Generally speaking, there are a tons of things we can add to increase the visual representation of real NYC. That doesn't just apply to policevehicles only. While the visual destinction between different police forces is perhaps nice to have, it serves no purpose to add them. There are already many different police vehicles in the mod anyway.
Fair enough. I was sort of thinking of the way LAWA police and port police were included as astedics of the LA mod. NYC actually has more law enforcement agencies operating within it than any other city in the United States, though the NYPD of course is the dominant force.
Regardless, the attention given to other aspects of the mod already seem to make this a very accurate represention of the city. Very excited to see the finished product. Awesome stuff!