Residence Locations and Mobility Tool Ownership During the Life Course: Results from a Retrospective Survey in Switzerland
Sigrun Beige, Kay W. Axhausen, IVT ETH Zurich, CH
The paper will analyse the dynamics of long-term spatial mobility including the locations of residence, education and employment as well as the ownership of mobility tools. In this context retrospective data for the years 1985 to 2004 is used.
Decisions concerning the locations of residence as well as the ownership of mobility tools are two aspects of long-term spatial mobility of people which are closely connected to one another. In the context of residential choices and the corresponding moving behaviour distance and direction, frequency of moves and durations of stays as well as reasons for moving are of central interest. On the other hand the ownership of mobility tools, such as cars and different public transport tickets are complementary elements in this process, which also bind substantial resources.
A longitudinal perspective on the relationship between these two aspects of spatial mobility is available from people?s life courses, which link different dimensions of life together. Besides the personal and family history locations of residence, education and employment as well as the ownership of mobility tools can be taken into account.
In this context a longitudinal survey was carried out in a stratified sample of municipalities in the Zurich region, Switzerland. The survey was conducted by means of a written self-completion questionnaire which consisted of two parts, a household form and a person form. The household form asked for the current address, a short description of all persons living in the household and the household income. In the person form socio-demographic and socio-economic characteristics of the respondents were collected. The essential part of this form was a multidimensional life course calendar for the years 1985 to 2004. For this twenty year period retrospective information about the personal and family history, the household size as well as data on moves and corresponding places of residence was collected. In addition, the respondents were asked to indicate their changing ownership of cars and different public transport tickets. Furthermore information on the places of education and employment, on the main mode of transport for the commuting trip as well as on the personal income was collected for the last 20 years. Each household received two person forms that were to be filled in by persons aged 18 years and older. The questionnaire, together with a self-addressed envelope was sent per post to 3600 households. Overall the response rate of the survey amounted to 23.0%, which seems to be rather low, but which is related to the complexity of the questionnaire. For further analyses 780 household forms and 1166 person forms are available. An associated non-response survey as well as detailed aggregate and disaggregate information on moving from national sources allows an appropriate weighting of the data.
Life course dynamics can be described with the concepts of trajectory and transition. In this context the life course is seen as a sequence of events. By means of event history modelling differences in timing, duration, rates of change and probabilities for the occurrence of certain events within a period of time as well as influencing variables can be determined. Further developments in duration modelling include the estimation of more flexible hazard models with the form of discrete choice models that allow for inter-individual and intra-individual variability of people (Bhat, 2003; Bhat, Srinivasan und Axhausen, 2003). These analyses are applied for the residential moving behaviour as well as for the mobility tool ownership taking the personal and family history as well as changes in education and employment into account. In addition the points in time when events occur in the different life course dimensions and the delays between these events are of interest (Rouwendal and Vlist, 2005). Furthermore cross-sectional analyses are carried out for the ownership of the different mobility tools by means of univariate and multivariate discrete choice models (Axhausen and Beige, 2004).
Besides exploring the temporal dimensions of the life course the spatial structures are also considered. This includes the different places of residence, education and employment as well as the distances between them. In this context further information describing the municipalities in regard to location, accessibility, type and size is incorporated into the investigations.
The paper will briefly describe the survey conducted and explain the weighting scheme implemented. It will concentrate on the analyses of the long-term mobility decisions during the life course using the collected retrospective data. The main focus will lie on the dynamics of mobility tool ownership over the last 20 years, while at the same time looking at their contemporaneous relationships with residential choices as well as with education and employment locations.
Axhausen, K. W. and S. Beige (2004) Vertiefte Auswertungen zur langfristigen räumlichen Mobilität, Forschungsprogramm UNIVOX 2003 Teil I G Verkehr, Vertiefungsbericht, Arbeitsberichte Verkehrs- und Raumplanung, 238, Institut für Verkehrsplanung und Transportsysteme (IVT), ETH Zürich, Zürich.
Bhat, C. R. (2003) Econometric choice formulations: Alternative model structures, estimation techniques and emerging directions, paper presented at the 10th International Conference on Travel Behaviour Research, Lucerne, August 2003.
Bhat, C. R., S. Srinivasan and K. W. Axhausen (2003) An analysis of multiple interactivity durations using a unifying multivariate hazard model, Arbeitsberichte Verkehrs- und Raumplanung, 191, Institut für Verkehrsplanung und Transportsysteme (IVT), ETH Zürich, Zürich.
Rouwendal, J. and A. van der Vlist (2005) A dynamic model of commutes, Environment and Planning A, 37, 2209-2232.
Residence Locations, Mobility Tool Ownership, Life Course, Longitudinal Survey, European Transport Conference 2006
Association for European Transport