Side impact was and is still a challenge in automo-tive safety. In the real world 1 out of 4 crashes are side impacts. According to an NHTSA investiga-tion involving accidents with 28 children, direct contacts with vehicle interior are responsible for 45 % of injuries. The majority of the observed injuries were to the head. Therefore when considering children restrained in child seats, the key safety objective is:​ Provide energy absorption for the whole body and avoid head contact, with for in-stance the intruding door. To reach this objective countermeasures have to be developed in terms of child restraint construction.

A project aiming at developing side impact coun-termeasures was launched at Britax some years ago. System basic requirements were:​ 1) Anticipate child seat to door contact, and 2) Absorb as much as energy possible “outside” the occupant zone. Another aspect of the specification was to ensure it is transposable to different testing environments or regulations.

This paper deals with applications aiming at im-plementing side air cushion technology to child restraint systems. The first part summarizes some development efforts to improve head containment on a booster seat. The second part deals with the technology basics as well as its application to a US-type convertible seat and to an EU-type booster seat. In the absence of established regulatory test procedure, internal methods were developed. These methods are described in the paper;​ they are based on deceleration sled system and a fixed door. Anth-ropomorphic Test Devices (ATDs) used were the 3year old Hybrid III and Q3. An additional method corresponding to the EU Draft Regulation –moving sled, fixed door - was also used.

The third part of the paper discusses the perfor-mance of the side air cushion. Performance was judged utilizing measurements of head, chest and pelvic accelerations and neck loads in the case of the Q3. In both test configurations the side air cu-shion allowed to reduce significantly dummy res-ponses.

The findings, as detailed in the paper, allow consi-dering the side air cushion approach as a viable and tangible countermeasure to address the challenges posed by side impact.