Exploration and Conceptual Design of Child Restraint Systems to Prevent Misuse

Abstract: Children are, by law, required to use specialised child restraint systems (CRS) when riding in cars. The protective capabilities are required as the children’s bodies are not developed enough toproperly take the forces of a collision (Folksam, 2019). CRS today are regulated by various standards and have proven to be very efficient in protecting the child, but incorrect use reduces the effectiveness of the restraints. This thesis was carried out in collaboration with Folksam to study the frequency of misuse within Stockholm, Sweden and to design a CRS that combats them. The study involved a larger observation study that took place in 12 different and randomly selected kindergartens around the greater Stockholm area. The findings showed that CRS fastened with ISOFIX had double the rate (82%) of correct installation in comparison to belt fastening (42%). At the same time, belt fastening was also much more common (72% occurrence rate) than ISOFIX. 10.9% of all registered did not use a CRS at all. The most common misuse was found to be for group 1 CRS, generally being around too loose tether straps and incorrect use of internal belt. The conceptual designs were developed using both quantitative and qualitative research methods and were then evaluated on how well they fulfilled each requirement. A double belt concept was chosen due to its potential to minimise misuse the most. The thesis ended with concluding that its purpose has been fulfilled and includes recommendations for future work.