Construction of China's first cross-sea bridge accommodating both vehicles and railway traffic - the longest of its type in the world - will be completed this year and will open to traffic early next year, said Yao Pengyuan, one of its top engineers.

Pingtan Haixia Rail-Road Bridge will provide a 16.3-kilometer connection between downtown Fuzhou, Fujian province, and the island county of Pingtan off the east coast of Fujian.

The new bridge will cut travel time from two hours to about 30 minutes between the two areas.

In the past, Pingtan has been a development bottleneck because of poor transportation. Since the establishment of the Pingtan Comprehensive Pilot Zone in 2010, the local government has ramped up its efforts to build a comprehensive transportation system.

In 2010, the Strait Bridge began operating for cars only. It links the island with an outlying county of Fuzhou and is currently the only entrance and exit for the island. It takes about two hours to get from the island to Fuzhou's downtown. Before the bridge opened, a ship was required to get from Pingtan to the mainland.

Yao, the engineer from the bridge building bureau of China Railway Construction Co, said, "Strong winds make it tough to build a bridge over the water, where about 300 days a year the wind is heavy and impedes construction."

The new bridge has two layers, with the upper deck consisting of a six-lane highway with speeds up to 100 kilometers per hour. The lower deck carries a double-track railway, on which trains can run up to 200 kilometers per hour. Construction started in November 2013, with an estimated investment of 10.9 billion yuan ($1.7 billion).

The cross-sea rail link will be an integral part of the 88-km Fuzhou-Pingtan railway, which starts at Songxia Port in neighboring Changle county, Fuzhou, and terminates at Su'ao town in Pingtan.

In the draft outline of the 13th Five-Year Plan (2016-20), a high-speed railway linking Beijing and Taipei, Taiwan, was proposed. The Fuzhou-Pingtan railway represents the southeast end of that railway. For the remainder of the distance - Pingtan to Taiwan - an underwater tunnel has been proposed.

Pingtan is the nearest mainland jurisdiction to Taiwan, with only 68 sea miles to Taiwan's Hsinchu city.