The theme song to the show: There's a hold up in the Bronx, Brooklyn's broken out in fights/ There's a traffic jam in Harlem that's backed up to Jackson Heights/ There's a scout troop short a child, Khrushchev's due at Idlewild! Car 54 where are you?
The show was filmed at the "Biograph Studios" in the Bronx, New York. The studio was originally built in 1912 by the American Mutoscope & Biograph [us] which is still in existence today. The Biograph studio facilities were sold several times through the years, until it burned down in 1980.
Al Lewis joined the cast as Officer Leo Schnauser beginning with the 13th episode of season 1. Prior to that he appeared in episode 7 "The Paint Job" playing Al, the owner of Al's Garage where he would repair and repaint stolen cars for a car theft ring.
Real-life NYPD squad cars of the period had white roofs and trunk lids and green bodies, with all or parts of the fenders painted black. The cars on the black and white TV series seem to follow this striping design except for the black fenders.