A car landed in a drain near Balmoral Plaza in Bukit Timah Road after an accident with a pedestrian on Tuesday night.
The Straits Times understands that the driver apparently lost control of the car, which hit a 31-year-old pedestrian before hurtling into the drain.
A resident from nearby condominium Rich Mansion said he came down after he heard a loud noise to see a man lying on the grass.
He said the man was motionless but was still talking, and seemed to be in a lot of pain.
Bystanders pulled the 57-year-old driver from the car, he added. Both men were taken to Tan Tock Seng Hospital.