The accident happened near Hariyabara village under Araria Town police station, when lawyer Poonam Kumari Rai (40), who practises at the local court, was pillion riding on the two-wheeler being driven by her son Agastya Rai (14).
"Suddenly a speeding truck coming from the opposite direction hit them near the toll plaza outside the town. Poonam died on the spot, while her son received severe injuries," said Araria Town SHO Mukesh Kumar Saha.
Agastya has been hospitalised while his mother's body was sent for postmortem.