Driving While Sleepy

May 18, 2018

Driving While Sleepy


It’s been a long, difficult shift at work, and your eyelids are heavy as you get in your car and get ready to drive home.  Yawning, you set the air conditioning to “cool” and turn on the radio for noise.  Like 60% of Americans you’ll be driving home while battling the urge to fall asleep.  

If you happen to have sleep apnea—a condition that causes severe daytime sleepiness and fatigue—then you’re three to five times more likely than normal to get into a serious crash involving personal injury.  Such an occurrence is fairly common:  according to the National Highway Traffic Safety Administration, crashes because of drowsy driving claim at least 1,550 lives, produce 71,000 injuries, and cost $12.5 billion each year.


Drowsy driving crashes typically occur during two time periods:  from midnight to six in the morning, when the body’s need for sleep is very high, and in the mid-afternoon, during the “circadian dip”—a period where the body’s changing internal rhythms cause naturally lower energy levels and a tired feeling.  Drivers involved in crashes due to drowsiness tend to be male, driving alone.  They also tend to be young: one estimate is that 55% of all crashes where a driver fell asleep involved drivers twenty-five years old or younger.  Jobs with workers most at risk for sleep-related crashes include any kind of shift work and commercial drivers—although with enough sleep deprivation, or a long and boring trip with no rest breaks, any driver can be at risk.


Poor Sleep = Poor Driving


Driving is very complex activity utilizing extremely heavy and powerful equipment that requires high levels of alertness, decision-making and quick reactions.  Studies investigating the effects of poor sleep leading to daytime drowsiness have found that participants experienced slower reaction times, impaired judgment and vision, problems with short-term memory and the information processing necessary to make quick decisions, and decreased alertness. 


Additionally, fatigue can lead to increased moodiness and aggressive behavior—which for drivers may translate into “road rage” and further place themselves and those around them at greater risk for a crash.  Microsleeps—brief episodes of sleep during conscious wake—are also common, and can contribute to a driver feeling like they’re on “autopilot” and not maintaining awareness of road conditions


Legal Consequences of Drowsy Driving


Currently, only the state of New Jersey has a law that makes it a crime to drive while “knowingly fatigued”, which is defined as being awake for more than twenty-four consecutive hours.  The law went into effect in 2003, although similar bills are pending in Illinois, Kentucky, and Massachusetts.  If found guilty, offenders may be punished by up to ten years and prison and a $100,000 fine. 


Enforcement of the law typically relies on drivers’ responses to questioning if stopped, although drivers cannot be stopped merely because they were tired.  However, in studies comparing the two, tired drivers perform as poorly or worse as drivers who are intoxicated.  For example, after twenty-four hours of sustained wakefulness, driving performance is equivalent to having a blood alcohol content of 0.10%–which is 0.02% higher that what is considered legally drunk in every state.


Sleeping Soundly, Driving Safely