"headlights"? "wall-eyed"?
Darn, I had to study that picture for a long time to figure out what the heck you're talking about. It's a dirty job, but somebody had to do it. Based on an enhancement and enlargement, and drawing a number of vector lines on the image, I would say that the answer is a combination of gravity and cocking the hips to one side and the shoulders to the other. Can't say for sure though, not until I can study many more of the thousands of pictures the photographer claims to have. I'd need to correlate across a number of poses to determine whether the headlights are in alignment when the vehicle's traveling on the straight and level.
Got a line on more?