Cool! Very nice pavement! The wet look is greatly done actually - the high contrast is a must of course, but the white paint is almost a bit too harsh, especially at left (while the red light could take more saturation - and maybe even a little blooming on the final render).
The cabs look fine. A crit could be the refections on the windows - the contrast there should be quite extreme IMO and some mirroring will be nice (when having the texture on the buildings). And evtl even more contrast on the area cleaned by the wipers.(they could be in an other position btw.)
Here a photo, showing beautiful yellow cab window reflections. Such a billboard on the roof of one of your cabs would be a nice detail btw.
Apropos details: That iron plate at right looks almost like floating - the effect is caused by the reflections on the road, but nonetheless distracting a bit. Oh, and some puddles would be nice - you need almost overknee-boots when walking in the rain in Manhattan (ive rarely seen larger and deeper puddles).
Its getting a masterpiece!