Quantifying the driver stress using a driving simulator and physiological measurements -

Abstract

Distraction while driving due to engagement in secondary tasks is considered a leading factor that contributes to car accidents. It affects the driver’s reaction towards critical road situations and induces stress. The driver stress in turn affects the driver’s performance and physiology. This study utilizes a driving simulation experiment with physiological sensors in order to quantify stress arising from an increase in workload and the resulting impacts on driving performance and physiological measures in the presence of road situations frequently encountered in an urban context: pedestrians, trucks, and traffic lights. A secondary cognitive task with multiple levels of difficulty designed to simulate auditory-vocal distraction is added to the primary driving task. Driving performance (speed, lane position, pedal depression, brake, reaction time) and physiological indices (heart rate, skin conductance) are recorded throughout the experiment. The sample consists of students of the American University of Beirut. Using non-parametric statistical tests, it is found that the driver adopts a regulatory behavior at the operational level (e.g., reduces the speed) in order to allow the performance of the additional task and driving at the same time. The effect of the regulatory behavior is minor on the longitudinal and lateral control measures (e.g., the speed, the pedal depression, the lane position). However, the impact on the reaction time can have important implications for road safety. An increase in the heart rate and skin conductance level reflects the increase in the cognitive workload when performing the secondary task. No effect is found for the level of difficulty of the secondary task on the driving performance and physiological measures at the three considered road situations. In order to maintain control of driving, particularly at the high levels of difficulty, some subjects are found to pay less attention to the secondary task and shift their focus towards the primary driving task. Driving b