On October 27, contractors deployed heavy machinery and workers along a section of the pass between kilometre markers 224+900 and 225+250 in Xuan Huong-Dalat Ward, Lam Dong Province.
Pine trees at risk of falling have been removed to allow workers to excavate and reduce the weight of a large mass of soil and rock on the hillside, which rises dozens of metres above the road.
The construction area extends for about one kilometre from the Datanla viaduct towards the entrance to Datanla Waterfall Tourist Area.
Two of the pass's four lanes have been closed and separated by metal barriers to protect traffic from falling rocks and soil. The remaining two lanes remain open for vehicles travelling in both directions.
Warning signs, night-time lights and a 40 km/h speed limit have been introduced through the construction zone.
According to the Lam Dong Department of Construction, inspections found that a 120-metre stretch of excavated hillside, standing 20-25 metres high, had become unstable due to geological conditions and large embedded boulders.
The proposed solution involves cutting back the unstable slope and reinforcing it with double-twisted steel mesh secured by steel anchors approximately six metres long, spaced at two-metre intervals.
The works follow several landslides that sent soil and rocks onto Prenn Pass during the 2026 rainy season.
On October 8, Lam Dong authorities issued an emergency construction order to address landslide damage along the affected section.
The project is estimated to cost VND 16 billion (USD 608,000) and take around four months to complete.
It aims to stabilise the hillside, protect road infrastructure and improve traffic safety, particularly during the upcoming festival and holiday periods.
