SOURCE: J. I. Pickard, Dimensions of Metropolitan ism, (op. cit.) pp. 48-53.
SOURCE: J. 1. Pickard, Dimensions of Metropolitanism, (Research Monograph 14, Urban Land Institute, 1967) table II 2, p. 19.
NOTE: Major areas are considered those with a population of at least 100,000, Areas in lawaii and Alaska are not included.
Social Security data on employment in cach county in the United States indicates that, for the SMSA's with more than one county, total employment increased 13 percent from 1959 to 1965 in the central or main county, but it increased 22 per- cent in the suburban counties. From 1960 to 1965, about half of the value of new construction in SMSA's for business pur- poses occurred outside the central cities. Percentages outside the central cities for major business categories were: Industrial, 62 percent; commercial stores, 52 percent; and office buildings, 27 percent.
The growing, shifting population of cities has also spread and thinned out. With more area occupied, the average popula- tion density of an entire metropolitan area is reduced. Suburban development is generally low density, contrasted to the high or medium density central city pattern, and thus requiries more land per person. As shown in figure 1.3, between 1940 and 1960, the average density of urban areas decreased by 1,640 persons per square mile-from 5,870 to 4,230 persons per square mile and trends indicate a further decrease in den- sity. Average trip length in urban areas also appears to be in- creasing over time, as data gathered in Boston and Houston indicate.
These figures add up to one irrefutable fact: The task of urban transportation systems in metropolitan areas in the future must be to transport more people over greater distances between where they are and where they want to go.
PUBLIC TRANSPORTATION TODAY
Urban mass transit systems have not developed adequately in response to changing conditions. Routes have tended to remain constant despite large population shifts and important changes in land use. Central city mass transit service often stops for no valid reason other than central city political boundaries. When transit lines were first established, few people lived outside the city. Transit charters and legal restraints further limited expan- sion that could have responded to suburban growth.9
