GOING 20MPH, WHEN VEHICLE IN FRONT STARTED TO STOP. APPLIED THE BRAKES & REAR ENDED FRONT VEHICLE. UPON IMPACT, REAR SEAT BELTS (SHOULDER/LAP) FAILED TO RESTRAIN CSS & GAVE WAY. CHILD WENT FORWARD & HIT REAR OF FRONT SEAT (DRIVER). DRIVER HAD NECK PROBLEMS. CHILD FACIAL PROBLEMS. *AK