Investigating the impact of driving workload on fatigue and performance for the purpose of road safety

Driver fatigue is a major contributor to road accidents, yet it remains difficult to quantify due to its subjective nature and inconsistent reporting. This experimental study investigates how fluctuations in driving workload influence fatigue development and driving performance. Utilizing a high-fidelity car simulator, thirty non-professional drivers participated in a controlled experimental protocol comparing optimal driving scenarios with stressful driving conditions characterized by heavy traffic and adverse weather. To ensure a comprehensive assessment, an integrated multimodal approach was adopted, combining continuous physiological monitoring (electroencephalography - EEG, electrocardiography - ECG) with psychomotor tests such as Flicker Fusion test, and reaction times. Subjective workload was further assessed using the NASA-TLX questionnaire. Preliminary results indicate a statistically significant reduction in the Flicker Fusion metrics during stressful driving sessions, consistent with the onset of mental fatigue. These findings are corroborated by increased NASA-TLX scores and a decrease in EEG-derived attention and stress metrics. Other measured parameters showed no significant differences between the two sessions, suggesting the need for further experimentation to investigate the underlying causes and potentially refine the experimental design. The proposed holistic framework for assessing driver state can offer valuable insights for the design of targeted road safety interventions, infrastructure improvements, and tailored driver training programs aimed at enhancing overall drivers’ well-being and safety.