Discription of Events: She was parked on the shoulder of I-85 by the exit for 4-85 between exits 48 and 46. Without warning she darted out in front of our vehicle which was traveling 70 miles an hour and even hung over into the middle lane making it even harder to avoid slamming into her. She didnt even try to match the flow of traffic as it took her multiple exits to attain the proper speed and multiple cars behind us also had to avoid her. I noticed her age and believe Alzheimers may have played a part.