FIRST UBER, NOW THIS: The Mathematics of Cab-Sharing. “It may be anathema to New Yorkers. But a team of mathematicians and engineers has calculated that if taxi riders were willing to share a cab, New York City could reduce the current fleet of 13,500 taxis up to 40 percent, in that way unclogging traffic, conserving fuel and fighting air pollution.” Or, you know, you could just keep the cabs and they’d be easier to get.