrastructure. The length of roads in Indonesia reached 368,360 kilometers until last year. It means the ratio of the length of road motor vehicles in Indonesia reached 138 units / kilometer. Furthermore, infrastructure grew only 0.1 percent per year. In conclusion, the government should make the rules that optimizing vehicle using–for example, one big car for five persons, must maintain supremacy of law, and increase the growth of infrastructure.