Documentation:FIB book/Child Safety Seats in Side Impacts

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Introduction

Front-facing child safety seat installed in the rear seat of a car.

Child safety seats (also known as child restraint systems) are an important safety device for children riding in automotive vehicles to prevent injury and death. They are generally required for children under the age of 12 with both international and regional regulations governing their use.[1] Three stages of car seats have been defined based on age and weight: rear-facing for infants (weight less than 10 kg), forward-facing for smaller children (weight between 10-18 kg), and booster seats for larger children (weight greater than 18 kg).[2] With rising concerns over the safety of vehicle occupants, child safety seats were first introduced in the late 1960’s by car manufacturers.[3] The safety protections provided by the seats have evolved drastically since this time and so have the policies surrounding child safety in vehicles.

In 2021, in the United States, an estimated 162,298 children were injured in a motor vehicle crash and 950 were killed as occupants in a vehicle.[4] Improving safety for children in vehicles is an important priority and children in forward-facing safety seats have a 71% reduction in likelihood of serious injury compared to children wearing a seatbelt alone.[5] Side-impacts make up the greatest proportion of crashes that result in child fatalities with 30% occurring in a side-impact compared to only 22% for rear impacts and 17% for frontal collisions.[6] Similarly, side-impacts produce more 2+ maximum abbreviated injury scale (AIS) injuries for children than any other crash type. [7] 41% of these serious injuries occur from side-impacts with only 17% from frontal and 3% from rear collisions. Long-term medical impairment due to a crash is less common in children than adults, but even low AIS level injuries (<3), especially of the head and cervical spine, can result in long-term medical consequences.[8] There is a need for more rigorous biomechanical testing to investigate child safety seats in side impact collisions. Ensuring that child safety seats are effective in preventing injury during side-impacts is paramount.

Biomechanics of Children in Side Impacts

The most common serious crash injuries for children occur in side-impacts and specifically when sitting on the struck side of the car.[9] The majority of injuries are to the head and face with the most severe injuries (AIS 3+) occurring when the child impacts the seat back or car interior (including the interior door panelling).[10] Cadavers are not commonly used in tests to assess the biomechanics of side-impacts since there are few child cadavers. Instead, child anthropometric devices (ATDs) are used in crash or sled tests. These ATDs have been previously validated for biofidelic responses using animal models or cadavers.[11] In some tests, specific real world crashes are replicated and the forces, moments, and accelerations on the ATD are correlated with the level of injury seen in the real crash.

Diagram of test setup in Yoshida et al. [9] Approaching vehicle travelling at 50 km/hr impacts stationary target vehicle at 45 degree angle with Q3s anthropomorphic test device (ATD) in struck side rear seat.

In a study performed by Yoshida et al., they used a Q3s dummy to investigate the motion of a child in a safety seat when sitting on the impact side.[9] The authors worked to fill a research gap in how exactly a child moves within the car in this type of collision to develop representative sled tests. They set up a crash test with a stationary car and an SUV approaching at a 45 degree angle travelling at 50 km/h. While testing setups vary by study, this paper's methods are representative of a typical crash testing scenario featuring an acute angle collision at representative speeds. The dummy experienced translational motion towards the far side and front of the vehicle until about 90 ms when the car safety seat harness engaged fully with approximately 300 N of force. Then, the head and neck flexion began and the head of the dummy impacted the car window. This resulted in a maximum head acceleration of 1586 m/s2 and a head injury criteria (HIC) 15 value of 702. This HIC15 value is greater than the injury assessment reference values (IARV) for a three year old indicating a high risk of serious head injury.[12] More generally, side-impacts with a child in a safety seat result in translational motion of the whole child and seat before the restraint system stops the motion. The head is still able to move relative to the upper torso while restrained and this results in high head acceleration and moments about the neck. As the child's head commonly impacts the seat or the interior of the intruding car the most frequent injuries seen are of the head and neck.

