A jackknifed semi left its trailer stuck on an on-ramp at Idaho-Maryland Road and Highway 20/49 Wednesday morning. The driver of the 18-wheeler reportedly tried to come up the on-ramp from Idaho-Maryland Road just before 8 a.m., then tried to back up. As a tow truck attempted to move the semi, traffic was re-routed by California Highway Patrol away from the northbound on-ramp at Idaho-Maryland Road. The truck was removed from the roadway and the highway was clear as of 9:45 a.m. …