Using Cool Stimulation as a Strategy to Keep High Vigilance Level of High-Speed Railway Driver

Decline of driver vigilance is a critical factor in fatal railway accidents. To prevent accidents induced by driver vigilance decline, intervention strategies are needed. The aim of this study is to investigate if cool stimulation intervention (CS-intervention) can be used as a countermeasure for the vigilance decline of high-speed railway (HSR) driver. The CS-intervention strategy was tested in an HSR driving simulator with 40 healthy participants with vigilance decline. Each participant completed two monotonous driving tasks: one without stimulation intervention (NO-intervention) and one with $20~^{\circ }$ C CS-intervention. Self-reported vigilance was assessed by using the Karolinska sleepiness scale (KSS), and the reaction time (RT) was used to estimate the objective vigilance. Eye-movement data, electrocardiogram (ECG), and electroencephalogram (EEG) signals were collected to investigate the potential arousing effects of CS-intervention. The CS-intervention can effectively awake drivers to reduce their RTs and KSS. The driver’s percentage of eye closure (PERCLOS) decreased while driving with CS-intervention. The high-frequency part of EEG signals is active, while the permutation entropy (PE) value in the frontal lobe is attenuated. The connectivity between brain lobes is enhanced. The physiological responses also prove the effectiveness of CS-intervention. This study indicates that CS-intervention is an effective strategy to alleviate fatigue and maintain vigilance. Given that CS-intervention can effectively counteract vigilance decline, the findings in this study are expected to provide evidence for the improvement of HSR driving safety.