Facts + Statistics: Drowsy driving

Research shows that fatigue is a significant factor in motor vehicle, commercial trucking and rail collisions.

  • According to the National Highway Traffic Safety Administration (NHTSA) in 2015 there were 824 fatalities (2.3 percent of all fatalities) that were drowsy-driving-related, matching the annual 2011 to 2015 average. In 2015, there were 736 crashes that were attributed to drowsy driving, slightly higher than the prior five-year average of 732 crashes.
  • A December 2016 study by the AAA Foundation for Traffic and Safety found that drivers who usually sleep for less than 5 hours daily, drivers who have slept for less than 7 hours in the past 24 hours, and drivers who have slept for 1 or more hours less than their usual amount of sleep in the past 24 hours have significantly elevated crash rates. The estimated rate ratio for crash involvement associated with driving after only 4-5 hours of sleep compared with 7 hours or more is similar to the U.S. government’s estimates of the risk associated with driving with a blood alcohol concentration equal to or slightly above the legal limit for alcohol in the U.S.
  • The Governors Highway Safety Association issued a report in August 2016 concluding that the estimated annual societal cost of fatigue-related fatal and injury crashes was $109 billion. This figure does not include property damage.
  • A 2014 AAA Traffic Safety Foundation study found that 37 percent of drivers report having fallen asleep behind the wheel at some point in their lives. An estimated 21 percent of fatal crashes, 13 percent of crashes resulting in severe injury and 6 percent of all crashes, involve a drowsy driver.
  • A 2013 study by the Federal Rail Administration found that fatigue greatly increases the chances of an accident in which human factors play a role, with the risk of such an accident rising from 11 percent to 65 percent.
  • Although sleepiness can affect all types of crashes during the entire day and night, drowsy-driving crashes most frequently occur between midnight and 6 a.m., or in the late-afternoon, according to NHTSA.
  • NHTSA found that many drowsy-driving crashes involve a single vehicle, with no passengers besides the driver, running off the road at a high rate of speed with no evidence of braking.
  • The beginning of daylight savings is linked to an increase in auto accidents, according to an analysis by the University of British Columbia and a study by researchers at John Hopkins and Stanford University.
  • In 2015, drowsiness or sleepiness was a factor for 2.6 percent of drivers and motorcycle operators involved in fatal crashes, as shown in the chart below.

Driving Behaviors Reported For Drivers And Motorcycle Operators Involved In Fatal Crashes, 2015

Behavior Number of drivers Percent
Driving too fast for conditions or in excess of posted speed limit or racing 8,778 18.1%
Under the influence of alcohol, drugs or medication 5,399 11.1
Failure to yield right of way 3,453 7.1
Failure to keep in proper lane or running off road 3,365 6.9
Distracted (phone, talking, eating, etc.) 3,263 6.7
Operating vehicle in a careless manner 2,606 5.4
Failure to obey traffic signs, signals or officer 1,908 3.9
Overcorrecting/oversteering 1,839 3.8
Operating vehicle in erratic, reckless, or negligent manner 1,755 3.6
Vision obscured (rain, snow, glare, lights, buildings, trees, etc.) 1,601 3.3
Swerving or avoiding due to wind, slippery surface, other
vehicle, object, nonmotorist in roadway, etc.
1,457 3.0
Drowsy, asleep, fatigued, ill, or blacked out 1,268 2.6
Driving wrong way in one-way traffic or on wrong side of road 1,064 2.2
Making improper turn 951 2.0
Other factors 5,649 11.6
None reported 14,812 30.5
Unknown 7,139 14.7
Total drivers (1) 48,613 100.0%

(1) The sum of percentages is greater than total drivers as more than one factor may be present for the same driver.

Source: U.S. Department of Transportation, National Highway Traffic Safety Administration.

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