The road crossing the pass was once an old unsurfaced track travelled only by a weekly bus and trucks heading west to avoid the boggy parts of the south of the country.[4][2] The construction of paved road through the pass, Tibet Provincial Road S206, was finished in late 2015.[5]
Elevation
The height according to the Tibet Department of Transportation is 5,565 m (18,258 ft);[1] however, the signage at the road rounded it up to 5,566 m (18,261 ft). In 2005, a Catalan cartographic expedition certified the height to be 5,565.1 m (18,258 ft).[4][2]
At 5,565 metres (18,258 ft), Semo La may be the highest asphalted road in the world. Khardung La was once thought to be the world record holder at 5,602 metres (18,379 ft); in reality, according to modern surveys, it measures 5,359 m (17,582 ft), 243 m (797 ft) less than previously thought.[4][2]