I took mine up to an indicated 100 mph a few weeks ago, while I had my GPS mounted. I was curious as what my GPS registered and was shocked when I opened that feature and found.............549 mph.
Than, I remembered that I used the GPS to play MP3's while on a Southwest flight to Floriday this spring. At some point it must have picked up a satellite. Apparently we were motoring long at a fine rate of speed.