ILLINOIS ENVIRONMENTAL PROTECTION AGENCY

IN THE MATTER OF:

The State Implementation Plan

Submittals for the Chicago

Illinois 8-Hour Ozone Nonattainment Area

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DLC26-09

Responsiveness Summary ofthe Rlinois Environmental

Protection Agency Following a Public Hearing on December 16, 2008

On Decem1?er 16, 200~, the Illinois Environmental Protection Agency ("Illinois EPA")

held a public hearing in Chicago, lllinois, on the Attainment Demonstration for the 1997 Chicago

8-hour ozone nonattainment area (''NAA'') and the associated establishment ofmotor vehicle

emissions budgets. The Illinois EPA proposes to submit these documents to the United States

Environmental Protection Agency (''U.S. EPA") as State Implementation Plan ("SIP") revisions.

The Attainment Demonstration contains the State's plan to meet the requirements ofthe federal

Clean Air Act ("CAA") to achieve the National Ambi~nt Air Quality Standard (''NAAQS'') for

8-hour ozone for the Chicago area. The Chicago NAA includes Cook, DuPage, Kane, Lake,

McHenry, and Will counties, and Aux Sable and Goose Lake Townships in Grundy C,ounty, and

Oswego Township in Kendall County. This designation became effective on June 15,2004.

The SIP revision will establish new motor vehicle budgets for the attaim:nent year, 2009, for the

same area. The hearing satisfies the requirements ofSection_II0(1) ofthe CAA.

The Notice for the public hearing was published by the lllinois EPA in accordance with

40 CFR 51.102, entitled ''Public Hearings," and the lllinQis EPA's ''Procedures for Informational

and Quasi-Legislative Public Hearings" (''Public Hearing Procedures").

On December 16, 2008, the public hearing was held to fulfill the public participation

requirements for SIP revisions. Close ofthe record was January 15, 2009. Following the public

hearing, the Illinois EPA received three comments from the interested public. A summary ofthe .

comments and the·lllinois EPA's responses are as follows:

1) One commenter requested that the Illinois EPA consider updating the vehicle

registration distribution database to a more recent timeframe in establishing motor vehicle

emissions budgets for confonnity purposes.

.' 1 ••

ATTACHMENT 5
Response: The commenter is correct in stating that the proposed motor vehicle emissions

budgets contained in the lllinois EPA's November 15, 2008 draft attainment demonstration and

maintenance plan documents were developed using a 2003 Registration Distribution dataset.

The Regis~ti0!l pistribution data hreaks down the vehicle fleet by m.9del year providing an

annual percentage ofvehicles from one model year old to 25 model years old. Since guidelines

. established by the Federal Highway Administration and the U.S. EPA recommend the use of

planning assumptions that are no more than five years old, the illinois EPA has updated the

motor vehicle emissions budgets in both documents to reflect the most recent Registration

'. Distribution database.

The Dlinois EPA downloaded data representative ofthe year 2008 for the Chicago area from the

dataset acquired from the Dlinois Secretary ofState and used in the Illinois Vehicle Inspection

and Maintenance Program. Comparing the updated 2008 vehicle registration dataset to the 2003

dataset included in the original proposal indicated that the percentage ofvehicles in the region , .

that were between one and five model years old was significantly lower in 2008 than in 2003.

. This would suggest that vehicle owners in the Chicago region'had slowed their purchasing of

new cars and were keeping their current vehicles longer. This lower percentage ofnewer

vehicles impacts the' expected level ofemissions from the vehicle fleet in the region as newer,

cleaner vehicles make up 'a lesser fraction than what was previously projected. The updated

2008 Registration Distribution, de~ribed in the TransportationConformity sections ofboth

documents, was used to replace the 2003 dataset in the MOBILE6 input file and resulted in an

increase in estimated emissions ofvolatile organic compounds (''VOC'') and oxides ofnitrogen

("NOx'') from on-road mobile sources for all future ye~ projected in the attainment

demonstration and maintenance plan documents.

Ofnote, these emissions changes increased the level ofemissions proposed as motor vehicle

emissions budgets for the attainment y~ar, 2009, and the maintenance year, 2020. The motor

vehicle emissions budgets contained in the final attainment demonstration and maintenance plan

documents reflect this change. The increases in estimated emissic:>ns also affect the Reasonable

Further Progress (''RFP'') demonstration and Contingency Measures contained in the attainment

2
demonstration. The updated emissions estimates have been incorporated into the appropriate

RFP and Contingency Measures sections ofthe final attainment demonstration document.

__2) A ~ommenter not~ _that th~ a~ent demoristration document c~ntained

apparently conflicting statements regarding lllinois' NOx Reasonably Available Control

Technology (''RACT'') proposal and requested clarification.

Response: The lllinois EPA agrees that the wording regarding NOx RACT as contained

in the draft attainment demonstration document is unclear. The final document has been revised

to reflect the fact that the modeling performed for the attainment year, 2009, did not include

emission reductions reflective'oflllinois' NOx RACT program since it was recognized that

Dlinois' mlemaking process would not be completed in time to allow industries sufficient time to

implement controls. The 2009 modeling demonstrated that the Chicago nonattainment area

would attain the standards by the attainment deadline without reliance on these emission

reductions. Since it is expected that rulemaking for lllinois' NOx RACT program will be

completed in time for controls on most emission units t~. be installed by 2012, emission

reductions from NOx RACT were included in the modeling for 2012. As stated in the attainment

demonstration, the 2012 modeling demonstrates attainment ofthe monitor in Holland, MI.

3) One commenter urged lllinois to adjust its attainment strategy to allow the

monitor in Holland, MI, to attain the ozone standard by the 2009 attainment deadline, noting the

strong contribution oflllinois emission sources to ozone concentrations in western Michigan.

Response: The lllinois EPA acknowledges the contribution oflllinois emission sources to

ozone levels in western Michigan and haSworked diligently to mitigate lllinois' contribution to

downwind states. lllinois has participated in regional planning efforts through the Lake

Michigan Air Directors Consortium ("LADCO''), the Midwest Regional Planning Organization

("RPO''), and the State Collaborative efforts with other Midwestern and Northeastern states.

lllinois has adopted regulations affecting coal-fired electric generating units ("EGUs") that are

more stringent than the federal Clean Air Interstate Rule ("CAIR''). The lllinois EPA has also

proposed NOx RACT requirements for industrial sources in the Chicago area, and has proposed

requirements on consumer products and architectural, industrial, and maintenance coatings

3
which will reduce precursor emissions statewide sooner than federal requirements. The lllinois

EPA believes that it has pursued all feasible control measures that could be implemented to

address lllinois' contribution to downwind states including western Michigan, and that these

measures are being implemented as expeditiously as possible.

4) One commenter requested that the lllinois EPA provide a schedule for proposing

required rules to address recently revised Control Techniques Guidelines ("CTGs'').

