A child safety seat assembly, including a base for being positioned on a vehicle seat bottom. An anti-rebound bar is carried by the base and extends outwardly and upwardly from a foot end of the base for engaging a seat back of the vehicle seat to which the seat is attached for retarding inertia-induced rotation of the base and the attached carrier by transmitting rotational force applied to the seat during a sudden change in velocity into the seat back of the vehicle seat onto which the seat is attached.