The victims were coming from Sambalpur to here when the incident took place near Rasarajpur under Sundargarh Sadar police limit, 80 km from here yesterday, police said.
The deceased were identified as Radha Agarwala (56) and her son Bikash (38).
Bikash's wife and their two minor children sustained serioues injuries and admitted at the Sundargarh hospital. They were later shifted to VSS Medical College and hospital at Burla today as their condition deteriorated, the sources said.
The truck has been seized, but its driver fled from the spot, police said. PTI SP SKN PR