I understand the wheel means someone used a wheel for the time trial, and the wrench means someone used a custom setup... but what is the gray open wheel car icon means?
Thank Yuri!! Then, it begs the question "why would a ghost no be available in a time trial"?? Perhaps, a faulty recording or a disabled old session.
Some car/track combos seem to be buggy and ghost isn't saved; I've noticed this with, I think, the old Porsche GT at Nords. The other reason is if the user leaves the session quickly the ghost may not be uploaded.