The Relationship Between Heart Rate and Driver Behavior: Impacts of Cognitive Overload As a Result of Mobile Phone Conversation

ObjectiveThe aim of this study was to determine the correlation between the physiological and behavioral responses of drivers in the context of varying cognitive workloads.BackgroundSafe driving is a complex task that requires numerous cognitive and behavioral functions. Any internal or external factor that impairs a driver's cognition may result in accidents and compromise road safety. Quantification of cognitive load present in driving currently and area of significant research. This paper extends this topic by identifying a physiological factor which is both affected by cognitive load and is easily measurable, heart rate, and relating heart rate with driver behavior. The relationship developed could be used in the creation of wearable smart devices to forecast and prevent future road traffic crashes.Method34 students participated in a dual-task experiment that took place in a driving simulator. Cardiovascular responses (heart rate and heart rate variability) and driving performance (lane position and time headways) of the participants were recorded while driving. To create a variable cognitive workload, mobile phone conversations were created with three levels of mental effort (Neutral, problem-solving, and arousal conversations) across a series of driving trials.ResultsThe results show that cognitive load increases significantly for the problem-solving and arousal tasks, with reductions in time headway (0.58 and 1 second respectively) and greater deviations in lane position (0.19 and 0.28 meters respectively), whilst there was no significant change for the neutral conversation. Furthermore, heart rate and heart rate variability increases significantly in problem-solving and arousal tasks where indices identified nearly double There is also a significant positive correlation between a deterioration of driver behavioral performance (lane position) and indicators of heart rate variability (LF/HF ratio) during problem-solving (R=0.6, P value =0.01) and arousal (R=0.61, P value =0.04) tasks.ConclusionThe level of mental processing is a determining factor in the driver's behavioral performance. As the cognitive load of the conversation increases, the driver's behavioral performance is impaired.