Smartwatch-based driver alertness monitoring with wearable motion and physiological sensor

Studies have shown that a high precision driver alertness monitoring system is an essential and a monetary countermeasure to reduce the road accidents. This paper presents a novel approach to measure the driver alertness, evaluated by a smartwatch device based on fusion of direct and indirect method. The driver chronic physiological state is monitor by adopting a photoplethysmography sensor on the driver finger that is connected to a wrist-type wearable device. A Bluetooth Low Energy module connected to the wearable device transmits the PPG data to the smartwatch in real-time. Meanwhile, the indirect method, driver steering wheel movement can be derived by utilizing the motion sensors integrated in the smartwatch which include a tri-axis accelerometer and a gyroscope sensors. The respiration signals can be derived from the PPG time- and frequency-domains attributes. The data obtained from both methods aforementioned are subsequently decomposed into relevant features in time, spectral context and phase space domain, and thus computes the alertness index. Here, the correlations between the extracted features and the subjective Koralinska Sleepiness Scale are studied as well along with the recorded experimental videos. This study reveals that the alertness index prediction accuracy can be reached up to 96.3% based on the descriptive extracted features.

I. Introduction

Majority of the road accidents are essentially related to driver behavioral state accounted for relatively 30% of traffic accidents worldwide, which is a major concern in decades as reported by the National Highway Traffic Safety Administration (NHTSA) [1]. Most of the road accidents are caused by the driver fatigue or drowsiness. In regular cases, fatigue or drowsiness can be defined as an intermediate state between wakefulness and sleep [2], leading the driver in reduced arousal and slow reaction time, thus resulting in an abnormal driving aptitude. Even though most drivers are aware of the consequences, many drivers are continuously drive in extremely low alertness level especially during night time and situations surrounded by dull driving environment. Indeed, reports stated in [3] implied that vehicle drivers are enthusiastic in reliable alertness monitoring system to ensure their safety while driving. Thus, a highly effective and inexpensive method is required to implement such system to reduce the traffic tragedy.