Out here it can be a long way between towns or rest stops, particularly on older two land highways. As I drive a lot in my work I've had to stop often and piss along the roadside. I try to find a pull off or the entrance to a field pee there inspecting the surroundings as if I'm interested in them.
I've used picnic areas without facilities along the Interstate as well, parking so that traffic can't get a good look pissing on the grass or if it's convenient is a trash can. I've never been caught as far as I know anyway.
If I'm outside at home I'll piss in the corner should the need ar