To me, P-mode is, or I should say “was”, for when I didn’t care about the shutter speed or aperture.
For racing photos, shutter speed seems to be very important, depending on whether I want a sharp, clear, photo, or if I want to show. motion. So for those photos, once I found a shutter speed that worked, I locked it in.
There weren’t too many photos where I decided I needed more depth of field. If I shot the drivers while I was up on the driver’s stand, unless I forgot to do so, I would adjust the camera to also have the track reasonably sharp in front of them. As I recall, if I had no particular interest in either setting, I left the camera in Program mode.
After the discussions we’ve had here recently, I doubt I will have much use for Program mode. My Leica is semi-permanently set to Aperture Priority mode, and Auto-ISO. I may set my D750 to auto-ISO. Most of my negative feelings about it date back to when too high an ISO resulted in an awful image, but with PL5, that’s irrelevant. I guess old habits die hard.
I did photograph full-size car racing at Homestead Speedway. It was SO much easier than photographing the r/c cars. I had lots more time to think, and I could use a monopod.