Quantitative evaluation on mental worklosd reduction for hands free driving

Abstract

Advanced driver assistance systems (ADAS) for cars have been in market for a few decades and gaining popularity. The automation level for these systems are getting higher over years and automated driving is expected to be launched in near future. Advantage of those systems is not only for safety, but also for reducing the workload in driving. Especially the system which allows drivers to leave their hands off the steering wheel is considered to provide additional benefits to drivers compared to the system requiring hands on the steering wheel or to manual driving. The one of the additional benefits is the mental workload reduction, in other words stress level reduction, by free of their hands in driving. In this paper, we propose the method to measure mental workload which allows quantitative comparison in stress level between hands off and hands on the steering wheel system including manual driving, taking individual initial stress level and temporal change of stress level in a day into account. The proposed method is relatively easier on the measurement procedure and not requires complex measurement tools. In this sense, it fits to evaluate ADAS systems with actual driving. We report with experiments that our proposed method is effective for the purpose of evaluating the mental workload reduction for highly advanced driver assistance systems.