This came up on another board and I can't find information on how/if the kids were restrained. Based on the injuries, I would guess the girl was in a booster and the boys were in seatbelts with the shoulder belts behind their backs or lap belts. It is horribly sad all around, but as a car seat person, my mind first goes to this.
http://www.khou.com/home/2-Houston-...3-children-remain-hospitalized-124976894.html
http://www.khou.com/home/2-Houston-...3-children-remain-hospitalized-124976894.html