How does time pressure differentiate the built environment’s association with single-person household mobility?

In large metropolitan areas, the relationship between the built environment and everyday mobility may depend critically on time pressure. Using a balanced spatial panel of 424 administrative neighborhoods in Seoul over 36 months, this study examines whether an area-level time pressure proxy (TP) differentiates the associations between five built-environment dimensions and out-of-neighborhood trips, travel distance, and residential-neighborhood stay time among the estimated population of single-person households. A two-way fixed-effects spatial panel model jointly estimates the five dimension × TP interactions and decomposes direct, indirect, and total effects. The interactions are jointly significant for trips and residential-neighborhood stay time, but not for travel distance. The Design × TP and Transit access × TP interactions show positive direct effects on trips. For stay time, higher Density weakens the negative TP–stay-time association, whereas higher Diversity, Design, Destination accessibility, and Transit access strengthen it, indicating dimension-specific moderation. Sensitivity analyses broadly preserve the stay-time pattern, while trip evidence is less stable. Taken together, the findings suggest that greater time pressure is associated with more boundary-crossing activity and less residential-neighborhood presence in some connectivity-related settings, without clear evidence of greater overall travel distance. This pattern is more consistent with a spatial reorganization of constrained activity than with a simple increase in travel intensity. The estimated effects are modest and associational, but the built environment–mobility relationship varies systematically by time pressure. These findings suggest that discussions of time welfare should distinguish built-environment dimensions rather than assume that a supportive environment necessarily promotes localized activity.