At around 11:20 p.m., a sleeper bus traveling from Son La to Hanoi, Vietnam, when reaching a curve in Sap Vat commune, Yen Chau district, crashed into a tractor-trailer carrying goods traveling in the opposite direction.

The strong impact caused the left side of the sleeper bus to be torn apart, about 5-6 passengers were thrown unconscious onto the road. Many others were injured by the sleeper cabin and debris from the car's side that came loose and hit them.

The cabin of the tractor-trailer was crushed, crushing the driver and assistant. The surviving passengers and passersby spent several dozen minutes using crowbars to break the cabin to get two people out.

According to the leader of Sap Vat commune, 5 passengers on the sleeper bus and the driver of the tractor-trailer died on the spot. The assistant truck driver and 7 passengers on the sleeper bus were injured and taken to Yen Chau District General Hospital, then transferred to Son La General Hospital, one person to Viet Duc Hospital, Hanoi.

The sleeper bus driver is Nguyen Dinh Hung, 42 years old, residing in Hanoi; the tractor-trailer driver has not been identified. After testing, driver Hung did not have alcohol in his breath and tested negative for drugs.

At the scene, the sleeper bus with Son La license plate and the tractor-trailer with Thanh Hoa license plate were deformed, blocking both directions of National Highway 6. Debris was scattered on the road within a radius of 200 m2. Vehicles had to stop and find another way.

The Vietnam Register said that the sleeper bus was last inspected on November 2, 2024, and is valid until May 1, 2025. The tractor-trailer's inspection is due on July 23, 2025, but the semi-trailer expired on January 25, 2025.

National Highway 6 is a vital route connecting Hanoi with the Northwestern provinces. The section through Yen Chau district, Son La province, is 48 km long, mainly two lanes about 8-10 m wide with many hairpin bends winding around hills and mountains.

Son La has been having light rain for the past few days, with limited visibility due to the impact of cold air shifting eastward, bringing moisture from the sea.

The cause of the accident is under investigation.