Comparison of ATD and Driver Knee Positions

Document Type

Conference Proceeding

Publication Date


Publication Title

SAE International

Conference Name

SAE World Congress & Exhibition


Contact between the knees and knee bolster commonly occurs in frontal collisions. The contact region on the bolster and the knee anatomy involved are related to the pre-crash positioning of the knees. The location of the distal (or infra-) patella was recorded on volunteers of widely varying stature after they had selected a comfortable driving position in mockups of three vehicles representing a large variation in size and shape: sedan, crossover SUV, and full-size pickup. On average, the right knees were grouped more tightly and were located more forward and lower than the left knees. On average, the knees were positioned 200 mm from the knee bolster for all subjects. The range of distance separating the distal patellae (within subject knee-to-knee distance) varied from 184–559 mm for all subjects for the three vehicles. Three adult Hybrid-III ATDs (small female, midsize male, large male) positioned in the test vehicles using the positioning protocol for crash testing (FMVSS 208) yielded positions that were reflective of the volunteers in two vehicles (sedan, pickup) in the fore-aft direction. For the remaining vehicle (crossover SUV), the ATD knees were forward of the subjects. In all cases, the ATD 208 position placed the knees closer together than the volunteers selected knee-to-knee distance. Maximally abducting the hips of the ATD revealed that it was possible to separate the knees to reflect the mean volunteer knee-to-knee distances.

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