The infant car restraint devices are a critical part of infant safety during transportation. The crash tolerance and the critical safety features of each seat are well established. Infant transportation may be via a car seat or car bed. The effect of the sitting position on the airway is a concern in an infant with poor head control. Because of this concern, car seat tests during which oxygen saturation is measured, are performed on many low birth weight infants before discharge from the nursery. Indeed, a number of deaths have occurred in car seats probably related to airway obstruction. The relative effects of position on the ventilation need to be established.