The driver behind the wheel of the SMRT bus which crashed along Dairy Farm Road on Sunday morning had a clean driving record, his company confirmed.
He also had adequate rest when he was deployed on Sunday.
No brake or steering problems were noted when the bus, which skidded and flipped on the road, was last maintained on June 21.
One man, understood to be a 19-year-old, was pronounced dead on the scene after being trapped in the overturned vehicle.
Both the unnamed driver, who is 39, and an injured passenger were sent to hospital after the accident and are in stable condition.
"The bus captain has been with SMRT since January 2012," said SMRT in a statement on Sunday evening. "We confirm that (he) has a clean service record with no prior accidents nor complaints against him. We can also confirm that he had been last at work on an 8.5 hour shift on 20 July, and was deployed at 7am today, having had more than the required 8-hour rest period between his shifts.
"The bus involved in this morning's accident was last maintained on June 21 and was given a clean bill of health. No brake or steering related problems were noted during the inspection."