She was reading.
There was a paperback propped up on her steering wheel, and every now and then she would look up.
I'm not sure if she was reading by the time it was her turn to ramp it up to 55. I wasn't close enough. She did use her turn signal to merge, which is more than I can say for 85% of the drivers using cellphones.
At first I laughed, then I was a little horrified, now I'm nearly nostalgic. I used to walk home from school while reading a book. I listen to books on long drives, read on the exercycle, read while eating most of my meals, read before I go to bed at night. But few books leave me with that "I must read this book at all costs" feeling.