A trucker rammed his tractor-trailer into more than 20 cars, seriously injuring at least two people, during an 80-mile chase Friday that snarled San Antonio morning rush-hour traffic, authorities said.

Stephen Odell Dillard, 41, of Coolidge, Ga., was charged with possession of cocaine and was held in the Medina County Jail here under $50,000 bond while authorities in other counties prepared other charges against him, officials said.