Thomas Hunter has been jailed for six years for causing the death of three-year-old Isla Wiggin by dangerous driving.
The court heard Hunter was travelling at 54mph and only tried to brake a second before running into the line of cars on the A34 in Oxfordshire.
Isla from Fleet in Hampshire, died in a collision on the A34 in Hinksey Hill, Oxfordshire, on 25 August. Her unborn brother also died as a result of the collision.
At the time Isla's family issued a statement saying she was "a loving and caring" daughter who "would have made an amazing big sister".
A lorry and seven cars were involved in the accident, which closed the northbound carriageway for almost 10 hours.