根据下面资料，回答题
The automobile has many advantages． Above all ,it offers people freedom to go wherev-er and whenever they want to go． However, to most people, cars also serve as symbols of power, success, speed, excitement, and adventure． In addition, much of the world´ s economy is built on producing motor vehicles and supplying roads, services, and repairs for those vehi-cles． In the United States, one of every six ．dollars spent and one of every six non-farm jobs are connected to the automobile or related industries, such as oil, steel, rubber, plastics, auto- mobile services,and highway construction．
In spite of their advantages, motor vehicles have many harmful effects on human lives and on air, water, land, and wildlife resources． Though we tend to deny it, riding in cars is one of the most dangerous things we do in our daily lives． Since 1885,when Karl Benz built the first automobile, almost 18 million people have been killed by motor vehicles． Every year,cars and trucks worldwide kill an average of 250,000 people and injure or permanently disable ten million more． Half of the world´s people will be involved in an auto accident at some time during their lives． In addition to the tragic loss of life, these accidents cost Ameri-can society about $ 60 billion annually in lost income and in insurance, administrative, and legal expenses．
Streets that used to be for people are now for cars． Pedestrians and people riding bicy-cles in the streets are subjected to noise, pollution, stress, and danger． Motor vehicles are the largest source of air pollution,producing a haze of smog over the world´s cities． In the Unit- ed States, they produce at least 50 % of the country´s air pollution．
 Cars can NOT represent people´s_ __________．