The most important biomechanical characteristics of infants from birth to about six months are compiled in view of the development of adequate restraining devices for this group. The conventional engineering approaches are discussed, also a new method, a swinging bed. The long axis of the shell of this bed is placed perpendicular to the main axis of the vehicle on the rear seat. The top of the shell is attached at both sides by a strap to the vehicle frame for example by the adult belt. As the center of gravity of the shell plus infant is below the attachment points, the shell turns in a frontal crash. This transfers the impact load over a large area of the infant and also reduces the duration of maximal impact for each area element.The development from the first models for studying the kinematics to the final models for production is discussed. Results from European and United States sled tests are included.