Quoted from MrBally:That is how we are taught in driver's training class in high school. The lane is called an "Acceleration Lane".
My daughter's driving lesson was to stay in the right lane of the I-5 from San Clemente to Fullerton on a Friday after 3:00 PM. I told her she would see every idiot and idiotic maneuver that she would probably ever come across. And it didn't disappoint.