Dr. Yung has conducted an expert qualification of the digital speed enforcement camera (SEC) system used by Hong Kong Police Force (HKPF) in 2003. A number of these camera systems are currently deployed in fixed locations in HK on rotation. These systems, which entered service in mid 2004, capture speed violations using a Doppler radar and record each event in two digital images.
Since 2005, Dr. Yung has been acting as expert witness for the prosecutions in a number of cases. At the beginning of this year, Dr. Yung was invited by HKPF to be the person authorized to certify document for the accuracy of all radar speed detection apparatus. The document was issued in February and will be submitted to court in each SEC case, as expert evidence.