It seems so.  The following NY website indicates you are subject to the tax if your net self-employment (after expenses) is over 50,000:  self-employed individuals (including partners).  On the following website:  Metropolitan commuter transportation mobility tax, the tax is defined as follows:  

The metropolitan commuter transportation mobility tax (MCTMT) is a tax imposed on certain employers and self-employed individuals engaging in business within the metropolitan commuter transportation district (MCTD). This department administers the tax for the Metropolitan Transportation Authority. The MCTD includes the counties of New York (Manhattan), Bronx, Kings (Brooklyn), Queens, Richmond (Staten Island), Rockland, Nassau, Suffolk, Orange, Putnam, Dutchess, and Westchester.

For more information on the tax, please click on this link to download the booklet which describes it in greater detail:  Publication 420, Guide to the Metropolitan Commuter Transportation Mobility tax