I had a Ford F-250. It was a big ol' farm truck, but it wasn't a rig. That's about the biggest I've ever driven. That's what I drove back and forth to high school. I was a poor guy, and it was a truck that my uncle owned and let me drive because I had no money.
You want to try and bring a character to life in an honest a way as you possibly can. It doesn't matter whether he's a doctor, an actor, a car salesman or a captain of a starship. If you can bring truth and honesty to that character, then your audience will believe you.