Discription of Events: Was in carpool lane. BMW was next to me in fast lane. BMW signalled and started moving into my lane. Layed on horn to let them know I was there. They then did standard road rage BS, honked their horn, pulled into carpool lane in front of me, slowed down to 50, and threw garbage at me. They then took the 57 offramp from the 5 North Carpool.