Section 489.09. Procedures for conformity determinations of general federal actions.

 

(1)  The analyses required under this chapter shall be based on the latest planning assumptions.

(a) All planning assumptions, including, but not limited to, per capita water and sewer use, vehicle miles traveled per capita or per household, trip generation per household, vehicle occupancy, household size, vehicle fleet mix, vehicle ownership, wood stoves per household, and the geographic distribution of population growth, shall be derived from the estimates of current and future population, employment, travel and congestion most recently developed by the MPO, or other agency authorized to make such estimates for the area. The conformity determination shall also be based on assumptions and estimates about current and future background concentrations that are included in the current applicable implementation plan and based on the latest assumptions and estimates about other federal actions.

(b) Any revisions to these estimates used as part of the conformity determination, including projected shifts in geographic location or level of population, employment, travel and congestion, shall be approved by the MPO or other agency authorized to make such estimates for the area.

(2)  The analyses required under this chapter shall be based on the latest and most accurate emission estimation techniques available as described below, unless such techniques are inappropriate. If such techniques are inappropriate and written approval of the EPA regional administrator is obtained for any modification or substitution, they may be modified or another technique substituted on a case-by-case basis or, where appropriate, on a generic basis for a specific federal agency program.

(a) For motor vehicle emissions, the most current version of the motor vehicle emissions model specified by EPA for use in the preparation or revision of implementation plans in the state or area shall be used for the conformity analysis as specified below in subds. 1. and 2. :

1. A new motor vehicle emissions model shall be used after EPA publishes in the federal register a notice of its availability.

2. A grace period of 3 months shall apply during which the motor vehicle emissions model previously specified by EPA as the most current version may be used. Conformity analyses for which the analysis was begun during the grace period or no more than 3 years before the federal register notice of availability of the latest emission model may continue to use the previous version of the model specified by EPA, if a final determination as to conformity is made within 3 years of such analysis.

(b) For non-motor vehicle sources, including stationary and area source emissions, the latest emission factors specified by EPA in the Compilation of Air Pollutant Emission Factors, AP-42, incorporated by reference in s. NR 484.05 , shall be used for the conformity analysis unless more accurate emission data are available, such as actual stack test data from stationary sources which are part of the conformity analysis.

(3)  The air quality modeling analyses required under this chapter shall be based on the applicable air quality models, databases, and other requirements specified in the most recent version of the Guideline on Air Quality Models in Appendix W of 40 CFR part 51 , incorporated by reference in s. NR 484.04 , unless:

(a) The guideline techniques are inappropriate, in which case the model may be modified or another model substituted on a case-by-case basis or, where appropriate, on a generic basis for a specific federal agency program; and

(b) Written approval of the administrator is obtained for any modification or substitution.

(4)  The analyses required under this chapter shall be based on the total of direct and indirect emissions from the action and shall reflect emission scenarios that are expected to occur under each of the following cases:

(a) The act mandated attainment year or, if applicable, the last year for which emissions are projected in the maintenance plan;

(b) The year during which the total of direct and indirect emissions from the action for each pollutant analyzed is expected to be the greatest on an annual basis; and

(c) Any year for which the applicable implementation plan specifies an emissions budget.

History: Cr. Register, September, 1995, No. 477 , eff. 10-1-95.