Are Rising Dramatically Overview Transportation of all types already accounts for more than one quarter of the world's commercial energy use. That makes the rapid increase in the global transport sector, particularly the world's vehicle fleet, a real concern. Motor vehicles have brought enormous social and economic benefits. They have enabled flexibility in where people live and work, the rapid and timely distribution of manufactured goods, and ready access to a variety of services and leisure options. But the widespread use of vehicles also has real environmental and economic costs, which have ballooned as vehicle numbers have risen sharply in the past few decades.
Vehicles are major sources of urban air pollution and greenhouse gas emissions.
They also represent an important threat to the economic security of many nations because of the need to import oil to fuel them. The adoption of cars as common items in family life and commerce began after World War II in developed countries. In 1950, there were only 70 million cars, trucks, and buses on the world's roads. By 1994, there were about nine times that number, or 630 million. Since about 1970, the global fleet has been growing at the rate of about 16 million vehicles per year.