FORT RUCKER, ALA. - Do you have drooping eyelids, persistent yawning or wandering thoughts, or feeling irritable, restless or impatient behind the wheel? Are you having trouble staying in your lane and can't remember the last few miles you drove? How about driving at abnormal speeds, tailgating and ignoring traffic signs?If this sounds like you, take a look in the mirror and see what's staring back. It may be scary. In fact, the National Safety Council says you just might be looking at the next highway "z-z-z-zombie."Did that thought wake you up? If it didn't, your next address may well be engraved on a headstone.Think that's an exaggeration? Dr. Lisa Shives, founder of Northshore Sleep Medicine in Evanston, Ill., said fatigue-related crashes can be worse than drunk driving accidents. The reason, she explained, is what happens in the final moments before impact."Investigators have figured out that a crash due to fatigue often shows no skid marks or signs that the driver tried to correct the course of the vehicle, which they see with crashes due to intoxication," she said. Because this leads to more violent impacts, "A grisly feature of crashes associated with sleepiness is that they are often fatal."According to a National Highway Traffic Safety Administration study, asphalt zombies are like their cinematic counterparts -- they're active both day and night. However, that doesn't mean they don't have their favorite times. Darkness brings out the worst in these drivers, with midnight to 6 a.m. being the most dangerous time. The roads also get a little scarier during the mid-afternoon slump, usually around 2:30 p.m. Both times, the NHTSA study noted, tend to reflect human circadian sleep patterns.There are other factors, too. Certain medications used to treat pain, depression, anxiety or allergies can also deaden alertness, helping move you to a zombie state. Medical conditions such as sleep apnea or narcolepsy also put you at heightened risk. And heightened is a good description, as these accidents typically combine high speeds and reduced reaction times.So how can you keep yourself from joining the ranks of the "driving dead?"First, get adequate sleep before hitting the road. Understand your body is programmed to sleep at night so, if possible, avoid driving between midnight and 6 a.m. If you find yourself falling asleep, find a rest stop or place where you can pull off the road and safely take a nap. Better yet, look for a place where you can get some extended sleep. After all, resting in a hotel tends to be a lot cheaper than a hospital.If you must drive, caffeine does help, whether you consume it in the form of coffee or caffeine-fortified soft drinks or tablets. However, be aware that caffeine is only a short-term answer (good for perhaps an hour), not a long-term solution.The NSC and the Army's TRiPS program recommend you stop periodically and take a few minutes to stretch your legs to get the blood moving and the brain cells firing again. Stopping for a light snack can keep your furnace fueled, giving you energy to help keep you alert. But the emphasis is on "light." Heavy meals can awaken the zombie in you, sending you careening down the road in a trance-like state.Know the signs of fatigued driving and remember these safety tips as you drive. After all, the Army of Darkness doesn't need you nearly as much as our Army!