I was driving 75mph in heavy, morning traffic. I was behind a large tractor trailer, switching lanes. My caras a€˜obstacle aheada warning was attempting to slow me down or stop me. The air pressure inside my car changed suddenly and I could feel the pressure difference. Then there was a huge explosion. It sounded like my back windshield broke. Instead, it was my sunroof. It had exploded outwards from the inside. It just shattered and blew up spontaneously.