Evaluation of Forward-Facing Child Safety Seat Harness Retainer Clip Position in 35 mph Frontal Barrier Crash Tests

Abstract

Abstract The National Highway Traffic Safety Administration (NHTSA) recommends that children ages 4 to 7 years old should travel in a forward-facing child safety seat (FFCSS) with a harness until reaching the maximum weight or height limit allowed by the car seat manufacturer. There are five types of FFCSS, including convertible, combination, all-in-one, forward-facing only, and integrated (built-in). In the United States, most of the harness systems in FFCSS also include a retainer clip or chest clip; this is a plastic clip that holds the harness shoulder straps together over the child’s chest. NHTSA, National Child Passenger Safety Board (NCPSB), and Safe Kids Worldwide recommend that with the child buckled and the straps tightened snugly, the harness retainer clip should be secured and then positioned at the child’s armpit level. According to NHTSA, the purpose of the clip is as a pre-crash positioner, holding the harness straps together for correct positioning in the event of a crash.[1] Analysis of child dummies placed in various types of FFCSSs and in various makes and models of vehicles during 35 mph New Car Assessment Program (NCAP) frontal crash tests were used to draw conclusions relative to how the child safety seat was loaded during the collision. Comparison of the position of the clip before, during, and after the crash test was assessed. This additional data was reviewed relative to the University of Michigan Transportation Research Institute (UMTRI) Research Review’s Crash Protection for Child Passengers conclusion that “clips slide down the straps as the child presses forward or may break if sliding is restricted.”[2] Also, for a subset of the crash data collected, direct measurement of the clip displacement was measured. Analysis of this data was used to draw conclusions regarding how much clip movement is typical in a FFCSS when installed in the rear occupant positions of vehicles in a 35 mph frontal barrier crash test.