John Woodcock, 44, of Sutton, known as Dan to his family and friends, and his two-year-old son, Lewis, died in hospital following the collision in Chesterfield Road North in Mansfield, close to the junction with Pleasley Hill, which happened just after 6.10pm on Saturday 15 January 2022.
Detective Inspector Clare Gibson, of Nottinghamshire Police's Serious Collision Investigation Unit, said: “Our thoughts are with their family who continue to be provided with support by specialist officers at this difficult time.
“We continue to investigate the full circumstances and our appeal for information remains. Anyone who witnessed the incident or who has dash-cam footage is urged to please get in touch.”
Three cars are believed to have been involved in the incident.
The driver of one of the other vehicles was also taken to hospital where he remains. His injuries are not currently believed to be life-threatening.
Anyone with information is asked to call Nottinghamshire Police on 101, quoting incident 561 of 15 January 2022, or Crimestoppers anonymously on 0800 555 111.