Ignition problems of the 2006 Audi A6

I bought a used 2006 Audi A6 two months before the accident. I had been using the "keyless" option when starting and stopping the vehicle. I stopped at a library, pushed the button twice to turn off the ignition and the vehicle's electrical system. I got out of the vehicle and noticed that it was rolling forward. I attempted to stop it; I opened the driver's door and as I was getting in the door struck a trash can in the parking lot, knocking me down. The vehicle's rear wheel caught my left heel and drug me across a curb before stopping on my left foot. Several men in the parking lot lifted the vehicle off my foot. I was transported to the hospital and kept for injuries to my left leg. Evidently I failed to put the vehicle's transmission in "p" and had left it in "d". Cars that use a physical key to start and stop the vehicle will not allow a driver to remove the key unless the vehicle's transmission has been shifted to "park. " a vehicle that does not utilize a physical key, does not that built-in safety feature. Five weeks later I am in physical therapy and am grateful I did not sustain more serious injuries, or that an innocent bystander was not killed by a driverless car rolling through a parking lot at a library that is frequented by children. Now I am adamant about always setting the emergency brake. My concern is real: as more and more vehicles are manufactured with "keyless" ignition systems that contain no fail-safe feature to prevent "inadvertent rolling" as explained in the Audi's owner's manual, I believe more injuries and deaths will be realized. In speaking with the regional representative at Audi, he explained that Audi publishes a "book" explaining the vehicle and what happened was totally my fault. My Audi has a sensor in the passenger the seat that prevents an expensive airbag from deploying unnecessarily; how about a sensor in the driver's seat that prevents a vehicle from rolling when there is no driver?.