according to him the Carpool lane is considered a passing lane insomuch as when you have someone behind you that is wanting to overtake you, you are obligated to move to the right as soon as you get to a dotted line (entrance/exit) area. If they cross the double white line to pass you, they are breaking the law, but simply going 10 over does not mean you don't need to get out of someone's way when they're going faster than you. You have mirrors on your car for a reason.