UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: November 7, 2013

SUBJECT: Technical Support Document for the Motor Vehicle Emissions Budgets for the 

Lancaster 1997 8-Hour Ozone Maintenance Area 

FROM: Asrah Khadr, Environmental Engineer, EIT /s/

Office of Air Program Planning 

TO: File

THRU: Cristina Fernandez, Associate Director /s/

Office of Air Program Planning

A. BACKGROUND: 

On November 19, 2012, the Pennsylvania Department of Environmental Protection (PADEP) 

submitted a revision to the Commonwealth of Pennsylvania’s (Pennsylvania) State 

Implementation Plan (SIP). The SIP revision consists of updated Motor Vehicle Emissions 

Budgets (MVEBs) for nitrogen oxides (NOx) and volatile organic compounds (VOCs) for the 

1997 8-Hour Ozone National Ambient Air Quality Standard (NAAQS). The SIP revision also 

includes an updated point source inventory for NOx and VOCs. The updated budgets were 

calculated using the Environmental Protection Agency’s (EPA) Motor Vehicle Emission 

Simulator model (MOVES2010a). The intention of the revised SIP is to replace the approved 

MOBILE6.2-based MVEBs with budgets based on MOVES2010a and to ensure that the SIP 

revision still provides for attainment of the 1997 8-Hour Ozone NAAQS. 

On July 18, 1997 (62 FR 38856), EPA established the 1997 8-Hour Ozone NAAQS. On April 

30, 2004 (69 FR 23860), Lancaster County was designated as nonattainment for the 1997 8-Hour 

Ozone NAAQS. On September 20, 2006, PADEP submitted a SIP revision which consisted of a 

maintenance plan, a 2002 base year inventory and MVEBs for transportation conformity 

purposes. On November 8, 2006, PADEP supplemented their September 20, 2006 submittal. 

On July 6, 2007 (72 FR 36889), EPA approved the SIP revision as well as the redesignation 

request made by PADEP and Lancaster County was redesignated as a maintenance area.1 

 

1 These are not the only rulemakings published by EPA for the Lancaster County 1997 8-Hour Ozone NAAQS SIP. 

On August 8, 2013 (78 FR 48323), EPA published a direct final rulemaking notice to approve this SIP revision. But 

due to a numerical data error in EPA’s publication, EPA withdrew the rulemaking. On September 26, 2013 (78 FR 

59258) EPA withdrew the direct final rulemaking notice. On September 26, 2013 (78 FR 59317), EPA also 

withdrew the related proposed rulemaking notice. The numerical data error has been corrected in this rulemaking. 
2

The MVEBs are a mobile source inventory to which an area’s transportation improvement 

program (TIP) and long range transportation plan must conform. Conformity to MVEBs in a SIP 

means that transportation activities will not produce new air quality violations, worsen existing 

violations, or delay timely attainment of the NAAQS or any required interim milestones. This 

January 31, 2013 SIP revision submittal provides updated MVEBs for NOx and VOCs. The 

budgets were developed utilizing MOVES2010a. On March 2, 2010 (75 FR 9411), EPA 

published a notice of availability for the MOVES2010 model for use in SIP submissions and 

started a two year grace period for the use of MOVES2010 for transportation conformity 

purposes. The two year grace period was scheduled to end on March 2, 2012. On February 27, 

2012 (77 FR 11394), EPA published a final rule extending the grace period another year to 

March 2, 2013 to ensure adequate time for affected parties to adopt the model. On September 8, 

2010, EPA released MOVES2010a, which is a minor update to MOVES2010. Pennsylvania 

utilized MOVES2010a in its November 19, 2012 SIP revision. MOVES2010a was used in order 

to ensure that the nonattainment area can demonstrate transportation conformity using 

MOVES2010a once the 3-year conformity grace period expires. Pennsylvania updated their 

SIP-approved MVEBs with the use of MOVES2010a. The budgets were previously developed 

with the use of the Highway Mobile Source Emission Factor Model (MOBILE6.2). 

