Effects of LATCH versus Available Seatbelt Installation of Rear Facing Child Restraint Systems on Head Injury Criteria for 6 Month Old Infants in Rear End Collisions

Methods

The test matrix included 36 rear impact sled tests conducted using 3 installation methods on 3 models of RFCRS: the Graco SnugRide® with and without the base, the Britax Chaperone with base-mounted anti-rebound bar, and the Evenflo Tribute® , a model of convertible rearward/forward facing restraint system used in the rearward facing mode. The seats were installed using the LATCH system, ELR lap/shoulder belts, or ALR lap/shoulder belts in seating positions 4 and 6 on a vehicle buck mounted to the sled test base.

The infant seat and 6 month old CRABI anthropometric test device (ATD) installation methods were in accordance with standards set forth in the National Highway Traffic Safety Administration's (NHTSA) FMVSS No. 213, Child Restraint Systems. All tests were conducted on pneumatic controlled acceleration sled (HYGE, Inc., PA, USA) at 48 km/h. Results: Installation of infant seat type RFCRS using the LATCH system resulted in higher HIC 15 values when compared to using the available lap/shoulder seatbelt (ELR or ALR).

The mean HIC 15 values were most severe when infant seat type RFCRS were installed using LATCH ( Graco SnugRide® HIC 15 = 394 and Britax Chaperone HIC 15 = 133) compared to using either ELR lap/shoulder belts ( Graco SnugRide® HIC 15 = 218 and Britax Chaperone HIC 15 = 65) or ALR lap/shoulder belts ( Graco SnugRide® HIC 15 = 194 and Britax Chaperone HIC 15 = 78). The installation method did not result in a statistically significant difference in HIC for the convertible type RFCRS ( Evenflo Tribute® ).

In many of the tests, the ATD's head struck the seatback in which the RFCRS was installed. These head strikes resulted in the higher HIC 15 scores recorded throughout the testing. Conclusions: The results of this study suggest that LATCH does not offer equal protection to lap/shoulder belts from head injuries in rear impacts when used with infant seat type RFCRS.