A vehicle accident yesterday on Interstate 40 in Roane County resulted in traffic backing up for a while. Troopers say a Ford Expedition driven by 77-year-old Louis Keen of Soddy Daisy was traveling east near the 350 mile marker when a tire blew out in a curve, causing a trailer he was pulling to flip on its side, blocking both lanes of travel. Keen refused medical treatment at the scene. A passenger, 67-year-old Violet Keen, was not hurt.