LOL! Come ON! I'm sure that (like me) you folks don't wear a diaper on road trips because it cuts down on the stops you need to make or because it's "convenient"! You do it because (1) it's fun and (2) because you know you can get away with being in semi-public with a (wet) diaper on and get away with it!
I used to do quite a bit of traveling on the highways and almost always wore a diaper - at least on the way home! I used to make trips of 3-1/2 to 9 hours 2 or 3 times per month and always carried along a stash to wear on the trip home. Much of the time I was not on the interstate highways, but on smaller US and State highways instead. I loved stopping at little rest and picnic areas, getting out, walking around a little while feeling my progressively wetter, heavier diaper under my jeans. There were even time when the urge hit (and I had planned on it!) that I would "accidentally" poop a little as well.
I would prepare well, as I didn't want any telltale stains or odor on the seats. I'd wear 2 or 3 layers of (*blush*) lady's undies under my diaper to help spread the wetness around (which felt really good, too!). Then the diaper, usually a pull-up, and pair of cotton panties over that. That way, the cotton panties would help take care of any leaks. Then a pair of plastic pants and yet another pair of cotton panties to quiet any noise. A sheet of thin plastic and a towel were placed on the seat as well. Seems like quite a bit of thickness, I know. Perhaps it was, but looking in the mirror, it didn't look unusual at all.
The only thing missing was having lovely lady sitting next to me. I would have loved to be able to gently run my hand up her leg, under her skirt and feel a warm, wet diaper!underneath!