Response: The lllinois EPA recognizes that revised rulesto address Group II and Group

III CTGs issued by U.S. EPA in 2006 and 2007 are overdue. The illinois EPA has prepared draft

rules to address the Group II CTGs and initiated outreach with stakeholders in late 2008.. illinois

EPA expects to conclude the stakeholder process soon and anticipates proposing Group II

revisions to the illinois Pollution Control Board ("IPCB'') in the next feW weeks. Similarly, the

.lllinois EPA has drafted a regulatory proposal to address the Group ill CTGs and will soon

initiate a review by stakeholders prior to filing the proposal with the IPCB. The illinois EPA

~ll seek expedited rulemaking by the IPCB for both proposal~.

5) At hearing, one commenter asked for a clarification in Table C2 in the

Maintenan~e Plan regarding appropriate units (tons per day versus tons per year) represented in

the table.

Response: Table C2 referenced at hearing is actually contained in the attainment

demonstration.document, not in the maintenance plan. The illinois EPA has clarified the table,

as well as the corresponding Table Ct, to include both tons per day ~d tons per year emission

~es for the listed pollutants.

6) At hearing, one commenter.requested more details be provided in the attainment

demonstration regarding Dynegy's consent decree. In particular, the commenter requested that . . the document provide a summary ofthe schedule for installing control equipment at Dynegy's

electric generating stations.

Response: The text in the final attainment demonstration has been updated from the draft

document to include additiona1language regarding the implementation of control measures at

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Dynegy's facilities. According to the consent decree, Dynegywas required to meet specified

emission limits within 30 - 45 days after entry ofthe consent decree. The consent decree was

eIJtered on May 27, 2005, so the implementation ofcontrol measures occurred well before the

attainment year, 2009.

7) At hearing, one commenter questioned the level ofproposed NOx RAeT

emission reductions that are necessary for maintenance purposes, as described in the draft

maintenance plan.

Response: As mentioned in the document, a maintenance plan is to provide for the

continued attainment ofthe 8-hoUr ozone NAAQS for a nonattainment area for a period often

years after U.S. EPA has formally redesignated the area ~o attainment. There are several

required elements ofa maintenance plan, including requirements for the state to' provide a

projection ofthe emission inventory forward to a year at least ten years after redesignation, and a

demonstration that the projected level of emissions is sufficient to maintain the ozone NAAQS.

The lllinois EPA has addressed these requirements by prgviding a projected emissions inventory

for 2020, which is at least ten years after a presumed re~esignation by U.S. EPA in 2009 or 2010.

The requirement to provide a demonstration that the projected level ofemissions is sufficient to .

maintain the ozone NAAQS is met by showing that the projected level ofprecursor emissions in

. 2020 is less than it is in the year attainment was achieved. lllinois EPA's inventory for 2020

includes reductions expected from implementation ofNOx RAeT since it is expected that this

program, in addition to numerous others, will be in place by then. The demonstration does not

rely on emission reduction targets specific to any particular control measure.

5
On behalfofthe Director Douglas Scott and the lllinois EPA staff, we would like to

thank all those who participated at the public hearing and for your comments and questions.

lllinois Environmental Protection Agency

Dated: March 18, 2009

TIlinois Environmental Protection Agency

Division ofLegal Counsel

1021 North Grand Avenue East

Springfield, lllinois 62702

(217) 782-5544

6
·,

Illinois Environmental Regulatory Group

An Affiliate of the illinois Chamber ofCommerce

January 15,2009

Pana Vetterhoffer

Illinois Environmental Protection Agency

1021 North Grand Avenue East

P.O. Box 19276

Springfiel~, IL 62794-9276

3150 Roland Avenue

Springfield, It 62703

217-523-4942 (FAX -4948)

Email: iergstaff@ierg.org

REC·EIVE:D - Division of Legal Counsel

JAN 16 2009

Environment~ Protection

Agency

Subject: Comments, Chicago Ozone Attainment Demonstra~onand Maintenance Plan .

The Dlinois Environmental Regulatory Group ("IERG") submits the following in regard to the

lllinois Environmental Protection Agency's ("Illinois EPA" or "Agency") r~uest for comments

on the State Implementation Plan ("SIP") Submittals for the Chicago, lllinois Ozone

Nonatta~entArea at its Public Hearing held December 16, 2008 in Chicago ("Hearing").

IERG's comments are based on the Agency presentation made at Hearing, on the Draft

Attainment Demonstration for the 1997 B-Hour Ozone National Ambient Air Quality Standard

for the Oricago Nonattainment Area [AQPSTR08-07, dated November IS, 2008] ("Draft"), and

on the Draft Maintenance Plan for the'lllinois Portion of the Chicago Ozone Nonattainment

Area for the 1997 8-Hour Ozone Standard [AQPSTR 08-OB, dated November IS, 2008]

("Maintenance Plan"). .

Given the nature of the Notice of Public Hearing, the posting of the Draft and Maintenance Plan

- both addressing the 1997 8-HourOzone NatioitalAmbient Air Quality Standard for the

Chicago Nonattainment Area - IERG must question ~e rationale for the Agency to have

articulated its intent to move ahead to plan attaiI)ment of the 2008 B-Hour Ozone Standard in

the context of this attainment demonstration (Hearing Transcript, page 55). The 2008 8-hour

standard, currently the subject oJ litigation, is a separate matter to be the subject of future

exploration and dialogue. IERG, therefore, restricts its comments below to attainment of the

19978-hour standard and its maintenance.

IERG fully supports Illinois EPA's request that U.S. EPA re-designate the Chicago area to

attainment of the 1997 8-hour ozone ("current") National Ambient Air Quality Standard

("NAAQS"), based on ambient monitoring data from 2006 through 2008. IERG commends the

Agency in its efforts to improve the region's air quality and to achieve this milestone, which

will protect the health of Chica\o's citizen,s and the quality pf.the environment, while

facilitating the growth and development necessary to supPQrt lllinois' economic future.

IERG understands that existing ("on the books") controls are expected to produce sigrlmcant

improvement in ozone air quality to allow all sites in the Lake Michigan region to meet the

current 8-hour standard by the applicable attainment date, with the exception of the Holland,

Provided by the lllinois Environmental Regulatory Group
. J~nuary 15, 2009

I Comments .

Page2of4

MI monitoring station. (Draft, page 8). That station is projected to attain the 85 ppb level by

2012 with no additional control measures. (Draft, page 9; emphasis added).

IERG further imderstands the following"on the books" emission.reduction measures to account

for the success of the attainment demonstration (Draft, pages 11 through 16):

1. Title IV (Phases I ~d II) (Clean Air Act of1990, as amended)

2. NOx SIP Call (Federal Register: October 27, 1998, vol. 63, no.207 pp. 57355-57538)

(35 II. Adm. Code Part 217) .

3. New Source Performance Standards (NSPS) and National Emission Standards for

Hazardous Air Pollutants (NESHAPS)/Maximum Achievable Control Technology

(MACT) Standards (Clean AirAct 0[1990, as amended)

4. Vex: SolventCategories: Aerosol Coatings, Architectural and Industrial

Maintenance (AIM) Coatings, Consumer Solvents (Federal Register: March 24,

2008,001.73, no.57, pp. 15421-15631) (Federal Register: September 11, 1998, vol.63,

no.176, pp. 48848-48887) (Federal Register: September 11,1998, vol.63, no.176, pp.