Regulatory Tests

FMVSS

Diagram of head excursion measurement during impact

Within the United States, the Federal Motor Vehicle Safety Standards (FMVSS) are regulations issued by the National Highway Traffic Safety Administration (NHTSA).[13] FMVSS No. 213 is the standard for child restraint systems which includes frontal impact testing. Most recently it has been updated to include FMVSS No. 213a, which includes a dynamic side-impact test.[14]

Following the latest addition to these standards, child restraint systems must comply with this regulation and the performance requirements it sets out. Child restraint systems for FMVSS 213 regulation testing are for children weighing up to 40 lbs or as tall as 3.6 feet.[14] For side-impacts specifically, the child restraint system must meet performance criteria, which states that the system must “provide proper restraint, manage side crash forces, and protect against harmful head and chest contact with intruding structures”.[14] This criterion requires that the child restraint system limits the inertial load exerted on the head and chest of the child dummy throughout the side-impact test, to demonstrate the efficacy of the restraint system and its ability to remove these loads. As well, this standard requires the restraint system to limit the head excursion to the obligatory amount to decrease the possibility of head injury due to impacts on interior vehicle surfaces.[14] Head excursion is defined as the distance the child ATD's head translates from it's initial position during impact.[14] Sled testing is also mandated, to ensure the restraint system can withstand crash forces and will not collapse or injure the child.[14]

Additionally, FMVSS 213 also establishes requirements for the belt webbing of the restraint system. The buckles must be designed to be released quickly by an adult, while remaining difficult to unbuckle by the child in the restraint system. The restraint systems must also pass requirements depending on if the system is only anchored by a seatbelt, or anchored by the restraint anchorage system.[14] The FMVSS 213 includes a dynamic sled test to simulate a vehicle-to-vehicle slide impact, as well as an intruding door.[14] NHTSA performed a series of tests to determine the most representative testing parameters. The chosen sled test has a 10 degree buck impact angle, a trapezoidal sliding seat acceleration profile, and a 31 km/h door velocity.[14] The Q3s dummy is used to represent a 3 year old weighing 30 to 40 lbs. After the tests, the dummy is inspected, as it is for the FMVSS 213 frontal impacts. The requirements for the sled test include a head excursion limit of 813mm without the use of a tether (lap belt only) at 30 mph, and a head excursion limit of 720mm with the use of tether, using the universal anchorage system at 30 mph.[15] The HIC15 value for the 3 year old dummy shall not exceed 570 throughout any of the tests within FMVSS 213.[16]

As 60% of the fatalities in side-impacts occurred to children sitting on the side of the impact, the FMVSS regulations only test side-impacts with the child-restraint on the near side.[14] Utilizing only one position in the vehicle in a simulated side-impact as a standard could limit the results and conclusions from these tests, and therefore future work should be done to improve upon this.

Regulatory Controversy

It’s worth noting that there is significant controversy around NHTSA's delay in development of side-impact regulations for child restraints. US congress mandated the development of standards to protect children during side-impact collisions in 2000, however it was not until 2022 that these standards were brought forward by NHTSA. Public pressure to implement side-impact standards for child restraints mounted in 2020 after investigations by CBC News and ProPublica about the lack of regulatory requirements.[17] [18] This was initiated after a five year old child was paralyzed from the neck down after a side-impact collision while seated in a booster seat marketed as being side-impact tested.[17] ProPublica’s investigation revealed that the side-impact testing conducted by the manufacturer of the seat only marked a test as a failure if the ATD fell completely out of the restraint or if the restraint itself broke.[18] There was no consideration for mitigation of serious injury. US regulation allows a child 30 pounds and over to use a booster seat instead of a 5-point harness safety seat.[18] In Canada, the regulatory limit, established in 1987, to transition to a booster seat is 40 pounds.[18] The limit of 40 pounds has also been recommended by the American Academy of Pediatrics since 2002.[18] Following these investigations, 18 US state Attorney Generals wrote a letter urging NHTSA to implement standards for side-impact testing swiftly, as well as change the regulation around transitioning into booster seats to 40 lbs.[19] The letter argues that due to lack of standards in place side-impact testing is at the manufacturers discretion.[19] This makes it difficult for parents to assess the safety of the child-restraint they are purchasing. Additionally, most consumers are not aware that there are no governmental standards for side-testing.[19] As of 2022, car seats for children will now have to comply with the regulatory testing of side-impacts at 30 mph, however child restraint system manufacturers have until June 30, 2025 to comply.[18] Further rules about delayed transition to booster seats are to follow;[18] several state laws already mandate that children under 40 lbs use child-restraint systems and not booster seats.[20]

