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Abstract: To represent heterogeneous group decision-making mechanisms in choice behavior, this paper attempts to develop a new household discrete choice model by integrating different types of household choice models based on latent class modeling approach under the principle of random utility maximization, where household utility function at each model is defined to theoretically reflect its members’ preferences and intra-household interaction. A latent class corresponds to a particular group decision-making mechanism. The proposed model can deal with not only the choice situations where multiple household members involved in joint decision are known a priori, but also the situations where the involved members are unknown. As a case study, three types of household utility functions are dealt with: multi-linear, maximum and minimum types, in the context of couples’ car ownership behaviors. Due to the limited sample size, paired combinations of the three utilities are examined and compared. Using the data collected in two Japanese cities in 2004, the effectiveness of the proposed household decision model is empirically confirmed. It is found that changes of utility combinations result in very complicated variations in both signs and values of the model parameters and choice probabilities by multi-linear utility show small variations across different combinations. [Copyright &y& Elsevier]

Abstract: Even though the importance of representing group decision-making mechanisms of household behavior has been recognized since the 1980s in the context of the activity-based approach, studies about group behavior in transportation are relatively new and consequently limited, compared with the research about individual decisions. In line with the special issue “Modeling Intra-Household Interactions and Group Decision-Making” published in the Journal of Transportation in 2005, and motivated by the recent progress of group behavior research in transportation, this special issue presents examples of state-of-the-art modeling approaches to household activity travel decisions. We hope it will stimulate more intensive discussion about future research directions from both methodological and practical perspectives. Five papers are selected to cover diverse methodologies, including group decision theory, utility theory, latent class modeling, rule-based modeling, and micro-simulation approaches. The topics cover household task and time allocation, car ownership, vehicle transaction, mode choice, activity generation, and activity scheduling behavior. [Copyright &y& Elsevier]

Abstract: Travel behavior models assuming individual decision-making processes have been a dominant theme in transportation studies. While the assumption that an individual can decide on all relevant aspects of some types of travel behavior may be reasonable, in many other aspects household members interact before making decisions about different activities that they perform and the time that is involved. On the other hand, different types of households may show different group decision-making mechanisms. In other words, there might exist diverse intra-household interactions during joint decision-making processes. To reflect this point, this paper aims to develop a new household time allocation model based on the iso-elastic class of social welfare function, which can include different types of household utility functions as special cases (e.g., Nash, utilitarianism, autocratic and max–min types). Throughout this empirical analysis, which uses an activity diary data collected in a depopulated region of Japan, the effectiveness of the proposed model is confirmed. Furthermore, the model’s applicability in evaluating transportation policies for elderly people is examined based on a simulation analysis. [Copyright &y& Elsevier]

Most existing activity-based models of transport demand are based on individual activity-travel choice. Although it has been realized that activities in multiple person households need to be coordinated and sometimes synchronized in time and space, there is still a lack of household-level models of activity-travel demand. Recently, several potentially productive areas of time use research have been identified, including the allocation of tasks, resources and possessions to household members, and joint activity engagement by household members. This paper reports on the development of a household task allocation and time use model based on a multi-linear group utility function. Using activity-travel diary data, collected in the South Rotterdam Region, the Netherlands, a model of household task allocation and time use, incorporating the influence of travel time, was estimated. The model also allows quantifying the relative influence of the household members. The results indicate that, on weekdays, for nearly half of the households the husband mostly influences task allocation and time use, for one-fifth of the households it is the wife and the remaining households show an equal relative influence for the husband and wife. [Copyright &y& Elsevier]

Individual choice behavior usually involves a complex decision-making process, and is often context-dependent reflecting the influence of choice environment and the fact that the individual has limited information processing ability and varying levels of interest in alternatives. However, the existing models in transportation have not represented these behavioral mechanisms satisfactorily, although to avoid the Independence of Irrelevant Alternatives (IIA) property of the widely used multinomial logit (MNL) model, a variety of non-IIA models have been suggested in the literature. This paper will propose another random utility choice model by introducing the concepts of relative utility and relative interest. A revised MNL model and a revised Nested-MNL model will be developed. Both of these models do not have the IIA property. The performance of these new models will be assessed using conjoint-based activity diary data about the choice of destination and stop pattern. [Copyright &y& Elsevier]