【明報專訊】The Transport Department has installed 1,200 traffic detector sets on major arteries (幹道) for collecting traffic flow and driving speed figures. A set comprises a video or auto vehicle plate detector, and a Bluetooth detector, among which the Bluetooth one is the most controversial. It can detect Bluetooth devices of drivers and passengers, including phones, headsets, smart watches, etc. An IT practitioner said that they had not been consulted.