One time a medium sized dog began to give chase on my right side. I was going about 15MPH and I noticed a car parked on my right about 25 feet away. As the dog was nipping at my right heels I rode as close to the parked car as I could using it as a stationary block. The dog ran smack into the parked car and came to an abrupt stop as I pedaled away with a grin on my face.