Interested in testing the all-important sensors that help a car to make sense of its surroundings and make decisions at speed, security researchers at the University of Washington recently tampered with a street sign — under lab conditions, of course — to see if it would confuse the technology.

The researchers said that by printing off some stickers and attaching them in a particular way to different street signs, the alterations were able to confuse cameras that are used by “most” autonomous vehicles, Car and Driver reported.