Introduction: Fatigue and sleepiness can negatively affect driver’s consciousness and their cognitive function. Traffic accidents due to sleepiness are more common among people who work more than 60 hours a week, or have irregular working hours or night shifts.

Methods: Last available literature and the most authentic sources were assessed and different aspects of the issue were evaluated.

Results: Drowsy driving increases the risk of a crash four times. Fatigue reduces performance in tasks that require alertness, manipulation and retrieval of stored information. There are several instruments to measure drivers’ sleepiness including Multiple Sleep Latency Test, Maintenance of Wakefulness Test, Epworth Sleepiness Scale, Karolinska Sleepiness Scale, and Stanford Sleepiness Scale.

Conclusion: Careful consideration and scientific approach to professional drivers’ work schedule to prevent sleepiness, fatigue, and driving for long and consecutive hours and also the study of underlying sleep diseases, are highly important.