(Portland, OR)  --  Police in Washington County say they've arrested a man accused of dragging a police officer with his car while fleeing from a traffic stop.  Police arrested 32-year-old William Callaway at an Aloha home yesterday for the incident last Tuesday on Highway 26.  Police say an officer had pulled Callaway over and was speaking to him when Callaway sped off, running over the officer's foot and dragging him a short distance.  The officer suffered minor injuries.