This YouTube clip is posted with the title “Sleeping While Driving is Scary,” but the comments over on the Reddit Trucking channel make a good case that the truck driver suffered some sort of medical emergency—although, if anything, that makes this Dash Cam of the Week even scarier.

Granted, if there’s a stretch of super slab where one could easily drift off, this is it: flat, straight, and empty. And in this case, empty was good.

And talk about luck all around: the truck, after crossing the median, just squeezes between the only two vehicles in sight on the other side of the interstate. The truck driver couldn’t have threaded that needed if he was trying—which adds to the suggestion that he wasn’t just asleep, he was unconscious and unresponsive.

Since the clip doesn’t offer any hints as to time or location, we haven’t been able to track down a report on the incident to find out what happened to the driver so we hope for the best. Lessons? You can’t anticipate an incapacitating medical event, of course, but you can pay attention to your health. We all know the drill: diet, exercise, blah blah blah.

But—underlying medical reasons aside—we all certainly can and should be aware of fatigue and drowsiness. The rule of thumb ought to be: If you think you’re sleepy, you are. Get off the road. But anyone who wakes up the morning looking at 500 or 600 miles every day might never pull out of the parking lot. Still, it’s a biological fact: If you catch yourself nodding, you’ve already been asleep—you just didn’t know it.

Here’s a nice reminder from ABC Nightline’s Ron Claiborne: