A Secret Harbour driver has been fined $800 and received six demerits points after travelling 30 kilometres over the speed limit, on Wednesday.
Mandurah Police Acting Senior Sergeant Phil Woods said the driver of a BMW Coupe was clocked travelling at 82 km/h, in a 50 km/h zone.
Acting Senior Sergeant Woods said the infringement was one of nine issued in Secret Harbour within an hour, in a 50km/h zone.
On Tuesday, 15 traffic infringements were issued for various offences.
Acting Senior Sergeant Woods said speeding in built up zones was "unacceptable" and would be a police focus in the future.