The family hailing from Guntur district in Andhra Pradesh was en route to Udupi when the accident occurred at around 4 am, they said.
Citing preliminary investigation, a senior police officer said the car driver allegedly dozed off while driving and entered the opposite lane resulting in a head-on collision with the lorry which was heading towards Ballari from Mangaluru.
Three members of the family, including a woman, died, he said.
The car driver sustained injuries but is stated to be out of danger now. He is currently being treated at a hospital in Chitradurga, the officer said.
A case of accident was registered, police said, adding further investigation is underway. PTI AMP ROH