I strongly suspect many Strava performances are achieved like that.It depends on your gps device and signal. My edge 500 is set to update every second so is accurate enough.
My wife went for a 5 mile run and hit a top speed of 51mph due to leaving her garmin watch running when she got back in the car
Mostly nonsense, is that off a phone?
According to Strava i did 180kph the other day!