The influence of car passengers' sitting postures in intersection crashes

Area of Science:

• Biomechanics
• Automotive Safety
• Human Factors Engineering

Background:

• Passenger vehicles allow diverse non-nominal postures, unlike driver roles.
• Autonomous vehicles may enable drivers to adopt passenger-like postures.
• Understanding non-nominal posture effects in crashes is crucial for evolving vehicle safety.

Purpose of the Study:

• To analyze the kinematic and kinetic responses of a front-seat occupant in various non-nominal postures during simulated intersection crashes.
• To quantify the impact of different lower and upper extremity, torso, and head positions on occupant safety.

Main Methods:

• A Human Body Model (HBM) was simulated in 35 distinct postures within a virtual midsize SUV passenger seat.
• Three urban intersection crash scenarios were simulated: near-side impact, far-side impact, and frontal impact.
• Occupant kinematics and internal loads were analyzed, with deviations quantified via cross-correlation.

Main Results:

• Lower extremity posture variations exerted the most significant influence on lower limbs, pelvis, and whole-body responses across all crash types.
• Leg crossing in frontal impacts led to maximal pelvis excursions and rotations, impacting overall body response.
• Torso leaning in side impacts altered head and torso kinematics; upper extremity support on the center console increased torso excursions in far-side impacts.

Conclusions:

• Non-nominal postures, particularly those of the lower extremities, substantially alter occupant responses in various crash scenarios.
• Specific posture variations have distinct effects on kinematics and kinetics, emphasizing the need for adaptable safety systems.
• Findings are critical for designing occupant safety systems in future autonomous vehicles accommodating diverse seating positions.