One in 24 adults in the U.S. admitted to recently falling asleep while driving. This dangerous practice contributes to car crashes and fatalities, according to a new report released by the Centers for Disease Control and Prevention (CDC).

Health officials believe that the percentage of adults driving in a drowsy state could be even higher than the one reported because many people do not notice when they nod off for a few seconds while driving. The report said nearly four percent of U.S. adults fall asleep or doze off while behind the wheel.

To examine the incidence of falling asleep while driving, the CDC looked at data gathered from a questionnaire about insufficient sleep that was given by the Behavioral Risk Factor Surveillance System (BRFSS) during 2009-2010. There were approximately 147,076 respondents in 19 states and the District of Columbia.

Sleepy driving was seen to be more common among adults who sleep less than six hours per night, snore, or fall asleep randomly throughout the day, compared with other people who did not have these traits.

Drowsy driving was less seen in older people. The report documented 4.9 percent among 18-44 year olds and only 1.7 percent among adults 65 years of age or older. Men were more likely to drive sleepy than women (5.3 percent versus 3.2 percent).

Retired participants (1.0%), students or homemakers (2.1%), and unemployed people (3.1%) were less likely to document sleepy driving than those who were employed (5.1%) or unable to work (6.1%). The state with the highest rate of sleepy driving was Texas with 6.1 percent and the state with the lowest rate was Oregon with 2.5 percent.

The current study contains the largest number of U.S. survey participants to examine the topic of drowsy driving to date. Drowsiness can retard reaction time, affect decision-making, and make drivers distracted, all of which are factors that can lead to car crashes.

Sleep-related crashes normally take place at night or mid-afternoon and most often involve one car going off of the road. Most notably, drowsy driving crashes are more likely to end in death or injury than non-drowsy driving crashes.

Commercial drivers, people who work night or long shifts, drivers using drowsy medications, people with inadequate sleep, and drivers with undiagnosed sleep disorders are at a higher risk for sleepy driving.

Anyone driving should make sure they get at least 7 to 9 hours of sleep per night, abstain from alcohol before getting behind the wheel, and get treatment for sleep disorders.

Methods typically used to stay awake while driving, such as opening the window, turning up the air conditioner, and turning up the radio, have been found to not be successful. Warning signs of sleepiness include:

  • hitting a rumble strip
  • drifting from one’s lane
  • missing exits
  • yawning or blinking
  • trouble remembering driving the last few miles

A previous study established that rates of drowsy driving increase around daylight savings times. Time change as well as earlier nightfall can become a dangerous combination for sleepy people that are behind the wheel.

Written by Kelly Fitzgerald