More Than One in Ten Car Accidents Caused By Tired Drivers: Study

A new study highlights the impact that drowsy drivers are having on U.S. roadways, indicating that the rate of car accidents caused by tired drivers is much larger than previously believed, with drowsiness potentially being a factor in more than 10 percent of all serious crashes. 

The AAA Foundation for Traffic Safety released a new drowsy driving study this week, indicating that night time drivers could be up to three times more likely to be involved in a crash when sleepiness is a factor.

AAA Foundation researchers conducted a three year observational study that spanned October 2010 through December 2013, involving 3,593 drivers. The drivers were continuously monitored with in-vehicle cameras and other data collection equipment for a period of several months.

The study was part of the federally funded Second Strategic Highway Research Program Naturalistic Driving Study, to determine the rate of drowsy driving on U.S. roadways.

AAA researchers used the PERCLOS measure, to determine the percentage of time that a person’s eyes are closed over a defined measurement interval. The PERCLOS measure has been shown in past studies to accurately predict drowsiness, lapses in attention, and increased variability in lane position.

After observing the data collected from the study, researchers identified a total of 905 severe, moderate, and minor crashes and another 628 crashes that were classified as low risk tire strikes not requiring a call to the police.

Approximately 31% of the crashes examined were classified as severe or moderately severe and resulted in significant property damage, airbag deployment, rollover, injury, or substantial change in speed associated with the crash impact.

Researchers using the PERCLOS measure found that 8.8% to 9.5% of crashes involved a drowsy driver, and between 10.6% and 10.8% of all moderate to severe crashes involved a drowsy driver.

The findings indicate drivers between the ages of 16 to 24 years of age accounted for roughly 32% of all drowsy driving crashes, while those over the age of 65 accounted for nearly 25% of all drowsy driving crashes.

Researchers noted that the majority of vehicle crashes occurred during the daytime, when roadway traffic was heaviest. However, the percentage of all accidents that involved a drowsy driver were three times higher at night.

The National Highway Traffic Safety Administration (NHTSA) has found that drowsy driving causes approximately 4 million automobile crashes annually, resulting in about 6,000 fatalities. In addition to the lives that are lost, drowsy driving is anticipated to cost an estimated $109 billion on the industry each year.

According to the NHTSA, drowsiness causes a person to have slower reaction times. Drowsy drivers will also experience impaired attention, impaired mental processing, judgment and decision making, similarly to impaired drivers under the influence of alcohol.