There is an increased risk of the shoulder belt slipping off in certain crash configurations, resulting in sub‐optimal protection. An extra seat belt would improve the restraint system. The objective of this study was to identify children’s and adult’s attitudes toward extra seat 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 extra seat 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, extra seat 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.