congested traffic, I, have on occasion, seen the carpool lane be more backed up than a couple of the left most lanes, due to someone thinking going just the speed limit or sightly under is a good idea. I define slightly congested as when you can go the speed limit in the normal lanes, but lane changes are a little tight.

But no, even in this case, the carpool lane should not be considered a passing lane. But I do think it should be considered a faster than the far right lane.