The lawsuit claims that while the van was traveling on Interstate 84 west of Tremonton, tread peeled off a tire, causing the van's driver to lose control and the vehicle to roll over several times when it left the roadway. In addition, the vehicle had a dangerously high center of gravity and an unsafe seat belt design, among other flaws, the suit alleges.

The suit, filed in U.S. District Court in Salt Lake City, seeks unspecified monetary damages.

Named as defendants are DaimlerChrysler Corp. and Cooper Tire & Rubber Company.

On Sept. 26, 2005, USU instructor Evan Parker, who was driving the van, and 10 agricultural students were on their way back to Logan from a field trip when the van blew a tire and rolled four times down an embankment along I-84.

Six were pronounced dead at the scene. Three later died in hospitals.

Parker was among the deceased.

The Utah Highway Patrol later determined the van was traveling between 95 mph and 100 mph when it rolled. Investigators also found none of the 11 occupants was wearing a seat belt. Officials said there would have been more survivors had the occupants been belted.

However, the parents of the two surviving students said their sons were buckled up.

The plaintiffs filed a claim in December against USU, a required step before a lawsuit can be filed. The two sides say they are trying to mediate the matter.

After the tragedy, the university stopped using all of its 12- and 15-passenger vans, except to haul cargo, and is replacing them with small buses and minivans.