The injured man, who studies at Waikato University and lived alone at Brookfield Accommodation, was last night in Waikato Hospital's intensive care unit.
It is understood he has a fractured skull and bleeding on the brain and is in a coma.
Members of his family had flown from England and were yesterday at his bedside.
The family did not want to be interviewed but it is understood they are upset by earlier reports that the man was joy-riding on the vehicle at the time of the accident.
Acting Detective Senior Sergeant Andy Bu Bear of the Hamilton CIB said the driver was found at his home a short time after the incident.
He said the man was arrested after police spoke to several witnesses who saw the incident.
Mr Bu Bear said the incident highlighted the risk of people confronting offenders and he urged members of the public to allow police to deal with such situations.
"We need the community's assistance in such matters but we need to ensure people keep themselves safe."
Police are not ruling out further charges for the driver, who will appear in the Hamilton District Court tomorrow.
