DILLARD — A freight truck driver was seriously injured Wednesday night when his tractor and two trailers overturned on Interstate 5 after striking a concrete median at the base of Roberts Mountain. R. David Lee, 51, of Central Point, suffered major head trauma and a collapsed lung, according to the Oregon State Police. He was initially treated at Mercy Medical Center and then transferred to Sacred Heart Medical Center at RiverBend in Springfield. He was listed late this morning in critical condition, a hospital spokeswoman said. The wreck caused 6,500 gallons of an industrial glue to spill onto the southbound …