Quite possible drag marks are insignificant. I wonder if this is near the lookout? Or near or across from a turnout? Because IMO, as he described them, they could have been made by someone walking on the vegetation I would think, and unfortunately some tourists just don't understand the danger of walking off the road on the cliff side and they do go over guardrails, etc to get the "perfect" shot.
A 12'yr old boy did that a few years ago, interestingly enough between Paraquat Rd and Keanae. Fell 200-250 ft to his death after trying to look over the roadway. Sooooo many places to drop a body or body parts on that road.
Also creepy (to me anyway), is two other tragedies happened in that area, within a mile or two, in the last few years, I think after Charli actually. One, mudslide about 8 feet high completely covered the road. Luckily no cars on the road when it happened. Other is local (Hana) teenager went off cliff, he died, his passenger lived. He was high school football star. Official word was he fell asleep. This is my LEAST favorite part of this drive..... I couldn't pass it without shuddering for quite a while. I used to love the road to Hana, not so much anymore. There's been a lot of tragedy on that road.