I wonder how it handles merging in tight traffic, such as when the current lane is closed ahead and you need to merge into the other lane. If the car doesn't have rerouting information in its database, does it go all the way up to the "closed ahead" sign blocking the road before it considers switching lanes?

Or when coming onto something like a highway where traffic has slowed down to a crawl. Normally you have to be a bit pushy and squeeze into the traffic, otherwise drivers in the other lane will never yield. Will the self-driving car know to do this, or will it wait forever for an opening in the traffic?