Driver fell asleep and vehicle want off the road into a ditch that led to a stone wall protecting a culvert. Vehicle hit the stone wall and was launched into the air across the driveway where it came to a rest on its right side. I estimate that the vehicle left the highway at 45 mph (the cruise control setting) and hit the stone wall at approximately 25-30 mph. During this violent event all airbags deployed EXCEPT DRIVER'S AIRBAG located in the center of the steering wheel. I have a severely bruised and very painful sternum as a result. All systems were normal with no indication of a safety system fault.