Driving Tired is like Driving Drunk

This piece, by Onno Berkan, was published on 02/04/25. The original text, by Zhao et al., was published by the journal of Accident Analysis and Prevention on 03/2012.

This Engineering College of Armed Police Force (China) study investigated how mental fatigue affects drivers by conducting a driving simulation experiment with thirteen male university students. The study aimed to better understand driver fatigue, which is a serious safety concern responsible for 20-30% of all traffic accidents.

The experiment was conducted in a controlled laboratory environment where participants had to follow strict guidelines, including getting adequate sleep and avoiding substances like alcohol, caffeine, and food for 12 hours before the test. Interestingly, while the study initially included both males and females, they ultimately chose to focus only on male participants because female subjects couldn't sustain the driving task for the full 90-minute duration.

The simulation used a monotonous highway scene that was intentionally designed to be repetitive and less stimulating than real-world driving. The researchers monitored the participants' brain activity (EEG) and heart activity (ECG) while they performed a 90-minute driving task. To ensure consistency, all participants were trained on the simulator until they could operate it skillfully, with training times ranging from 3 to 6 hours.

The results showed clear signs of mental fatigue in the participants. According to self-reports, eleven out of thirteen subjects started feeling tired and having difficulty concentrating after just 30 minutes of driving. They experienced symptoms like tiredness, boredom, and drowsiness, with their mental fatigue scores increasing significantly from 1.31 to 5.46 by the end of the task.

The physiological measurements revealed several important changes. When participants became mentally fatigued, their brain activity showed increased alpha and theta rhythms and decreased beta rhythms, indicating lower alertness levels. The study also found that heart rate patterns changed during mental fatigue, suggesting that driving fatigue affects both the central nervous system and cardiovascular system. Researchers noted that driving in this drowsy state was similar to driving while drunk.

The study's findings could contribute to developing more accurate and non-invasive systems for monitoring driver fatigue in real-time, which could ultimately help reduce road accidents and improve traffic safety.

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