Didn't get the evidence for DUI manslaughter, but they need to throw the book at this motorist for vehicular manslaughter, he has enough priors for driving infractions that should get him a lighter, yet still stiff penalty even though it'll never be enough.
Yeah that guy disappeared for too long and any video without the BAL results is going to be speculation as opposed to the slam dunk. He may have even lied to his father or whoever it was, said he hit a concrete barrier, or a truck dropped a board or whatever out of the bed of the truck ? Or it was dark and he didn't know what he hit and wasn't sure if it was a human being or what ? 15 years as a max, probably not nearly enough, but add a civil decision for monetary damages and garnish wages, what more can be done ?