Catching a cab in a big, busy city can feel like a competitive sport: one eye on the traffic, one hand waving frantically, silently hoping the driver doesn't refuse the ride. And when you do finally manage to slide into the backseat, the relief is short-lived as the meter starts its steady climb. By the time you reach your destination, there's that familiar sting of parting with big bucks for a trip that took all of 10 minutes.