It happened around 3 a.m. Saturday on King George Boulevard and 108 Avenue in Surrey, B.C.
Lonny Pennell was in a nearby parking lot when he heard the crash.
"I heard some skid marks, really long, and a big thud," said Pennell, who immediately ran over to the intersection.
Pennell said he didn't think the pedestrian survived the crash, and saw paramedics trying to resuscitate the man. "I noticed shoes in the middle of the road and a body laying just past the intersection."
Sgt. Mike Sanchez with Surrey RCMP said the pedestrian is still alive, but is in critical condition. He said police were getting updates from Royal Columbian Hospital every 10 or 15 minutes.
The driver of the car, which is said to be a small blue hatchback, was seen wearing a security guard uniform. Police walked him to a RCMP cruiser, and he got into the back seat.
"The driver of the vehicle is not under arrest, because we haven't obtained any grounds to arrest the individual at this time," said Sanchez, who added alcohol has been ruled out as a factor.
Sanchez said it had not yet been determined whether speed was a factor in the crash.
Police say there are several cameras in the area that should help with the investigation.
King George Boulevard was closed for several hours at 108 Avenue, while police inspected the evidence on the street.