Yes I would certainly wear adult diapers while on a road trip and in fact I do wear diapers on a road trip since I gave up the toilet a few years ago and now use adult diapers full time for my potty.
I love to wear diapers and now enjoy life much more that I don't have to stop what I'm doing to run to the bathroom to pee or poop.
Whenever the urge to pee or poop hits me I just go to the bathroom in my diaper wherever I am at the moment and same goes for road trips.
When I'm on road trips I always have to pee when there's no restroom nearby so I just pee in my diaper when in the car and change later at a rest stop.
I find that Abuniverse line of diapers such as the little Pawz or Abu Simples work great for long road trips and can hold up to a lot of wetting without needing changed.
All of the diapers on Abuniverse website are good absorbent adult diapers so give them a try if you want a diaper to last long on a road trip.
Wear a diaper on a road trip and you'll be much happier since you can pee whenever you want to or need to and don't have to hold your urine in which is bad for your kidneys.