Research In Action

Over the past few months, there has been renewed dialogue about the best practice recommendation from the American Academy of Pediatrics (AAP) that advises child passengers be restrained in rear-facing child restraint systems (RFCRS) until at least age 2. The AAP based this 2011 recommendation on years of research that demonstrated a safety benefit to keeping younger children rear-facing, including biomechanical studies and sled testing/field data from Swedish researchers, and a study from Henary et al. (2007) that established a reduction in injury risk for children 0-23 months riding rear-facing using data from the National Automotive Sampling System Crashworthiness Data System (NASS-CDS).

A new study published in Injury Prevention by McMurry et al. reevaluates the safety benefits of restraining child passengers in RFCRS versus forward-facing child restraint systems (FFCRS) using NASS-CDS data, both from years 1988-2003 to compare with the 2007 Henary et al. study and with updated analyses to include all available data using NASS-CDS years 1988-2015.

The study found that for both 0- to 11-month-olds and 12- to 23-month-olds, those in RFCRS had a lower rate of injury compared to FFCRS. However, the amount of data on child injuries available in the NASS-CDS database are insufficient to confirm that these differences are statistically significant.

Does This Change Anything?

Child passenger safety technicians, pediatricians, and others may be wondering how the results of this reanalysis might impact the child passenger safety guidance provided to parents and caregivers.

First and foremost, the best practice recommendation from the AAP remains that children should ride in RFCRS until at least age 2 or they have outgrown the height or weight limits for their RFCRS.  This message should not change when advising parents or parents-to-be about CPS best practice for infants and toddlers.

What has changed is that we can’t get too specific with claims of significance based on the field data. The results of the Henary et al. study indicated that children 0-23 months were five times safer in RFCRS compared to FFCRS. While these data suggest that children are indeed safer riding rear-facing and align with other research in this area, we cannot associate a specific number or figure to that safety benefit. We compiled a list of common questions and answers about keeping children rear-facing longer that are often received at car seat checks.

What About State Laws?

According to the Governors Highway Safety Association, there are currently eight US states that require children under age 2 to be restrained rear-facing with one additional state law confirmed to go into effect in 2019. We previously posted about the complexities of translating best practice recommendation into law, saying in part: Laws cannot account for the myriad of variations in children and restraint systems that are on the road, but can set a common standard for a given population. Click here to read the full post.

Finally, it is of vital importance to note that the recommendation to restrain children under age 2 rear-facing is not based on a single study, but rather on a broad body of research from the US and Sweden. These citations are included below for easy reference.

1. Sherwood CP, Crandall JR. Frontal sled tests comparing rear and forward facing child restraints with 1-3 year old dummies. Annual Proceedings of the Association for the Advancement of Automotive Medicine. Association for the Advancement of Automotive Medicine, 2007,51: 169-80.
2. Planath I, Rygaard C, Nilsson S. Synthesis of data towards neck protection criteria for children. Proceedings of the 1992 International IRCOB Conference on the Biomechanics of Impacts. Verona, Italy:155-66.
3. Kamren B, Koch M, Kullgren A, et al. The protective effects of rearward facing CRS: an overview of possibilities and problems associated with child restraints for children aged 0-3 years. Child Occupant Protection Symposium: SAE International, 1993.
4. Klinich KD, Manary MA, Weber KB. Crash protection for child passengers: rationale for best practice. UMTRI Res Rev 2012;43:1-35.
5. Isaksson-Hellman I, Jakobsson L, Gustafsson C, et al. Trends and effects of child restraint systems based on Volvo’s Swedish accident database. 41^st Stapp Car Crash Conference: SAE International, 1997.
6. Jakobsson L, Isaksson-Hellman I, Lundell B. Safety for the growing child: experiences from Swedish accident data. Proceedings of the 17^th ESV Conference, 2005.