Do Provincial Boundaries Hinder Population Flow in China? Evidence from Big Data of Coach Flows

Abstract This paper constructs a monthly intercity population flow index using high-frequency coach flow data from 2018 to 2019 in China. Within a framework integrating geographic, cultural, and institutional factors, it investigates the potential institutional barriers to cross-regional population flow. The findings reveal that both non-institutional factors (natural geographic barriers and cultural differences) and institutional factors—primarily administrative forces—significantly hinder cross-regional population movements, revealing strong provincial border effects. These findings remain robust after controlling for geographic proximity, substitution effects of direct rail services, and validation using mobile signaling data. Further analysis indicates that population flow, compared with commodity flow measured by truck traffic, faces a more pronounced provincial border effect, particularly in cross-regional labor mobility. While the traditional household registration system (hukou) significantly affects long-term migration, its impact on short-term population flow is relatively limited.