You might think that choosing to sleep off a night of heavy drinking rather than getting behind the wheel is the responsible choice. But while you can pat yourself on the back for not driving while intoxicated, research shows that driving hungover may be just as dangerous as driving drunk.

Researchers had the 48 participants of the study perform two driving tests: once after a regular night and once after a night of heavy drinking. On average, the participants reported consuming 10 alcoholic beverages on the night of heavy drinking.

In both driving simulation tests, the participants were told to stay in the right lane of a highway while driving 60 mph for one hour. Surprisingly, even with a blood alcohol concentration (BAC) of 0.0%, the participants drove as if they were drunk on the day after the night of heavy drinking.

The participants noticed they were driving poorly and unpredictably while hungover and reported that more effort was needed to perform during the driving test. The driving impairment from the hangovers was comparable to a BAC of .05% and .08% and negatively affected several cognitive skills related to driving.

How does a hangover impact driving?

While the study didn’t find any correlation between the severity of the hangover and driving impairment, one explanation for risker driving could be that drivers are distracted by the pain, discomfort and nausea of a bad hangover.

Another explanation was that a lack of sleep was to blame for the dangerous driving. Those who got six or fewer hours of sleep while hungover had drastically worse driving impairment than those who got six or more hours. Fatigue delays reaction times on the road and impairs motor skills necessary for driving.

When is it safe for you to drive?

Unfortunately, having a BAC of 0.0% doesn’t necessarily mean you are in good condition to drive. If you are experiencing any of these common hangover symptoms, it might be useful to wait until you feel better to get behind the wheel:

  • Drowsiness and fatigue
  • Headaches and muscle aches
  • Sensitivity to light and sound
  • Nausea, vomiting or stomach pain
  • Dizziness or poor coordination
  • Decreased ability to focus
  • Mood disturbances such as depression or irritability

While it’s always an excellent decision to sober up before driving after drinking, you may want to hold off if you are feeling hungover. Avoid severe accidents and injuries by finding a safe ride to your destination.