Jeanna Grunewald's most terrifying moment on the road occurred a couple weeks ago, and she never saw it coming.

She was headed from home in Lamberton, Minn., to class at Southwest State University in Marshall on a foggy Monday morning when her eyes started feeling heavy, partly from waking up early and partly from taking medicine that sometimes makes her drowsy. Halfway into her 45-minute drive, her eyes shut for only a few seconds. But that was long enough to send her Ford Taurus across the centerline on Hwy. 68 and into a drop-off on the opposite side of the highway. That sent the car airborne before it landed in the ditch perilously close to a ravine.

"I don't remember falling asleep," said Grunewald, who is studying to be a preschool teacher. "I just remember waking up when I hit the ground."

She has rods in her lower back to stabilize two fractured vertebrae and will be in a brace for the next three months. Fortunately, she is expected to make a full recovery.

Cases such as Grunewald's are all too common, says a recent report from the Governor's Highway Safety Association, which conservatively estimates that 328,000 crashes, 6,400 deaths and 109,000 injuries annually can be attributed to motorists who fall asleep at the wheel. That's why the National Sleep Foundation has proclaimed this as Drowsy Driving Prevention Week, to draw attention to the fact that sleepy drivers are just as dangerous as those who drive distracted or drunk.

The Centers for Disease Control and Prevention says the average adult needs seven to eight hours of sleep to maintain good health, yet more than a third of people 18 and older routinely get less. That puts into 86.3 million tired drivers on the roads every day. A National Sleep Foundation survey found 28 percent of drivers admitted to falling asleep at the wheel and more than half (54 percent) said they have driven while drowsy.

The danger goes far beyond slow reaction times, impaired judgment and the proclivity to take unnecessary risks. Fatigued drivers can fall into a micro sleep, meaning they unknowingly doze off for a couple seconds. A lack of sleep can sneak up on you, said Ranji Varghese, medical director of the Minnesota Regional Sleep Disorders Center at Hennepin County Medical Center.

"It's not a dramatic effect that we are awake and then all of a sudden we are sleepy," he said. "It only takes 2 to 3 seconds for the brain to disengage, and that is long enough to make a catastrophic mistake."

Signs along highways in Utah warn motorists that "Drowsy Driving Causes Crashes" and encourage "Drowsy Drivers [to] Pull Over if Necessary." But people are notoriously bad at recognizing that they are fatigued and forge ahead, Varghese said. Drivers need to recognize the symptoms: yawning, heavy eyes or veering off onto the rumble strips.

Tired drivers try all kinds of things to stay awake, including caffeine, blasting the radio, sticking their head out the window, singing or talking to somebody on the phone — but does that work?

"Yes and no," Varghese said. "That may be enough external stimuli to overcome the pressure of the need to sleep, but even with wind on our face we can still fall asleep."

A better remedy for tuckered-out drivers, he says, is to take a 15- to 20-minute nap. Grunewald suggests, "Get somebody to drive you, or pull over if driving and call somebody." That's what she said she'll be doing.

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