FOLLOW THE SIGNAL

I was driving home from the library and approached the place where I needed to make a left-hand turn. I put on my left directional signal so that I could move to the leftmost lane. I waited for the car to pass that was going by on my left side. I then looked in the rear view mirror and, before I could safely switch into the left lane, the lady in the car behind me swerved over to the left lane and shot past me. I guess she thought that the flashing light on the left side of my van meant that she should go around me.