Hello Philippe,
I could imagine a classic but modern tractor, i.e. Peterbilt, Kenworth or International. Maybe a Daycab or short Sleeper, I think that the Trailer is used on short routes between chemical plants. Maybe like this:
or this:
As colour I would prefer a clean white, as the trailer, no big chrome accesories, only the company logo decals. Just a working animal.
Greetings