Emergency services responded to the incident at the Hobson St on-ramp about 9.35pm on Sunday, which left the pedestrian unconscious in a pool of blood.
Police cordoned off the on-ramp to the Northwestern Motorway as they attended the scene.
The witness told the Herald the man had been walking in front of him for a few blocks and was on the opposite side of the road when he was hit.
“The response was shockingly adept, reasoned and level-headed. The only yelling was the initial ‘call an ambulance’ and after that it was quiet organising to make sure he was correctly looked after,” he said.
An off-duty medical worker kept the victim in the recovery position until an ambulance was flagged down.
An NZME photographer at the scene said Hato Hone St John had transported one person to hospital in a serious condition.
An Auckland Hospital spokesperson said the patient was in a stable condition on Monday morning.
The Serious Crash Unit and a police photographer were also in attendance, and police confirmed they were speaking with the driver.
Police said there was no update to the incident on Monday night.
Another witness told the Herald last night a person was lying on the ground in a pool of blood who had clearly been hit by a vehicle and was unconscious.
“The person was lying in the middle of the on-ramp while paramedics attended the scene, with the passengers of the other vehicles standing nearby crying and screaming,” they said.
Benjamin Plummer is an Auckland-based reporter who covers breaking news. He has worked for the Herald since 2022.