MOBILE6.2 is a motor vehicle emissions factor model that was utilized for SIPs and 

transportation conformity. MOBILE6.2 was made available for use in SIPs and transportation 

conformity purposes on May 19, 2004 (69 FR 28830). MOBILE6.2 was merely an update to 

MOBILE6 that added the ability for the program to estimate direct exhaust and brake and tire 

wear particulate matter emission factors as well as exhaust emission factors for particulate matter 

precursors. 

MOVES2010 improves upon MOBILE6.2 in many aspects. MOVES2010 utilizes a plethora of 

vehicle data that has been made available since the release of MOBILE6.2; this vehicle data 

includes emissions data for different kinds of vehicles. The new data has allowed EPA to better 

understand on-road mobile source emissions and their contribution to emissions inventories as 

well as how effective different control strategies are. The MOVES2010 model offers more 

flexibility because the program has a database design that allows easier organization of input and 

output files and data. The database design of the MOVES2010 model allows much easier update 

of input data upon the release of new data. MOVES2010 also accounts for temperature and 

speed variations and allows the model to run at a higher resolution which allows for the input of 

more activity data. 

Under section 176(c) of the Clean Air Act (CAA), any federal action is required to conform to 

the applicable SIP. A part of this requirement for conformity is transportation conformity. 

Transportation conformity requires that any federally funded transportation plan, program or 

project conform to the applicable SIP for the transportation-related criteria pollutants (ozone, 

carbon monoxide, fine particulate matter (PM2.5), coarse particulate matter (PM10), and nitrogen 

dioxide). The transportation conformity rules can be found at 40 CFR 93, Subpart A. One of the 

requirements found under 40 CFR 93, Subpart A is that any transportation plan, TIP or project 

not in a conforming TIP must conform to the MVEBs in the applicable SIP. In order for the 

MVEBs in a SIP to be used to determine conformity of a transportation plan, TIP or project, the 

MVEBs must be either approved or deemed adequate. In this case, the budgets must be 
3

approved because this SIP revision is revising already approved budgets. However, in reviewing 

such a submitted SIP it remains useful to apply the criteria used to make an adequacy finding. 

The requirements for adequacy are set forth in 40 CFR 93.118(e)(4)(i)-(vi). The criteria for 

adequacy and how they are met by the Pennsylvania submittal are found below in Table 1. 

Table 1. Adequacy Criteria for the Lancaster Maintenance Area

Criterion Submittal

(i) The submitted control strategy implementation plan 

revision or maintenance plan was endorsed by the 

Governor (or his or her designee) and was subject to a 

State public hearing;

 Letter addressed to Shawn M. Garvin, 

Regional Administrator, EPA Region 

III from Michael L. Krancer, 

Secretary, PADEP.

 Public hearing documents were 

submitted.

(ii) Before the control strategy implementation plan or 

maintenance plan was submitted to EPA, consultation 

among federal, State, and local agencies occurred; full 

implementation plan documentation was provided to 

EPA; and EPA's stated concerns, if any, were addressed;

 N/A. This revision does not 

accompany a control strategy 

implementation plan or maintenance 

plan.

(iii) The motor vehicle emissions budget(s) is clearly 

identified and precisely quantified;

 Appendix C-2 of the submittal 

provides detailed emission summary 

tables.

(iv) The motor vehicle emissions budget(s), when 

considered together with all other emissions sources, is 

consistent with applicable requirements for reasonable 

further progress, attainment, or maintenance (whichever 

is relevant to the given implementation plan 

submission);

 Maintenance plan for Lancaster 

County was already approved on July 

6, 2007 (72 FR 36889), no changes 

to area and nonroad source emissions, 

point source emissions were updated.

 Lancaster County continues to attain 

the 1997 8-Hr Ozone NAAQS as 

shown by the design value obtained 

from 2009-2011 data.

