This intriguing bit of street art is the work of Peter Gibson, a.k.a. "Roadsworth", who's been painting Montreal streets, sidewalks, and public spaces since 2001. He's motivated by "a desire for more bike paths in the city and a questioning of 'car culture' in general," according to the design blog Toxel, where you can catch more of his pieces.
Here's how Roadsworth describes his inspiration in his artist's statement, which is a pretty good read:
The ubiquitousness of the asphalt road and the utilitarian sterility of the "language" of road markings provided fertile ground for a form of subversion that I found irresistible. I was provoked by a desire to jolt the driver from his impassive and linear gaze and give the more slow-moving pedestrian pause for reflection.