The automobility cohort as a tool in the study of urban travel

Most metropolitan areas of industrialized countries underwent substantial changes in the second half of the 20^th century. Some research have shown that this substantial change stems more from structural change than from change in demographic and socio-economic characteristics of urban residents. This structural change is due to increasingly prevailing automobility, i.e., conversion of social and economic system and way of life to adapt to the ownership and use of the automobile. Using results of household travel surveys from 1970, 1980, 1990 and 2000, and land use and network data from the Kei-han-shin metropolitan area of Japan, this paper documents how the processes of decentralization and motorization progressed, how auto accessibility changed as a consequence, and further how the automobility characteristics of each automobility cohort have changed. The relationship between automobility characteristics and automobility cohorts is examined by using Chi-square tests. The analyses offer ample evidence that the structural change in most metropolitan areas is due to increasingly prevailing automobility and cohort effects play a great role in automobility.