I have no knowledge of what the proper restraints are.
Interestingly, on a thread today, it was stated that the policy to provide the proper restraints was only a few days old. That it is possible that the officer charged did not know the policy existed because time is required for such measures to filter down to the cops implementing the regulation.
In my mind, one wonders if the van actually had the undefined restraints.
In my Family I have one retired Major(Homicide Miami), One Grandson Newbie, Palm Beach Co. Deputy Sheriff, and one Nephew, Policeman in Homestead, Fl.
They have related to me that they have on seen/used seat belts on a few prisoners and those are in cars only!