A very tall figure in Sutton County, Texas

I was driving eastbound on I-10 near Sonora, Texas at 1:00 AM watching out intently for mule deer, which were everywhere, grazing beside the freeway and running across the road. What I at first assumed to be a tree, saguaro, or bush appeared in my headlights in the center median at mile marker 406 approximately 5 yards off the pavement. As I passed, I noticed the subject was turning in synchrony with my motion, displaying the same right side of his body to my view, until we were parallel to one another. Other reports indicate subjects shielding their eyes from bright lights at night, but this guy was simply rotating his body with no other obvious motion. Just as the headlights were fading on the subject, the subject turned directly to face my vehicle and began to move. In that instant, I realized how incredibly wide the shoulders were, and how much the body tapered down to the feet, and observed two very long arms. Immediately upon passing the subject, I was still watching in my rear view mirrors with the subject illuminated by the headlights from a truck perhaps 1/4 mile behind me, as it ran across the road in a southerly direction, leaning forward, arms pumping almost parallel to the ground, knees bent at all times. I noted the mile marker, reversed course, and returned to the site looking for a tree or a bush that could explain the sight, circling several times for about 30 minutes, but found nothing but grass in the median. The subject was perhaps seven feet tall, all dark brown in color, perhaps 3 inch long hair overall, very wide shoulders, and long arms, the fingertips about parallel with the tops of the knees. No other details were evident in the short sighting period.