Abstract: A vehicle seat assembly includes a seat base connected to a seat back. The seat base has a cushion portion and a support portion for supporting the cushion portion. The cushion portion is movable between a seating condition where the cushion portion forms a seating surface and non-seating condition where the cushion portion is tilted forward relative to the seat back about a forward end portion of the support portion. A rail system is mounted to the support portion. In the seating condition the rail system is covered by the cushion portion, and in the non-seating condition the rail system is configured to have mounted thereto an associated child car seat. The rail system is configured to move the associated child seat along a lateral direction of the vehicle seat assembly between a first outboard seating location and a center seating location defined by the seat base.