In 200x, the old rotation plan based on zones was abolished and a new No Zone plan was instituted. The old plan was dropped because it allowed sites in North American to bid only once every three years and with a perceived general decrease in available sites, it was believed that we were losing potential good bids because their site was not available when it was their zone's turn.
To prevent a site from selecting itself or a near neighbor (like Philadelphia in 2001 being selected over Boston in 2001 in an election held in 1998 at Bucconeer in Baltimore), an exclusion zone of 500 miles was established around the site which administers the vote. So, for example, the site selection held in San Antonio in 2013 will not be able to select sites located within 500 miles of San Antonio.
