WASHINGTON (Dec. 3)—U.S. total tire shipments increased 5.9 percent to 30.6 million units during September, according to information gathered by the Rubber Manufacturers Association. Passenger tire shipments also were up for the month, increasing 3.6 percent to 24.4 million tires. The light truck segment jumped 17.3 percent and the medium tire sector grew 13.8 percent for the month. Heavy truck tire shipments rose 36.4 percent to 352,000 units.