A man and his son died and two children were injured in a crash on the A47 near Glaston on Thursday.
Yasar Mushtaq, 34, from Peterborough suffered fatal injuries and was pronounced dead at the scene.
His son, aged about four, was air lifted to Birmingham Children’s Hospital with serious head injuries but died on Friday.
His two daughters were injured in the crash.
Mr Mushtag, who had four children, has been described as a “family man” who was devoted to his children by friends and family.
His black BMW 535D car was involved in a collision with a white Iveco Stralis lorry and a white and blue DAF lorry at about 1.50pm.
His eldest daughter, believed to be in her early teens, was released from Peterborough City Hospital after treatment.
A girl, aged about seven, was flown by helicopter to the Queen’s Medical Centre in Nottingham with a suspected broken leg.
Police would not give ages for the three children.
The drivers of the lorries were not injured.
The road was closed in both directions and police, the fire service and two air ambulances were at the scene.
The road reopened at about 8.45pm.
Mr Mushtag had worked as a switchboard operator for private car hire firm Peterborough Cars for three years.
Det Con David Sharpe, who is investigating the incident, said: “The BMW and white and blue DAF were travelling along the A47 towards Morcott and the white Iveco lorry was travelling in the opposite direction when the collision occurred.
“I would urge anyone who was travelling along this stretch of road to contact me if they witnessed the collision or saw any of the vehicles beforehand. The smallest detail could help with our enquiries. Any calls received will be treated in confidence.”
Anyone with any information can contact Det Con David Sharpe on 0116 222 2222. Follow the instructions to leave a message for a police officer and when prompted key in the officer’s identification number 1291.