For the child seat standard , different countries and regions provisions , in the end from a security point of view , how much children must use a child seat , the teens can use the car 's own seat belts ? 4 -year-old article says you can not , this fly it ? Car seat belt is designed according to adult standards , it is more suitable for weight 36kg , height 140cm above adult use. Because our national laws on child seat is no law , so in theory meet the above parameters children can not use the child seat and seat belt use . In addition, the co-pilot airbag Some cars are based on the weight of the weight and the co-pilot to select whether the collision spread out , so there is under the rear seat belt , the child should be sitting in the back of the vehicle .