Rotating convertible child restraint systems and their potential effect on correct use in rear-facing mode

Field obervation of CRS use shows that a large portion (65% to 94%) of CRS are misused. In this study, we compared the field use of three different 5-point harness CRSs in rear-facing convertible mode: the first was a "rotating" car seat (RCRS), where the seat portion of the RCRS can be completely detached from the base and can be rotated to face the parent/caregiver during child ingress and egress. The other two CRSs were conventional convertibles (CRS1 and CRS2). We hypothesize that the RCRS has higher correct use rates on initial inspection compared to two other CRS designs in rear-facing mode.

The National Digital Car Seat Check Form (NDCF) is a data collection instrument used by certified Child Passenger Safety Technicians to record data on child restraint use and interventions during child passenger safety inspections throughout the United States. The NDCF database was searched for children using an RCRS, CRS1 or CRS2. Outcome variables were binary (1 = proper; 0 = improper) measures of common misuse parameters - correct harness use, correct recline angle, and correct lower attachment. Child age in whole years, state law, body mass, and vehicle type and age were considered as explanatory variables.

752 records were included in the dataset from inspections in 48 U.S. states. Compared to conventional car seats, children seated in an RCRS had 1.4 [95% CI: 1.0, 2.0] times greater adjusted odds of correct harness use when controlling for state law and vehicle type. RCRS children had 2.6 [95% CI: 1.8, 3.8] times greater odds of having the correct recline angle with a modest effect of vehicle age (aOR = 0.97 [95% CI: 0.944, 0.999]). RCRS children had 1.9 [95% CI: 1.3, 2.8] times greater odds of having a correct lower attachment to the vehicle. Outboard seating and LATCH were significant factors in proper CRS-to-vehicle lower attachment.

Rear facing rotating-type convertible car seats increased overall proper use in a population that sought child passenger safety instruction from qualified technicians. More research is necessary to determine if these effects persist in the general population, in forward facing modes of use, and with other rotating car seat models.