 Update of point source emissions 

shows less emissions than those 

predicted in the maintenance plan.

(v) The motor vehicle emissions budget(s) is consistent 

with and clearly related to the emissions inventory and 

the control measures in the submitted control strategy 

implementation plan revision or maintenance plan; and

 The SIP revision shows no change in 

any control measures in the 

previously submitted maintenance 

plan.

(vi) Revisions to previously submitted control strategy 

implementation plans or maintenance plans explain and 

document any changes to previously submitted budgets 

and control measures; impacts on point and area source 

emissions; any changes to established safety margins 

(see § 93.101 for definition); and reasons for the changes 

(including the basis for any changes related to emission 

 Changes in MVEBs are clearly 

documented and explained in the 

submittal. The higher emissions are 

due to the use of MOVES2010a 

which is a more accurate emissions 

model and is based on more recent 

data on vehicle emissions than 
4

factors or estimates of vehicle miles traveled). MOBILE6.2. Update of point source 

emissions and addition of small safety 

margin are well explained. 

B. STATE SUBMITTAL:

On November 19, 2012, PADEP submitted a SIP revision which included an update to the 

MVEBs for NOx and VOCs for the years 2009 (interim year) and 2018 (maintenance year). The 

updated MVEBs were produced using the MOVES2010a model. The MVEBs were developed 

with guidance from the following EPA guidance documents: Policy Guidance on the Use of 

MOVES2010 for SIP Development, Transportation Conformity, and Other Purposes and 

Technical Guidance on the Use of MOVES2010 for Emission Inventory Preparation in State 

Implementation Plans and Transportation Conformity. The submittal also includes an updated 

point source emissions inventory. 

I. Methodology for Developing Data for Use in MOVES2010a

PADEP utilized MOVES2010a to provide emissions rates for emissions of NOx and VOCs. 

PPSUITE is a program that was utilized for the processing of highway information and to 

provide input files that are usable by the MOVES2010a model. PPSUITE was run utilizing 

CENTRAL; CENTRAL is a program that provides a process for the proper function of PPSUITE 

and MOVES2010a. The MVEBs were developed for NOx and VOCs since they are the two 

biggest contributors to the formation of ozone. 

In PPSUITE, the Pennsylvania Department of Transportation (PennDOT) Roadway Management 

System (RMS) data among other data was utilized to produce vehicle miles traveled (VMT) 

estimates. The VMT produced via PPSUITE was then imported into the county data manager 

(CDM) in MOVES2010a. Since VOCs and NOx emissions differ with respect to travel speed, 

travel speed is utilized as an input in MOVES2010a. To develop an array of travel speeds, 

PPSUITE was utilized to develop vehicle hours of travel (VHT) by speed bin file which allows 

for the distribution of speeds across links into MOVES2010a speed bins. The travel speed 

calculations were completed with guidance from Technical Guidance on the Use of MOVES2010 

for Emission Inventory Preparation in State Implementation Plans and Transportation 

Conformity. 

Road type distribution was another traffic input for MOVES2010a. Road type distribution was 

developed with the use of PPSUITE. The five different road types utilized by MOVES2010a are 

off network, rural restricted access, rural unrestricted access, urban restricted access and urban 

unrestricted access. In addition, ramps are not included in road type distribution so it is assumed 

that 8% of the roadway VHT is ramp VHT. This traffic input assumption is consistent with 

EPA’s technical guidance. 

Before RMS data is utilized by PPSUITE to develop various traffic inputs, several adjustments 

must be made. The RMS VMT is adjusted to meet the Highway Performance Monitoring 

System (HPMS) VMT totals. HPMS VMT utilizes snapshots of RMS VMT to satisfy reporting 
5

requirements established by the Federal Highway Administration (FHWA). To make this 

adjustment, adjustment factors were calculated and utilized. 

