The National Institute for Occupational Safety and Health (NIOSH) Center for Motor Vehicle Safety is observing Drowsy Driving Prevention Week, hosted by the National Sleep Foundation. The campaign is designed to reduce the number of fatigue-related crashes and to save lives. Follow @NIOSH_MVSafety for #Awake2Drive tips throughout the week, and catch up on the Center’s sleep-focused issue of Behind the Wheel at Work.

Fatigued driving v. drowsy driving

Fatigue is a known contributor to roadway crashes among commercial motor vehicle drivers, others who drive for work, and the general public. Not surprisingly, the issue of fatigued driving is a growing safety concern for government agencies, businesses, and safety advocates. However, in media reports and safety materials, we often see the terms "drowsy driving" and “fatigued driving” used interchangeably. But do they really mean the same thing?

"Drowsiness" generally refers to the result of sleep restriction, disturbed sleep, or poor quality sleep. It may also result from medication side effects. According to a study by the AAA Foundation for Traffic Safety, people who sleep 6 to 7 hours a night are twice as likely to be involved in a sleep-related crash as those sleeping 8 hours or more. People sleeping less than 5 hours increase their risk four to five times.

"Fatigue," on the other hand, is a broader concept that has been defined in many different ways. While drowsiness can be a component of fatigue, fatigue can also result from a range of other sources such as stress, physical demands, or health conditions. These can have a combined or cumulative effect, with long-lasting consequences. All these sources affect the same region in the brain that is responsible for cognitive functions such as concentration, hand-eye coordination, and decision-making – skills that are needed for safe driving.

Fatigue can affect anyone, and it can be difficult to predict. Whether cognitive impairments stem from lack of sleep, sleep disruptions, or other sources, it’s critical from a safety perspective to recognize when your driving skills may be compromised, and to take appropriate precautions.

Strategies for reducing fatigue behind the wheel:

• Improve sleep habits to obtain adequate, quality sleep (see NIOSH's "Quick sleep tips for truck drivers").
• Take frequent breaks during your journey to break up the monotony of driving.
• Reduce or eliminate distractions such as mobile phones. As we become more fatigued, our ability to sustain concentration is compromised.
• Adopt a healthy lifestyle (e.g., diet and exercise).
• Reduce the need for driving by doing work by phone or video-conferencing, choosing safer modes of transportation such as air or rail, or combining trips and loads.