The Effects of Forward Vision Restriction on Automobile Driver Posture

Abstract

A simulator study of the effects of the height of the top of the instrument panel (IP) on driving posture was conducted. Eight midsize men and 8 small women drove an interactive simulator with a large-screen display under 5 different IP-height conditions. The 3-dimensional locations of body landmarks were recorded to characterize their driving postures. In a confirmatory study, 32 men and women drove a sport-utility vehicle over a 15-min road route with and without a mask that restricted part of the windshield above the IP. These restrictions on drivers' forward vision had only small effects on driving posture. In the driving simulator, an increase in IP height of 150 mm caused drivers to sit with their hips an average of 7 mm farther forward with a hip-to-eye angle that was 1° more upright. No significant differences were found in postural response between the small female and midsize male participants. In the vehicle, no significant effects of the windshield mask on posture were observed. These findings indicate that the vision restriction imposed by the IP is unlikely to have an important effect on driving posture over the range of restriction that is reasonable for production vehicles and that predictive models of driving posture do not need to include the effects of IP height when the driver is not provided with a seat height adjustment.