This is the link to the VTA general manager's memo to the board of directors regarding the increase in sales tax projection. This online copy can be found at the Board of Supervisors' web site. The Board of Supervisors will be discussing the tax proposal on January 10 at 10:00am.
One of the troubling issues in the new projection is that VTA only anticipates increased revenue until 2015. These are supposedly the critical years of BART construction. If the actual revenue misses the projection anytime during those years, the projection will be way off and VTA will not be able to keep its promises. It seems apparent that VTA is making its revenue projections up to make the BART extension work, at the expense of other transit projects.