I need some help here. Our daughter was on the smaller side, so we kept her rear-facing until 5 years old! She is going to be 9 years old in a few weeks, and she is still in a 5-point harness high back car seat (forward facing). Her shoulders are now hitting the head protectors, and the straps are too low, so we want to move her to a backless booster, finally. She is about 48 lbs, so she weight-wise, the carseat still works. She has outgrown it. Obviously, we want to keep her safe. What are some recommended backless boosters for older children once they outgrow the high-backs?
In 2003 after the breakup of Columbia during re-entry, the Columbia Accident Investigation Board conducted tests at Southwest Research Institute , which used an air gun to shoot foam blocks of similar size, mass and speed to that which struck Columbia at a test structure which mechanically replicated the orbiter wing leading edge. They removed a section of fiberglass leading edge from Enterprise 's wing to perform analysis of the material and attached it to the test structure, then shot a foam block at it.  While the leading edge was not broken as a result of the test, which took place on May 29, 2003, the impact was enough to permanently deform a seal and leave a thin gap 22 inches (56 cm) long.    Since the strength of the reinforced carbon–carbon (RCC) on Columbia is "substantially weaker and less flexible" than the test section from Enterprise , this result suggested that the RCC would have been shattered.  A section of RCC leading edge from Discovery was tested on June 6, to determine the effects of the foam on a similarly aged leading edge, resulting in a three-inch ( cm) crack on panel 6 and cracking on a "T"-shaped seal between panels 6 and 7.   On July 7, using a leading edge from Atlantis and focused on panel 8 with refined parameters stemming from the Columbia accident investigation, a second test created a ragged hole approximately 16 by 16 in (41 by 41 cm) in the RCC structure.   The tests clearly demonstrated that a foam impact of the type Columbia sustained could seriously breach the protective RCC panels on the wing leading edge.