Adjustments to average annual daily traffic (AADT) were completed because calculations for 

ozone precursors are based on a summer weekday, since that is when ozone formation tends to 

be the greatest. The RMS AADT volumes are adjusted by the use of a seasonal factor that was 

developed by PennDOT’s Bureau of Planning and Research (BPR) to produce July traffic 

volumes. The RMS data was also adjusted for differences in hourly traffic volumes. The 24-

hour pattern data provided to PPSUITE allowed PPSUITE to provide roadway segment volumes 

by the hour. The 24-hour pattern data was obtained from PennDOT’s PBR. 

Traffic volume forecasts had to be applied to estimate future emissions from vehicles. The 

growth rates utilized for these forecasts are the PennDOT PBR growth rate forecasting system, 

the regional travel model and any applicable Marcellus Shale related activity growth. 

Additionally, county specific growth rates were utilized from a 2005 PennDOT report titled 

Statistical Evaluation of Projected Traffic Growth, Traffic Growth Forecasting System: Final 

Report, March 14, 2005. 

MOVES2010a utilizes 13 vehicle source types. Since HPMS utilizes different categories for 

vehicle types, the RMS traffic volumes were disaggregated to the 13 vehicle source types which 

were then combined into the 6 HPMS vehicle classes. Vehicle type data input into PPSUITE is 

used to divide the roadway segment volumes with respect to the MOVES2010a source types. 

The source types are split into percentages among the 24-hours of the day. The vehicle source 

type percentages are then utilized to adjust vehicle speeds in response to trucks. 

Vehicle population is also another important input for MOVES2010a. Vehicle population is 

input into MOVES2010a with respect to the 13 vehicle source types utilized by the model. 

County level vehicle registration data is utilized for light duty vehicles and school buses. Transit 

bus data is obtained from PennDOT’s National Transit Database (NTD); it is utilized to estimate 

county level transit bus counts. Heavy duty vehicle population data is estimated by utilizing 

source type VMT and vehicle source and pattern data are utilized. Vehicle age is input into the 

model as well. The vehicle age is input into the model as a percentage of vehicles of the fleet 

between ages 0 and 31. 

Outside of vehicle and roadway data, environmental variables are utilized as inputs since 

evaporative emissions are dependent on the surrounding temperatures. The environmental 

variables used included hourly temperatures and humidity values. The temperatures were 

retrieved by Weather Bank Inc. Humidity values were produced according to EPA’s technical 

guidance. Minimum and maximum monthly temperatures were converted to hourly temperatures 

using EPA converters in the MOVES2010a model. 

Fuel parameters were also input since different fuels produce different emissions. The 

MOVES2010a default fuel formulation and supply data was utilized and updated with local 

volumetric fuel property data. Gasohol market penetration and RVP values were updated at the 

county level. Other fuel parameters were obtained through the MOVES2010a default data.
6

Refueling emissions were not included as an input because Pennsylvania provides the refueling 

emissions in its area source inventory; hence it is not required for the production of MVEBs. 

Additionally, MOVES2010a also includes input parameters for inspection and maintenance 

(I/M) programs. The inputs for the I/M program include: program start year, stringency level, 

first and last model years subject to the program, waiver rates, compliance rates, program type 

and effectiveness, frequency of inspection, vehicle type coverage and test type. The defaults for 

an I/M program in MOVES2010a were modified to accurately represent the I/M program for 

Lancaster County. 

II. Running MOVES2010a

As stated in Section I, the data utilized to run MOVES2010a is a mixture of local and national 

data. Local data is utilized for all inputs that have significant impact on the emissions rates that 

are calculated by MOVES2010a. The local data utilized as inputs for MOVES2010a is 

categorized into five categories which include: traffic data, vehicle descriptions, fuel parameters, 

I/M programs, and environmental variables. The inputs for traffic data include vehicle type 

VMT, vehicle population, VMT fractions, road type distribution, and ramp fractions. The inputs 

for vehicle descriptions include vehicle type mix, vehicle age distribution, average speeds and 

hourly distributions of different vehicles. The inputs for fuel parameters include RVP, sulfur 

level and ethanol volume. The inputs for I/M programs include start and model years, the 

frequency of tests, test standards, source types, stringency of tests, the waiver rate, and 

compliance rates. The inputs for environmental variables include hourly temperatures and 

humidity. 

