This is a car that had an accident right in front of me this morning. I was going north on US 75/69 north of Sherman, TX, when I came up behind this car. I was about 150 feet back when it started to change lanes to the left. I thought maybe it was pulling over to let me pass it (people do that sometimes). However, when it kept drifting to the right, I got worried and sounded my air horn. No response. It drifted to the outside of the left lane, and onto the rumble strips. The driver jerked the steering wheel to the right, overcorrected, lost control, and went broadside into the energy-absorbing guard rail, then rolled over. I stopped as soon as I could and ran back, but other people (including some nurses) were already helping the elderly lady, who admitted she probably went to sleep. I don't think her injuries were life-threatening, but it didn't make my day any better!