A 20-year-old man from De Soto was seriously injured early this morning in a traffic accident on Route P in Jefferson County. The highway patrol says Tyson Petri was driving north when his Dodge Dakota ran off the road and hit a ditch before running down an embankment. He was taken to Mercy Hospital South for treatment. Petri was also charged with a DWI by the highway patrol. The accident happened just after midnight on Route P, south of Petes Drive.