A highway linking Medog, the last roadless county in China, with neighboring Bome county in Tibet Autonomous Region formally opened to traffic on Thursday, ending the county's isolation from the outside world.

The 117-kilometer highway, which cost 950 million yuan ($155 million), links Zhamog Township, the county seat of Bome, and Medog in Nyingchi Prefecture in southeastern Tibet.

The road will be accessible for 8 to 9 months per year, barring major natural disasters, said Ge Yutao, Communist Party chief of the Tibet regional transportation department.

Getting out of Medog, a county of  a population of 12,000, used to be a dangerous journey that required people to climb over Galung La and Doxong La, two snow-capped mountains rising over 4,000 meters above sea level. The mountains were the site of frequent  landslides and avalanches.

The construction work officially began in April 2009.

The lack of modern transportation infrastructure has isolated Medog, dubbed the "secret lotus," from the outside world and restricted its development, said Ngodrup Dorje, former head of the county government.

Foot travel and horses have long been the only transportation method for goods in Medog, and locals have had to pay inflated prices.

The opening of the Medog road will greatly lower transportation costs and will also improve medical care and educational facilities, said Tashi, head of the Medog county government.