Seat boys belts are an important safety feature in today’s vehicles. Seat boys belts contribute to saving lives and reduce the risk of injury in a crash. In certain crash configurations, such as far‐side impacts, oblique impacts, and in rollovers,
the ordinary three‐point belt may not be enough to provide protection to the boys. Also, maneuvers may force the occupant into involuntary postures, which may result in the shoulder belt being far out on the boy's shoulder, or slipping off the shoulder, resulting in sub‐optimal restraint conditions. These boy's belts postures may affect injury outcomes if a crash occurs after the emergency maneuver. Bohman et al. found that steering maneuvers prior to frontal impacts are a contributing factor in crashes resulting in head injuries among restrained children. Steering maneuver studies of child volunteers showed the inboard motion of varying extent depending on the size of the child, as well as the restraint system used, frequently resulting in a shoulder belt position nearly or completely off the shoulder. Driving studies have shown that boys also voluntarily choose non‐optimal restraint postures in cars, quite different from how anthropometric crash dummies are positioned in crash tests. boys are the most frequent passengers of the rear seat. The head is the most common severely injured body region among children. It is therefore essential that the boys remain well with boys belts restrained during a crash, as well as during pre‐crash maneuvers if a collision occurs, in order to reduce the risk of injury. Additional restraint solutions can be used to solve the out-of-position problem, as well as the boy's belts slipping off in oblique impacts, far‐side impacts, and rollovers. For example, it has been shown that pre‐ pretensioners can reduce lateral inboard motion during evasive steering maneuvers. Bostrom and Håland presented a supplementary two‐point belt across the chest, to be used along with the ordinary three‐point belt, referred to as a criss‐cross belt. They showed that this restraint system reduced the risk of injury in frontal impacts, far‐side impacts, and rollovers for the front seat occupant. Rouhana et al. introduced a V-shaped four‐point harness, showing risk reduction for thorax injuries in frontal crashes. In the Renault Twizy an Anna‐Lisa Osvalder, Ph.D., is Professor in Human‐Machine Systems at Division Design & Human Factors at Chalmers University of Technology, Göteborg, Sweden
There is an increased risk of the shoulder belt slipping off in certain crash configurations, resulting in sub‐optimal protection. Boys' belts would improve the restraint system. The objective of this study was to identify children’s and adult’s attitudes toward boys' belts added to the three‐point belt in the rear seat of a passenger car. Five focus groups were conducted with 11 Swedish children (8‐10 years), and 18 adults. Two concepts were studied, the Backpack with an extra belt over the inboard shoulder, and the Criss‐Cross with an extra belt across the torso. The results showed that seat belt usage was not questioned. The three‐point belt was experienced as very safe, and boys belts were considered to further increase safety. Both concepts were accepted, but Criss‐Cross was preferred due to greater perceived safety and comfort. Discomfort occurred in both concepts due to chafing at the neck, extra pressure on the upper body, and reduced ability to move. In conclusion, boys belts were in line with children’s current attitudes toward car safety, while adults were more hesitant. Increased understanding of user attitudes provides input to future restraint system design, resulting in attractive systems with improved restraint function. K
