Leave it to the Canadians to use an optical illusory speed bump to slow down drivers. Named "Pavement Patty" the 2D image resembles a child chasing after a ball and the pavement painting appears to rise up as the driver gets closer to it, reaching full 3-D realism at around 100 feet: "Its designers created the image to give drivers who travel at the street's recommended 18 miles per hour (30 km per hour) enough time to stop before hitting Pavement Patty -- acknowledging the spectacle before they continue to safely roll over her."
The effect is only visual as the entire painting is flat. Critics warn that drivers will become accustomed to seeing these "children in the street" faux speed bumps and suffer what Scientific America calls "situational blindness." Or put another way, like the child who cried wolf too many times, drivers may just start to associate the image of children in the street as something fake, with tragic consequences.
Canada isn't the first country to use faux speed bumps. They're common in Europe, although their effectiveness wears off the longer they remain in one place and drivers become accustomed to them.
In 2008, Philadelphia started using plastic road paintings resembling spikes.