There we are again, in the car!

Did you use a tripod? (Just kidding). Interesting shot. I imagine you saw your reflection and it gave you an idea? While you could not exactly choose your surroundings, a better background might have added to the photo. Maybe next time keep following and see what comes up as the surroundings change? As is it's kinda boring. But different.

What could I have done better?

Maybe you also had to close in more to get a bigger reflection. You can also try how cropping the picture would influence the quality of it.

You could have asked truck driver to stop and asked permission to shoot the reflection. I like the shot though...

Jeez, I like the surroundings. It's stark, not drab. Barren landscape, shiny metal man things---21st century Hittites!