A motorcyclist travelling at a staggering 153mph on the A120 near Braintree will not be prosecuted because police could not read his registration plate.
Sunlight glaring on the number plate in video footage made it unreadable – so they cannot track the culprit down.
Speed checks were carried out on the 70mph dual carriageway near Stebbing last weekend and used digital recorders to catch people driving at more than 100mph.
Anyone driving at more than 25mph over the limit will be reported to court.
Adam Pipe, casualty reduction manager at Essex Police, said 148 drivers were found to be speeding over the three hours.
Driving on a 70mph road between 101 and 110mph can result in a fine plus six points or a driving ban for between seven and 56 days.
Mr Pipe said: “We are naturally very disappointed."
See this week's Braintree and Witham Times for the full story.