If one had enough space to run before diving, not jumping, and landed on their head, that might do the trick. It might not be an immediate death but certainly an immediate knock out.
It would be wise to make it clear beforehand ones wishes regarding being sustained on life support as well, in the event of survival as a vegetable.
If I were to try this, I'd do it at late at night so there's not much traffic. As much as I want my life over already, I wouldn't want to land on someone's vehicle and possibly cause grave injury to others.