48819-48847)

5. Portable Fuel Containers (Federal Register: February 26,2007, vol.n, no.37, pp.

8427-8570)

6. Vehicle Inspection & Maintenance Program (Clean Air Act 0[1990, as amended)

7. Reformulated Gasoline (Clean AirAct 0[1990, as amende.d)

8. Tier 2 Motor Vehicie Emissions Standards and·Gasoline Sulfur Control

Requirements (Federal Register: February 10,2000, vol. 65, no.28, pp. 6697-6870)

9. On-Highway Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel

Sulfur Control Requirements (Federal Register: January 18, 2001, vol. 66, nC?o 12,

.. pp. 5002-5193)

10. Federal Control Programs Incorporated into NONROAD Model (e.g., Nonroad

Diesel Rule), plus Evaporative Large Spark Ignition and Recreational Vehicle

Standards (Federal Register: November 8,2002, vol.67, no.217, pp. 68241"-68447)

11. Tier 4 Nonroad Diesel Engine Standards and Diesel Fuel Sulfur Content

Restrictions (Federal Register: June 29,2004, vol. 69, no. 124, pp. 38957-39273)

. .

12. Marine Compression-Ignition Engine Standards and Locomotive Engine

Standards (Federal Register: April 16, 1998, vol. 63, no. 73, pp. 18977-19084)

(Federal Register: December 29,1999, vol.64, no. 249, pp. 73299-73373)

Provided by the Illinois Environmental Regulatory Group
, january 15, 2009

Conunents

Page30f4

13. Consent Decrees-Dynegy Midwest Generation, Refineries' (ConocoPhillips, CITGO, ExxonMobil, Marathon Ashland), Ethanol Plants (Archer Daniels

Midland).

IERG Members are pleased to have significantly contributed to the successful implementation

of the above strategies. We recognize them as the culmination of the c'onsid.era~le effort

employed by the Agency in the development of workable regulatory solutions that positively

contribute to the quality of the enviro~ent, and their application by the regulated community

at industrial faqIities to improve the region's air quality.

IERG further understands that emissions reductions to be achieved under the Illinois

(Nonattainment Area) NOx RACf requirements currently before, but not yet adopted, by the

Illinois Pollution Control Board (R08-19), which cannot practicably be implemented until 2010,

will not contribute to attainment by the 2009 attainment deadline (Draft, page 17). Nor as IERG

understands, is the pending NOx RACf proposal considered to be "on the books" controls'for

purposes of this attainment demonstration (Hearing Transcript, pages 24 through 25). Rather,

the Agency identifies NOx RACT as'a requirement that is contained in the Oean Air Act, which ,-

it commits, to adopt and submit to U.S. EPA when the Board finishes the rulemaking.(Hearing

Transcript, pages 48 through 49). .

IERG notes ~t the Illinois EPA states tha~ emissions reductions achieved under this NOx

RACf proposal (presuniably R08-19) will help to maintain attainment beginning in 2010, and

will also contn'bute to attainment in Holland, M1 by 2012 (emphasis added, Draft, page 17).

However, IERG finds it necessary to point out that on page 9 of the Draft, the Agency stated .

that the Holland, MI station is projected to attain the 85 ppb level by 2012 with no additional

control measures. IERG must question these apparently conflicting statements, and would ask

the Agency's clarification in this regard.

IERG commends the Illinois EPA for having determined its "on the books" control measures

and continuing reductions in YOM emissions will achieve the 15% RFP target for the Chicago

nonattainment area, and that all control measutes that were reasonably available and would

expedite attainment already have been implemented. (Draft, pages 18 through 21). This speaks

well of Illinois EPA's long-term participation in regional o~one planning and dedication to ,

stakeholder involvement in its processes. Further, given Illinois industry's role in contributing

to the requirement for contingency measures, we are pleased that the Agency has

acknowledged that these measures will help ensure the nonattainment ~ea will continue to

achieve attainment in subsequent years, once the current 8-hour ozone NAAQS is met.

With regard to maintaining the attainment status, IERG notes positively the Agency's statement

that the Section 5.0 Control Mea~ures and Regulations (Maintenance Plan, pages 19 through 23),

particularly those required in past ozone SIP revisions and the more recent control programs

implemented, will continue to provide emissions reductions in fpture years. (Maintenance Plan,

page 19). This speaks to the success of Illinois' regulatory efforts.

Provided by the lllinois Environmental Regulatory Group

"
JimuC\ry 15, 2009

Comments

Page 4 of4

IERG further notes the lllinois EPA'sstatement that it will submit regulations to implement

NOx RACT in the NAA for purposes of what IERG understands to be the current (i.e., 1997) 8-

hour ozone NAAQS (Maintenance Plan, pages 21 through 22). IERG acknowledges that NOx

RACf in the current Chicago nonattainment area is a requirement that must be met under the

Oean-Air Act, and offers nQ._argwn~nt in .~~ regard: However, wha~remains unclear is the

quantity of emissions reductio~ that must achieved under any NOx RACf propOw, given that

the area has achieved attainment absent any emission reductions due to NOx RACf. IERG

further questions the level of proposed NOx RACf emissions reductions n~essary for

maintenance purposes, given the Agency's statement that its contiitgency plan anticipates

emissions reductions from the Section 5 Control Measures and Regulations that Illinois "has

adopted and is continuing to implement ... will be sufficient to mitigate exceedances or

violations of the NAAQS that may occur in the coming years without further regulatory action."

(Maintenance Plan, page ~4, emphasis added).

In addition, IERG understands that the gean Air Act requires RACf rules to be in place for

sources of YOM that are subject to Control Technique Guidelines (".CfGs"). (Draft, page 19,

and Maintenance Plan, page 21). ~G further understands that the lllinois EPA has yet to

propose regulations for some sources for which revised CfGs have been issued by the U.S.

EPA, but that it plans to do so. (Id., and Hearing Transcript, page 48). At the December 16

Hearing, the Agency stated that U~S. EPA Will likely not approve the SIP revisions being

proposed until those regulations are final. (Hearing Transcript, page-48). In light of the fact that

the proposed regulations have yet to be filed wiJh the Illinois Pollution Control Board, IERG

would request that the AgencY explain when it-anticipates these SIP revisions will be presented

tO'the Board for adoption.

Thank you for the opportunity to comment. Again, we applaud the Agency recommendation to

re-designate the Chicago area to attainment of the 1997 8-hour ozone NAAQS, and its

confidence that the attainment designation can be·maintained. Illinois industry appreciates

having been a partner in the effort to improve air quality.

Deirdre K. Himer

Executive Director'

Pr6vided by the Illinois Environmental Regulatory Group
January 13, 2009

Ms. Dana Vetterhoffer

illinois Environmental Protection Agency

Division of Legal Counsel

1021 North Grand Avenue East

Springfield, It 62794-~276

Sum BOO, SeaJs Tower

ChIcago. 1160606

voice 312-454-0400

fax 312-454-0411

www.anap.lllilois.gov

RECEIVED

Divisi~n of Legal Counsel

JAN 1 2009

Environm~ntal Proteetio~

Agency

Subject: Motor Vehicle Emissions Budgets for Proposed 8-Hour Ozone Attainment

Dem~nstrati.onand Maintenance Plan State Implementation Plans

Dear Ms. Vetterhoffer:

. - The Chicago Metropolitan Agency for Planning (CMAP) appreciates this opportunity. to

comment of the proposed motor vehicle emissions budgets inclu4ed in' the 8-. hour ozone

Attamment Demonstration and Maintenance Plan State Implementation Plans (SIPs).

