Commonwealth of Pennsylvania

Department of Environmental Protection

Final

State Implementation Plan Revision: Motor Vehicle Sub-area Emissions
Budgets 

York-Adams Eight-Hour Ozone Maintenance Area

May 2008

Bureau of Air Quality

Pennsylvania Department of Environmental Protection

P.O. Box 8468

Harrisburg, PA 17105-8468

717-787-9495

www.depweb.state.pa.us

Blank page for copying purposes

INTRODUCTION AND OVERVIEW

Section 176 of the federal Clean Air Act (CAA) provides a mechanism by
which federally funded or approved highway and transit plans, programs,
and projects are determined not to produce new air quality violations,
worsen existing violations, or delay timely attainment of national air
quality standards.  Regulations of the U.S. Environmental Protection
Agency (EPA), issued to implement transportation conformity, provide
that motor vehicle emission “budgets” establish caps of these
emissions that cannot be exceeded by the predicted transportation system
emissions in the future (40 CFR Part 93).  Transportation agencies in
Pennsylvania are responsible for making timely transportation conformity
determinations.

  

On January 14, 2008, EPA approved a State Implementation Plan (SIP)
revision submitted by the Department of Environmental Protection (the
Department) on June 14, 2007, for the York-Adams Eight-Hour Ozone
Maintenance Area (York and Adams Counties).  The maintenance plan
portion of the approved SIP revision establishes motor vehicle emission
budgets (MVEBs) for purposes of transportation conformity for the entire
area. The Department’s revision included the following:

A request that the York-Adams ozone nonattainment area be redesignated
as attainment for the 8-hour ozone national ambient air quality standard
(NAAQS),

A 2002 base year inventory for the area, and

A maintenance plan for the area that provides for continued attainment
of the 8-hour ozone NAAQS for at least 10 years after redesignation.

Metropolitan Planning Organizations (MPOs) and the Pennsylvania
Department of Transportation (PennDOT), in conjunction with state Rural
Planning Organizations (RPOs), share transportation conformity
determination responsibility across the Commonwealth. The York-Adams
Area contains one MPO and one RPO.  Table 1 lists the MPO or RPO name
and the counties included in that agency’s responsibility. 

Table 1

York-Adams Area MPO/RPO County Coverage

MPO/RPO 	County

Adams County Transportation Planning Organization (RPO)	Adams

York County Planning Commission (MPO)	York



The Department’s June 14, 2007 SIP revision established motor vehicle
emission budgets (MVEBs) for the entire York-Adams Area. Given the
multi-jurisdictional nature of the area, PennDOT has requested separate
budgets to allow the planning organizations to move their transportation
conformity determinations through the approval processes separately.
This SIP revision will establish two sub-area budgets for the York-Adams
Area corresponding to the MPO/RPO structure of the area.  The total of
the two sub-area budgets is the same as the MVEB that was submitted to
EPA for the entire area. 

 

Section 93.124(d) of the transportation conformity regulations (40 CFR
§ 93.124(d)) allow a SIP to establish motor vehicle budgets for each
MPO if a nonattainment area includes more than one MPO. Furthermore,
recognizing the complexity of areas with multi-MPO jurisdictions, the
U.S. Department of Transportation Federal Highways Administration (FHWA)
allows States to develop separate sub-area transportation conformity
budgets for each MPO or some other subset of the area (such as by
county). For the York-Adams Area, PennDOT performs the emissions
modeling and analysis required for transportation conformity
determinations for the RPOs, and works closely with MPOs to prepare
conformity determinations. All transportation conformity processes in
the Commonwealth are coordinated through a robust interagency
consultation process, of which the Department, PennDOT, EPA, FHWA and
the MPO are members. 

When a SIP establishes separate transportation conformity budgets for
individual MPOs and RPOs, all of the MPOs and RPOs in that nonattainment
or maintenance area must be in conformity in order for any MPO or RPO
within that State's portion of the nonattainment or maintenance area to
make a conformity determination. In other words, if conformity lapses
for one MPO or RPO with a separate sub-area budget, the other MPOs and
RPOs within that State's portion of the nonattainment or maintenance
area will not lapse immediately, but they will be unable to make new
conformity determinations until the first MPO once again determines
conformity.  Separating budgets in this SIP revision will allow
conformity to be determined separately.  Increases in emissions in one
sub-area cannot be offset by decreases in emissions in another sub-area.
  

Requirements for a public comment process are set forth in Section
110(a)(2) of the CAA and 40 CFR Section 51.102(d).  A public hearing on
the proposed revision to separate MVEBs for the York-Adams Area into
sub-area budgets was scheduled for Wednesday, April 23, 2008. Notice of
the hearing was published in the Pennsylvania Bulletin March 22, 2008. 
No request for a public hearing was received so the hearing was
cancelled.  

MOTOR VEHICLE SUB-AREA EMISSIONS BUDGETS

     

Once approved by EPA, this SIP revision will establish sub-area budgets
for highway emissions in order to ensure that transportation emissions
do not impede clean air goals in the next decade and beyond.  The
information in Table 2-1 and Table 2-2 will replace the MVEBs in Table
2-3 on page 16 of the June 2007 SIP revision, establishing sub-area
budgets for the York-Adams Area.   

Table 2-1

Adams County Motor Vehicle Emission Budgets in Tons/Summer Day (tpd)

	2009	2018

 	VOC (tpd)	NOx (tpd)	VOC (tpd)	NOx (tpd)

Predicted	3.54	4.50	1.93	2.11

 	 	 	 	 

Safety Margin	0.30	0.37	0.41	0.43

 	 	 	 	 

Total Budget	3.84	4.87	2.34	2.54



Table 2-2

York County Motor Vehicle Emission Budgets in Tons/Summer Day (tpd)

	2009	2018

 	VOC (tpd)	NOx (tpd)	VOC (tpd)	NOx (tpd)

Predicted	11.52	17.30	6.02	6.87

 	 	 	 	 

Safety Margin	0.57	0.66	0.70	0.63

 	 	 	 	 

Total Budget	12.09	17.96	6.72	7.50



Note: Tons per day are informational only.  Differences occur due to
rounding.

 U.S. DOT, Federal Highways Administration,  “Transportation
Conformity in Complex Areas”
http://www.fhwa.dot.gov/environment/conformity/complex/group2.htm

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Kathleen A. McGinty

Secretary

Edward G. Rendell

Governor

