According to a list online (compiled by Jeffrey Stanton), auto polo was a show for only one season on Coney Island, in 1927 (show - two - 4 car teams - closed July 1st). Elsewhere (1776) the date of 1912 is used. Considering the damage being done in the photos it must have been an expensive and dangerous show to put on. From the Library of Congress photostream on flickr, so many may have seen these already... good stuff.