The holster shown certainly looks like it would do the job while seated in the car. I'll bet it would print on the shirt if you were walking around with it, however, because of the large Sig P220 shown and the position of the gun on the belt. So it would strictly be a dedicated driving holster in my opinion.
If you want a gun and holster that is reachable while driving, yet would be suitable for use elsewhere, you might consider a small semiauto in a Comp Tac "2 O'clock" appendix carry holster:
Comp Tac 2 O'Clock web page
I have one of these for a Kahr MK9 and it works fine. The gun barrel and holster are very short, so they don't dig into you when seated. And because it is in front, it is not blocked by the car seat when driving. The concealment while walking around is excellent using a shirt worn out, if you have a fairly flat stomach. And the draw from appendix carry is very fast, probably faster than strong side hip carry.