The transportation confoI'IIl!ty regulations require that updated plannii'lg assumptions be used

in ~e development of motor vehicle emissions budgets and transportation conformity

determinations. Guidelines established by the Federal Highway Administration and the United

States Environmental Protection Agency state that planning assumptions should be no older

than five years to be considered current. One of the key planning assumptions used in both

SIPs and conformity determinations is the vehicle registration distribution.

The Transportation Conformity section of the two SIPs states that the registration distribution

used in the development of the proposed motor vehicle emissions budgets was from 2003.

CMAP suggests that the lllinois Environmental Protection Agency consider updating the

vehicle registration distribution database to more recent time frame. The use of an updated

vehicle registration distribution will result in a more accurate representation of the Chicago area

vehicle fleet, more accurate emissions estimates, and more consistency between the -SIPs and ,

CMAP conformity analyses.

Please contact Ross Patronsky' at 312-386-8796, rpatronsky@cmap.illinois.gov, if you have any·

questions,

Sincerely,

~6lP,/~.

Donald P. Kopec

Deputy Executive Director

conf09001
~§',' . . )

", _.-';,ll ".

JENNIFER M. GRANHOLM

GOVERNOR

STATE OF MICIIIGAN

DEPARTMENT OF ENVIRONMENTAL QUALITY

LANSING. DEC:

'STEVEN E. CHESTER

DIRECTOR

January 15, 2009

Ms. Rachel Doctors

Illinois Environmental Protection Agency

p·.a. Box 19276

Springfield, Illinois 62794-9276

Dear Ms. Doctors:

RECEIVED

Division of Legal Counsel

JAN 2C2009 .

Environmental Protection

A~ency

The Michigan Department of Environmental Quality (MDEQ) offers' the following comments

on the Illinois Environmental Protection Agency's (IEPA's) draft attainment demonstratipn

and maintenance plan, dated November 15, 2008, proposed for submittal as State

Implementation Plan revisions.

The MDEQ is heartened to note that air quality in the Lake Michigan air shed has improved

to the degree in which all the Chicago area monitors are attaining the 0.08 parts per million

ozone Nation·al. Ambient-Air Quality Standard. This is a substantial achievement and

reflects well on:the·effo·rts of the 'regional planning process undertaken by the .Lake

Michigan Air bkectors Consortium partners.

. The MDEQ would like to see an adjustment in:fhe:.s·{rategy to provide for earlier emissions

reductions in our upwind neighboring states'that would result in attainment at the Holland,

Michigan monitor. Although the photochemicarmodelingIndicates that this shoreline

monitor location will be·attaining by 2012, the federal Clean Air Act deadline for attainment

in Holland is 2009. Transport studies clearly demonstrate that ozone precursor emissions

'from sources in Illinois are large contrjbutors to ozone levels at shoreline monitors in West

Michigan, and that local· emissions have a negligible impact on ozone levels. For that

reason, the MDEQ urges Illinois to take additional steps to curtail ozone precursor

emissions in the near term. .

The MDEQ congratulates the IEPA for accomplishing the goal of.ozone attainment.

Michigan would like to reach this goal for ~II of our communiti.es as .well.·- .

"1 ::_.: '••

. . . Steven E:. Chester' . .:

'. ..'..Dir.ect6r· .:' '. .•..... ,.. ' ...:.. ' ....;. ,. '.; .' :~':,:, '.

:.,,~ '..: .... ". ::· ..·:-··:·:'!5f7-373~7917: .;... .. . '., .:,'.>';' ~"""_::'. '.

cc:: Mr.. Do'uglas P; Scott, Director, IEPA

. Mr. 'Jim Sygo,' '£?eputy Director, ~D!=Q

Mr. G. Vinson Hellwig, MDEQ· ..

. :.':'~. ..:: "; " .

I •••: ~:: ;.••

CONSTlTVTION HAll- 525 v-'EST ALLEGAN STREET - P.O. BOX 30473 - LANSING. MICHIGA", 48909·7973

www.michlgan.gov - (800) 682·9278
Maintenance Plan for the

Illinois Portion ofthe

Chicago Ozone Nonattainment Area

for the 1997 8-Hour Ozone Standard

AQPSTR 09-04

April 5, 2009

Illinois Environmental Protection Agency

1021 North Grand Avenue East

Springfield, Illinois 62794-9276

______1 ...

ATTACHMENT 6
i

TABLE OF CONTENTS

 Page

LIST OF TABLES . . . . . . . . . iii

LIST OF FIGURES . . . . . . . . . iv

EXECUTIVE SUMMARY . . . . . . . . 5

1.0 INTRODUCTION . . . . . . . . 6

1.1 Regulatory Background . . . . . . 6

1.2 Status of Air Quality . . . . . . . 8

2.0 REDESIGNATION AND MAINTENANCE PLAN REQUIREMENTS 9

3.0 OZONE MONITORING . . . . . . . 11

3.1 Monitored Design Values . . . . . . 11

3.2 Quality Assurance . . . . . . . 13

3.3 Continued Monitoring . . . . . . 13

4.0 EMISSION INVENTORY . . . . . . . 14

4.1 Attainment Year Inventory – 2006 . . . . . 14

4.2 Air Quality Improvements and Emission Controls . . . 15

4.3 Emission Projections . . . . . . . 16

4.4 Demonstration of Maintenance . . . . . 17

4.5 Provisions for Future Updates . . . . . 18

5.0 CONTROL MEASURES AND REGULATIONS . . . 19

5.1 Attainment Demonstration Control Measures . . . 19

5.2 Reasonable Further Progress (RFP) . . . . 20

5.3 Reasonably Available Control Technology (RACT) . . . 20

5.4 Controls to Remain in Effect . . . . . . 21

5.5 Provisions for Permitting New or Modified Emission Sources . 22

5.6 Transportation Conformity . . . . . . 22

6.0 CONTINGENCY MEASURES . . . . . . 24

6.1 Contingency Measures . . . . . . 24

6.2 Commitment to Revise Plan . . . . . . 26

6.3 Public Participation . . . . . . . 26

6.4 Legal Authority to Implement and Enforce . . . . 27

7.0 CONCLUSIONS . . . . . . . . 28
ii

TABLE OF CONTENTS (Continued)

APPENDIX A Summary of Ambient Air Monitoring Data (2006-2008)

