Abstaining from drinking alcohol; while still using other drugs. Typically someone who is LA sober will claim sobriety while being completely in denial about their addiction to drugs besides alcohol.
Person 1: Cody is just smoking weed all day in our apartment now that he quit drinking. He's driving me crazy.
Person 2: Yeah he's LA sober now I guess.
Person A: You don't drink?
Person B: Nope, never have. I like being sober; drinking is really bad for you.
Person C: I saw you take three adderalls before we came out tonight you hypocrite, you're LA sober at best.