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Evidence-Based Strategies for Common Clinical Questions

September 2021

One Can’t Beat the Safety of a Seat


Author: Michelle Brown, DO | Chief Resident – Pediatrics


Column Editor: Kathleen Berg, MD | Co-Director, Office of Evidence-Based Practice | Pediatric Hospitalist, Division of Pediatric Hospital Medicine | Clinical Assistant Professor of Pediatrics, UMKC School of Medicine 


With return to in-person learning, many children are taking the roads to schools and day cares this fall. To get there safely, parents and other caregivers must be prepared to use child car seats properly. Motor vehicle accidents are a leading cause of death in children, and the National Highway Traffic Safety Administration (NHTSA) found that 37% of these children were improperly restrained or not in a restraint system at all.1 To ensure the safety of our patients, we should review the following car seat quick tips and resources. This brief anticipatory guidance can be seamlessly integrated into a busy clinic schedule.

Children transition slowly from a rear-facing infant seat to a rear- or forward-facing convertible seat, a booster seat and finally a seatbelt alone. As a child grows, their body composition changes, influencing how it responds to the impact of a collision. Parents may be excited about milestones and eager to transition to the next seat, but it is almost always safer to wait until the child is nearing the height or weight limits of the seat before making the change. Each seat is different, so encourage parents to research their specific seat specifications, and clarify that the seat needs to be changed if they outgrow any one of the limitations.  

Choosing the best seat is the first step, but if not properly installed, it will not be effective in keeping the child safe. Most (91.7%) of surveyed caregivers reported confidence that their seat was correctly installed.2 However, the NHTSA reported car seats are improperly installed 46% of the time.3 Much of the confusion is related to angle of recline, chest strap placement and seat securement.4,5

  • Angle of recline: Like height and weight guidelines, each manufacturer has its own specifications for seat angles. Recline angles are typically 30-45 degrees to optimize airway patency and reduce head movement. Infants and small children have disproportionately large heads and predominantly cartilaginous necks with weak musculature. With proper recline, the head is less likely to roll forward, preventing airway occlusion and severe neck injury. This can be indicated through a ball, color zone or line on the seat.
  • Chest strap placement: Strap installation can be particularly confusing. Placement of straps in relation to a child’s shoulders depends on the type of seat. For rear-facing seats, straps should enter just below the top of the shoulders, allowing it to wrap up and around, hugging the shoulders. This prevents excess movement, ensuring the child remains within the protective shell of the car seat. A forward-facing seat should have straps originating at or just above the child’s shoulders. For both, the chest clip should fall over the sternum and be tightened so only one finger can fit between the sternum and clip.
  • Seat securement: When securing a car seat, seatbelts and LATCH systems are equally efficacious; that said, parents should only choose one. Regardless of which system, remind parents that when using a forward-facing seat, it is critical to use the back tether strap. This secures the head portion of the seat more securely to the vehicle. A good rule of thumb is that, once secured, the car seat should not be able to shift in any direction more than one inch.

Once meeting forward-facing limitations, children transition to a booster seat. By this time, bones are more ossified and head control is largely improved with strengthened musculature. Boosters ensure proper placement of the seat belt through lifting hips, allowing direct contact with the pelvis and sternum. Boosters are used until children are both 4 feet 9 inches AND 8-12 years old.5,6 However, even children of this height may not meet the five-point fit test requirements in some larger vehicles.7

Car seat installation and guidelines can be quite complex, so pediatricians should remind caregivers about car seat safety during clinic visits. In a survey of caregivers, those who reported discussing car seat safety with a pediatrician were more likely to comply with rear-facing guidelines.8 One valuable resource is the American Academy of Pediatrics 2018 Policy Statement which includes an algorithm to determine the correct car seat type.5 Another is the NHTSA website (, which provides local inspection stations, staffed with certified inspectors, who can provide installations, checks and instruction.9



  1. Traffic Safety Facts. (2019, May). Report No. DOT HS 812 719. Washington, DC: National Highway Traffic Safety Administration.
  2. Levi S, Lee H, Ren W, McCloskey S, Polson A. (2020). Reducing child restraint misuse: National survey of awareness and use of inspection stations. Traffic injury prevention, 21(7), 453–458.
  3. Greenwall NK. (2015, June). National Child Restraint Use Special Study. Traffic Safety Facts Research Note. Report No. DOT HS 812 157. Washington, DC: National Highway Traffic Safety Administration.
  4. American Academy of Pediatrics Car Seats: Information for Families. Last accessed Aug. 15, 2021.
  5. Durbin DR, Hoffman BD, and Council on Injury, Violence, and Poison Prevention (2018). Child Passenger Safety. Pediatrics, 142(5), e20182460.
  6. Brolin K, Stockman I, Andersson M, Bohman K, Gras L, Jakobsson L. (2015). Safety of children in cars: A review of biomechanical aspects and human body models. IATSS Research, 38(2), 92-102.
  7. Morse AM, Aitken ME, Mullins SH, Miller BK, Pomtree MM, Ulloa EM, Montgomery JS,  Saylors ME. (2017). Child seat belt guidelines: Examining the 4 feet 9 inches rule as the standard. The Journal of Trauma and Acute Care Surgery, 83(2), 305–309.
  8. Jones AT, Hoffman BD, Gallardo AR, Gilbert TA,  Carlson KF. (2017). Rear-facing car safety seat use for children 18 months of age: Prevalence and determinants. The Journal of Pediatrics, 189, 189–195.e9.
  9. National Highway Traffic and Safety Administration. Car Seats and Booster Seats. Last accessed Aug. 15, 2021.