Nonsense. When you need radar to tell if someone is 5mph over or write tickets to a motorist who was 8mph over because all of the traffic was, that has nothing to do with "safety" and everything to do with "revenue". That is why seatbelt laws are the new darling of "law enforcement". Big fines to tack on for a person bother no one. It is theft, and not surprisingly these thefts are way up since the economy tanked.
Interestingly, if the local seat-belt law references the federal seat-belt law then [likely] you don’t have to have/wear a seat-belt in your fare if it was manufactured before 1968.
“or write tickets to a motorist who was 8mph over because all of the traffic was”
“But mommy, all the other kids were doing it too” never passed the smell test when I was growing up.