Updated at 7.06pm: The Transport Department on Monday signed a $70 million contract with Siemens and Siemens PLC Joint Venture to construct an area traffic control (ATC) system for Tuen Mun and Yuen Long. The total contract is valued at $70 million. This will include construction costs of $52 million and five-year maintenance costs of $18 million. 'The ATC systems for the two districts would co-ordinate traffic signal timings to minimise vehicle stoppage and delay at road junctions, which would improve the efficiency of the road networks,' a department spokesman said. 'The rapid housing and new town developments in Tuen Mun and Yuen Long in recent years resulted in a significant increase in traffic flow in both the regional and local road networks. 'The department plans to implement an ATC system to increase the efficiency of traffic management and monitoring of the road networks,' the spokesman added. The contract comprises a central computer system, covering about 249 on-site traffic signal controllers, associated detectors and peripheral equipment, as well as maintenance services for five years. Work implementing the system is scheduled for completion in October 2008. Delcan Arup Joint Venture has been appointed to supervise construction.