The crash occurred at about 2 pm on Tuesday near the entrance gate of Phuc Truong Village in Truong Luu Commune, according to local officials.
Authorities said a truck carrying soil, driven by a 34-year-old man from Ha Tinh, collided with an electric bicycle ridden by a 56-year-old man, who was carrying his 86-year-old mother.
Both victims died at the scene.
Security camera footage showed residents had spread rice across more than half of one side of the road, forcing vehicles, including the truck involved in the crash, to veer into the opposite lane to avoid the drying grain.
Traffic police in Ha Tinh are investigating the cause of the accident.