Thats when it gets to sort of like splitting hairs.FWIW, I probably rearranged the VSSB 3-4 times before I got a speedo reading that matched my GPS. Either the speed calculator is a bit off or my GPS is?
For the DOT, they started installing distance meters for setting work zone signs. Too many Tort claims because signs was off by feet or yards.
The vehicles that got the distance meters, the meters had to be calibrated. The engineer dept went out on the interstate and marked off a stretch that was two miles. Once we got the meter installed then we got to go out and drive the shoulder of the interstate that distance and recalibrate, with dip switches, until the meter read correct to the distance. It was usually off a foot or two but with the dip switch that was as close as we could get them.
If the sign said men working 1,000 feet then that distance had to be accurate within XX amount of feet in order for the state to keep from getting sued if there was an accident within that distancez