(Portland, OR)  --  Police are investigating a rollover crash that left a man dead in Southwest Portland.  Authorities say a car driven by a man in his 30s drove off the roadway and went down an embankment off Barbur Boulevard near Capitol Highway around four p.m. yesterday.  Police say northbound Barbur Boulevard was closed afterward from Southwest Terwilliger Boulevard and southbound from Highway 10.  The man's name hasn't been released.