Effect of drowsiness on mechanical arm admittance and driving performances

Drowsiness as one of the impaired driving behaviour is an important area of concern in ground transportation safety. It can coincide with skill‐demanding situations that may lead to vehicle control loss and possibly traffic accidents. Although drowsiness effects on driving performances have been widely investigated, there are few studies that propose a description of its effect on human neuromuscular state. To address this issue, this study aims to investigate the effects of drowsiness on driver neuromuscular state via the estimation of mechanical arm admittance. Mechanical arm admittance is a car dedicated parameter that gives information about arm stiffness of driver and its corresponding response in the frequency domain. Ten participants performed an experiment on a driving simulator, where they experienced steering disturbances, which aims to estimate variations of mechanical arm admittance as well as variations of driving performances between alert and drowsy states. Moreover, variation in driving performances were assessed by the variation of steering reversal rate and standard deviation of lane position. Results indicate that drowsiness increases the gain of mechanical arm admittance for arm movements <2.5 Hz and also deteriorates car steering control, increasing the steering operations amplitude and leading to larger vehicle lateral deviations.