This happened to me about 5 years ago, in 2013, and I still am baffled by it.
I was on my way to work early in the morning, around 6:30, so it was still dark. As I rounded a corner on my road, I came upon a car stopped in the middle of the road. I halted behind it for a moment, before realizing that they must have been having issues, so I drove around it to the left. As I passed the car, I noticed an old man in the drivers seat. He was balding, dressed in what looked like a white sweater, and was hunched over.
I drove up the road for about half a mile when guilt got the better of me. What is this older gentleman didn't have a cell phone to call for help? So I found a spot to turn around and headed back to the vehicle.
When I arrived at the spot, I was immediately confused. The elderly man was no where to be found, but there was a middle-aged man standing outside of the car, attempting to call someone on his cell phone. THIS man had dark hair, was in his late 30's or so, and looked NOTHING like the older man I'd seen in the vehicle earlier. I rolled down the window, and asked if he needed assistance. The man kindly replied that he was visiting a friend and had gotten lost, running out of gas in the process. I directed him to the nearest gas station, and he stated that his friend was coming to help him out.
Before I left, I asked him if he had anyone in the vehicle with him... He replied that he did not.
So, just who-or what- did I see in the drivers seat that morning?
The way you describe it makes me think of a person passing out (away?) while driving. Perhaps you saw the residual imprint of the old gentleman's last moments.
Thanks for sharing and welcome to YGS.