Tax for public transit system, construction, maintenance and repair of public roads, improvement of air quality or any combination thereof: Reduction of amount; limitation on repeal, amendment or modification; dissolution of regional transportation commission

1. Subject to the provisions of subsection 2, the board may gradually reduce the amount of any tax imposed pursuant to this chapter for a public transit system, for the construction, maintenance and repair of public roads, for the improvement of air quality or for any combination of those purposes as revenue from the operation of those projects permits. The date on which any reduction in the tax becomes effective must be the first day of the first calendar quarter that begins at least 120 days after the effective date of the ordinance reducing the amount of tax imposed. 2. No such taxing ordinance may be repealed or amended or otherwise directly or indirectly modified in such a manner as to impair any outstanding bonds issued under this chapter, or other obligations incurred under this chapter, until all obligations, for which revenues from the ordinance have been pledged or otherwise made payable from such revenues pursuant to this chapter, have been discharged in full, but the board may at any time dissolve the regional transportation commission as provided in NRS 373.120 and provide that no further obligations be incurred thereafter.