APPENDIX B Transportation Conformity
iii

LIST OF TABLES

Page

Table 4.1 2006 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 14

Table 4.2 2002 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 15

Table 4.3 2013 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 16

Table 4.4 2020 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 17

Table 4.5 Comparison of 2006, 2013, and 2020 Emission Estimates

Chicago Nonattainment Area . . . . . . 17

Table 4.6 Estimated NOx Emission Reductions from Utility Boilers 

Resulting from Implementation of Illinois’ Multi-Pollutant Standards. 18

Table 5.1 Proposed Chicago NAA Year 2020 Motor Vehicle Emissions 

Budgets for the 1997 8-Hour Ozone NAAQS. . . . 23

Table 6.1 Contingency Plan for the Chicago 8-Hour Ozone

Nonattainment Area . . . . . . . 25
iv

LIST OF FIGURES

Page

Figure 1.1 Map of the Lake Michigan Ozone Nonattainment Areas . . 7

Figure 3.1 Ozone Monitors in the Lake Michigan Area . . . . 11

Figure 3.2 Comparison of 8-Hour Ozone Design Values for the 

Lake Michigan Region Between 2001-2003 and 2006-2008 . . 12
5

EXECUTIVE SUMMARY

This document describes Illinois’ Maintenance Plan for the Illinois portion of the Chicago 

ozone nonattainment area. A Maintenance Plan is required before the area can be 

redesignated from nonattainment to attainment of the 8-hour ozone National Ambient Air 

Quality Standard (NAAQS) promulgated in 1997. This document also provides technical 

information required to support a redesignation request. Illinois intends to submit such a 

request to the U. S. Environmental Protection Agency (U.S. EPA). The Illinois 

Environmental Protection Agency (Illinois EPA) has prepared this plan in consultation

with the Indiana Department of Environmental Management (IDEM), the Wisconsin 

Department of Natural Resources (WDNR), and the Michigan Department of 

Environmental Quality (MDEQ), the Lake Michigan Air Directors Consortium 

(LADCO), and the U.S. EPA. The IDEM is preparing a similar plan for the Indiana 

portion of the Chicago nonattainment area.

Ozone air quality has dramatically improved in the Lake Michigan region as a result of 

implementation of State and Federal control measures since the designation of the 

Chicago area as nonattainment in 2004. With the exception of Holland, Michigan, the 

entire Lake Michigan region, including the Chicago nonattainment area, has at least three 

years of complete, quality assured ambient air quality monitoring data for 2006-2008 that 

demonstrates compliance with the 1997 8-hour ozone NAAQS. These air quality 

improvements are due to permanent and enforceable emission control measures.

This Maintenance Plan provides for continued attainment of the 1997 8-hour ozone air 

quality standard for the Chicago nonattainment area for a period of ten years after U.S. 

EPA has formally redesignated the area to attainment. The Plan also provides assurances 

that, even if there is a subsequent violation of the air quality standard, measures listed in 

the Plan will prevent any future occurrences through contingency measures that would be 

triggered upon such an occurrence. Finally, the Plan includes on-road motor vehicle 

emissions budgets for use in transportation conformity determinations to assure that any 

increases in emissions from this sector do not jeopardize continued attainment of the 8-

hour ozone standard during the ten-year maintenance period.
6

1.0 INTRODUCTION

This document describes Illinois’ Maintenance Plan for the Illinois portion of the Chicago 

ozone nonattainment area. A maintenance plan is required before the area can be 

redesignated from nonattainment to attainment of the 8-hour ozone National Ambient Air 

Quality Standard (NAAQS) promulgated by the U. S. Environmental Protection Agency 

(U.S. EPA) in 1997. Illinois intends to submit such a request to the U.S. EPA in 

conjunction with this Maintenance Plan. The Illinois EPA has prepared this plan in 

consultation with the Indiana Department of Environmental Management (IDEM), the 

Wisconsin Department of Natural Resources (WDNR), and the Michigan Department of 

Environmental Quality (MDEQ), the Lake Michigan Air Directors Consortium 

(LADCO), and U.S. EPA. The IDEM is preparing a similar plan for the Indiana portion 

of the Chicago nonattainment area. With the exception of Holland, Michigan, the entire 

Lake Michigan region, including the Chicago area, has at least three years of complete, 

quality assured ambient air quality monitoring data for 2006-2008, demonstrating 

attainment with the 1997 8-hour ozone NAAQS.

This document also provides the technical information needed to support a request to 

redesignate the Chicago area to attainment of the 8-hour ozone NAAQS. Section 107 of 

the Clean Air Act (CAA) establishes specific requirements to be met in order for a 

nonattainment area to be considered for redesignation. Before an area can be reclassified 

to attainment, U.S. EPA must make a determination that the area has attained the 8-hour

ozone NAAQS based on at least three complete years of ambient monitoring data. U.S. 

EPA must have approved a State Implementation Plan (SIP) for the area under Section 

110 and Part D of the CAA. The state must demonstrate that the improvement in air 

quality is due to permanent and enforceable reductions in emissions resulting from 

implementation of the SIP and other federal requirements. Finally, the state must submit, 

and U.S. EPA must approve, a maintenance plan under Section 175(A) of the CAA, 

including provisions for contingency measures that will be implemented if future 

violations of the 8-hour ozone NAAQS are measured.

This Maintenance Plan provides for the continued attainment of the 8-hour ozone 

NAAQS for the Chicago nonattainment area (NAA) for a period of ten years after U.S. 

EPA has formally redesignated the area to attainment. The Plan also provides assurances 

that even if a subsequent violation of the ozone NAAQS occurs, provisions in the Plan 

will prevent any future occurrences through contingency measures that would be 

triggered upon such occurrence.

This document addresses the maintenance plan requirements established by the CAA and 

U.S. EPA, and includes additional information to support continued compliance with the 

8-hour ozone NAAQS.

1.1 Regulatory Background

The CAA, as amended in 1990, requires areas that fail to meet the NAAQS for ozone to 

develop SIPs to expeditiously attain and maintain the NAAQS. Historically, exceedances 

of the ozone NAAQS have been monitored in Cook and Lake Counties in Illinois, and in 
7

portions of Wisconsin, Indiana, and Michigan immediately downwind of the Chicago, 

Gary, and Milwaukee metropolitan areas.

The Chicago NAA, which includes Lake and Porter Counties in northwest Indiana, was 

originally designated as nonattainment in 2004 pursuant to the 1997 revisions to the 

ozone NAAQS. Several counties in eastern Wisconsin, and one county in western 

Michigan adjacent to Lake Michigan were also designated as nonattainment of the 8-hour

ozone NAAQS, although these areas are separate from the Chicago NAA. Figure 1.1 

depicts the current NAAs in the Lake Michigan region.

Figure 1.1

Map of the Lake Michigan Ozone Nonattainment Areas

The following is a list of the counties, and portions thereof, contained in the Chicago 8-

hour ozone severe nonattainment area:

Cook County, IL

Lake County, IL

DuPage County, IL

McHenry County, IL
8

Kane County, IL

Will County, IL

Grundy County, IL (Aux Sable and Goose Lake Townships)

Kendall County, IL (Oswego Township)

Lake County, IN

Porter County, IN

As a result of the designation as nonattainment and the accompanying classification as 

moderate, these areas were subject to new requirements, including development of a plan 

demonstrating that the area would meet the federal 8-hour NAAQS for ozone by June 15, 

2010.

