After a 13-year-old girl was struck and killed by an Edmonton city bus on Nov. 26, transit unions are now saying that a design flaw may be to blame for the tragic accident.

According to the Amalgamated Transit Union (ATU), a blind spot on the driver’s left-hand side renders pedestrians invisible on Edmonton city buses. The union is now pushing for upgrades to fix the issue and help prevent future injuries and deaths.

According to ATU Canada president Paul Thorpe, the blind spot can hide as many as 13 people from view during a left-hand turn.

“It is absolutely amazing that amount of people can vanish before a driver’s eye,” Thorpe told CTV News.

The teenage girl was the second pedestrian killed by a bus making a left-hand turn in the city in the past two months, after an 83-year-old woman was struck and killed on Oct. 4. An internal investigation is currently looking into whether the alleged blind spot played a role in the two deaths.

“It’s being looked at with appropriate concern,” Edmonton Mayor Don Iveson said on Nov. 29.

Across North America, transit unions have been talking about the issue for years.

“Roughly one pedestrian is killed every 10 days in America due to the dangerous blind spots,” the ATU states.

New Flyer Industries, the Winnipeg-based company that manufactures Edmonton’s buses, did not return CTV News’ request for comment.

The same buses are also used in Winnipeg, though no pedestrian fatalities have been attributed to blind spots in the city. Still, Winnipeg’s transit union is hoping for a fix.

“A camera system that provides a 360 degree view of the bus,” ATU Local 1505 president John Callahan explained to CTV News. “It’s live. There’s a camera in the front and rear and either side."

There are concerns, however, that additional cameras could cause an element of driver distraction.

“That could actually be detrimental to safe operation of a transit bus,” Winnipeg public works committee chair Marty Morantz told CTV News.

In other cities, loudspeakers are used or drivers honk to alert pedestrians during left turns. Thorpe, of ATU Canada, however, wants to see buses retrofitted with lower mirrors and thinner pillars to overcome the problem. He says that would cost about $300 per bus.

“We’ve been approaching manufacturers and employers saying, ‘What’s a life worth to you?’” Thorpe told CTV News.

With files from CTV’s Winnipeg bureau chief Jill Macyshon