A 36-km bridge, the world's longest sea-spanning structure, will open to traffic on May 1, a spokesman for the project headquarters said.

"The main part of the project has been completed and 95 percent of the ancillary works has also been finished," said Wang Yong, chief commander of the bridge construction project.

The bridge, spanning Hangzhou Bay near Shanghai, will cut the length of road trip from Shanghai to Ningbo, a busy port in east China's Zhejiang Province, by 120 km.

The bridge is a cable-stayed structure built at a cost of 11.8 billion yuan ($1.64 billion).

Construction of the six-lane bridge, which will allow a speed of 100 km per hour, began in November 2003.

The bridge would boost economic integration and development in the Yangtze River Delta, which covers almost 100,000 square km comprising Shanghai, Zhejiang and Jiangsu and is home to 72.4 million people, Wang said.