A double-deck city bus smashed into a transit shelter during rush hour on Friday.
Graham said police will be flying drones today to take aerial shots and they hope to clear the scene, and the accompanying roadblocks, by the end of the day.
"I live in Carlingwood and that's my bus stop when I'm not biking". The third had been standing on the station platform, Watson said.
"Outstanding investigators are doing that work, but it takes time", Bordeleau said.
Mike Sharp was onboard the bus at the time of the accident.
The driver of the bus was arrested at the scene, Chief Charles Bordeleau of the Ottawa police added at an evening news conference at Ottawa city hall.
Driver crashed while participating in 'Bird Box Challenge'
A 12-year-old U.S. girl gave herself burns to about 50 per cent of her body last year. That's when she veered into oncoming traffic and collided with another vehicle.
"My first thoughts are with those who have been injured and their families".
OC Transpo general manager John Manconi told reporters the bus could have been holding as many as 90 passengers and that the agency would be co-operating fully with the investigation.
"I was shocked to hear of this horrific incident", Ottawa Mayor Jim Watson said. Despite mid-afternoon temperatures of about minus-15, it had not snowed in Ottawa Friday and the busway is treated as a top priority for the city's snowplows, salters and sanders.
Prime Minister Justin Trudeau, who was in Saskatchewan, tweeted his "deepest condolences to the families of victims".
"Where I was (at the back of the bus), there was blood pooling underneath the seats just in front of me", he told CTV Ottawa, describing the immediate aftermath of the crash. In 2013, a double-decker commuter bus crashed into a passenger train, killing six people including the driver. The investigation into that case found the cause was a combination of excessive speed, a hard curve before the tracks and driver distraction.