Four people were killed and ten others were injured when a bus plunged into a roadside field and overturned on National Highway 1A in Thua Thien Hue Province on Saturday.
The accident happened at around 4:30 p.m. when the bus was en route from the north-central province to Dak Lak in the Central Highlands.
Five of the ten people injured and being treated at the Hue Central Hospital have suffered serious injuries, including two with spinal fractures.
It was unclear how many people were on the bus and whether 44-year-old driver Vo Van Thuan of Hue was injured. Thuan was detained for investigation.
Witnesses said the driver had apparently lost control over the speeding vehicle at a slippery section in heavy rain.
In another traffic accident the same day, one person died and three others were injured in Vinh Phuc Province's Vinh Yen Town.
The accident happened at around 2 p.m. when a speeding taxi hit a five-seater UAZ from behind.
A 70-year-old woman in the UAZ was killed on the spot while three others were injured and admitted to the Vinh Phuc General Hospital.
According to the Road and Railway Traffic Police Department, more than 23,000 traffic accidents nationwide over the first half of this year have killed 5,662 and injured 25,600 others.
The National Traffic Safety Committee launched the Traffic Safety Month this month, with enforced patrols against traffic violations, including drinking and driving.