Injury potential at center rear seating positions in rear-facing child restraint systems in side impacts.

Head injuries occur to occupants of rear-facing child restraint systems in side impacts. This study examined the head injury potential of center-seated occupants using sled tests at change in velocities of 35, 29 and 24 km/h. Other parameters included combinations of with and without a simulated door. A twelve-month-old child dummy was used in combination, convertible and infant rear-facing child restraint systems. Head excursions and head injury criteria (HIC) were obtained. In 35 km/h tests without simulated door, head excursions ranged from 568 to 655 mm, exceeding the simulated door intrusion plane. HIC ranged from 87 to 157, below the 390 limit. At this velocity but with the simulated door, HIC ranged from 804 to 1297. Head excursions ranged from 424 to 480 mm. In 29 and 24 km/h tests, the dummy and child restraint system impacted the simulated door. HIC ranged from 275 to 604 and 141 to 314, and head excursions ranged from 388 to 470 mm and 365 to 460 mm, respectively. Far-side belt loads were 2.4-3.2 kN and 1.7-2.3 kN for the 35 km/h tests without and with the simulated door, and 1.5-2.1 kN and 1.0-1.6 kN for 29 and 24 km/h tests with the simulated door. These findings indicate that occupants in the center seating position in smaller/medium-size vehicles may impact an intruding door and sustain head injuries. A need exists for better protection/attachment methods for center positioned rear-facing child restraint systems to reduce the injury potential in side impacts at velocities greater than 29 km/h.