If every car in your traffic jam has only one person the area taken up by  bikes needed to equal movement of the number of people is a fraction so it often looks like far less bikes.  Try sitting near a bike lane in rush hour one day and counting both number of people in cars and number of cyclists.  I guarantee you'll find far more cyclists on the road than you think there are.  Now imagine just how much more backed up your commute would be if every one of them switched to an individual car.