The Long-Range Plan studies are done, providing the Sound Transit Board with a menu of projects with which they can compose the next ballot measure. That assumes that the legislature, one day soon, gives them the authority to do so. But now that they have the price list for various projects, how much money would there be to spend?
In principle, the legislature can do whatever it wants in granting revenue authority, although what regional lobbyists request will shape the legislation. To provide some form to this exercise, I’ll make two assumptions:
Subarea Equity. Under current law, Sound Transit must use money collected in each subarea in that subarea. In principle, new legislation could change this rule, and no less than the Mayor of Seattle is in favor of doing so. A transfer from high-revenue, low-demand East King to low-revenue, high-demand South King has its merits. However, regardless of the law, a substantial transfer of funds from one area to another is likely electoral suicide. ST sent me the most recent revenue projections for 2009-2023 (below), which state that tax revenue from Snohomish, North King, South King, East King, and Pierce will arrive in the ratio 1 : 2.4 : 1.2 : 2.0 : 1.4, respectively. Of course, different taxes will generate money in different ratios, and the ST3 revenue period will be different than this one, but using this is much better than a wild guess.
(Before you take these actual numbers and start buying stuff, note that these are year of expenditure dollars, while the ST Long Range Plan figures are 2014 dollars. In other words, the LRP projects cost more if you’re using these figures.)