Prius Speedo Error

[Hicardo]

Additionally, i was advised once by an ex traffic policeman that the police allow (+ 10% +1mph) when clocking speeding motorists with calibrated equipment. Therefore at 70mph, you wouldnt get stopped unless you were travelling more than a true 78mph. Dont want to put this to the test, but that's what i was told. This conversation was about a year ago with a retired officer who patrolled the M25. Not sure whether it relates to speed camera settings too..