3 ms·

The parent post already noted that the GPS doesn't know your instantaneous speed, just the average speed since your last reading. If your signal was blocked by

The parent post already noted that the GPS doesn't know your instantaneous speed, just the average speed since your last reading. If your signal was blocked by trees, buildings, bridges, (not to mention your car itself), you can go at least several seconds without a reading, and what happened in between those points is unknown to the GPS, except for total ground covered. And that's even before you account for GPS inaccuracy, which is ~3m in optimal conditions.

Bud 16y ago
In my experience, those outages don't tend to be frequent on main roads, where there is usually an unobstructed sight-line to the GPS satellites. Sure, it's possible that this dude floored it, hit 50-60mph for a second or two, slammed on the brakes leaving rubber all over the pavement, slowed to 15mph for a while to make the averages all work out, and proceeded on his merry way at 25mph. But it doesn't seem that likely.