I like long road trips, but like anyone I get tired too. At first I didn't like taking naps in the car because I would wake up and think I fell asleep driving. This causes me to panic a little. Once I got sleepy while driving so I parked the car on the edge of a gas station parking lot right under a tree. When I woke up I was like "AAA! I'M GOING TO HIT THIS TREE!" and yanked on the wheel. Napping in the back seat also didn't help because since childhood I have had recurring nightmares that I'm in the back seat of a car with no driver.
Now, I sleep with a spare t-shirt wrapped around my head, so that when I wake up, I first think about why I would do that to my head, and then by the time I figure out how to get it off, I am fully awake enough to remember that I'm in a parked car, not a moving car.

Maybe I look like a crazy person to other people in the parking lot, but no one messes with a crazy person either I guess, because I've never been bothered.
Around 50 years ago when I was a young whippersnapper I drove cross country. It was very late at night. Maybe 1 or 2 AM. I fell asleep at the wheel. I woke up a couple hours later, a few hundred miles down the road. It was like even though I was asleep, I had put my brain on auto drive. When I was driving something spooked me, like a road sign and I woke up in a start. It was really strange. I didn't even know that my mind could do this.