According to the police, the deceased, identified as Mahendra Singh and his son Inderjeet Singh (33) along with a woman and a minor girl were on their way to Chandigarh from Mumbai when their car rammed into a truck approaching from the opposite direction around 6 AM due to dense fog near Kotputali area here.
Traffic on the highway came to a standstill for some time following the accident, but was later cleared.
Police is probing the matter.