Like so many other overland routes in Southern Sudan, the road from the Central Equatoria State town of Yei to the border town of Kaya is out of service for several months of the year during the region's rainy season.
The segment between Kaya and the town of Morobo that snakes through the Pokii Hills has been especially prone to potholing with the onset of the rains.
That has posed serious problems in the past for area residents who are so dependent on imported food and building materials from neighboring Uganda.
But a major road works programme led by UNMIS is upgrading ground transport conditions significantly in that corner of Southern Sudan.
The drive from Kaya to Morobo used to take four hours, but can now be covered in as little as 45 minutes, which that has bolstered the local economy.
"Our customers are benefiting since the road is now maintained," said Morobo County Engineer Mawa John. "Business is now booming, especially at the entrance to Southern Sudan (from Uganda)."
The rehabilitation of the Yei-Kaya road is one in a series of ground transport infrastructure improvements involving UNMIS personnel in Southern Sudan.
A team of UN Volunteers and Sudanese independent contractors upgraded a 12-kilometer-long road linking Yei to an airstrip that services the town during the first half of 2008.
In partnership with the World Food Programme and the UN Office for Projects, UNMIS has also provided bridges and building materials to six locations in Southern Sudan, along with assistance from engineers in the Bangladesh Battallion.
Another seven bridges are scheduled to be installed in the region.
The team of 10 UN Volunteers (UNVs) and 70 Sudanese laborers have been adding gravel and widening segments of the 72-kilometer-long road from Yei to Kaya since last year.
"This keeps open the lines of commerce to the south of Sudan with its traditional trading partners," said James Boynton, chief of UNMIS Integrated Support Services.
The road works have also lowered the frequency of traffic accidents along the stretch between Morobo and Kaya.
UNMIS project engineer Arip Kituyan Olekambainei has been in charge of the work on the Yei-Kaya road, and UNV Stephen Aguta of Nigeria has led the team, who will return to Juba to support the rehabilitation of the regional capital's airport.
"We call the UNVs working on this project ambassadors of the UN," said Anil Kapoor, outgoing deputy chief of Integrated Support Services. "It will be of great help to the nation when this road starts to function normally."
Morobo County Engineer Mawa John said maintenance of the upgraded road would be funded by a tax to be levied on truck drivers and other motorists.