CMVSS

Under the Canada Motor Vehicle Safety Standards, Transport Canada conducts similar tests to the FMVSS for child restraint systems to determine the performance of a range of child restraint systems during vehicle impacts.[21] Transport Canada conducts tests including using 1) the seatbelt and upper tether, 2) using universal anchorage system (lower anchors) and the upper tether, as well as 3) using the universal anchorage system, the upper tether, and the seatbelt together.[21] The side impact tests are conducted by simulating a car-to-car collision at 50 km/h.[22]

Similar to the FMVSS, the CMVSS includes testing for the belt webbing and buckles, with a requirement of the buckle not releasing if less than 40N of force is applied as well as not releasing during the dynamic sled testing.[22] In addition, the CMVSS requires no rigid structures in front of the child restraint system unless used to limit the movement of the child, no protrusions more than 9.5mm, and no exposed edges with a radius less than 6.4mm.[21] The dynamic testing, with exceptions specified in the Code of Federal Regulations by the United States - as noted in CMVSS 215, includes the requirements of the child restraint system remaining in the same placement as when the test began, and no resulting exposure to protrusions or edges as specified before.[21]

Safety Features

Harnesses

The safest harness available for front-facing child safety seats is the 5-point harness system which is built into the seat itself.[22] The straps are thinner than that of a regular seat belt and go over the shoulders, across the lap and between the legs of the child. Due to the many points of the harness, the force can be spread out over the shoulders, chest, abdomen, and hips of the child, reducing the chance of injury in a collision.[22] This harness provides greater safety for the child than a lap and seat belt, or seat belt alone, with points of contact that are correct for the smaller anatomy of the child.

Appropriate restraints for the size and weight of the child, such as a harness or lap belt, play a large role in the risk of a severe injury.[23] Higher risk of injury is predominantly seen in children using adult seat belts, as the belt does not properly fit, leading to an increase in head and torso excursion during side-impacts.[24] Harnesses are tightened by the adult securing the child, and loose harnesses can increase the chance of injury through increased head excursion or larger impacts to the side wings.[23] Harness looseness has been documented as an “extremely common misuse” mechanism, and is a significant cause of increased injury.[24] Despite the requirement for manufacturers to provide clear instructions on proper restraint system installation and positioning of the child in the restraint system, there is always the possibility of human error.[21] For example, a winter coat may provide the illusion that the harness is tight and secure around the child, while in reality it may still be too loose, thus leading to an increase in injury severity in the event of a collision.[25] The studies referenced above determined the injury mechanisms in children restrained in child restraint systems during side-impacts, as well as the overall risk of children in various restraint systems or misused restraint systems.

Side Wings

Child safety seat with wings present on the top right and left of the seat.

Side wings are added to child safety seats to: 1) provide a padded barrier between the child and intrusion of any car components and 2) provide a structure that limits lateral head movement.[26] During near side-impacts, the most serious injuries for children have historically been head, neck, and brain injuries related to occupant compartment intrusion, as seen by crash tests and the FARS and CDS databases.[6] While the wings help limit this, Kapoor et al. found that they can also cause strong head decelerations due to contact of the head with the side wings. Additional energy absorption foam can help to lengthen this deceleration and protect the child's head.[27] During side collisions where the child safety seat was positioned in the middle or far side, Hauschild et al. found that the presence of side wings had no influence on lateral head excursion, resultant acceleration, neck tension, or HIC15 values.[26] This is due to the movement of the seat towards the point of impact, causing the child's head to roll out of the child safety seat regardless of the wings being present or not. Overall, properly padded wings on the child safety seat can help protect them from head injuries during near side-impacts but do not protect them while seated in middle or far side positions. Prior to these studies by Kapoor et al. and Hauschild et al., there had been no specific research on the effects of side wings on the safety of children seated in the near impact, middle, or far impact side of the car during a side-impact collision.[27][26]

