Boom - it wasn't serious! It was meant to spark discussion on how on earth do these cars handle trickier aspects of driving on unmodified grids, such as traffic lights.
I would assume since they've already logged lots of hours driving around CA that the various sensors and cameras can already detect traffic lights. On that same line of thought I'd love to know how they adjust for speed in construction zones with non standard speed limit signs, the randomness of other drivers etc.