Rear-Seat Frontal Crash Protection Research with Application to Vehicles with Automated Driving Systems, Volume 1

Hardy, Warren N; Kemper, Andrew R; Untaroiu, Costin Daniel; Albert, Devon L; Meng, Yunzhu; Yates, Keegan M; Guettler, Allison J; Bianco, Samuel T; Boyle, David M; Tatem, Whitney; Chaka, Michelle · 2022 · ROSA P / United States. Department of Transportation. National Highway Traffic Safety Administration

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Summary

This report, conducted by the Virginia Tech Transportation Institute for the National Highway Traffic Safety Administration, investigates rear-seat frontal crash protection with specific application to vehicles equipped with Automated Driving Systems (ADS). The research addresses the potential shift in occupant seating preferences toward rear seats in ADS-equipped vehicles, necessitating a deeper understanding of injury risks and restraint system performance for rear-seat passengers. The study aims to quantify injury incidence, assess safety performance across various vehicle models, and validate finite element (FE) models for future parametric studies. The methodology involved a multi-stage approach combining computational modeling and physical sled testing. Initially, FE models of seats and anthropometric test devices (ATDs) were used to screen late-model vehicles, identifying seven specific vehicles for physical testing based on their relative safety performance. Seven vehicle bucks were constructed to replicate the interior structures of these selected vehicles. Twenty-five sled tests were conducted using a 1.4-MN Seattle Safety ServoSled. Each vehicle was subjected to three crash pulses: an “NCAP85” pulse (scaled to a delta V of 56 km/h), a “scaled” pulse (delta V of 32 km/h), and a “generic” pulse representing the average of the scaled pulses. In each test, a THOR-50M ATD was positioned in the left-rear seat and a Hybrid III ATD in the right-rear seat. Notably, the THOR-50M utilized a prototype abdomen equipped with dual pressure sensors to better capture abdominal loading. Injury metrics were recorded for both ATDs, and injury risk was estimated for all measured parameters. Additionally, FE simulations of six vehicles were quantitatively compared to the physical test data to verify model validity. The results highlighted significant differences in occupant kinematics and injury risk between the two ATD types. Submarining, where the occupant slides under the lap belt, was a prevalent issue for the THOR-50M, occurring in 16 out of 25 tests. In contrast, the Hybrid III ATD did not exhibit submarining in any test. When submarining occurred in the THOR-50M, data traces showed a rapid drop in lap belt tension as the belt slipped off the anterior superior iliac spine (ASIS) and loaded the abdomen, resulting in elevated abdominal pressures. The study also compared injury metrics such as head acceleration, chest deflection, and neck loads between the Hybrid III and THOR-50M, noting variations in injury risk estimates based on age-specific risk functions. The FE models demonstrated sufficient accuracy when compared to the physical test data, validating their use for further parametric studies. The significance of this research lies in its contribution to the development of safety standards for rear-seat occupants, particularly in the context of ADS where rear-seat usage may increase. The findings underscore the limitations of current restraint systems in preventing submarining for certain occupant postures or ATD types, suggesting a need for improved rear-seat restraint designs. Furthermore, the validation of FE models provides a reliable tool for future research to optimize vehicle safety without extensive physical testing. The report concludes that while the Hybrid III performed well in preventing submarining, the THOR-50M’s susceptibility highlights potential gaps in current safety assessments, emphasizing the importance of comprehensive testing protocols that account for varied occupant kinematics and injury mechanisms in rear-seat scenarios.

Key finding

Submarining was observed in 64% of tests with the THOR-50M dummy but never with the Hybrid III, and finite element models were validated against physical sled test data.

Methodology

simulator

Sample size: 25

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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• adas effectiveness

Information type

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• Applied Guidance: standards test procedures
• Empirical Findings: crash risk outcomes