Despite the press announcement made back in April, it wasn't until yesterday that we finally spotted one of the New York Police Department's new Nissan Altima Hybrid Patrol Cars prowling the streets of downtown.

(Unfortunately the lead-footed copper was faster than our cameraphone, but click here to see some awesome captures by NYC's Flickr brigade.)

The Altima Hybrids have been assigned to areas of the city where their fuel efficiency presents the greatest economic and environmental benefit - both in precincts with a large coverage area and smaller precincts prone to heavy stop-and-go traffic.

"These new patrol cars will help fulfill the PlaNYC goal of reducing City government's carbon footprint," said Mayor Bloomberg. "Through savings in fuel, these Altimas can quickly cover their additional cost, from then they will save taxpayers money - another example of how going green is good for our environment and our pocketbooks."

...At $25,391 per vehicle, the Altima hybrids cost about $1,500 more than the conventional Impala. At 35 miles per gallon for city driving, the hybrid Altima gets double the gas mileage of the Impala, which gets only 16 miles per gallon.