URBAN PLANNING

the programs pursued in most industrialized countries in an attempt to achieve certain social and economic objectives, in particular to shape and improve the urban environment in which increasing proportions of the world's population spend their lives. Evidence of urban planningsuch as orderly street systems; division of a city into specialized, functional districts, or quarters; fortifications; and conduits for the water supply and sewage disposalcan be found in the ancient ruins of cities in China, India, Egypt, Asia Minor, the Mediterranean region, and South and Central America. During the Renaissance, European city areas were consciously planned to achieve practical circulation and also to provide fortification against invasion. The radial boulevards of Paris were designed with military as well as aesthetic objectives. The planning concepts of the European Renaissance were exported to the New World. William Penn developed the gridiron planthe laying out of streets and plots of land adaptable to rapid change in land usethat dominated American urban planning as the society expanded westward. By dividing land into lots, the gridiron plan accommodates itself to urban expansion, but it uses land inefficiently and creates traffic-flow problems. The modern urban planning and redevelopment movement arose in response to the disorder and squalor of the slum areas created by the Industrial Revolution in the 19th century. Reformation of these areas was the objective of the early city planners, who imposed regulatory laws establishing standards for housing, sanitation, water supply, sewage, and public health conditions. Urban planners also introduced parks and playgrounds into congested city neighbourhoods, providing places for recreation, as well as visual relief. The chief new urban-planning concept of the early 20th century was zoningthe regulation of building activity to set limits of height and density and to protect established neighbourhoods. This arose in response to the sprawling, haphazard growth of industrial cities, where factories invaded residential areas, and where skyscrapers blocked out the sunlight of smaller buildings. Urban territory expanded further as a result of improved public transportation. Workers could live far from their jobs, traveling back and forth by bus, subway, or car. The sprawling and crowded metropolis, especially its downtown and commercial areas, required well-planned circulation systems. By the middle of the 20th century, urban planning changed its focus. Planners realized that factors of city living must be considered as a whole, so they aimed less at attacking specific problems than at the improvement of the entire urban milieu. This movement aimed at an ideal urban environment, which would give the city dweller maximum amenity. Another aspect of urban planning has been the building of experimental new towns and cities. In Great Britain, India, Israel, and South America a few new cities were built entirely from plans. Urban planning was an important factor in Europe after World War II, when urban planners directed the reconstruction of war-shattered areas.