"A left-turning motorist cannot discharge his burden of ascertaining whether the turn can be made in safety by making his observation some distance from the intersection, but he is required to look to his rear immediately before attempting the turn. Ulmer v. Travelers Insurance Company, 156 So.2d 98 (La. App. 1st Cir. 1963). The physical facts clearly show that Mrs. Whittington was already in the passing lane and overtaking the plaintiff at the time he commenced his turn.