Required accuracy / resolution of truck scales?

Anyone know the required legal accuracy resolution of truck scales?

I'm speaking "generally" but more specifically, the two scales such as used in our local waste transfer. These have to weigh everything from very light vehicles with a couple of garbage cans to heavy trucks

I ran my Ranger through there today. I did not so much as throw out a candy wrapper. There was 60 pounds difference between the "in" and "out" scales.

I've Googled this, and found nothing "easy." And yes, LOL, I found NIST "handbook 44". This was written in Far Eastern Russian Hebrew, translated to Manderin Chinese, then to something I've never heard of and finally, "American."

In short, I don't understand any of it

So what did you take out that was 60lbs. J/k