MOVES2010a inputs that were prepared by PPSUITE included vehicle type VMT, vehicle 

population, VMT fractions, average speed distributions, road type distribution and ramp 

fractions. These files were input into the MOVES2010a county data importer. Additional nonPPSUITE inputs included fuel and vehicle ages, as well as temperatures and I/M programs. The 

county data importer was run in batch mode. Running the county data importer converts input 

files into a MYSQL format which is accepted by MOVES2010a. Afterwards, a MOVES run 

specification file (.mrs) was created. This file includes options and different data locations for 

the execution of the model. MOVES2010a can be executed to provide an emissions rate or an 

emissions inventory. In this submittal, MOVES2010a was executed to provide an emissions 

inventory. The emissions estimates of VOCs and NOx produced for the years 2004, 2009 and 

2018 by MOVES2010a are provided in Table 2. The emissions estimates are provided in tons 

per day (tpd); also provided in Table 2 is the comparison between the emissions produced by 

MOBILE6.2 and MOVES2010a. The revised MVEBs produced with MOVES2010a are found 

below in Table 3. After reviewing this submittal, EPA concurs with Pennsylvania that even 

though the emissions results produced by MOVES2010a are greater than those previously 

calculated using MOBILE6.2. EPA’s review of the SIP revision indicates these higher emissions 

result from improvements in the MOVES model rather than from unanticipated growth or 

changes in control measures. The MOVES results are more accurate estimates of the emissions 

that actually occurred in 2002 and 2009, rather than an indication that emissions are increasing. 

More importantly, Lancaster county attained the 1997 8-Hour Ozone NAAQS and was 

redesignated to a maintenance area on July 6, 2007 (72 FR 36889). Lancaster County continues 
7

to attain the 1997 8-Hour Ozone NAAQS as shown by its 2009-2011 design values. The two air 

quality monitors in Lancaster County are providing design values of 76 parts per million (ppm) 

and 77 ppm, which are below the 1997 8-Hour Ozone NAAQS of 0.08 ppm. Therefore, EPA 

finds this update to the MVEBs does not interfere with Lancaster County’s ability to maintain its 

attainment of the1997 8-Hour Ozone NAAQS.

Table 2. Summary of Motor Vehicle Emissions for the Lancaster 

Maintenance Area

Model MOBILE6.2 MOVES2010a

Year 2004 2009 2018 2004 2009 2018

VOCs (tpd) 19.75 14.33 7.77 16.41 14.29 8.14

NOx (tpd) 32.33 22.32 8.99 42.10 33.18 18.57

Table 3. Revised MVEBs 

for the Lancaster 

Maintenance Area

Year 2009 2018

VOCs (tpd) 14.29 10.14

NOx (tpd) 35.18 20.57

III. Revision of Point Source Emissions

In addition to revising the MVEBs for the Lancaster County Maintenance Area, PADEP 

submitted revisions to its inventory of point source emissions. The change accounts for a 

decrease in point source emissions. The point source emissions were projected for the 2009 

interim year in the 2006 maintenance plan SIP submittal and the actual emissions were less than 

the projected emissions at the time. Company-reported point source emissions were utilized to 

update the 2009 interim year inventory. The previously estimated and the actual interim year 

inventories are provided in Table 4. The update to the 2018 maintenance year was produced by 

linear extrapolation between the point source emissions for 2007 and 2020. These point source 

emissions were produced by the Mid-Atlantic Regional Air Management Association, Inc. 

