Construction of the 2.74 kilometer Gongbei tunnel was completed on Monday in the Zhuhai Special Economic Zone, the final link that should enable the 50 km Hong Kong-Zhuhai-Macao Bridge project to open before year's end.

Zhi Yufeng, chairman of Guangdong Nanyue Transportation Investment and Construction Co, said the Gongbei tunnel is a major component of the gigantic bridge, linking the three regions, located at the mouth of the Pearl River.

Once in operation, the bridge will help shorten the current four-hour drive from Hong Kong to Zhuhai to a half-hour.

Construction of the six-lane tunnel started about four years ago. The speed limit will be 80 kilometers per hour.

Located near Zhuhai's busy downtown areas, the Gongbei tunnel links to bordering Macao Special Administrative Region to the bridge.

Zhang Yisheng, vice-mayor of Zhuhai, said completion of the Gongbei tunnel will help boost Zhuhai's transportation industry and the city's government will continue to work toward increased investment to ensure construction of the bridge's finishing touches are completed in the following months.

Experts said the Hong Kong-Zhuhai-Macao Bridge, with the main work now completed, will play a significant role in boosting economic ties between Hong Kong, Macao and Guangdong.

Insiders have forecast the bridge will open to traffic on Dec 20, when Macao celebrates its 18th anniversary of its return to China from Portuguese control.

Chen Guanghan, vice-dean of the Research Institute of the Development of Guangdong, Hong Kong and Macao, said the bridge will help Hong Kong further expand its economy when it works with the vast western part of the Pearl River Delta region in Guangdong after traffic begins to flow.

"The western part of the delta region, which includes the prosperous cities of Zhuhai, Zhongshan, Jiangmen, Yangjiang and Taishan, still has huge room for expansion and cooperation with Hong Kong," Chen said.

"The bridge will help accelerate the development of Hong Kong's international airport and its ports and the development of region's Lantou Island area," Chen said. It also is expected to help the airport and ports attract more businesses from the mainland, he added.

The Hong Kong-Zhuhai-Macao Bridge includes a 6.7 km tunnel beneath the water and a 22.9 km bridge that passes over the sea, making it the longest cross-sea bridge in the world.

Construction of the Y-shaped bridge started in 2009 and will cost more than 10 billion yuan ($1.5 billion). It is part of the country's planned national highway network, linking the western and eastern banks of the Pearl River.

The service life of the bridge is expected to reach more than 120 years.

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