As I drove into a parking lot, I noticed that a pickup truck with a dog sitting behind the wheel was rolling toward a female pedestrian. She seemed oblivious, so I hit my horn to get her attention. She looked up just in time to jump out of the way of the truck's path, and the vehicle bumped harmlessly into the curb and stopped.
I rushed to the woman's side to see if she was all right. "I'm fine," she assured me, "but I hate to think what could have happened to me if that dog hadn't honked."