In Hidden Obstacles for Google’s Self-Driving Cars article we can read that:

Google’s cars can detect and respond to stop signs that aren’t on its map, a feature that was introduced to deal with temporary signs used at construction sites.

Google says that its cars can identify almost all unmapped stop signs, and would remain safe if they miss a sign because the vehicles are always looking out for traffic, pedestrians and other obstacles.

What would happen if a car spotted somebody in front of it (but not on the collision path) wearing a T-shirt that has a stop sign printed on it. Would it react and stop the car?


1 Answer 1


Google’s self-driving car most likely uses mapping of traffic signs using google street view images for roadway inventory management. If traffic signs are not in its database, it can still “see” and detect moving objects which can be distinguished from the presence of certain stationary objects, like traffic lights. So its software can classify objects based on the size, shape and movement patterns. Therefore it is highly unlikely that a person would be mistaken for a traffic sign. See: How does Google's self-driving car identify pedestrians?

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Image: Technology Review

To support such a claim, Illah Nourbakhsh, a professor of robotics at Carnegie Mellon University, gave an interview to the New York Times magazine cover story on autonomous driving cars, and includes this hypothetical scenario, saying:

If they’re outside walking, and the sun is at just the right glare level, and there’s a mirrored truck stopped next to you, and the sun bounces off that truck and hits the guy so that you can’t see his face anymore — well, now your car just sees a stop sign. The chances of all that happening are diminishingly small — it’s very, very unlikely — but the problem is we will have millions of these cars. The very unlikely will happen all the time.

Even so, the risk would be minimal, since the car is always looking out for traffic, pedestrians and other obstacles.



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