The heavy vehicle lost control and ran over the 'kanwarias' (devotees of Lord Shiva) sleeping on the roadside, Superintendent of Police Upendra Kumar Sharma said.
After running over the sleeping Kawarias, it hit a parked bus in which some other kanwarias were taking rest, the SP said, adding 12 kanwarias were killed in the mishap.
The pilgrims were resting after returning from Deogarh temple in Jharkhand.
The mishap took place under Muffasil police station area, 10 km from Aurangabad town and about 160 KM from capital Patna.