Mobility-system compatibility and bus underuse in Ho Chi Minh City: Explaining elastic mobility mismatch

Public transport underuse is commonly attributed to service quality, accessibility, travel time, cost, and individual preferences. These explanations say less about how travellers evaluate public transport within mobility environments already organised around established modes and practices, and may treat categories derived from particular transport histories as universally applicable. In Ho Chi Minh City, fixed-route buses operate within a motorcycle-based mobility ecology that supports direct access, flexible routing, intermediate stops, trip chaining, and rapid adaptation to changing circumstances. Elastic mobility refers to the adaptive capacity generated by such an ecology, while elastic mobility mismatch describes the difficulty of reproducing that capacity through another transport system. The study draws on 42 brief, open-ended intercept interviews conducted at 11 bus stops, supplemented by field observations. A hybrid deductive–inductive thematic analysis identified four interrelated sources of friction: spatial and access, informational, temporal, and functional. Participants valued buses for their affordability, comfort, and protection from traffic and weather, especially when direct routes matched stable routines. Bus travel became less viable when journeys required uncertain waiting, transfers, intermediate stops, trip chaining, or rapid responses to changing circumstances. The coordination required across a complete journey can reduce the perceived viability of public transport within an established mobility ecology; bus underuse is not simply a failure to adopt a supposedly more advanced mode. Treating HCMC as a source of conceptual knowledge also opens a decolonising conversation about how mobility transitions are understood. The small, non-probabilistic sample supports the identification of this mechanism but not an estimate of its prevalence.