Counteracting driver sleepiness: effects of napping, caffeine, and placebo

Area of Science:

• Neuroscience
• Human Factors
• Sleep Science

Background:

• Drowsy driving is a significant public safety concern.
• The effectiveness of countermeasures during breaks for sleepy drivers remains unclear.
• Simple rest breaks may not sufficiently mitigate driving impairment.

Purpose of the Study:

• To evaluate the efficacy of a short nap and caffeine as countermeasures against drowsy driving.
• To compare the effects of a nap, caffeine, and placebo during a simulated driving task.

Main Methods:

• Ten sleepy participants underwent simulated monotonous drives.
• Interventions included a short nap (<15 min), 150 mg caffeine, or a placebo during a 30-min break.
• Driving performance, subjective sleepiness, and electroencephalography (EEG) were monitored.

Main Results:

• Both caffeine and napping significantly reduced driving impairments and subjective sleepiness.
• EEG data indicated decreased drowsiness after caffeine and napping.
• Blink rate was not affected; caffeine effects were more consistent than napping.

Conclusions:

• Short naps and caffeine are effective countermeasures for drowsy driving.
• Self-awareness of sleepiness preceded driving impairments.
• A simple break without additional countermeasures is insufficient to improve driving safety.