Driver drove 2012 Mercedes Benz ML350 to condominium and parked vehicle in parking space, placed vehicle in "park" and turned off the vehicle using the "keyless go" button. Driver opened the door, exited the vehicle and locked it. The area where the vehicle was parked was flat with only enough grade to cause water to run off of the pavers. A short time later, I looked out the window and saw that the 2012 Mercedes Benz ML350 had rolled away backwards approximately 30 feet into bushes and shrubs on the other side of the circular drive of the condominium complex. Fortunately, no one was injured and the only damage was a scratched bumper. Upon seeing the results of the rollaway, I grabbed my car key, called to the driver to look out the window and went to the vehicle. I unlocked the vehicle and opened the door of the ML350. I looked at the dashboard and it showed that the vehicle's transmission was in the "park" position. I note that the Mercedes Benz M-class "operator's manual states that the transmission shifts automatically in the "park" position if you open the driver's side door. Whether this would cause a rolled away vehicle to "automatically" shift into "park" is a question for Mercedes Benz to answer. The local mb dealer has examined the vehicle, mbusa sent an engineer to inspect the vehicle and separately and together they have not been able to "find anything wrong with the vehicle" and they performed no repairs. FMVSS 114 at 49 cfr 571.114 requires that vehicles of this type move no more than 150 mm when place in "park" on a 10 percent grade without benefit of the vehicle's "parking brake" (aka "emergency brake"). our ml 350 is either not in compliance with FMVSS 114 due to it's inability to maintain its position while in "park" or it's inability to remain in "park" on a grade considerably less than the required 10 percent grade. Is this a design defect??

- Naples, FL, USA