Construction workers inspect a bridge that connects the highway between Bijie and Duge in Guizhou province in October. LIU YELIN/CHINA DAILY

For 53-year-old TangHua, a farmer in Daozhen county, Guizhou province, Chongqing is a big city on the other side of a mountain near his home. It used to take six hours to get there. Not any longer. On the last day of 2015, an expressway linking Daozhen to the rest of the province and beyond opened. It was the last county in Guizhou to be linked to the transportation network.

"The muddy mountainous path to Chongqing will be deserted, as well as many old ways of life," said Tang.

Guizhou's rugged and rocky terrain can make traveling a burdensome task, increases transportation costs and aggravates poverty. By the end of 2015, about 4.9 million people in the province lived on less than $1.25 a day, a sharp reduction from the nearly 12 million in 2011.

"Traffic has been the main issue hindering the province's development," said Wang Bingqing, director of the provincial transportation department.

By the end of 2006, the total length of highways in Guizhou was less than 1,000 kilometers, a level that some coastal provinces in East China had attained by the late 1990s.

In early 2009, Guizhou focused on infrastructure, aiming to weave all of its 88 county-level regions into a highway network by 2015. The total investment was about 410 billion yuan ($68 billion). The province now has 5,126 kilometers of highways.

"The investment and construction scale are both all-time highs in the province's history," Wang said.

Wang Jianguo, chief engineer of the Wengan-Daozhen highway project, said the length of tunnels and bridges accounted for more than 50 percent of the highway, which "increased both budget costs and difficulties for construction".

Compared with areas where the terrain is flat and the highways go across plains, the cost of building a highway in Guizhou is generally about 30 percent higher, Wang said.

Building tunnels and bridges take up a great deal of time as they must be designed and measured to pinpoint accuracy, he added.

China Communications Construction Co will operate the road for 30 years, and use the earnings to repay loans that were spent building it. It will then present the road to the local government.

Li Ruguo, deputy general manager of the company, said this arrangement saves the government money, and ensures construction quality. "About two thirds of Guizhou's highways go through less well-off areas, and increased traffic will greatly boost logistics and attract investment", said Wang Bingqing, head of Guizhou transport department.

"The improvement in infrastructure gives the county government more confidence to attract investors," said Gan Liyi, deputy director of Meitan county's industrial park. "We had lost so many good investors due to the lack of a highway."

The Meitan industrial park was established in 2001, and up until 2010, when the two highways were finished, it had largely remained empty.

Now it's our turn to get businesses to settle in the industrial park, Gan said. "The road changes our status."

The highway network in Guizhou also integrates into regional cooperation in Southwest China that involves the provinces of Sichuan and Yunnan as well as Chongqing municipality, said Deng Ling, a professor of economics and development at Sichuan University.

"Guizhou is a member of the Yangtze River Economic Belt, a regional development plan made by the central government. A developed highway network in Guizhou can make it a regional hub connecting nearby provinces and let productive factors, say resources, funds and man-power penetrate into the less well-off areas in Guizhou," she said.

Li Yang contributed to this story.