This image is not public domain, the MTA is a private quasai-governmental organization, not government. From MTA website: Please note that, except solely for your own personal and non-commercial use, no part of these maps may be copied or used without the prior written permission of the Metropolitan Transportation Authority. and All images and documents copyright 2006 Metropolitan Transportation Authority. All rights reserved..
The standing consensus on wikipedia has been that MTA maps are not usable here, since even though you might argue that we can legally use them, wikipedia policy prevents their use since they are not in a free license. If anyone wants to make a case for using this particular image under fair use, Im all ears. -Lanoitarus(talk).:.23:29, 15 January 2006 (UTC)[reply]