WHILE DRIVING THE VEHICLE ON THE HIGHWAY AT 68MPH WITH NO TRAFFIC ALONGSIDE NOR IN FRONT OF ME THE SUNROOF GLASS SHATTERED VOLUNTARILY CAUSING SMALL SHARDS OF GLASS TO FALL INTO MY FACE AND CLOTHING AS WELL AS OUTSIDE THE TOP OF THE VEHICLE. THE SUN SHADE WAS OPEN AND THE GLASS ON CLOSED ON THE ROOF AND NOT VENTED. THERE WAS NO CHANCE OF ROAD DEBRIS HITTING THE CLOSED SUNROOF NOR WAS THERE AN OVERPASS FROM ANYTHING TO FALL OFF FROM TO MAKE IMPACT. THE GLASS EXPLODED AND SPIDER-WEBBED THE ENTIRE SUNROOF.