A few days ago the MTA announced that some subway lines are operating over 100% of capacity.
Mayor Bloomberg disputed that fact and said that he takes the Lexington Ave. line most days and it's not that crowded. I think he wants to downplay the train crowding so that his congestion pricing plan will go through. Imagine the subways if even half of the people driving into the city decided to take the subway.
When I worked, I took the Lexington Ave. line. Some days the station was so crowded, I felt it was unsafe. The lines waiting for a train are usually five deep and you usually have to let one or two trains go by, then you have to hope the crowd behind you doesn't start pushing and that you land on the tracks.
Obviously, the mayor doesn't ride the subway between 8:30 am and 9:00 am. That's when it's most packed, and of course again at 5:00 pm. Or maybe he has a private subway car.