Do residential location effects on travel behavior differ between the elderly and younger adults?

The built environment affects individuals' travel behavior in a variety of dimensions, such as trip generation, mode choice, and travel duration. However, it is not well understood how these effects differ across different socioeconomic groups (e.g. the elderly versus younger adults) and how residential self-selection contributes to these differences. Using the 2013 Nanjing (China) Travel Survey data, this study estimates the differential responsiveness to the variation in residential location for different age groups. The two-step clustering method is applied to characterize two types of residential locations and the propensity score matching approach is utilized to address self-selection effects. We find that, after control for self-selection, residential location effects on travel behavior differ significantly between the elderly (60 + years old) and younger respondents (18-59 years old). Changes in the living environment play a more important role in influencing the elderly's travel frequency and travel duration than those of younger adults. When we compare the observed effects of residential location, self-selection effects are modest for the elderly while they matter to a great extent for younger adults. In addition, due to differences in residential self-selection, there is an underestimation of residential location effects on the elderly's travel behavior versus an overestimation of those for younger adults. These findings indicate that overlooking the variation of built environment effects between different age groups may lead to ineffective housing and transportation policy implications.