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Transportation Conformity Practices in Complex Areas

Nonattainment and Maintenance Areas with

There are 24 nonattainment or maintenance areas where the nonattainment or maintenance area boundary is larger than the MPO(s) planning area, and therefore, contain "donut areas." Donut areas are geographic areas outside a metropolitan planning area boundary, but inside the boundary of a nonattainment or maintenance area that contains any part of a metropolitan areas(s). These areas are not isolated rural nonattainment and maintenance areas.

These areas include 41 MPOs as shown in Attachment C. State departments of transportation (DOTs) and MPOs within nonattainment/maintenance areas with donut areas must cooperatively ensure that the motor vehicle emissions within the nonattainment or maintenance area, but outside of the MPO(s) planning area are included in the regional emissions analysis supporting MPO conformity determinations. To demonstrate conformity of projects in the donut portion, such projects must have been included in the regional emissions analysis that supports the conformity determination of the MPO's plan and TIP. In nonattainment and maintenance areas with a donut portion, the MPO and State DOT may choose to include donut area projects in the MPO's plan and TIP. Challenges these areas face include:

SIP Issues:

In order to develop a SIP and budgets, motor vehicle emissions for the entire nonattainment or maintenance area, including any donut area, must be estimated. Areas must determine how to calculate vehicle activity and associated emissions in the donut area, where limited data may exist. Interagency consultation should be used to ensure that travel and emissions assumptions and calculations in the donut area are consistent with those in the metropolitan area.

In addition, States may wish to consider the use of sub-area budgets in these areas. If an area decides to create a sub-area budget for the donut area, the SIP would have to explicitly indicate that sub-area budgets have been created and would have to explicitly show the sub-area budgets for each portion of the nonattainment or maintenance area. This process would be similar to those discussed in Multi-MPO Nonattainment and Maintenance Areas. It should also be noted that, as can be seen in Attachment C, that 11 of these nonattainment and maintenance areas with donut areas also are Multi-MPO Nonattainment and Maintenance Areas (see also Attachment B) and that 4 of those areas are also Multi-State Nonattainment and Maintenance Areas (see also Attachment A).

Institutional Arrangements:

The conformity rule requires that interagency consultation procedures include specific procedures for where the metropolitan planning area does not include the entire nonattainment or maintenance area, including a process involving the MPO and the State DOT for cooperative planning and analysis for purposes of determining conformity of all projects outside the metropolitan area, but within the nonattainment or maintenance area.

Regardless of which agency takes the lead, once the decision is made as to which agency will perform the emissions analysis for the donut area, an agreement must be developed to outline the roles and responsibilities of the MPO, the State DOT, and possibly others (e.g., the State air agency or the jurisdiction(s) that lie within the donut area). The agreement is intended to facilitate regional emissions analysis in these areas to clearly state which agencies are involved in the analysis and their respective roles.

We found that in 5 of these nonattainment/maintenance areas with donut areas, the MPO took the lead in conducting the regional emissions analysis for the donut area. These areas are noted in Attachment C. The MPOs within these areas that take the lead on the donut area analysis include the Atlanta Regional Commission, the Chicago Area Transportation Study (CATS), Metro in the Portland, OR-WA area, the Mountainland Association of Governments in Utah County, UT, and the National Capitol Transportation Planning Board in the Washington, DC-MD-VA area. As it can be seen, these MPOs are typically larger metropolitan areas that have the staff capacity and resources to include the donut area in the regional emissions analysis. For example, conformity documentation for the Atlanta, Georgia metropolitan area includes a section related to the coordination process used for the donut area portion of the nonattainment area:

. . . "Georgia DOT agreed in 1995 that ARC would include the three counties outside the MPO planning area but within the Atlanta nonattainment region (Paulding, Coweta and Forsyth) into the ARC transportation and mobile source emissions modeling domain. This included creating land use and sub-county employment estimates for DRAM/EMPAL, expanding the travel demand model network analysis zones and expanding the transportation networks to include these areas. GDOT acts on the three counties' behalf in reviewing the population growth, facility and travel growth assumptions. At every major milestone, representatives from the three counties participate in the development of the RTP and TIP. GDOT is currently assessing the planning process in these counties and preparing Memoranda of Understanding (MOUs) that better define the planning process."

In the other 19 nonattainment and maintenance areas with donut areas, the State DOT takes the lead for regional emissions analysis for the area that falls outside of the MPO planning area but within the nonattainment or maintenance area. This is also noted in Attachment C. An example of this is in the State of North Carolina:

There are 3 1-hour ozone maintenance areas in North Carolina that have donut areas. A process has been developed between the State DOT and each of the 7 MPOs within these areas on how this analysis is completed. In short, the MPOs, with assistance from the State DOT, take the lead on regional emissions analysis for the metropolitan portion of the areas, and the State DOT conducts the regional emissions analysis on the donut portions. The combined emissions from both analyses are then shown to meet the applicable emissions budgets. The MPOs' conformity determinations on transportation plans and TIPs are then based on this result, as are any project-level conformity determinations in the donut area. There is no formal agreement between the State DOT and the MPOs on this process.

Analysis issues:

Close coordination occurs between the MPO and the State DOT and/or jurisdictions within the donut area adjacent to the MPO. However, we found that the majority of areas did not have a formal schedule in place for updating planning assumptions. The process varies somewhat between the MPOs in this type of area. For example, 6 MPOs update planning assumptions every 5 years, 10 MPOs update assumptions every 3 years, and 16 of the MPOs update planning assumptions as needed. The Atlanta Regional Commission, updates planning assumptions on an ongoing basis.

The majority of MPOs in this type of area use the interagency consultation process as the forum to develop concurrence on planning assumptions used in the conformity process. In addition, 10 MPOs require in writing, concurrence on planning assumptions by the planning partners.

Updated: 07/06/2011
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