Aerial photo taken on Dec. 27, 2017 shows the Hong Kong-Zhuhai-Macao Bridge in early morning, south China's Guangdong Province. The major work of the world's longest sea bridge was completed Sunday as scheduled, after its lighting system was installed and tested. It took six years preparation, and eight years to build the 55-kilometer-long bridge linking Hong Kong, Zhuhai and Macao. In the next month, engineers and constructors will test the coordination of the bridge's various systems and equipment, and proceed with inspection and cleaning work. The bridge will slash travel time between Hong Kong and Zhuhai from three hours to just 30 minutes, further integrating cities in the Pearl River Delta. (Xinhua/Liang Xu)

GUANGZHOU, Dec. 31 (Xinhua) -- The major work of the world's longest sea bridge was completed Sunday as scheduled, after its lighting system was installed and tested, authorities said.

It took six years preparation, and eight years to build the 55-kilometer-long bridge linking Hong Kong, Zhuhai and Macao.

Major work on the bridge consisted of a 22.9-kilometer-long main bridge, a 6.7-kilometer-long tunnel and an artificial island off the bridge, which is considered the most technically demanding part of the whole construction.

In the next month, engineers and constructors will test the coordination of the bridge's various systems and equipment, and proceed with inspection and cleaning work, said Zhang Jinwen, project director with the Hong Kong-Zhuhai-Macao Bridge (HZMB) Authority.

"The bridge will be put into trial operation after its port project is completed and taken over by customs, inspection and quarantine, and border control authorities," Zhang said.

In the past 14 years, the regional economy and transport network have undergone tremendous changes, leading authorities to re-assess the utilization rate of the bridge, said Su Yi, assistant to the chief of the HZMB Authority.

But Su dismissed worries that the bridge would not have enough traffic, saying, "we have full confidence for the future."

"We have a whole toolbox of policies at our disposal," Su said. "It is like playing cards. We can adjust our moves accordingly."

The bridge will slash travel time between Hong Kong and Zhuhai from three hours to just 30 minutes, further integrating cities in the Pearl River Delta.