Forbesganj Sub-divisional Police Officer (SDPO) Ajit Kumar Singh said the deceased have been identified as Bhuvan Jha (50) and Suman Jha (25).
Bhuvan's three-year old grand daughter has been admitted at a government hospital.
Agitated over the accident, villagers
blocked the NH-57 for several hours and damaged a few vehicles, as the truck sped away, the SDPO said.
The blockade was lifted after police and officials reached the spot.