The 2D decal becomes a 3D illusion as drivers approach it.

What would happen if you saw a 3D illusion of a young girl chasing a ball across the street near a school? 

A Canadian safety group hopes you'd slow down and think twice about speeding through a school zone. Critics of the image say it might scare drivers and lead to accidents. 

Either way, she's got your attention, which is the point, said a spokesman for Preventable, a British Columbia-based safety awareness group behind the stunt. 

"This is a way to reinvigorate what becomes a pretty tired message every year. We become anesthetized to the risks related to driving, but the risks are very real, especially in British Columbia, where we have more than 400 fatalities each year related to motor vehicles," said David Dunne, Director of the Traffic Safety Foundation and spokesperson for Preventable. 

Video: Will drivers stop for 3D illusion? 

The 45-foot, heat-treated 2D decal will stay on a busy intersection near the Ecole Pauline Johnson in West Vancouver for a week. The illusion's debut on Tuesday coincided with the start of school year, when children are at the greatest risk of pedestrian-related injuries, Preventable says on its website. 

The group, which uses guerrilla marketing in campaigns focusing on preventable injuries, developed the image with the support of the BCAA Traffic Safety Foundation, the District of West Vancouver, School District #45 West Vancouver, and the West Vancouver Police. 

With the help of a Youtube video that shows how it appears to an approaching driver, the illusion has sparked intense debate in British Columbia and outside Canada, with some claiming it could lead drivers to swerve or brake abruptly in a school zone. 

But Preventable says a detailed risk assessment was undertaken to address such concerns. 

Before drivers approach the image, they pass a "School Zone" sign, crosswalk, an extended curb and a sign by Preventable that reads, "You’re probably not expecting kids to run out on the road." 

The figure begins to take shape from about 50 feet away and appears in 3D for another 40 feet until the driver it about 10 feet away, where the image recedes into a "blob" on the street," Dunne said. 

"As you’re driving over it, it's not like driving over a little girl. The illusion, as it appears, looks like a cartoon, I've likened it to the difference between a photo and a cartoon." 

Preventable and its partner groups are monitoring the image to ascertain  how it affects drivers' behavior. In the meantime, the attention it has drawn has accomplished its intended effect,  said Dunne. 

"If hundreds of people were killed each year in British Columbia because of the airline industry, we wouldn't accept it. And these injuries and fatalities are preventable," he said. 

"We need to change people's attitudes to really change their behavior. Sometimes you have to get in people's faces to change their attitudes."