Changes in Commuting Flows in Metropolitan Areas, Japan: Effects of Cohort Size and Female Labour

Abstract

There have been many studies about structural changes of the three major metropolitan areas in Japan. One of the indexes to estimate these changes is commuting flow. This has changed from intensive concentration of trips to the central city to a more complex pattern because of the increase of intra-suburban trips.The purpose of this study is to consider the changes in commuting flow in the three major metropolitan areas in Japan in terms of cohort size and female labour using longitudinal data on residential, occupational and family careers and cohort analysis. The results of the analysis are summarized as follows:(1) Demographic features of the three major metropolitan areas in JapanThe three major metropolitan areas in Japan, Tokyo, Osaka and Nagoya have similar age structures in which specific cohorts born between 1935 and 1950 are notable for their large concentrations in the suburbs. Those included in these cohorts migrated into metropolitan centers from the non-metropolitan area during the period of rapid economic growth (1960s) and after that they moved to metropolitan suburbs at the time of marriage or childbirth.(2) Differences of occupational career between husband and wife in the metropolitan suburbsTo clarify the differences of occupational career between husband and wife, longitudinal data collected through a retrospective survey in Kozoji New Town, a suburb of Nagoya, is analysed.When households moved into the suburbs, many husbands continued to commute to the metropolitan center. On the other hand, many wives quit their jobs because of impending childbirth and child-rearing. After child-rearing, wives obtained employment, often part-time work near their home because getting a full-time job or commuting to the metropolitan center was difficult on account of the heavy responsibility of housework.(3) Changes in commuting flow in the metropolitan suburbsCommuting flows at the macro level are discussed using cohort analysis in Saitama prefecture, a suburb of Tokyo, in order to show that the individual commuting activity, as mentioned above, has contributed to changes in commuting flow in the metropolitan area.From the 1960s through to the early 1970s a large number of people born between 1935 and 1950 flowed into metropolitan suburb due to marriage or childbirth. Although men continued to commute to metropolitan center, women quit their jobs. Therefore only commuters to the metropolitan center increased at that time.After the mid-1970s women who had moved to the metropolitan suburbs completed child-rearing and got employment again near their home. Therefore middle-aged female workers, who constitute the bulk of intra-suburban commuters, increased rapidly.It should be concluded that the changes in commuting flow in the three major metropolitan areas result from the life-cycle changes of women suburbanites born between 1935 and 1950.(4) Demand side factors in the labour marketConcerning the rapid increase of middle-aged female labour there are also several demand side factors. One is the demand for white-collar workers and another is the demand for blue-collar workers. As for the later, secondary industry changed its employment structure from young women to middle-aged women part-timers after the first oil crisis.