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Court Decision on Transportation Conformity Rule

October 20, 2006

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The purpose of this message is to alert Division Offices and the Resource Center to a recent decision by the U.S. Court of Appeals vacating a provision of the Transportation Conformity Rule (40 CFR 93.109(e)(2)(v)), and to request information from any Division that has utilized this provision.

On October 20, 2006, the DC Circuit filed an opinion, vacating a provision of the Transportation Conformity Rule. A PDF copy of this decision, Case No. 04-1291, can be downloaded at (PDF - 149KB). Although we have not yet had the opportunity to fully understand the potential ramifications of this decision, it is important that States and MPOs be made aware of it.

The July 1, 2004 revisions to the Rule to address the 8-hour ozone standard required that areas continue to utilize their 1-hour motor vehicle emissions budgets until they had 8-hour budgets in place.

However, 40 CFR 93.109(e)(2)(v) was a provision that allowed areas to use the interim emissions tests instead of the 1-hour budgets where the interim tests could be shown to be more appropriate for ensuring that the plan, TIP, or project would not create new violations, worsen existing violations, or delay timely attainment of the 8-hour standard, as determined through interagency consultation. This is the provision that Court vacated.

All other provisions regarding the use of the interim emissions tests remain unaffected by the court decision.

While we work with EPA and the Chief Counsel's office to assess the implications of this opinion, please do not make any conformity determinations based on 40 CFR 93.109(e)(2)(v) and contact our Office if any pending conformity determinations in your State rely on this provision.

In addition, please contact our Office if any prior conformity determination in your State has relied on this provision.

For further information, or to reply regarding the use of this provision in your State, please contact Cecilia Ho at 202-366-9862 or, Gary Jensen at 202-366-2048 or, or Emily Biondi at 202-366-9482 or

Updated: 10/20/2015
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