A comparison of the effects of travel party size versus travel party composition on differences in travel behavior of spouses in Bhubaneswar, India

The present study compares and quantifies the importance of ‘travel party size’ and ‘travel party composition’ on themode choice decisions of spouses, an important behavioral aspect that is rarely explored in travel behavior literature. To fulfill this objective, a primary activity-travel diary data was collected in Bhubaneswar City, India, consisting of 978 households and 5476 out-of-home activity trips on weekdays. Mixed multinomial logit (MMNL) models are developed to capture the heterogeneity in mode choice decisions between spouses. The study findings indicate an unobserved complementarity effect for the utilities of public and personal modes for male spouses, whereas a substitution effect between these modes for female spouses. The MMNL model coefficients also reveal gender differences in mode preferences of spouses, different from the recent trends in developed countries that have observed gender convergence in travel behavior. In addition, individual characteristics (e.g., age, completed education), household characteristics (e.g., couple or lineally descendant household, presence of school-going children), and attitudes such as ‘green lifestyle’, significantly affect spouses’ choices of various modes. The study reveals that male heads consider monetary savings on travel time reductions of greater importance than female heads, especially when choosing personal modes. Regarding the importance between trip party size and trip party composition, the results indicate that the addition of an extra member to the existing trip party size does not alter the mode choice preferences of spouses. On the contrary, trip party composition affects mode choice differently for spouses: male heads prefer private modes when traveling with non-family members, whereas females prefer public modes. Spouses, however, prefer to choose personal modes for joint rides with immediate family members. Moreover, the cost implications associated with shared travel arrangements reveal that travel party composition has greater cost repercussions for personal and public modes than it does for travel party size for similar modes. Overall, the findings add to the understanding of travel behavior of spouses and suggest that policies targeting shared mobility and urban travel demand management may consider household-level trip compositions rather than party size.