Nobuhiro Sanko

Inter-temporal analysis of household car and motorcycle ownership behaviors: the case in the Nagoya metropolitan area of Japan, 1981-2001

This study investigates household car and motorcycle ownership in the Nagoya metropolitan area of Japan. Bivariate ordered probit models of household vehicle ownership were developed using the data from the case study area at 3 time points: 1981, 1991, and 2001. The accessibility that is generally known to be correlated with vehicle ownership decisions is incorporated as an input for the proposed vehicle ownership model to investigate the potential relationship between them. The mode choice models for the area were first estimated to quantify the accessibility indexes that were later integrated into the vehicle ownership models. Inter-temporal comparison and temporal transferability analysis were conducted. Some of the major findings suggest that: 1) age and gender differences have become less important in modal choices and car ownership as motorization proceeds; 2) the accessibility seems to have a significant correlation with vehicle ownership; 3) car and motorcycle ownership may not be independent and may have a complementary relationship; and 4) the deep insights concerning the model selection are obtained from the viewpoints of the temporal transferability.

Household car and motorcycle ownership in Bangkok and Kuala Lumpur in comparison with Nagoya

This study investigates household car and motorcycle ownership behaviours in the Asian metropolises of Bangkok and Kuala Lumpur (developing countries), and of Nagoya (developed country). Mode choice models are first estimated to calculate accessibility measures, and then car and motorcycle ownership models are estimated using bivariate ordered probit models with the accessibility measures as explanatory variables. Inter-regional comparisons and spatial transferability analysis are conducted. Results suggest that: (i) accessibility measures and car and motorcycle ownership behaviour are correlated; (ii) car and motorcycle ownership is substitutable in Bangkok and Kuala Lumpur, but is complementary in Nagoya; (iii) car and motorcycle ownership behaviour in Bangkok and Kuala Lumpur is similar and quite distinct from Nagoya; and (iv) car and motorcycle ownership behaviour in Nagoya in 1981 was closer than the ownership behaviour in Nagoya in 1991 and 2001 to the behaviour in Bangkok and Kuala Lumpur. Policy implications are also discussed.

Factors affecting temporal changes in mode choice model parameters

ABSTRACT In travel demand forecasting models, parameters are often assumed to be stable over time. The stability of these parameters, however, has been questioned. This study investigates the factors affecting temporal changes in mode choice model parameters using a method proposed by the author that jointly utilises repeated cross-sectional data. In this method, the parameters are assumed to follow functional forms and the parameter changes are modelled endogenously. While the author’s previous studies assumed that all parameters are the same function of the same variable, this study assumes that different parameters are different functions of different variables, including time (year) and macro-economic variables. The paper describes a case study of a journey-to-work mode choice analysis for Nagoya, Japan, that examines 288 combinations of the functional forms and variables. The analysis found that the functions of time had serious over-fitting problems and that parameter changes are more closely related to economic factors.