During Mardi Gras - Starting February 26 - moving about the French Quarter in New Orleans - especially Bourbon Street - is like being in a seven and a half block long, crowded elevator.  Filled with drunks.  The only way for a cop to get from place to place in an emergency is to get behind a police horse.  They move the crowds out of the way very nicely.  One may, however, hear the occasional high-pitched scream - "Ohshitgoddamnhesteppedonmyfoooot!"  Pity.

One also meets the odd college twit who wants to ride a police horse.  "You don't understand, officer.  I'm an equestrian."  He is then - it's almost always male - told what he really is, and is gently shoved back into the ranks of the milling crowd.

Above is a photo from the New Orleans Times Picayune, and displays some of the horses.  I've no idea who the guy on the bicycle is. Maybe he's trying to get out of the way before he hears multiple voices shout, "CHARGE!"