It happened a little before 4 a.m. on SW Marine Drive at W. 54th Avenue.
A red Dodge van was travelling eastbound on SW Marine when the driver left the road, hit a tree on the right side, then rolled over to the other side of the street.
Vancouver Fire Battalion Chief Jeff Coroliuc said there were initial reports that a second person was involved in the crash, and possibly ejected from the van, but a search of the area found nothing.
"When we showed up on scene, [the patient] was lying in the back of the van," said Coroliuc. "We don't know whether he crawled there, or if he wound up there, just because the vehicle did roll over several times."
"He wanted to know where his friend was," Coroliuc said, adding that the patient was conscious and breathing when paramedics, with help from firefighters, removed him through the rear door.
Coroliuc said it's not unusual to have someone missing from an accident scene.
"We've seen this before. We used our thermal imaging camera to see if we could get a heat signature on the seats to see if we could get a reading on how many people were in the vehicle, but it was too late in the incident to register any heat signatures."
Vancouver Police had the area closed to traffic for a couple hours while officers investigated the crash.