The private automobile  has long played an important role in the United States. In fact, it has become a necessary and important part of the American way of life. In 1986, sixty-nine percent of American families owned at least one car, and thirty-eight percent had more than one. By giving workers rapid transportation, the automobile has freed them from having to live near their place of work. This has encouraged the growth of the cities, but has also led to traffic problems. For farm families the automobile is very helpful. It has made it possible for them to travel to town very often for business and for pleasure, and also to transport their children to distant schools. Family life has been affected  in various ways. The car helps to keep families together when it is used for picnics, outings, and other shared experiences. However, when teenage children have the use of the car, their parents can't keep an eye on them. There is a great danger if the driver has been drinking alcohol or taking drugs, or is "showing off" by speeding or breaking other traffic laws. Mothers of victims  of such accidents have formed an organization called MADD(Mothers Against Drunk Driving). These women want to prevent further tragedies . They have worked to encourage the government to limit the youngest drinking age. Students have formed a similar organization, SADD (Students Against Drunk Driving) and are spreading the same message among their friends. For many Americans the automobile is a necessity. But for some, it is also a mark of social position and for young people, a sign of becoming an adult. Altogether, cars mean very much to Americans. Which of the following is NOT mentioned in the text?
Cars have encouraged the growth of the cities. Cars can bring families together when they go for picnics. Cars have enabled people to live far from their place of work. Cars help city families to transport their children to faraway schools.