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Transportation Conformity Highlights

April 2005

EPA Guidance for Determining the "Attainment Year" for Transportation Conformity. In March 2005, the EPA released attainment year guidance. The guidance provides information for 8-hour ozone and PM2.5 areas on the appropriate attainment dates to use in transportation conformity determinations. The guidance contains some flexibility for areas using interim emission or budget tests before the SIP is submitted. For more information see:

EPA Updates Final PM2.5 Nonattainment area Designations. On April 5, 2005 designations under the national air quality standards for fine particulate pollution or PM2.5 became effective. EPA announced its decision on these designations in December 2004. Because designations occurred close to the end of 2004, EPA provided an opportunity for states to submit quality-assured, certified air quality data for 2002 through 2004. After reviewing those submissions, EPA found that eight areas previously identified as nonattainment for the standards may now be designated as attaining the standards. EPA is also designating as attainment four areas identified in December 2004 as unclassifiable. These changes to the PM2.5 designations can be found at:

EPA Clarification on Whether 18-month SIP Triggers for a 1-hour SIP Budget Apply for 8-hour conformity. EPA recently issued clarification to two questions related to 18-month SIP clocks. Question #1: Does an 18-month clock for a 1-hour ozone SIP budget continue to apply for 8-hour conformity after the 1-hour ozone standard is revoked? Question #2: Does an EPA adequacy finding or approval of a 1-hour ozone SIP budget after revocation trigger a new 18-month clock for 8-hour conformity: Answer: No to both questions. Section 93.104(e) of the rule only applies for 8-hour conformity when 8-hour ozone SIPs are found adequate or approved. Once the 1-hour ozone standard is revoked, all 18-month clocks for 1-hour SIPs go away since the 1-hour ozone standard and conformity for that standard no longer applies. For additional information contact your FHWA Division Office representative or the Transportation Conformity Team.

FHWA/FTA Guidance: Planning Horizons for Metropolitan Long Range Transportation Plans. On April 12, 2005 the FHWA's Office of Natural and Human Environment and FTA's Office of Planning and Environment released updated and clarified information on the planning horizon requirement for metropolitan long-range transportation plans. This memorandum answers several questions posed by FHWA/FTA field office planning staffs on the planning horizon and supersedes an April 24, 1998 memorandum from FHWA/FTA. For more information see:

Transportation Research Board: Transportation and Air Quality Committee Summer Meeting. This year's summer meeting is scheduled to coincide with the Air & Waste Management Association Annual Conference at the Minneapolis Convention Center. The Committee meeting will be held on June 21 at the Holiday Inn Express, two blocks from the convention center. For information and the agenda see:

NTI Course: Introduction to Transportation Conformity. Courses will be offered in New York City on May 11-13 and in Chicago, Illinois on June 15-17. This will mark the completion of these classes until at least July. For information and to register go to:

FHWA Resource Center Training Activities.FHWA's Resource Center Air Quality Technical Services Team is available to offer air quality-related training opportunities and information can be found at:

If you have any suggestions for future monthly conformity highlights, please email:

FHWA Resource Center Air Quality Team Contacts:

Updated: 10/20/2015
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