In what circumstances will the court uphold implied malice murder charges against a driver who was over the legal alcohol limit?

In People v. Ferguson (2011) 194 Cal.App.4th 1070, 1080, the defendant was driving at about 75 miles per hour and was accelerating when he rear-ended a car that was stopped at a red light and killed one of the occupants of that car; his blood-alcohol level at the time of the accident was extrapolated to be from .16 to .21 percent. (Id. at pp. 1074-1075.) The court affirmed his conviction of second degree murder.

In People v. Johnigan (2011) 196 Cal.App.4th 1084, the defendant planned to drive to a bar and drive home alone after drinking. She consumed excessive amounts of alcohol; friends warned her she was too intoxicated to drive and could harm someone, and she turned down a ride home. After driving four miles, she stopped on a highway, partially blocking the traffic lane. When officers arrived, she sped off at up to 70 miles per hour, drove on the road shoulder for half a mile, and then swerved across two lanes, hitting another car head on. (Id. at p. 1087.) The court held the evidence was sufficient to support her conviction of implied malice murder. (Id. at p. 1092.)