WASHINGTON (June 4)—All available evidence shows the Ford Explorer to be safe, despite a study showing otherwise that Bridgestone/Firestone Inc. is circulating, according to Ford. "You can talk about testing data endlessly," the company said in a prepared statement. "We are replacing Firestone Wilderness AT tires because they have elevated rates of tread separation in the real world. Real world data also show the Explorer is among the safest vehicles on the road." Bridgestone/Firestone submitted to the National Highway Traffic Safety Administration a study on the Explorer by Dennis A. Guenther, an Ohio State University engineering professor. Guenther's study showed certain Explorers have an "oversteer" problem which makes them prone to rolling over when the tread separates on a left rear tire. "Firestone presented us with information, but no formal petition for an investigation, and we have no idea when there will be a formal response," a NHTSA spokesman said.