The quality of the child seat is determined primarily by its ability to perform its primary function: it is not constrained by the child during the trip, be able to securely hold and protect him from injury in an accident.
Appointment of child car seats - to keep the child in a safe position in case of a collision, extreme braking or abrupt maneuvers.
As demonstrated by crash tests and analysis of real accidents, sitting behind the child in a collision just off of the seat and seriously injured, suffering more than pristegnutye adult passengers. It is dangerous to carry children on his hands, especially in the front seat. In this case, if an adult attached, inertia is just pulling out of the hands of a child. Nepristegnuty adult himself rushes forward and the child presses his weight. A srabotavshaya airbag is capable of severely injure a baby, which is held on his knees.
http://tomius.wordpress.com/2010/10/28/all-that-you-need-to-know-about-child-car-seat/