In the ISOITC221SC 121WG 1 “Child Restraint Systems” an ad-hoc group was created to develop a test standard for side impact protection for children in child seats.This paper shortly sumniarizes the ongoing experience and activities of this ad hoc group, which started in 1993 with an international inquiry at accident research units. Up to now a total database of 139 side impacts with MAIS 2+ injured 0-12 year old children has been analyzed. Focussed on accident investigation, a draft proposal for lateral child impact test standard conditions is being developed. One of the major tasks is to simulate the door intrusion effect, especially where the struck-side sitting child is involved.The paper describes new single-sled test experiments to simulate the door intrusion effect by a hinged door with impactor and a hinged door with mass-spring impact system. Suggestions for further work with side impact test procedures will be included.