I don't think those speed board's are particularly accurate. I was once
clocked at 20 mph by one near my parents house - and I was walking! I
mean, I'm a fast walker but not THAT fast.....
My $.02 on this issue is that since the regulations generally state
that a speedo cannot read LOW, the manufacturers tend to calibrate them
to read higher so they don't read low.
'04 A4 1.8Tq MT-6
Central NJ USA