It happened on the Mullaghglass Road in Lisburn, Co Antrim.
Police are investigating the circumstances surrounding the assault and a possible linked collision involving a grey VW Polo car and a black VW Passat car on the Shaw’s Road earlier.
A 32 year old is being treated in hospital for serious injuries as a result of the assault.
Detective Sergeant John McKendry said, “I would appeal to anyone who was in the Shaw’s Road area around 1.30 am this morning, Monday 15 December, or in the Mullaghglass Road area of Lisburn just before 2 am and witnessed either the accident or the assault to contact Detectives at Lisburn on the non emergency number 101.
“Alternatively information can also be given anonymously through the independent charity Crimestoppers on 0800 555 111.”