If I was this guy who got nailed, I'd appeal also out of principle. It's total BULLSH*T!
I know for a fact when I have my GPS on that the speed registering on the screen is ALWAYS right on the money to what my speedometer is showing. This guys speed in the commercial vehicle with his GPS is logged and saved every 3 seconds.
Let's forget about the possibility that the GPS might be off or the signal as was argued in court...how about the cop and his reaction time? How about the cop having good visibility at the start of the painted line to the end of the painted line? How about the fact it was 6:50 am and still dark? How about the fact the cop is a lying POS and fabricated the speed?
Since I was born and raised in that area and know how the cops work, I'll have to go with all of the above. In addition to the fact the judge already had his mind made up to side with the cop.