Recognizing the need for a regional solution, the States of Illinois, Indiana, Michigan, 

Ohio, and Wisconsin worked cooperatively, under the auspices of the Lake Michigan Air 

Directors Consortium (LADCO), to jointly develop and evaluate an effective regional 

attainment strategy to enable the Lake Michigan region to attain the 8-hour ozone 

NAAQS. The attainment strategy recognizes the importance of both locally generated 

ozone precursor emissions and the need for significant reductions of incoming 

(transported) ozone and ozone precursor emissions (including oxides of nitrogen, or 

NOx) to allow the States to attain the NAAQS. The emission reductions needed to attain 

the 8-hour ozone NAAQS include both State and Federal measures that have reduced 

ozone precursor emissions both locally and regionally. These measures have allowed the 

Chicago nonattainment area to attain the 8-hour ozone standard by the attainment 

deadline established by the U.S. EPA.

1.2 Status of Air Quality

Ozone monitoring data for the most recent three-year period, 2006 through 2008, 

demonstrates that air quality has met the 1997 8-hour ozone NAAQS in the entire Lake 

Michigan region, including the Chicago nonattainment area, with the exception of 

Holland, Michigan. Modeling performed by LADCO shows that Holland, MI will attain 

the 1997 ozone NAAQS by 2012.
9

2.0 REDESIGNATION AND MAINTENANCE PLAN REQUIREMENTS

Sections 107 and 110 of the CAA list a number of requirements that must be met by 

nonattainment areas prior to consideration for redesignation to attainment. One of those 

requirements is the maintenance plan, which describes a state’s plan for maintaining the 

NAAQS for a ten-year period after redesignation to attainment. U.S. EPA has published 

guidance for the preparation of maintenance plans and redesignation requests. This 

guidance is contained in a document entitled ―Procedures for Processing Requests to 

Redesignate Areas to Attainment‖ (September 4, 1992).

Before a redesignation to attainment can be promulgated, U.S. EPA must:

Determine that the NAAQS for ozone, as published in 40 CFR 50.4, has been 

attained. Ozone monitoring data must show that violations of the ambient 

NAAQS are no longer occurring. This showing must rely on three consecutive 

years of data. The ambient air monitoring data must be quality assured in 

accordance with 40 CFR 58.10, recorded in U.S. EPA’s Air Quality System 

(AQS) data base, and is available to the public.

Approve the state’s plan for demonstrating attainment. The attainment plan, 

which is based on air quality modeling, must contain enforceable control 

measures and must be submitted as a revision to the state’s SIP after a public 

hearing.

Determine that the improvement in air quality between the year violations 

occurred and the year that attainment was achieved is based on permanent and 

enforceable emission reductions.

Approve the state’s maintenance plan. The requirements for the maintenance plan 

are discussed below.

Determine that all other requirements applicable to nonattainment areas have been 

met.

A maintenance plan provides for the continued attainment of the 8-hour ozone NAAQS 

for a nonattainment area for a period of ten years after U.S. EPA has formally 

redesignated the area to attainment. The plan also provides assurances that even if a 

subsequent violation of the NAAQS occurs, provisions in the plan will prevent any future 

occurrences through contingency measures that would be triggered upon such occurrence. 

To be approvable, the state is required to have a public hearing on the maintenance plan 

prior to adoption. The maintenance plan must contain the following elements:

A comprehensive emission inventory of the precursors of ozone completed for the 

―attainment year‖;
10

A projection of the emission inventory forward to a year at least ten years after 

redesignation and a demonstration that the projected level of emissions is 

sufficient to maintain the ozone NAAQS;

A commitment that, once redesignated, the state will continue to operate an 

appropriate monitoring network to verify maintenance of the attainment status;

A demonstration of legal authority to implement and enforce all control measures 

contained in the SIP;

Provisions for future updates of the inventory to enable tracking of emission 

levels, including an annual emission statement from major sources;

Motor vehicle emissions budgets for transportation conformity for the ten-year 

maintenance period;

A commitment to submit a revised maintenance plan eight years after 

redesignation;

A commitment to enact and implement additional contingency control measures 

expeditiously in the event that future violations of the NAAQS occur;

A list of potential contingency measures that would be implemented in such an 

event.

Illinois’ Maintenance Plan has been prepared in accordance with the requirements 

specified in U.S. EPA’s guidance document and additional guidance received from U.S. 

EPA staff.

The following sections of this document describe how U.S. EPA’s requirements have 

been met.
11

3.0 OZONE MONITORING

U.S. EPA’s published guidance document, ―Procedures for Processing Requests to 

Redesignate Areas to Attainment‖ (September 4, 1992), details specific requirements 

regarding the collection and use of ambient air monitoring data needed to support a 

redesignation request. Before the Chicago NAA can be redesignated, Illinois must 

demonstrate that the NAAQS for ozone, as published in 40 CFR 50.4, has been attained. 

Ozone monitoring data must show that violations of the NAAQS are no longer occurring 

within the nonattainment area. This showing must rely on three complete, consecutive 

calendar years of quality assured data. Further, the air monitoring data must be quality 

assured in accordance with 40 CFR 58.10, recorded in U.S. EPA’s AQS data base, and 

made available to the public. Finally, Illinois must commit to continue to operate an 

appropriate monitoring network to verify the maintenance of the attainment status, once 

the area has been redesignated.

The following subsections describe how each of these requirements has been addressed.

3.1 Monitored Design Values

Currently there are 55 ozone monitors located in the nonattainment counties in the Lake 

Michigan region; 9 are located in northwestern Indiana, 17 in northeastern Illinois, 13 in 

western Michigan, and 16 in eastern Wisconsin. 

 

Figure 3.1 Ozone Monitors in the Lake Michigan Area
12

To determine whether the NAAQS is being exceeded, the design value must be 

calculated. The current U.S. EPA method for calculating the ozone design value is to

average the 4th highest daily maximum 8-hour value for each year over the 3-year period. 

The calculated 8-hour ozone design values for the monitors in the Lake Michigan region 

for 2006-2008 are included as Appendix A of this report. Figure 3.2 compares the design 

values for the 2001-2003 period for monitoring stations in the Lake Michigan region to 

the corresponding design values from 2006-2008. The data demonstrate that ozone air 

quality has improved dramatically throughout the Lake Michigan region and that the 

NAAQS for ozone has been attained for the 2006-2008 period at all locations except 

Holland, Michigan.

Figure 3.2

Comparison of 8-Hour Ozone Design Values for the Lake Michigan Region

Between 2001-2003 and 2006-2008

 2001-2003 2006-2008 
13

3.2 Quality Assurance

Illinois EPA has quality assured all data shown in Appendix A for all sites located in 

Illinois in accordance with 40 CFR 58.10 and the Illinois EPA ’s Quality Assurance Plan, 

which describes Illinois EPA’s standard operating procedures for operating the ambient 

monitoring network and validating the data. The other states in the Lake Michigan region 

have similar quality assurance plans. Illinois EPA has recorded the data in the U.S. 

EPA’s AQS database, as have the other Lake Michigan states. U.S. EPA’s AQS database 

is available to the public.

3.3 Continued Monitoring

Illinois commits to continue monitoring ozone levels according to a U.S. EPA approved 

monitoring plan, as required to ensure maintenance of the ozone NAAQS. Should 

changes in the location of an ozone monitor become necessary, Illinois EPA will work 

with U.S. EPA to ensure the adequacy of the monitoring network. Illinois EPA will 

continue to quality assure the monitoring data to meet the requirements of 40 CFR 58. 