Anchorage Systems

How the child safety seat is attached to vehicles' seats, both through the top tether and the lower anchorage system, has been found to influence head kinematics during side-impacts. As head injuries are the most serious fatal injury observed in children in side-impact collisions, several studies have been done to better define the impact that the anchorage system has on head and neck kinematics in order to improve our understanding of how to best design child restraints.[28]

Top Tethers

A top tether is strap from the top back of the child restraint that is routed over the top of the vehicle's seat to secure to a built in attachment point on the back of the vehicle's seat or on the floor. The use of a top tether reduces the chance of injury to the head and neck. Hauschild et al. investigated the effect of top tethers on kinematics during side-impact as most of the previous research had focused on top tether use only during frontal collisions.[29] They discovered that the use of a top tether to secure the seat in oblique side-impacts reduced lateral head displacement, HIC15, lateral chest deflection, lateral shoulder deflection and resultant pelvis acceleration.[29] Most notably, HIC15 was recorded at an injurious level without the top tether (589) but was reduced by 40% when a top tether was used (to 332).[29] The HIC15 injury limit of a 3-year old child is 570.[29] It has also been determined that the type of top tether can further impact head and neck kinematics during far-side oblique impact. A tether that goes over an integrated headrest results in smaller head accelerations, HIC, and neck tension compared to one that is tethered through an adjustable headrest as shown in Hauschild et al.’s study.[26] They measured a neck tension of 2.0 kN and 1.2 kN for the adjustable headrest and integrated headrest respectively. However, the top tether of the integrated headrest slipped off the headrest shortly after impact resulting in greater head excursion, this would put a child seated on the near side of the car at risk of head impact with the door.[26] Overall, the use of a top tether significantly reduces the chance of head and neck injury in side-impact collisions.

Lower Anchorage Systems

Image of the where the seat back meets the seat cushion. A piece at this junction has been removed and you can see underneath a metal bar with square attachments points on the left and right side.
ISOFIX lower anchorage system

There are three lower anchorage systems for forward facing child restraints. ISOFIX was developed by the International Standards Organization Committee and consists of two rigid connectors built into a vehicle seat onto which the child restraint can snap on. LATCH is a modified version of ISOFIX, where instead of rigid connectors there are two flexible tethers, made from webbing, built into the seat bight. ISOFIX technology is common in Europe, while LATCH is favored in North-America. The adult seat belt can also be used to secure a child-restraint by routing it through a path at the back of the seat. Charlton et al. investigated how these anchorage systems compare in side-impact in order to better inform government regulations. For far-side lateral impacts, ISOFIX significantly reduces head excursion, compared to the other two anchorage systems. The maximum head excursion during a low impact crash (delta V = 15 km/h) was 280 mm using ISOFIX, 460 mm using LATCH and 450 mm using the seatbelt attachment. ISOFIX also prevents head impact during the rebound phase, while the other two anchorage systems do not. For near-side lateral impacts, the seat belt anchorage system results in the greatest head excursion (430 mm) during the rebound phase while the use of ISOFIX more than halves head excursion in comparison (200 mm). ISOFIX’s rigid attachments reduce the child safety seat’s movement during impact and thus reduces the chance of injury to the child. ISOFIX is the safest lower anchorage system for side-impact collisions.[28]