(MARAMA). The emissions data for the years 2007 and 2020 were obtained from the 

MARAMA document titled MARAMA 2007, 2017, and 2020 Baseline and Projected 

Inventories, Version 3. The emissions provided by this MARAMA document utilize the most 

recent growth assumptions, which are more recent than the growth assumptions utilized by 

PADEP in the Lancaster County Maintenance Plan that was submitted in 2006. The main reason 

the point source emissions were updated, is because some growth factors decreased while others 

increased, but overall there is a decrease in projected emissions from the previous 2018 

inventory and the 2018 inventory in this submittal. The previously submitted 2018 point source 

emissions inventory currently in the maintenance plan and the updated 2018 point source 

emissions inventory are provided below in Table 5. The update to the point source emissions has 

been reviewed and found to be reasonable, an additional technical support document in this
8

docket addresses the revision of the point source emissions. The document is titled Technical 

Support Document for Emissions Inventories for the State Implementation Plan Revision: NOx

and VOC Motor Vehicle Emission Budget Revision 

Based on MOVES2010a. 

Table 4. 2009 Point Source 

Emissions for the Lancaster 

Maintenance Area

Estimated Actual

VOCs (tpd) 8.7 5.5

NOx (tpd) 4.1 3.2

Table 5. 2018 Point Source Emissions for 

the Lancaster Maintenance Area

Maintenance Plan Updated

VOCs (tpd) 11 7.7

NOx (tpd) 4.6 3.6

IV. Safety Margins

Since there is a significant difference between the projected emissions for the maintenance year 

and the attainment year a small portion of that difference was made into a safety margin. A 2 tpd 

safety margin was added for VOCs and NOx emissions for the 2018 MVEBs and a 2 tpd safety 

margin was added for NOx for the 2009 MVEBs. The differences between the 2004 attainment 

year and the 2009 interim year and 2018 maintenance year for NOx are found below in Table 6. 

The differences between the 2004 attainment year and the 2009 interim year and 2018 

maintenance year for VOCs are found below in Table 7. Tables 6 and 7 show that there are 

decreases which are significant in some categories between the attainment, interim and 

maintenance years. Because the 2009 and 2018 emissions are less than the 2004 attainment year 

emissions, the excess emissions can be allocated to the MVEBs while the area can continue to 

attain the 1997 8-Hour Ozone NAAQS. 

Table 6. NOx Emissions and Differences for Years 2004, 2009 and 

2018 for the Lancaster Maintenance Area

Category 2004 2009 2004-2009 2018 2004-2018

Point (tpd) 3.89 3.2 0.79 3.6 0.29

Area (tpd) 2.6 2.8 -0.2 2.9 -0.3

Nonroad (tpd) 13.2 10.8 2.4 6.8 6.4

Mobile (tpd) 42.1 33.18 8.92 18.57 23.53

Total (tpd) 61.79 49.98 11.91 31.87 29.92
9

Table 7. VOCs Emissions and Differences for Years 2004, 2009 & 

2018

Category 2004 2009 2004-2009 2018 2004-2018

Point (tpd) 8.1 5.5 2.6 7.74 0.36

Area (tpd) 24.4 24.2 0.2 27.2 -2.8

Nonroad (tpd) 17.3 15 2.3 11.9 5.4

Mobile (tpd) 16.41 14.29 2.12 8.14 8.27

Total (tpd) 66.21 58.99 7.22 54.98 11.23

C. EPA EVALUATION AND CONCLUSION:

EPA thoroughly evaluated the submittal made by Pennsylvania through PADEP. Our detailed 

review has led us to conclude that the development methodology of the MVEBs is consistent 

with applicable guidance documents intended to guide the development of on-road inventories 

and MVEBs. We also reviewed the MVEBs using the adequacy criteria set forth in 40 CFR 

93.118(e)(4)(i)-(vi), and as documented above we found that the budgets meet all of the 

adequacy criteria. Based on the results of our in depth review of the SIP revision, the area’s 

continued attainment of the 1997 8-Hour Ozone NAAQS and the results of our review of the 

MVEBs using the adequacy criteria in the transportation conformity rule, EPA is proposing to 

approve the SIP revision.