The Asian Development Bank (ADB) has issued 17 billion U.S. dollars worth of loans over the past 30 years to support 95 transportation projects in China, an ADB official said Monday.

The amount on transportation is more than half of ADB's all loans to China, Robert Guild, director of the transport division of East Asia development of ADB, told a seminar marking the 30th anniversary of China-ADB cooperation.

Fifty-five percent of the loans were used for highways and roads, 27 percent for railways and the rest for urban transportation, ports and water transportation projects, said Guild.

Zhang Dawei, a senior official with the Ministry of Transport (MOT), told the seminar that China was the second largest borrower from ADB worldwide.

The loan effectively bridged the funding gap for transportation infrastructure in China and modernized the transportation sector, said Zhang.

MOT data showed that China's transportation network has reached 4.95 million kilometers by the end of 2015, with 19,000 km of high-speed railway and 124,000 km of expressway, both ranking first in the world.