Whenever you see a subcompact pick-up truck, go ahead and make arrangements to pass. They are all going to be driven VERY slowly. Some typical models: Chevy S10, Ford Ranger, etc.
I think the engines in them are small, but it has to be the driver. I drove a Citroën 2CV across southern Yugoslavia in 1996 without much trouble even getting on a multi-lane highway a few times. I mostly kept up. It’s all in the RPM’s.
Those little pickups usually go 15 to 20 mph below the posted speed.
Count on even slower with the addition of any of these:
— driver has on a straw hat
— driver is smoking
— there some disassembled POS in the bed
— it’s a defunct brand, like Datsun