Limitations

When considering the studies on child restraints in side-impacts, the complexity of the problem presents several limitations. There are many different variables that can affect child kinematics during side-impact. These include, but are not limited to, the model of the child safety seat tested, the type of anchorage system, the impact pulse, the presence of sidewings, and the tension of the harness. Many of the studies discussed above only explored one or two variables. This makes it challenging to determine how the other factors play a role in the results. In the study comparing different styles of top tethers, there were confounding variables of seat type and tether length.[28] Therefore, it could be these confounding factors that result in the top-tether that goes over the integrated headrest being safer. The study conducted by Yoshida et al., discussed in the Biomechanics of Children in Side Impacts section, was restricted to SUV striking a small car. Crash test parameters were simulated so that the vehicle was travelling at 50 km/h, this assumes that no evasive braking action was taken by the striking car.[9] Additionally, two studies neglect to account for the effects of intrusion. In the study by Hauschild et al. (2015) that examined both the effects of top tethers and side wings, no simulation door was included in the sled test. Therefore, the effects of intrusion and any possible associated head contact were excluded from the results. When testing the effects of lower anchorage systems, Charlton et al. included a simulation door on the sled test, however they also did not account for any intrusion. Therefore, it is possible that during real world collisions increased head contact would occur due to the narrowing of distance between the child restraint and the door. As well, in all of the biomechanics studies explored above, only one or two child safety seats were used in testing.[22] This evidently cannot reflect all variation of child restraints commercially available. Other considerations include how the vehicle seat interacts with the child safety seat and how varying car models have different distances between the child restraint and car door.

Furthermore, the epidemiological data does not account for correct use of the child-restraints. Incorrect use, particularly incorrect anchorage, of child restraints can increase chance of injury or fatality.[30] This makes test validation difficult, as it is hard to compare test data with data collected from real-world collisions. This issue of validation is heightened by the uncertainty surrounding the biofidelity of child ATDs. The critical issue with child ATDs is the lack of biomechanical data because the only methods available for researchers are animal testing or scaling from adult models. The study by Kapoor et al. studied the effects of side wings using validated FEA models of both the Hybrid III 3 year old ATD and the Q3 ATD to determine the effect of energy absorption foam, however, there was significant difference in the effect of foam on head kinematics between the two ATDs.[27] Due to child ATD validation issues it is difficult to determine which of the models is the most accurate representation of real world scenarios. The biofidelity of child ATDs is discussed in detail here.

The risk of injury is not well defined in children. Child values for Brain Injury Criterion (BrIC) have not been developed and there is no widely accepted criterion for the risk of neck injury during side-impact for children.[29] The risk of skull fracture has been defined under HIC, through scaling from adult data to account for difference in tissue properties and head size.[31] For these reasons many of the studies assessing the safety features of child restraints rely on comparisons of head excursion, resultant head acceleration and neck tension to determine if the risk of injury was reduced. However, these numbers are compared with limited understanding of their context in terms of likelihood of injury severity.

Future Work

The need for child safety seats is widely accepted by the public, but the data for how these seats perform is limited. More resources and time need to be put into analyzing the biomechanics of a properly and improperly restrained child in a side-impact crash. Following that, more crash tests need to be conducted with various models of cars and various child safety seats. The wide range of what is available on the market is not reflected in what has been tested in side-impact crashes. Future work completing tests with different car seats to quantify what features make a difference (such as angle of side wings, padding density, etc.) will increase the quality and relevance of data available to biomechanists and the public. Additionally, child safety seats being placed in the middle seat, or far side from the impact need to be explored more to see how the safety features of child safety seats can be improved for these occupants, as most of the research conducted focuses on near side-impacts. The addition of child safety seat testing to NHTSA Star Safety Ratings would also be a way to inform the public and improve the quantity and quality of testing being completed on child safety seats. This push by a government agency to highlight the need for crash testing of child safety seats would also likely encourage safety seat companies to make improvements based on the data collected.

