Yesterday morning, while driving north on i-35 to work, there was a loud "pop" from directly above my windshield. this scared me to death! the sound was so frightening that i ducked and for a moment, i thought i had been involved in a wreck but quickly noticed nothing out of the ordinary had occurred. typically, traffic is very heavy, only moving about 20mph. however, on this particular morning, traffic was somewhat lighter and moving about 40mph. i had clear visibility across the front window and could tell that nothing had flown in my direction. i was not trailing behind or around any suvs, dump trucks, or other large vehicles that could have kicked up a rock. i also had not driven under an overpass, so i knew nothing could have fallen from above. once i arrived at work, i discovered the front section of my panoramic roof was cracked and shattered all the way across the width of the vehicle and pressed inward, exposing the interior lining.