Drowsy Driving: A Common Cause of Car Crashes

Drowsy driving is a factor in more than one out of every five fatal car accidents in the United States, studies suggest. And while anyone can find themselves behind the wheel when they are not at their most alert, many people who drive while drowsy or fatigued lead lifestyles that contribute to this dangerous driving behavior.

A drowsy driving crash is one in which the driver was reported as drowsy, sleepy, asleep, or fatigued, according to the National Highway Traffic Safety Administration (NHTSA).

The AAA Foundation for Traffic Safety said in November 2014 that drowsy drivers are involved in an estimated 21 percent of fatal crashes.

The AAA Foundation says more than half of drowsy driving crashes involve drivers drifting out of their lanes, which includes crossing the centerline into oncoming traffic, or running off the road. And because a dozing driver does not apply the brakes, many drowsy driving crashes occur at full speed and cause catastrophic injury, if not death.

Drowsy2-300x178The Centers for Disease Control and Prevention (CDC) said in a July 4, 2014, report that drowsy driving is a factor in as many as 7,500 fatal motor vehicle crashes every year, approximately 25 percent of all motor vehicle fatalities.

The NHTSA said that drowsy driving is probably under-reported. There is usually no firm evidence of drowsy driving in crashes that are investigated after the fact and drivers involved in crashes are unlikely to disclose that they fell asleep or were tired.

Drowsiness and fatigue cause car accidents because they slow driver response and can ultimately lead to the inability to resist falling asleep at the wheel, the NHTSA says in a broader study by a panel of NHTSA and National Center on Sleep Disorders Research (NCSDR) experts. Sleepiness impairs several factors involved in safe driving:

  • Attention
  • Information processing
  • Reaction time
  • Vigilance


The CDC report was based on 92,102 survey responses in nine states and Puerto Rico. Among its findings:

  • 4 percent of respondents reported falling asleep while driving during the previous 30 days. That equates to approximately 1.8 million drowsy drivers in 30 days prior to the study in the nine states surveyed and Puerto Rico.
  • Drowsy driving decreased with age, from 5.9 percent among adults 18 to 24 years old, to 1.8 percent among adults 65 years old or older.
  • Drowsy driving was more prevalent among men than women (5 percent vs. 3 percent).
  • Drowsy driving was also more prevalent among binge drinkers and drivers who did not regularly use seatbelts.

According to the AAA Foundation study, which was drawn from 21,292 crashes from 2009 to 2013 in which a passenger vehicle was towed from the scene:

  • An estimated 328,000 crashes each year, including 109,000 injury crashes and 6,400 fatal crashes, involve a drowsy driver
  • 21 percent of fatal crashes involve a drowsy driver
  • 13 percent of crashes that result in severe injuries requiring hospitalization involve a drowsy driver
  • 7 percent of crashes that result in any injuries involve a drowsy driver
  • 6 percent of all crashes in which a passenger vehicle is towed from the scene involve a drowsy driver
  • 37 percent of drivers report having fallen asleep behind the wheel at some point in their lives
  • 11 percent report having fallen asleep behind the wheel in the previous year
  • Men are involved in twice as many drowsy driving crashes as women.

The National Sleep Foundation (NSF) says people who are excessively sleepy either because of lifestyle factors or because of an untreated sleep disorder are more likely to have crashes related to drowsy driving. Due to our natural circadian rhythms, sleepiness is most pronounced and drowsy driving accidents are more likely during the night and in mid-afternoon.

Drowsy5a-e1426765955527A person who has had six hours of sleep or less in the previous 24 hours triples their risk of getting into a drowsy driving accident, the NSF says. Working more than 60 hours a week increases the risk by 40 percent.

The use of sedating medications (antidepressants, cold tablets, antihistamines) or alcohol exacerbates the problem posed by fatigue or sleepiness behind the wheel.

In addition to young men, those who are more likely to drive while drowsy or fatigued and be at risk of having a fall-asleep crash are:

  • Night-time workers
  • Shift workers
  • People with long work hours
  • Commercial drivers (i.e., truck drivers) ­– at least 15 percent of all heavy truck crashes involve fatigue, the NSF says.
  • People with undiagnosed or untreated sleep disorders, such as untreated obstructive sleep apnea
  • Business travelers who spend many hours driving or who may be jet lagged.

People who have been injured in car or truck accidents caused by a drowsy driver in Georgia should speak to a knowledgeable Atlanta car accident lawyer about their legal options.