There's something about driving long distances that's daunting.
The longest drive I ever made was from Winnipeg, Manitoba, to Lincoln, Nebraska, back when I was 19 years old; I made it in a single day, but man, by the time I was in northern South Dakota, about halfway through the trip, I was already hallucinating. This, despite that it was day-time, that I was on no drugs or alcohol, and long stops about every hundred miles or so.
Four years ago, when an aunt of mine, in northeastern Pennsylvania, died, I decided I had to go there, and so took off, from here in northeastern Nebraska. Two-thirds of the way through Iowa, I had to stop for the night even though it was only early afternoon. The next day, in central Illinois, I had to stop for the night even though it was only early afternoon. The third day, in central Indiana, I had to stop for the night &c., &c., &c. The fourth day I managed to make it a-l-l the way from central Indiana to the westernmost part of Pennsylvania (i.e., driving all the way through Ohio), when I had to stop for the night &c, &c., &c. I finally made it to northeastern Pennsylvania on the fifth day, too late for the funeral but a chance to visit anyway.
After three days there, I turned around to come back.....and it took five days to get home.
For those who don't know, the distance, one-way, was 1200 miles.
I was gone two weeks for a three-day visit.
I suspect the deal is when I drive, I drive. I don't do anything else. I simply concentrate on the road. No radio or music (for obvious reasons), no chitchattery with a passenger, no drinking or eating while at the wheel, no admiring the scenery. Just driving. Perhaps so much intense concentration one burns out?
(I am describing instances where I've driven alone, nobody with me.)
Lincoln, Nebraska to Denver, Colorado, is usually considered a "fun" drive by many in this state, but for me, it was always a trial. Whenever I can, I let another person take the wheel, even if it's my automobile or an automobile I provided.
I've described trips with the senior business partner elsewhere; he too loathes driving (even though he's the junior partner in an automotive dealership). He once got a lot of flak from others because his 88-year-old grandmother needed to go to Valentine, Nebraska, about 100 miles away from their town, and he cheerfully let her do the driving, there and back.