Archana (32) and her two children aged 5 years and 3 years died while her husband Anil Pandey sustained serious injuries in the accident that took place last night.
Pandey, who is employed in a private company at Bhiwadi town of Alwar district in Rajasthan, was admitted to a local hospital at Dharuhera, they said.
The mishap took place when the family was returning to Bhiwadi after shopping at Dharuhera.
The driver of the unknown vehicle sped away after the accident, police said.