Regional variations in key factors of children's independent mobility across Japan

Regional differences may cause discrepancies in key factors of children's independent mobility (CIM), which is associated with physical activity. However, comparative research across diverse settings remains limited. This study aimed to identify the barriers and enablers of CIM across regions with varying levels of urbanization by developing a customized scale suited to the current Japanese context. An online survey in autumn 2023 collected responses from 6,000 women across Japan, aged 20–49, with children aged 6–12 attending municipal elementary schools. The CIM scale was customized through a stepwise process based on internal consistency and criterion-related validity, using physical activity as the criterion. Postcode-level population density was used as a proxy for urbanization. Generalized linear models were applied to examine associations between CIM and individual, social, and environmental factors. Five items related to parental permission, including going shopping alone, were selected to construct the CIM scale. CIM was higher in more densely populated areas, contrasting with results from other countries. Factors associated with higher CIM scores included being male, in a higher grade, not a first-born child, and attending after-school activities. Parents’ perceptions of safety from crime were positively associated with CIM, whereas perceptions of traffic safety were significantly associated only in medium-sized cities. Unexpectedly, higher urbanization was associated with higher CIM but lower physical activity levels, possibly reflecting the influence of sedentary after-school routines. The approach to contextualizing the CIM scale and the regional findings provides insights for countries undergoing similar social or demographic transitions. • Nationwide survey revealed higher CIM in more urbanized areas across Japan. • Parents' perception of crime safety was positively associated with CIM. • Traffic safety perception was significantly associated only in medium-sized cities. • Walking facilities were weakly linked to CIM only in small cities. • A CIM scale was customized and validated using children's physical activity levels.