The Hong Kong Government invested HK$1760 million (US$225 million) to build a 24 km trunk road with a dual 3-lane carriageway from Sha Tin to Fanling in the eastern New Territories to serve the new towns and also to cater to the increase in cross-border traffic with China. The section Tai Po Bypass, which is 2.9 km long, required the construction of four viaducts ranging from 116 to 242 m long with columns up to 30 m high. The original design of these bridges adopted precast prestressed concrete beam construction. An alternative design using the incremental launching method to construct these bridges was proposed by the contractor with a saving of HK$10 million in contract costs. Specialist subcontractor and consultants from overseas were involved in the design and construction of these launched bridges, which were the first to be constructed in Hong Kong. With the effort of engineers from four continents, this project was completed ahead of schedule, and the road system was open to traffic in September 1985.Key words: prestressed concrete, alternative design, incremental launching.