Based on the varying degrees of stress and cracking exhibited in samples from the March 2010 production, and in order to see how the seats would perform with the maximum allowable weight in the harness, we then tested four additional Cosco Highbacks with the test dummy weighted to 40 lbs. These included two seats with March 2010 production dates purchased from an online retailer in October 2011, and two seats produced on Oct. 26, 2011 that were purchased in December from a major retail store in Connecticut.
For our Round Three tests, lead weights were attached to the thigh and torso areas of standard 35-pound dummies to achieve the 40-pound maximum the manufacturer specifies for harnessed use of the seat.
Use of a weighted dummy is not a procedure used in our normal test protocol, but because some of the samples of the seat had cracked in crash tests using 35-pound dummies, we were interested to know what would happen if the seat held a child at the top end of the permitted weight range. For comparison, we also used the 40-lb. dummies and LATCH installation to test three other toddler-booster models designed to handle children up to 40 lbs. in harness mode.
Once again, one Cosco Highback seat from each production period was installed using the LATCH system and the other using the 3-point lap-and-shoulder belt. For tests utilizing the weighted dummies, we looked only at the structural integrity of the seat.
Results: We saw no cracking in the following models tested with the 40-lb. dummies: Evenflo Chase, Safety 1st Summit or Safety 1st Vantage. (Both of the Safety 1st seats are also made by Dorel Juvenile Group, manufacturer of the Cosco Highback.) The Cosco Highback manufactured in March 2010 that was installed with the LATCH system had cracking around the center front adjuster with loosening of the harness that was similar to Round One results. In the other Cosco Highback – the one attached with lap-and-shoulder belt – there was only moderate cracking and no harness loosening. And there was no cracking near the center front adjuster in either of the two Cosco Highback samples manufactured in 2011.
For an overview of our Cosco Highback results, including a response from the manufacturer, please click here.