I would also hope that the car uses contextual geolocation info. That a speed limit sign is not posted on the corner of a 4-way intersection, and a stop sign is

I would also hope that the car uses contextual geolocation info. That a speed limit sign is not posted on the corner of a 4-way intersection, and a stop sign is not typically put on the side of a limited access highway. In fact I would expect that most of the driving regulations should be encoded in the map. Anomalies would be treated with extreme caution (and reported back to the home office).