STOCKTON — A big rig driver crashed through a guardrail on Interstate 5 and plunged nearly 100 feet to his death Friday afternoon in Stockton, authorities said.The big rig driver was traveling north on I-5 over the Stockton Deep Water Channel about 2:15 p.m. when he collided with a truck towing a wood chipper, said Officer James Smith, a spokesman for the California Highway Patrol.