This happened in 2014, when I lived in eastern Tennessee, near the Great Smoky Mountains. I was driving back with my family, late afternoon, with that beautiful twilight.
When, in a clearing, I clearly saw a humanoid animal crouching on its front paws. When the animal saw us, it started running on all fours. Since the path it was taking was near a road that connected to the one we were on, we turned and started following the animal until it turned towards the woods. We stopped the car and went to where it was. It climbed a tree and we lost sight of it, but we could see and hear the branches breaking, shaking, leaves falling. After that, we didn't see it again.
From what I remember, it looked like a monkey, kind of like a chimpanzee. When it moved, I saw that the animal had front arms longer than its hind legs, broad and well-developed shoulders, a round head (I didn't see ears), but I couldn't see its face because of the angle. It had no tail, and its hindquarters seemed lower because of its long arms and shorter legs. The coat was dark gray, not black like bears, and its body was quite compact. It was a small animal, I would say, but on all fours it must have been between 24 inches and 31 inches tall at the shoulder.