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What is Drowsy Driving and How Can You Prevent It?

February 22nd 2021

What is Drowsy Driving and How Can You Prevent It?

Drowsy Driving Overview

Drowsy driving is a risk factor for motor vehicle accidents (MVAs). According to a 2017 summary released by the National Highway Traffic Safety Administration (NHTSA), from 2011 to 2015, drowsy driving was a factor in approximately 2.3 to 2.5% of all fatal MVAs in the United States [1]. In total, in the year 2017, NHTSA estimates that 91,000 police reported crashes were related to fatigue, resulting in 50,000 injuries and almost 800 fatalities [2]. Similarly, The Ministry of Transportation of Ontario (MTO) has identified drowsy driving as growing contributor to MVAs in the province [3].

It is quite likely that drowsy driving plays a larger role in MVAs than officially reported, as it is difficult to determine whether a driver was drowsy at the time of a crash, particularly if the driver died as a result of the collision [1][4]. Other reasons why drowsy driving may be underreported is because of a lack of firm evidence as most investigations are done after the MVA, drivers being unaware of their fatigue levels, and drivers being unwilling to admit their fatigue levels [1].

Drowsy driving can be as dangerous as drunk driving [3], and drivers who are fatigued have a slower reaction time and are less alert [3].

Research indicates that drowsy driving MVAs are most likely to occur late at night or in the late afternoon [2]. Drowsy driving MVAs are also more likely to take place on rural roads and involve a single driver with no passengers [2]. According to the MTO, shift workers, commercial vehicle operators, and those suffering from sleep disorders are at a greater risk of falling asleep behind the wheel [3].

NHTSA lists several steps drivers can take to minimize the chances of being drowsy while driving [2]:

  1. Getting at least 7-8 hours of sleep per night on regular basis.
  2. Taking extra care to be well-rested before starting a long trip.
  3. Not drinking any alcohol before driving.
  4. Checking prescription and over-the-counter medication to see if the side effects include drowsiness.
  5. Avoiding driving during the peak sleepiness periods of late afternoon or late at night.
  6. Pulling over at a designated rest stop for a nap if feeling seriously fatigued.

The National Safety Council (NSC) has also suggested that installing crash avoidance technologies, such as drowsiness alerts, in cars could detect common drowsy driving patterns and warn drivers to stay in their lane or take a break [4].

Additionally, awareness that there is a problem can prevent a possible drowsy driving accident. The MTO states that drivers should be aware of the following signs that they are becoming seriously fatigued [3]:

  1. Difficulty keeping their eyes open.
  2. Finding that their head keeps tilting forward.
  3. Difficulty concentrating.
  4. Frequent yawning.
  5. Difficulty remembering.
  6. Missing traffic lights and signals.
  7. Drifting into the next lane and/or off the road.

The MTO advises that drivers experiencing any of the above symptoms should immediately pull over to a safe space, lock their doors/windows, and take a nap [3].

Why LISKE Accident Reconstruction?

LISKE Transportation reconstruction experts complete a thorough forensic investigation of the available records and physical evidence to reconstruct your accident. Our unique team approach allows our Human Factors and Injury Biomechanics experts to provide additional analysis on both accident and injury causation, including whether drowsiness played a role in your accident.

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[1] NHTSA (October, 2017). “Drowsy Driving 2015”. NHTSA. Retrieved from:

[2] NHTSA (n.d). “Drowsy Driving” NHTSA. Retrieved from:

[3] MTO. “Dealing with particular situations” MTO. Retrieved from:

[4] NSC. (n.d) “Drivers are Falling Asleep Behind the Wheel”. NSC. Retrieved from: