Car was parked in Garage with garage door open. Wife and I wanted to go biking and the bikes needed air in the tires. Pre-positioned one bike directly behind parked car and one parallel with the pneumatic air pump prepositioned to inflate the tires. Went to driver's side door and started car with foot on the brake and pushed the button. I then plugged in the adapter for the air pump into the cigarette lighter. The whole time the driver's side door was open and the car was not moving. I exited the car and walked backwards and knelt down abeam the left rear automobile tire to inflate the bike tire. I started the pump at the unit and started to connect the hose to the bike tire, I was then hit from behind by the car door which bent backwards as it passed over me in reverse at low speed. The bike may have saved me by creating a wedge to bend the door back and away from me. The car started down my driveway and dragged the bike parked behind it underneath wedged and sparking across the ground. I got some scrapes but jumped after the car and tried to stop it by trying to slow it with my weight and strength and it was not stopping or slowing. I was worried I may get run over a second time and let it continue to roll at low idle speed across the street and into the neighbor's car that was parked. I am positive the car was not moving after I started it and I didn't have my foot on the brake to engage the reverse function one I exited the vehicle. I believe that the car engag