Might be a good argument that NYC needs more parking. Here, they'll be (legally) street-parked or pull over into a parking lot or something. If the police don't have space to park, probably a good bet that everyone else is also short on parking.

Brooklyn might not have density too-high to permit for ground-level parking lots, but they can still have municipal multistory parking garages.

EDIT: Also, tangentially-related, and it may not be appropriate in NYC, where there are taller buildings that will block some of the light, but I do think that if the concern is shade, rather than decoration, as seems to be the case here:

Robert Lopez was walking home past the 83rd Precinct at 480 Knickerbocker Avenue in Bushwick, Brooklyn, on an 87-degree Wednesday when he was faced with a particularly vexing challenge on that block: making it to tree-lined Menahan Street without melting into a puddle of his own sweat.

...it might be worth considering whether sticking up solar canopies to provide shade is a good option. That's one thing that I've seen done in California, where shade in a parking lot always makes a slot popular.

kagis

The story here is about Brooklyn, and it looks like there's a company, Brooklyn Solar Canopy Company, that does those installations. Means that one doesn't need to deal with leaf litter and all that. I dunno how the overall costs compare, though.