A. The authority shall develop a twenty year regional transportation plan that is subject to approval by the qualified electors of the county and financed by a transportation excise tax approved pursuant to section 42-6106 and bonds issued pursuant to article 2 of this chapter. The regional transportation plan:
1. May give priority to multimodal transportation operations and improvements along corridors where seventy-five percent or more of the adjacent census tracts had a population density of at least three thousand persons per square mile according to the most recent United States decennial census.
2. Shall include a public transportation component.
3. May, among other things:
(a) Define and identify regional transportation corridors.
(b) Define the transportation problems, goals and needs for each corridor.
(c) Determine environmental, economic, energy and social policies to guide transportation investment decisions.
(d) Determine the impact of the plan on air quality, with one of the goals of the plan being the improvement of air quality.
(e) Order the priority of regional transportation corridors for development.
(f) Determine the mix of alternative transportation modes appropriate for development consistent with the transportation goals and needs for each corridor. The mix may include sidewalks, rail service, buses, vans, para-transit, park and ride lots, bicycle facilities and any other facility or service reasonably related to transportation.
(g) Select appropriate public transportation technology.
(h) Determine the capacity for exclusive public transportation technologies.
(i) Determine operating performance criteria and costs for public transportation systems.
(j) Locate routes and access points to the public transportation systems.
(k) Determine the ridership of public transportation systems.
(l) Determine the need for landscape buffers, noise barriers, pedestrian bypasses, multiuse paths and other environmental impact mitigation measures relating to the regional transportation plan.
B. The regional transportation plan may not be amended to add or delete an element or substantially change an element without prior approval of the electorate at a general or special election pursuant to subsection D of this section. The prior approval of the electorate required by this subsection is waived if a political subdivision causing changes within its jurisdiction to the regional transportation plan incurs the incremental costs of implementing the proposed changes.
C. The proposition for a revised regional transportation plan considered at an election held pursuant to subsection D of this section shall adhere to the format applicable to the ballot proposition approved by the qualified electors voting on the initial regional transportation plan.
D. If a substantial change occurs, the board of directors shall request the county board of supervisors to provide a ballot proposition for consideration of a revised regional transportation plan on or before the date of the next general election. The board of supervisors shall provide the proposition at the next general election. If a majority of the qualified electors voting on the issue does not approve a revised regional transportation plan, the board of directors shall continue implementation of the previously approved regional transportation plan and may continue to make expenditures authorized pursuant to section 48-5308, subsection C, but may not make expenditures in excess of revenues received pursuant to section 48-5307, subsection A that are available for those purposes.
E. For the purposes of this section:
1. "Present worth" means the amount calculated by using the preceding five-year average of the GDP price deflator as defined in section 41-563 to discount the respective series of estimated revenues and expenditures.
2. "Substantial change" means a change that, based on data in the transportation improvement program developed pursuant to section 48-5304, paragraph 3, results in one or more of the following conditions:
(a) A present worth of estimated expenditures required to complete all elements of the regional transportation plan that exceeds the greater of:
(i) The present worth of estimated revenues available to the regional transportation fund during the comparable period by ten percent or more.
(ii) The original estimated revenue amount that was presented to the voters, except that estimated revenues from bond proceeds, if any, shall not exceed the bond capacity, less associated expenses, supported by estimates of unencumbered revenues for the initial ten years of authorization for the transportation excise tax.
(b) An estimated cost to complete one or more elements of the regional transportation plan that exceeds the expenditure limitations of the plan as adjusted by the GDP price deflator as defined in section 41-563 by the following or greater percentages:
(i) Ten percent for a single element of the plan.
(ii) Fifteen percent for any two elements of the plan.
(iii) Twenty percent for three or more elements of the plan.