NYC driving is traffic pandemonium. You can't turn your head without seeing cabs, trucks, pedestrians, cyclists, and regular cars all blocking lanes, double-parking, jumping/cutting in front of you with no warning, weaving, waiting out red lights in the middle of an intersection, jumping curbs....breaking the traffic laws in every direction. Pedestrians too. you really have to practice defensive biking if you want to stay alive. Being law-abiding doesn't always work well in that situation I'm afraid. You cannot be overly timid, either.
(all this from direct observation and from talking with my brother who uses his bicycle for all his getting around and commuting in Manhattan- he has no car.