Prepare a conceptual model that facilitates understanding of the relationships between the variables that lead children to adopt postures in school transportation vehicles that increase injuries in traffic accidents.For identification of the variables, direct information on school transportation was collected through focus groups, with bus aides and bus drivers, on-board filming during the transport of children, and recording of the dimensions of components in different types of school buses. The information collected was analyzed using the Atlas.ti v6 software and the construction of a model through deduction.Important relationships were found between adoption of potentially hazardous postures by children during transport to and from school and the seat and seat belt dimensions, the characteristics of the transportation service, and the role of bus aides.In order to adopt coherent interventions in school transportation safety, it is necessary to consider not only the technical aspects of the vehicle or posture that are controlled in crash tests but the specific variables of the activities that lead children to adopt postures that put them at greater risk of injury.