A Modeling Study on Child Occupant Safety with Unconventional Seating Configurations

Hu, Jingwen; Boyle, Kyle J.; Orton, Nichole Ritchie; Manary, Miriam A.; Reed, Matthew P.; Klinich, Kathleen D. · 2023 · ROSA P / United States. Department of Transportation. National Highway Traffic Safety Administration

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Summary

This study addresses the emerging safety challenges posed by unconventional seating configurations in vehicles equipped with Automated Driving Systems (ADS). As ADS technology allows for bi-directional operation and interior redesigns, occupants may sit in rear-facing, lateral-facing, or angled positions rather than traditional forward-facing seats. The research specifically investigates how these non-standard seating orientations affect the kinematics and injury potential of child occupants restrained by child restraint systems (CRS) with internal harnesses or vehicle lap-shoulder belts, with and without boosters. The motivation stems from the fact that existing Federal Motor Vehicle Safety Standard (FMVSS) No. 213 tests only cover forward-facing seats in frontal crashes, leaving a gap in understanding child safety in the varied crash scenarios and seating positions likely to occur in automated vehicles. To evaluate these risks, the researchers conducted a comprehensive literature review to define surrogate vehicles, seating arrangements, and impact scenarios. Due to a lack of existing impact test data for child anthropomorphic test devices (ATDs) in farside, oblique, and rear impacts, the team performed 16 physical sled tests. These tests utilized CRS harness-restrained and belt-restrained ATDs in both conventional and unconventional seat orientations across frontal, farside, oblique, and rear impact conditions. The sled test data were used to validate a suite of computational models. Subsequently, 550 simulations using Mathematical Dynamic Models (MADYMO) were executed. The simulations involved four child ATD models—CRABI 12MO, H33YO, H36YO, and H310YO—paired with various CRS types (rear-facing, forward-facing, and backless boosters) or vehicle belts. The simulations covered a wide range of seating locations, orientations, five impact directions, and different CRS installation methods. The primary finding was that no major safety concerns were identified for ATDs restrained using CRSs equipped with internal harnesses, based on the nature of ATD contacts and injury metrics. The study successfully characterized child occupant responses across a broad spectrum of crash conditions and seating orientations. However, the results also highlighted significant limitations in using ATDs designed primarily for frontal impacts to assess safety in other crash directions. The simulations provided detailed insights into head excursion, chest acceleration, and deflection for different age groups and restraint types, revealing how unconventional seating alters occupant kinematics compared to traditional configurations. The significance of this work lies in its role as the first study to utilize multiple child ATDs and CRSs to investigate occupant responses across a wide variety of impact directions and seating orientations. The findings provide a foundational understanding of child occupant safety in automated vehicles, informing future regulatory standards and CRS design. By identifying the limitations of current testing protocols and ATDs for non-frontal impacts, the study underscores the need for updated evaluation methods to ensure child safety in the evolving landscape of automated mobility.

Key finding

Simulations of child occupants in unconventional seating configurations revealed no major safety concerns for those restrained by child restraint systems with internal harnesses, but demonstrated limitations in using frontal anthropomorphic test devices for assessing responses in non-frontal crash directions.

Methodology

modeling

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via bulk_ingest_rosap on 2026-05-23 (6 acquisition events logged).

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

Topics

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• child passenger safety

Information type

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• Empirical Findings: crash risk outcomes