In order to pass the driving test, drivers need to learn many things in driving schools before they can having their licenses. In the first place, they need to know how to recognize all kinds of traffice lights. Traffic light is vital in a traffic system. Even pupils know that red is forbidden to move, yellow is stand-by, and green is to go. However, many car accidents happened not because drivers did not know the meaning of the traffic lights, but because they chose to take risks. Sometimes they just want to save time but the consequence is to waste lives. In the meantime, drunk driving is the main reason causing car accidents. Drunk driving can be treated as a serious crime in a traffic court. If the circumstances is grievous, the driver would be sentenced to be prisoned for years. Besides, speed is another killer on the road. Many young people like driving very fast, who are called as road runners or jehu. Speed limits is necessary for a traffic system and cities normally have their own rules about speed limits. Therefore, drunk driving and speed are both dangerous in the traffics.