NEW YORK — The first congestion pricing program in the United States is taking final shape in New York City, and it appears likely that most drivers will have to pay $15 to enter some of the busiest streets in Manhattan as soon as next spring. Officials on Wednesday provided the clearest picture yet of the tolls they hope to implement. They aim to collect roughly $1 billion annually to fund improvements to the city’s subway and bus networks. The program faces a few hurdles, including a final vot