References

  1. ↑ UNECE. Increasing the safety of children in vehicles For policymakers and concerned citizens [Internet]. Available from: https://unece.org/fileadmin/DAM/trans/publications/WP29/CHILD_RESTRAINT_SYSTEMS_brochure.pdf
  2. ↑ Transport Canada. Choosing a child car seat or Booster Seat [Internet]. / Gouvernement du Canada; 2019 [cited 2023 Nov 5]. Available from: https://tc.canada.ca/en/road-transportation/child-car-seat-safety/choosing-child-car-seat-booster-seat
  3. ↑ Levitt SD, Becker G, Cullen J, Dubner S, Heaton P, Murphy K, et al. Evidence that Seat Belts are as Effective as Child Safety Seats in Preventing Death for Children aged Two and Up. 2005.
  4. ↑ Highway Traffic Safety Administration, Department of Transportation. Traffic Safety Facts: 2021. 2023.
  5. ↑ Arbogast KB, Durbin DR, Cornejo RA, Kallan MJ, Winston FK. An evaluation of the effectiveness of forward facing child restraint systems. Accid Anal Prev. 2004 Jul;36(4):585–9.
  6. ↑ 6.0 6.1 Howard A, Rothman L, McKeag AM, Pazmino-Canizares J, Monk B, Comeau JL, et al. Children in Side-Impact Motor Vehicle Crashes: Seating Positions and Injury Mechanisms. The Journal of Trauma: Injury, Infection, and Critical Care. 2004 Jun;56(6):1276–85.
  7. ↑ Arbogast KB, Moll EK, Morris SD, Anderko RL, Durbin DR, Winston FK. Factors influencing pediatric injury in side impact collisions. Annu Proc Assoc Adv Automot Med. 2000;44:407–28.
  8. ↑ Bohman K, Stigson H, Krafft M. Long-Term Medical Consequences for Child Occupants 0 to 12 Years Injured in Car Crashes. Traffic Inj Prev. 2014 May 19;15(4):370–8.
  9. ↑ 9.0 9.1 9.2 9.3 Yoshida R, Okada H, Nomura M, Mizuno K, Tanaka Y, Hosokawa N. Head Impact Mechanisms of a Child Occupant Seated in a Child Restraint System as Determined by Impact Testing. In 2011.
  10. ↑ Mccray L, Scarboro M, Brewer J. Injuries to Children One to Three Years Old in Side Impact Crashes. 1996.
  11. ↑ National Highway Traffic Safety Administration (NHTSA), Department of Transportation (DOT) [Internet]. [cited 2023 Nov 6]. Available from: https://www.federalregister.gov/documents/2020/11/03/2020-21478/anthropomorphic-test-devices-q3s-3-year-old-child-side-impact-test-dummy-incorporation-by-reference
  12. ↑ Mertz HJ, Irwin AL, Prasad P. Biomechanical and Scaling Basis for Frontal and Side Impact Injury Assessment Reference Values. Stapp Car Crash J. 2016 Nov;60:625–57.
  13. ↑ Regulations [Internet]. [cited 2023 Nov 1]. Available from: https://www.nhtsa.gov/laws-regulations/fmvss
  14. ↑ 14.0 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 14.9 Federal Motor Vehicle Safety Standards; Child Restraint Systems, Child Restraint Systems-Side Impact Protection, Incorporation by Reference [Internet]. 2022 [cited 2023 Nov 1]. Available from: https://www.federalregister.gov/documents/2022/06/30/2022-13658/federal-motor-vehicle-safety-standards-child-restraint-systems-child-restraint-systems-side-impact
  15. ↑ Final economic assessment: FMVSS no. 213 and FMVSS No. 225 [Internet]. 1999 [cited 2023 Nov 1]. Available from: https://one.nhtsa.gov/cars/rules/rulings/UCRA-OMB-J08/Econ/RegEval.213.225.html
  16. ↑ Huntley M. Federal Motor Vehicle Safety Standard No. 213 Child Restraint Systems [Internet]. 2002 [cited 2023 Nov 1]. Available from: https://www.nhtsa.gov/sites/nhtsa.gov/files/mhuntley_sae2k2.pdf
  17. ↑ 17.0 17.1 Porat D, Callahan P. Evenflo, maker of the “big kid” booster seat, put profits over child safety [Internet]. 2020 [cited 2023 Nov 4]. Available from: https://www.propublica.org/article/evenflo-maker-of-the-big-kid-booster-seat-put-profits-over-child-safety
