Other state laws deal with these issues. An uncovered load will cost you $500 to $1000 and covers are Mandatory for all trucks including official trucks. If you get hit by flying debris ( and survive ) get the DOT number of the truck and call it in to claim repairs needed by flying debris. The picture from a national website ( AP ) showed the actual object. Think of a water hydrant cap on a fireplug usually secured with a chain. Roughly 15 to 20 pounds of solid brass. The object even had the little post and cap for a chain still on it. It should be easy to prove who is responsible for his death and homicide or manslaughter charges could be made. That chain fitting is there for a reason and it was not used.

CA state laws deal with these issues as well.
How could you tell the chain was not used rather than it failing/breaking?

Apparently no link attached, which at least makes it more probable (any link could have failed). In any case, if the chain DID break at the cap. it would still be a double failure -- cap not screwed on tightly (perhaps negligence) AND chain broke, much less likely than mere negligence (cap not screwed on tightly and no chain).

Condolences to Mr Schaefer's family and friends.

It was not just the "cap". It was the fitting and the cap. Something like this does not "fall off". It was likely improperly stowed somewhere on the truck or someone forgot to install it before the truck got on the road. I see this incident costing Caltrans MILLIONS in a lawsuit.

Just another example of government incompetence. I all likelihood no state employee will be fired.