For comparison, a man occupies about 5 square feet of space when he is walking. A car occupies about 350 square feet when it is standing still (including access); and at 30 miles an hour, when cars are 3 lengths apart, it occupies about 1000 square feet. Most of the time, cars have a single occupant. This means that when people use cars, each person occupies almost 100 times as much space as he does when he is a pedestrian. It is also notable in cities that when the area devoted to parking is too great, it destroys the land. Empirical observations suggest that an environment is not fit for human use when more than 9% of it is given over to parking. Another factor in the use of land by the automobile concerns the amount of paved road and highway that becomes necessary for its use. For example, in downtown Los Angeles more than 65% of the land is covered with concrete or asphalt paving. In Houston there are 30 parking spaces for every resident.
The Encyclopedia of World Problems and Human Potential is a collaboration between UIA and Mankind 2000, started in 1972. It is the result of an ambitious effort to collect and present information on the problems with which humanity is confronted, as well as the challenges such problems pose to concept formation, values and development strategies. Problems included are those identified in international periodicals but especially in the documents of some 60,000 international non-profit organizations, profiled in the Yearbook of International Organizations.
The Encyclopedia includes problems which such groups choose to perceive and act upon, whether or not their existence is denied by others claiming greater expertise. Indeed such claims and counter-claims figure in many of the problem descriptions in order to reflect the often paralyzing dynamics of international debate. In the light of the interdependence demonstrated among world problems in every sector, emphasis is placed on the need for approaches which are sufficiently complex to encompass the factions, conflicts and rival worldviews that undermine collective initiative towards a promising future.
Non-profit, apolitical, independent, and non-governmental in nature, the UIA has been a pioneer in the research, monitoring and provision of information on international organizations, international associations and their global challenges since 1907.