The victims were sleeping in the tempo which was parked on the roadside when a speeding truck hit it from behind.
The truck driver absconded, police said.
Arvind Vanzara, an eye-witness, said that the tempo was parked as it had run out of fuel, and the victims were returning after visiting a durgah at Unza (in north Gujarat).
The victims were identified as Kinjal Vanzara, Renuka Vanzara, Bhavesh Vanzara and Sunita Vanzara, said police.
