The incident took place when the victims were on their way to Jhunjhunu near Gaangwa village in Parbatsar on Hanumangarh Mega Highway, police said.
Mahendra and his daughter Khushi (13) died on the spot while his wife Suman (33), son Avijit (14) and brother Manoj (30) injured, they said.
The injured were admitted to a nearby hospital where their condition is stated to be stable.