Traffic jam In modern society, citizens are frequently caught up in a traffic jam. Most people do not know the reason why a traffic jam happens and why it is not prevented. An article from the BBC says the reasons and suggests a solution with a cutting-edge technology. Traffic jams are caused by some factors. One of the main factors, many people do not know, is a fluctuation of car speed. mathematicians and other scholars has said and demonstrated that if one car frequently up and down speed, others following the car cannot drive fast. Therefore, a car cluster drive slower and slower, finally stopping and creating a new traffic jam. It is said that the solution for the problem is to equip the new technology which controls a car automatically. The equipment can drive safer than humans with speed regulated. Keeping speed is crucial to diminishing congestions. Cars with the same speed on the high way do not need to stop, so that all can keep pace. On the condition, people can reach their distention with a shortest time.