Megabus USA LLC, Chaoch Leasing Inc., Coach USA Inc. and the driver, Preston Taylor have all been names as defendants in a lawsuit filed by the parents of an Indian graduate student who was killed after the double-decker bus she was riding in struck a concrete pillar on Interstate 55 in Litchfield, Ill., south of Chicago. Aditi Avhad, 25, a student at the University of Missouri, was traveling back to the university, accompanied by her parents when the accident occurred in August. The girl’s mother, who suffered a broken leg and broken hip, was just recently released from the hospital.…