  18. ↑ 18.0 18.1 18.2 18.3 18.4 18.5 18.6 Cleave KV. After missing its own deadline, NHTSA announces side-impact crash-test standard for Child Car Seats [Internet]. CBS Interactive; 2022 [cited 2023 Nov 4]. Available from: https://www.cbsnews.com/news/nhtsa-side-impact-crash-test-standard-child-car-seats/
  19. ↑ 19.0 19.1 19.2 James L, Tong W, Bonta R, Jennings K, Racine KA, Raoul K, et al. [Internet] 2021. [cited 2023 Nov 4]. Available from: https://ag.ny.gov/sites/default/files/boosters_side_impact_letter_to_nhtsa_with_ag_signatures_final_7122021.docx.pdf
  20. ↑ What does your state law say about car seats? car seat laws by State [Internet]. 2023 [cited 2023 Nov 4]. Available from: https://saferide4kids.com/car-seat-laws-by-state/
  21. ↑ 21.0 21.1 21.2 21.3 21.4 Consolidated federal laws of Canada, Motor Vehicle Restraint Systems and Booster Seats Safety Regulations [Internet]. 2023 [cited 2023 Nov 1]. Available from: https://laws-lois.justice.gc.ca/eng/regulations/SOR-2010-90/FullText.html
  22. ↑ 22.0 22.1 22.2 22.3 22.4 Transport Canada. Protecting children in forward-facing car seats [Internet]. / Gouvernement du Canada; 2020 [cited 2023 Nov 1]. Available from: https://tc.canada.ca/en/road-transportation/motor-vehicle-safety/protecting-children-forward-facing-car-seats
  23. ↑ 23.0 23.1 Arbogast KB, Moll EK, Morris SD, Anderko RL, Durbin DR, Winston FK. Factors influencing pediatric injury in side-impact collisions. Journal of Trauma and Acute Care Surgery. 2001;51(3):469–77. doi:10.1097/00005373-200109000-00008
  24. ↑ 24.0 24.1 Winston FK, Durbin DR, Kallan MJ, Moll EK. The danger of premature graduation to seat belts for young children. Pediatrics. 2000;105(6):1179–83. doi:10.1542/peds.105.6.1179
  25. ↑ Ultimate Car Seat Guide -RIGHT FIT BASIC TIP #5 [Internet]. [cited 2023 Oct]. Available from: https://ucsg.safekids.org/basic-tips/right-fit/#5
  26. ↑ 26.0 26.1 26.2 26.3 26.4 Hauschild HW, Humm JR, Pintar FA, Yoganandan N, Kaufman B, Maltese MR, et al. The influence of enhanced side-impact protection on kinematics and injury measures of far- or center-seated children in forward-facing child restraints. Traffic Injury Prevention. 2015;16(sup2). doi:10.1080/15389588.2015.1064116
  27. ↑ 27.0 27.1 27.2 Kapoor T, Altenhof W, Howard A, Rasico J, Zhu F. Methods to mitigate injury to toddlers in near-side-impact crashes. Accident Analysis &amp; Prevention. 2008 Jul 3;40(6):1880–92. doi:10.1016/j.aap.2008.07.008
  28. ↑ 28.0 28.1 28.2 Charlton JL, Fildes B, Laemmle R, Smith S, Douglas F. A Preliminary Evaluation of Child Restraints and Anchorage Systems for an Australian Car. Annual Proceeding Association for the Advancement of Automotive Medicine [Internet]. 2004;48:73–86. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3217436/
  29. ↑ 29.0 29.1 29.2 29.3 29.4 Hauschild HW, Humm JR, Pintar FA, Yoganandan N, Kaufman B, Kim J, et al. Protection of children in forward-facing child restraint systems during oblique side-impact sled tests: Intrusion and tether effects. Traffic Injury Prevention. 2016;17(sup1):156–62. doi:10.1080/15389588.2016.1194982
  30. ↑ Manary MA, Flannagan CA, Reed MP, Orton NR, Klinich KD. Effects of child restraint misuse on Dynamic Performance. Traffic Injury Prevention. 2019;20(8):860–5. doi:10.1080/15389588.2019.1665177
  31. ↑ Mertz HJ, Irwin AL, Prasad P. Biomechanical and Scaling Basis for Frontal and Side Impact Injury Assessment Reference Values. Stapp Car Crash Journal 2016 11;60:625-657.


External Links

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