The number of fatalities associated with traffic accidents has been declining owing to improvements in vehicle safety performance and changes in the law. However, injuries in children can lead to social and economic losses. We examined 10-year changes in the characteristics of traffic trauma among pediatric motor vehicle passengers by analyzing data from the Japan Trauma Data Bank (JTDB). Among the 36,715 injured motor vehicle passengers under the age of 15 years who were registered in the JTDB from 2004 to 2019, we compared the groups injured during 2004–2007 (n= 94) and 2017–2019 (n= 203). Physiologically, the 2004–2007 group had a lower body temperature and Glasgow Coma Scale score as well as a higher mortality. Anatomical severity was higher in the 2004–2007 group for the head, face, and neck, according to the Abbreviated Injury Scale. In terms of treatment, only craniotomy as a primary surgery was significantly lower in the 2017–2019 group. The 2017–2019 group had significantly higher rates of receiving whole-body computed tomography (CT). Because the rate of performing CT has increased, with no changes in the injury severities of the trunk and extremities, limiting the number of CT examinations is suggested for pediatric motor vehicle passengers involved in road traffic collisions. The severity of trunk and extremity injuries has not improved in more than 10 years; further preventive measures for these injuries should be considered.