Impairment suspected in fatal crash Impairment suspected in fatal crash Advocate staff report Jan. 09, 2013 Comments WALKER — State Police investigators said impairment might have been a factor in a single-vehicle accident 11:30 p.m. Saturday on La. 447 south of I-12 that claimed the life of a 60-year-old Denham Springs man, a spokesman said. Troopers say Johnnie W. Johnson was traveling south on La. 447 in his 1997 Ford F-150 pickup when he ran off the road to the right at a left-hand curve, overcorrected and crossed both lanes of La. 447 before striking a utility pole, Trooper First Class Jared L. Sandifer said in a news release. Johnson, who was not wearing a seat belt, sustained fatal injuries in the crash, Sandifer said. Troopers submitted a blood sample to the State Police Crime lab for toxicology analysis, he said.