Regional disparities in road traffic injury rates involving elementary and junior high school children while commuting among Japan’s 47 prefectures between 2004 and 2013

Abstract Objectives To investigate the extent and patterns of regional disparities of road traffic injury rates involving elementary and junior high school children while commuting among Japan’s 47 prefectures. Methods We conducted a cross-sectional ecological study using the national police data for 2004–2013 on the number of children who were killed or seriously injured (KSI) in traffic collisions stratified by prefecture, grade, mode of transport, and purpose of trip (commuting or non-commuting). We calculated stratified KSI rates by dividing the number of KSI cases by the corresponding number of children and presented these rates for the 47 prefectures. Also, for pedestrian elementary school children and cyclist junior high school children, we regressed the KSI rates while commuting by prefecture on the non-commuting KSI rates and the proportion of people who live in the urban, densely inhabited districts. Results There were 6463 KSI cases while commuting. The ratios of the highest KSI rate to the lowest KSI rate among prefectures were 12, 30, and 58 for pedestrian elementary school children and pedestrian and cyclist junior high school children, respectively. The non-commuting KSI rates and the proportion of those living in densely inhabited districts were positively and inversely associated with the commuting KSI rates, respectively. The analysis of the residuals of the regression models did not identify prefectures with significantly higher or lower KSI rates while commuting than others. Conclusions There were large inter-prefecture disparities in the KSI rates while commuting, and the disparity was especially large among cyclist junior high school children.