The Influence Of Mobile Phone Distraction On Driver’s Mental Workload In Automatic Driving Mode

With the popularity of autonomous vehicles,there are no clear legal regulations in various countries on whether the use of mobile phones is allowed during the driving of smart vehicles.Simultaneous mobile phone calls in various forms（such as increasing the driver’s cognitive load,longer reaction time to events,etc.）have resulted in a decrease in driving performance and an increase in the probability of collisions.When and how the driver can use the phone in autonomous driving mode,how long it can be used,the complexity of the call content and the accumulated mental load need to be accurately measured and defined.Therefore,this study firstly divides the mental workload level of drivers using mobile phone calls in automatic driving mode.Automatic driving,manual driving)*2（complexity of call content: simple call content,complex call content）*6（driving stage: 6 stages）three-factor mixed experimental design,by measuring the driver’s detection response task performance,pupil diameter The EEG components of different brain regions in the alpha and alpha frequency bands are used to comprehensively investigate the influence of these factors on the mental workload of drivers,so as to provide a theoretical basis for regulating the use of mobile phones in automatic driving mode and the formulation of a grading system.Study 1: Investigate the mental workload level caused by whether the driver uses a mobile phone to talk in the L2 level automatic driving mode.Twenty-nine drivers were recruited,and the driver’s detection response task performance and the EEG components of different brain regions in the alpha frequency band were used as dependent variables to comprehensively investigate the effects of mobile phone calls on drivers’ mental workload in different driving stages.Study 2: After determining the stage of the difference in the mental workload of drivers due to the presence or absence of mobile phone calls in the L2 level automatic driving mode,this study further explores the complexity of the content of mobile phone calls,and at the same time increases the independent variable of driving mode to drive manually.The mode is the baseline,and the differences in the level of the driver’s mental workload caused by the content of mobile phone calls with different degrees of complexity are compared between the automatic driving mode and the manual driving mode at the same stage.Fifty-eight drivers were recruited,and the performance of the driver detection response task,pupil diameter and EEG components in different brain regions of the alpha frequency band were measured simultaneously to comprehensively evaluate the effects of driving stages,driving patterns,and complexity of call content on drivers’ mental workload.Based on the findings of Study 1 and Study 2,the conclusions are as follows:（1）In the initial stage of driving（10-20 minutes）,in the automatic driving mode,the mental workload induced by simple mobile phone calls is higher than that in the manual driving state during the same period,occupying more brain resources in the driver’s prefrontal lobe area,resulting in a decrease in its cognitive control ability and a slower response of the driver to peripheral visual detection signals.（2）In the automatic driving mode,the activation degree of the frontal lobe area of the complex mobile phone call content group is lower than that in the manual driving mode during the same period（60 minutes）,indicating that the complex mobile phone call,even in the automatic driving state,it can also impair the normal functioning of the driver’s brain functions such as problem solving,judgment,and impulse control.（3）Regardless of the complexity of the mobile phone calls made by the driver,with the increase of the driving time,the mental workload level of the driver in manual driving and automatic driving modes tends to be the same,resulting in a cumulative effect of mental workload.This shows that mobile phone calls in automatic driving mode will also destroy the driver’s cognitive resource balance,resulting in a decline in his cognitive control ability and impairing driving safety.