Rear-facing car seats have been shown to significantly reduce infant and toddler fatalities and injuries in frontal and side-impact crashes, but they're rarely discussed in terms of rear-impact collisions.
Because rear-impact crashes account for more than 25% of all accidents, researchers at The Ohio State University Wexner Medical Centre conducted a new study to explore the effectiveness of rear-facing car seats in this scenario.
"It's a question that parents ask me a lot, because they are concerned about the child facing the impact of the crash," said Julie Mansfield, lead author of the study and research engineer at Ohio State College of Medicine's Injury Biomechanics Research Centre. "It shows parents are really thinking about where these impacts are coming from."
Mansfield and her team conducted crash tests with multiple rear-facing car seats, investigating the effects of various features like the carry handle position and anti-rebound bars. The study, which is published in SAE International, shows that when used correctly, all were effective because they absorbed crash forces while controlling the motion of the child, making rear-facing car seats a good choice in this scenario.
"Even though the child is facing the direction of the impact, it doesn't mean that a rear-facing car seat isn't going to do its job," said Mansfield. "It still has lots of different features and mechanisms to absorb that crash energy and protect the child."
Mansfield says what they found aligns well with what is known from crash data in the real world, and it's important for parents to follow the recommended guidelines on the correct type of car seat for their child's height, weight and age.
"The rear-facing seat is able to support the child's head, neck and spine and keep those really vulnerable body regions well protected. These regions are especially vulnerable in the newborns and younger children whose spine and vertebrae haven't fused and fully developed yet," said Mansfield.
This research was funded by the Center for Child Injury Prevention Studies (CChIPS) at The Children's Hospital of Philadelphia.
This study examines the performance of rear-facing child restraint systems (RF CRS) in moderate severity rear impact sled tests. The study also investigates the effects of RF CRS features on CRS kinematics and anthropomorphic test device (ATD) injury metrics in this scenario. Twelve tests were conducted at a moderate severity rear impact sled pulse (approximately 28.2 km/h and 18.4 g). Four models of RF CRS were tested in the rear outboard positions of a sedan seat. The CRABI 12-month-old and Hybrid III 3-year-old ATDs were instrumented with head and chest accelerometers, head angular rate sensors, six-axis upper neck load cells, and a chest linear potentiometer (3-year-old only). The effects of carry handle position, occupant size, presence of anti-rebound bar, Swedish style tethering, and lower anchor vs. seat belt installation were investigated. Data were also compared to pediatric injury assessment reference values (IARV). Head Injury Criterion (HIC15) values ranged from 9.6 to 89.2. Chest resultant accelerations (3 ms duration) ranged from 21.3 to 39.9 g. Neck loads and head contact against seat structures varied depending on the features of the CRS. The results indicate that RF CRS mitigate crash forces with a variety of methods in the moderate severity rear impacts performed in this series. This study provides experimental data to address this crash scenario, which are currently lacking in the literature. These conclusions are supported by epidemiological and field data which indicate RF CRS provide good protection for young occupants.
Julie Mansfield, Yun-Seok Kang, John Bolte
[link url="http://osuwmc.multimedia-newsroom.com/index.php/2018/04/03/study-are-rear-facing-car-seats-safe-in-rear-end-crashes/"]The Ohio State Wexner Medical Centre material[/link]
[link url="https://www.sae.org/publications/technical-papers/content/2018-01-1325/"]SAE International abstract[/link]