I started the jail theory, completely based on proximity and knowing there isn't much up there. I was looking for places on the map he may have come from when I realized the jail complex was right there.
From the information below, he face must have been swollen from the injuries. He was very tall and on the skinny side for that height.
The FDLE flyer was linked in a post above, but I don't think the text was ever copied over:
NARRATIVE: On November 18, 1990 an unknown man was struck and killed on Interstate 75 near the County Road 329 overpass, 10 miles north of Ocala. The man was wearing white jeans, a dark colored wind breaker and white tennis shoes. He was in his 20's and had a height of about 6'4" and weight of 152 pounds. He had long brown hair and hazel eyes. If you have any information please contact the District 5 Medical Examiner at (352) 326-5961 or the Florida Highway Patrol.
Newspapers.com does not have any articles that may give more details and the Star Banner's archive only goes back to 1991.