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Frontal and oblique crash tests of HIII 6-year-old child ATD using real-world, observed child passenger postures
Katarina Bohman1, Kristy B Arbogast2, Helen Loeb2
1a Autoliv Research , Vargarda , Sweden.
Insights
Child passenger postures in car seats can lead to shoulder belt slip-off and increased head excursion, raising head injury risks. Current child anthropometric test devices (ATDs) need improvement to better represent real-world seating positions for enhanced safety.
Area of Science:
- Biomechanical Engineering
- Automotive Safety
- Human Factors Engineering
Background:
- Child passenger safety is a critical area in automotive research.
- Current child anthropometric test devices (ATDs) and testing protocols may not fully represent real-world child seating postures.
- Naturalistic driving studies (NDS) provide valuable data on actual child passenger behavior.
Purpose of the Study:
- To evaluate the impact of real-world child passenger postures on restraint system performance during frontal and oblique crashes.
- To assess the effectiveness of current testing protocols using a Hybrid III (HIII) 6-year-old child ATD.
- To identify potential risks associated with non-standard seating positions.
Main Methods:
- Utilized a Hybrid III 6-year-old child ATD in various real-world observed postures (forward and lateral torso tilt) during sled tests.
- Simulated frontal and 15° oblique crashes at 64 km/h using a mid-sized vehicle body and an Offset Deformable Barrier pulse.
- Analyzed ATD responses including head, neck, and chest kinematics, and shoulder belt interaction.
Main Results:
- Shoulder belt slip-off occurred in all oblique crash tests and in most frontal tests.
- Forward-leaning postures reduced head acceleration and neck tension but increased head excursion due to belt slip.
- Observed postures led to increased head excursion compared to the reference position.
Conclusions:
- Real-world child seating postures can compromise restraint effectiveness, increasing head injury risk.
- Child restraint system development should incorporate a broader range of postures beyond standard ATD protocols.
- There is a need for advanced child ATDs and human body models that can better replicate diverse real-world child postures for improved crash safety evaluations.
Objective:
The aim of this study was to evaluate the consequences of frontal and oblique crashes when positioning a Hybrid III (HIII) 6-year-old child anthropometric test device (ATD) using observed child passenger postures from a naturalistic driving study (NDS).
Methods:
Five positions for booster-seated children aged 4-7 years were selected, including one reference position according to the FMVSS 213 ATD seating protocol and 4 based on real-world observed child passenger postures from an NDS including 2 user positions with forward tilting torso and 2 that combined both forward and lateral inboard tilting of the torso. Seventeen sled tests were conducted in a mid-sized vehicle body at 64 km/h (European New Car Assessment Programme [Euro NCAP] Offset Deformable Barrier [ODB] pulse), in full frontal and oblique (15°) crash directions. The rear-seated HIII 6-year-old child ATD was restrained on a high-back booster seat. In 10 tests, the booster seat was also attached with a top tether. In the oblique tests, the ATD was positioned on the far side. Three camera views and ATD responses (head, neck, and chest) were analyzed.
Results:
The shoulder belt slipped off the shoulder in all ATD positions in the oblique test configuration. In full frontal tests, the shoulder belt stayed on the shoulder in 3 out of 9 tests. Head acceleration and neck tension were decreased in the forward leaning positions; however, the total head excursion increased up to 210 mm compared to te reference position, due to belt slip-off and initial forward leaning position.
Conclusions:
These results suggest that real-world child passenger postures may contribute to shoulder belt slip-off and increased head excursion, thus increasing the risk of head injury. Restraint system development needs to include a wider range of sitting postures that children may choose, in addition to the specified postures of ATDs in seating test protocols, to ensure robust performance across diverse use cases. In addition, these tests revealed that the child ATD is limited in its ability to mimic real-world child passenger postures. There is a need to develop child human body models that may offer greater flexibility for these types of crash evaluations.
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