Scale signs should be on both sides of the road so they can be seen by a vehicle passing another vehicle.
also
The driver should present to the shipper the working empty weight of the driver's vehicle and the driver should only be responsible for that weight.
My truck and trailer empty with full fuel normally weighs about 32,500 lbs. So I normally round it to 33,000 when I'm asked. Let's say my Bill of Lading says I'm carrying 47,000 lbs. of cargo, but when I cross the scale at the weigh station it reads "80,500". It is later determined that I was actually loaded with 48,000 lbs. I should not be responsible for the overweight ticket.
If the BOL had said 48,000 lbs and I accepted it and left that way then I would have been responsible.
There does need to be a safety requirement to insure that the load is not severely over loaded. I was once loaded with the wrong gauge of pipe. We caught it when I scaled out at over 90,000. This top heavy load could have been a real problem had we not scaled it.
also
Drivers should be able to use a DOT scale to check their weight if it is closer than a commercial scale. I picked a load up about a mile south of a scale in Ft. Smith, AR and had to drive several miles into the city to get to a scale, just so I could turn around and go over the DOT scale with confidence. There are some commercial scales just north of the DOT scale.