Quantifying rider posture variability in powered two- and three-wheelers for safety assessment

Area of Science:

• Biomechanics
• Human Factors Engineering
• Motorcycle Safety

Background:

• Rider posture is a key factor in powered two- and three-wheeler (PTW) injury outcomes.
• Detailed whole-body posture data is essential for analyzing PTW accidents and designing safety systems.

Purpose of the Study:

• To provide average male whole-body postures for different PTW types, including subpopulation variability.
• To enable future research on the influence of PTW rider posture variation on safety.

Main Methods:

• 3D photometric measurements of 51 anatomical landmarks on 20 male volunteers in preferred riding postures across three PTW types.
• Principal Component Analysis (PCA) to calculate average postures and describe posture variation.
• Kinematic linkage representations for visualizing principal components (PCs) and joint angles.

Main Results:

• The first seven PCs explained 80% of posture variance for each PTW type.
• Distinct differences in average postures were found across PTW types (10° ± 9° variation in joint angles).
• Individual variability in joint angles within a single PTW type was more than twice the variation between PTW types (26° ± 11°).

Conclusions:

• PTW rider posture variation involves simultaneous adjustments of multiple body parts.
• Individual variability, rather than solely vehicle geometry, substantially influences rider posture and must be considered in PTW safety development.