Am assuming based on description (city bus) and location (LA) you're talking about LA MTA. Don't di*k around with LAPD; at best they'll just refer it to MTA. File an official complaint (
Customer Comment Form) and -- in addition to describing incident details -- sprinkle into your description red flag keywords like 'safety,' 'liability,' 'recklessness,' 'inspector general,' and 'lawsuit' as you're comfortable with. Better chance of geting escalated.
At the very least this little punk-a** douche-nozzle will get investigated for this incident and it'll go in his jacket; maybe he'll think twice next time. Could get a rip/reprimand, or more if not an isolated incident. If this is a route you ride regularly, file a separate complaint each time you see something like this happen, and encourage your cycling buddies to do the same. Slap some volume on the OIG; they'll prioritize pattern/systematic problems over single events.
If you want to press further, have a lawyer friend send a letter directly to the MTA Office of the Inspector General (
The Office of the Inspector General (OIG)), currently Karen Gorman (
Board of Directors | Board Members & Executives) with cc: to the MTA Board of Directors.
Good luck.