Illinois EPA will continue to enter all data into AQS on a timely basis in accordance with 

federal guidelines.
14

4.0 EMISSIONS INVENTORY

A redesignation request must contain a demonstration that the improvement in air quality 

between the year that violations occurred and the year that attainment was achieved is 

based on permanent and enforceable emission reductions. As described previously in 

Section 3.0, a three-year monitoring period is used to evaluate whether attainment has 

been achieved. In this Section, the ―attainment year‖ refers to the first year (2006) of the 

three-year period (2006-2008) used to demonstrate attainment. The request should also 

include a projection of the emission inventory to a year at least 10 years following 

redesignation, a demonstration that the projected level of emissions is sufficient to 

maintain the ozone NAAQS, and a commitment to provide future updates of the 

inventory to enable tracking of emission levels during the 10-year maintenance period.

4.1 Attainment Year Inventory, 2006

Illinois EPA has prepared a comprehensive emissions inventory for the Illinois portion of 

the Chicago ozone nonattainment area, including point, area, and on-road and off-road 

mobile sources for precursors of ozone (VOM and NOx) for the attainment year, 2006. 

This inventory is based on Illinois EPA’s SIP submittal entitled, ―Illinois Base Year 

Ozone Inventory for 2002‖, (June 2006). Point source information was compiled from 

2006 annual emission reports submitted to the Illinois EPA by emission sources and the 

U.S. EPA’s Clean Air Markets Division database for electric utilities. Area source 

emissions were ―grown‖ from 2002 activity levels appropriate for each source category. 

Biogenic emissions are not included in these summaries. On-road mobile source 

emissions were calculated using U.S. EPA’s MOBILE6 emissions model with vehicle 

miles traveled (VMT) data provided by the Illinois Department of Transportation (IDOT). 

Off-road mobile source emissions were calculated using U.S. EPA’s NONROAD 

emissions model.

Table 4.1 summarizes the 2006 emissions estimates for the Chicago ozone nonattainment 

area.

Table 4.1

2006 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 61.20 194.03

Area Sources 281.43 35.64

On-Road Mobile Sources 130.03 302.43

Off-Road Mobile Sources 152.90 279.95

Total 625.56 812.05
15

4.2 Air Quality Improvements and Emission Controls

The Chicago area was designated nonattainment in 2004, based on ozone air quality 

monitoring data collected between 2001 and 2003. Since that time, permanent and 

enforceable reductions of ozone precursor emissions have contributed to improvements in 

ozone air quality and to the attainment of the ozone NAAQS. Some of these emission 

reductions were due to the application of tighter federal emission standards on motor

vehicles and fuels, and some due to the requirements of the federal NOx SIP Call. 

Section 5.0 of this report describes these reductions in more detail, along with an 

explanation of their regulatory status. In this subsection, the emission levels from 2006

are compared to emission levels estimated in 2002 when the Chicago area was first 

proposed for a nonattainment designation for the 1997 8-hour ozone standard.

U.S. EPA’s 8-hour ozone Implementation Rule required that states with ozone 

nonattainment areas prepare and submit a 2002 base year anthropogenic inventory of 

sources of ozone precursor emissions. The base year inventory included emissions from 

point, area, on-road mobile and off-road mobile emissions. Illinois EPA prepared and 

submitted this inventory in June 2006. Table 4.2 summarizes 2002 emissions by major 

source category and by pollutant for the Illinois portion of the Chicago nonattainment 

area.

Table 4.2

2002 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 76.62 307.73

Area Sources 273.33 42.93

On-Road Mobile Sources 168.63 408.88

Off-Road Mobile Sources 233.77 326.65

Total 752.35 1086.19

Comparing the 2002 inventory to that for 2006 indicates that total VOM emissions in the 

Chicago area decreased by about 126 tons per day (tpd), due largely to reductions from

on-road and off-road mobile sources. NOx emissions in the Chicago NAA decreased 

significantly, about 274 tpd, during the same time period. These sizeable emission 

reductions in ozone precursor emissions, plus reductions in upwind areas in Illinois and 

other nearby states, resulted in a substantial improvement in ozone air quality in the 

Chicago area, ultimately resulting in attainment of the 1997 8-hour ozone NAAQS.
16

4.3 Emission Projections

A maintenance plan must contain a demonstration that the level of emissions projected

for the ten-year period following redesignation are sufficient to maintain the ozone 

NAAQS. Accordingly, Illinois EPA has projected VOM and NOx emissions for the 

Illinois portion of the Chicago nonattainment area for 2020. Illinois EPA has also 

projected emissions to 2013, to represent a midpoint during the ten-year maintenance 

period. Emissions for these two projection years are compared to emission levels in 2006

to determine if emissions are sufficient to maintain the NAAQS during this period.

Chicago area point source emissions for 2013 and 2020 were estimated using the 2002 

base year inventory and growth factors appropriate for each source category. Area source 

emissions were projected by applying category-specific growth factors to estimates 

contained in the 2002 base year inventory. County population projections for 2013 and 

2020 were used to estimate emissions for categories which rely on a per capita emissions 

factors. Off-road emissions projections were also developed using the 2002 inventory

and growth factors contained in U.S. EPA’s NONROAD model. On-road motor vehicle 

emissions were estimated using U.S. EPA’s MOBILE6 motor vehicle emissions model. 

The figures assume the continued use of reformulated gasoline, the continued phase-in of 

the Tier 2 motor vehicle emissions standards, and operation of an enhanced vehicle 

inspection and maintenance program. Total vehicle miles of travel (VMT) for 2013 and 

2020 were assumed to increase at a rate of 1.27 percent per year from 2002.

Tables 4.3 and 4.4 include the VOM and NOx emissions estimates for the years 2013 and 

2020, respectively, for the Illinois portion of the Chicago nonattainment area.

Table 4.3

2013 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 70.27 155.02

Area Sources 266.33 37.58

On-Road Mobile Sources 94.16 179.14

Off-Road Mobile Sources 122.82 249.28

Total 553.58 621.02
17

Table 4.4

2020 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 81.43 153.12

Area Sources 293.25 39.62

On-Road Mobile Sources 73.68 88.17

Off-Road Mobile Sources 129.15 246.54

Total 577.51 527.45

4.4 Demonstration of Maintenance

Table 4.5 demonstrates that the level of emissions projected for the ten-year period 

following redesignation is sufficient to maintain the ozone NAAQS. As shown in the 

table, both VOM and NOx emissions within the nonattainment area are expected to 

decrease significantly between 2006 and 2020. Projected VOM and NOx emissions for 

the mid-point year, 2013, are also less than the emission levels in 2006. Based on these 

emission trends it is expected that air quality will continue to meet the 8-hour ozone 

NAAQS throughout the maintenance period.

In addition to the overall emission reductions projected to occur within the nonattainment 

area, significant reductions of statewide NOx emissions resulting from implementation of 

Illinois’ multi-pollutant standards affecting electric utilities by 2012, will also help to 

ensure continued attainment of the 8-hour ozone NAAQS. Table 4.6 provides a summary 

of the expected reductions of NOx emissions resulting from implementation of Illinois’ 

multi-pollutant standards.

