NPR asked transport economist Charles Komanoff his opinion of the plan and his take isn't so positive. Sure, he says, 2,000 more cabs should make it easier to get a ride, but more cars means more traffic. And not just more traffic, but more constant traffic. While private cars eventually reach their destinations and park, taxis take up precious road space 24 hours a day. That slows down all traffic including buses, cars, other taxis, etc.
Komanoff estimates the city's traffic would move at least 12-percent slower. You'll be able to catch a cab about 60 seconds faster, but take more time than before to reach your destination. His figures show the slowdown could cost the city about $500 million a year in lost time. Which kinda negates the one-time $1 billion the city expects to make from auctioning the 2,000 new cab licenses.
But the plan to add more cabs is being held up by a lawsuit. Not by residents afraid of getting around town slower, but by the cabbies themselves. More cabs equals more competition.
In the video below, Komanoff gives a brief and interesting history of traffic in New York City.