Problems with eavesdroppers, interference and poor reception on rainy days have prompted traffic police to install a $100 million radio system. The new technology will also be used by the police driving school and the VIP protection unit. The system has been in operation since April in Kowloon. Hong Kong Island and the New Territories are expected to follow this year. The system uses radio trunking technology similar to that in cellular phones, minimising interference that the old VHF traffic system has been subject to. With the new system, traffic officers in emergency situations are given the highest priority, which ensures them a free channel within milliseconds of making a call. Superintendent Tsang King-man said eavesdropping had been a problem during their operations against illegal car racing. Kowloon West traffic constable Wong Tak-wah said: 'In the past, messages are sometimes jammed or very unclear. But now I can hear clearly the registration number of a speeding car spotted by colleagues and respond to the call quickly.'