You know people who own big rigs to show off? I haven't really seen people driving those as personal vehicles before, the closest I've seen are F550 based RVs since smaller truck chassis wouldn't be legal or able to carry that much weight.
I had assumed they were using "truck" in the US sense (e.g. a ute or pickup) rather than big rigs, because wtf would you want to force trucks to use bigger and less efficient engines, instead of oversized utes which are the bigger environmental hazard.