From the first result I see that the cloth needs more time to settle, and in [Simulation Settings…] (panel 1) I extend the 30 frames (1 sec) to 90.
And I [Calculate Simulation] again.
Now I see the car poking through (some red spots), and I do have my doubts about the quality of the folds.
So I adjust the [Simulation Settings…] another time. By checking the first (Object vertex…) option – always the first step in improvements, by checking the third (Self-collision) option to prevent the cloth to fold into itself, and I double she Steps per Frame from 2 to 4 to refine the calculations. That’s fine, I did not need the 2nd
The more options I check the more time it takes to complete a proper simulation.
The collision options don’t need a change at all. Let’s peek behind the [Collide Against…].
The little triangle lets me choose between the collision objects Figure (aka the Car) and Ground. The Offset reads 1, that is: the cloth will remain 1 cm from the car. The Depth needs attention only when the cloth and car are moving rapidly towards each other which might introduce artifacts (not the case now), Friction is meaningful when cloth and car slide along each other, and the options are meaningless as the car is not a character, and hence has no ‘zero pose’ nor a head, hands or feet. Save your file.