This driver was in the left hand lane which is clearly marked for turning left and I was in the middle lane which is for going straight across. As I pulled away I became aware that this driver was also trying to go straight ahead. I was forced to stop suddenly otherwise she would have hit me in the side. I honked her to make her aware of my presence as she seemed totally oblivious and away with the fairies! A little further on she couldn't decide which lane of two to drive in so drove down the middle. Great lane discipline and even better observation!