TABLE 4.5

Comparison of 2006, 2013 and 2020 Emission Estimates 

Chicago Nonattainment Area

(Emissions stated in tons per ozone season weekday)

2006 2013

Difference

(2006 – 2013) 2020

Difference

(2006 – 2020)
18

VOM 625.56 553.58 71.98 577.51 48.05

NOx 812.05 621.02 191.03 527.45 284.60

Table 4.6

Estimated NOx Emission Reductions From Utility Boilers 

Resulting from Implementation of Illinois’ Multi-Pollutant Standards

(Emissions stated in tons per day)

2006 NOx Emissions 256.0

2012 NOx Emissions 130.5

Net reduction 125.5

4.5 Provisions for Future Updates

As required by Section 175A(b) of the CAA, Illinois commits to submit to U.S. EPA, 

eight years after redesignation, a revised version of this Maintenance Plan. The revision 

will contain Illinois’ plan for maintaining the 8-hour ozone NAAQS for ten years beyond 

the first 10-year period after redesignation.
19

5.0 CONTROL MEASURES AND REGULATIONS

This section provides specific information on the control measures implemented in the 

Chicago nonattainment area, including the measures that were part of Illinois’ Attainment 

Demonstration, Reasonable Further Progress (RFP) demonstration, CAA requirements, 

and other state and federal measures. The control measures required in past ozone SIP 

revisions have been fully implemented, and other, more recent control programs will 

continue to provide emission reductions in future years. Illinois EPA commits to keep 

these measures in effect after redesignation, or to provide equivalent emissions levels 

using alternate measures. Illinois’ SIP contains acceptable provisions to provide for 

preconstruction review of new emission sources. After redesignation to attainment, 

Prevention of Significant Deterioration (PSD) requirements will apply to the construction 

of new major sources and to significant modifications of existing sources. Illinois has 

accepted delegation from U.S. EPA of this program. Illinois further commits to continue 

to require that all future transportation plans in the Chicago area conform with the SIP.

5.1 Attainment Demonstration Control Measures

Illinois’ attainment demonstration for the Chicago nonattainment area identifies control 

measures that have been promulgated at either the state or federal level that are sufficient 

to allow the Lake Michigan region, with the exception of Holland, MI, to meet the 1997 

8-hour ozone NAAQS by the required attainment date. The attainment demonstration, 

which was submitted to U.S. EPA after a public hearing and public comment period, is 

described in the Illinois EPA’s document: ―Attainment Demonstration for the 1997 8-

Hour Ozone National Ambient Air Quality for the Chicago Nonattainment Area‖ (Report 

Number AQPSTR 09-03, March 18, 2009). The primary emission reduction measures for

demonstrating attainment of the ozone standard are as follows:

NOx SIP Call 

New Source Performance Standards (NSPS) and National Emission Standards for 

Hazardous Air Pollutants (NESHAPS)/Maximum Achievable Control 

Technology (MACT) Standards 

VOM Solvent Categories: Aerosol Coatings, Architectural and Industrial 

Maintenance (AIM) Coatings, Consumer Solvents 

Enhanced Vehicle Inspection & Maintenance Program 

Reformulated Gasoline 

Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control 

Requirements
20

On-Highway Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel 

Sulfur Control Requirements 

Federal Control Programs Incorporated into NONROAD Model (e.g., Nonroad 

Diesel Rule), plus Evaporative Large Spark Ignition and Recreational Vehicle 

Standards 

Tier 4 Nonroad Diesel Engine Standards and Diesel Fuel Sulfur Content 

Restrictions 

Marine Compression-Ignition Engine Standards and Locomotive Engine 

Standards 

Consent Decrees---Dynegy Midwest Generation, ConocoPhillips, CITGO, ExxonMobil, Marathon Ashland, Archer Daniels Midland 

5.2 Reasonable Further Progress (RFP)

Since the Chicago region is classified as a moderate nonattainment area for the 8-hour 

ozone standard, a 15 percent net reduction in VOM emissions from 2002 levels is 

required by 2008 in order to meet the RFP requirement. The Illinois EPA has not relied 

on NOx substitution to meet its 15 percent RFP reduction, relying solely on VOM 

emission reductions. 

Reductions in VOM emissions are primarily achieved through implementation of the 

control measures listed in Section 5.1.

The RFP demonstration is contained in Illinois EPA’s document: ―Chicago 

Nonattainment Area 8-Hour Ozone Reasonable Further Progress Demonstration‖, (Report

Number AQPSTR 09-05, March 18, 2009). The control measures identified in the RFP 

document, including those listed above, will result in a 15.7 percent reduction in VOM 

emissions from 2002 emissions levels by the year 2008. In addition, continuing 

reductions in 2009 and 2010 are estimated to result in year 2010 VOM emissions at 21.0

percent below 2002 levels. These emission reductions achieve the 15% RFP target for 

the Chicago nonattainment area.

5.3 Reasonably Available Control Technology (RACT)

Pursuant to Sections 172, 182(b) and (f) of the CAA, RACT is required for all existing 

major sources of the applicable criteria pollutant and its precursors (VOM and NOx) 

located in NAAs. U.S. EPA defines RACT as the lowest emission limitation that a 

particular source is capable of meeting by the application of control technology that is 

reasonably available considering technological feasibility and economic reasonableness 

(70 FR 71612; November 29, 2005). The major source threshold for moderate NAAs is 
21

defined as 100 tpy. A source generally consists of several units that emit pollutants. The 

sum of emissions from all units at the source determines if a unit is major and thus 

subject to RACT requirements. 

RACT is not a new requirement under the CAA. Illinois previously addressed RACT 

requirements in the Chicago area in developing attainment plans for the 1-hour ozone 

standard. The RACT requirement for NOx was previously waived under the 1-hour 

ozone standard, and Illinois must adopt new regulations to implement NOx RACT in the 

NAA. However, Illinois has previously adopted RACT requirements for VOM emissions 

in the NAA. (See 35 Ill. Adm. Code Part 219) The Illinois EPA has evaluated the 

previously adopted regulations to determine if the RACT requirement is still being met 

for 8-hour ozone. 

Sections 172, 182(b)(2), and 182(f) of the CAA require implementation of RACT for 

sources that are subject to Control Techniques Guidelines (CTGs) that are promulgated 

by U.S. EPA. 

The U.S. EPA has issued CTGs defining RACT for those categories of sources that emit 

the greatest amounts of VOM emissions. Illinois EPA will soon be proposing regulations 

to implement the revised CTGs issued by the U.S. EPA in 2006. Other than the 2006 

CTGs, Illinois has adopted applicable rules addressing all CTGs published by U.S. EPA 

for which there are existing sources in the Chicago NAA. 

Non-CTG sources are defined as major VOM sources which are not subject to CTGs, but 

for which RACT is required. All major sources of ozone precursors located in the ozone 

NAA that are not subject to individual RACT rules are subject to a generic RACT rule. 

These rules apply to non-CTG sources that have the potential to emit 100 tons or more 

per year of VOM. Thus, Illinois has met the obligation to implement RACT on non-CTG 

VOM sources in the NAA. 

It should be noted that other regulatory requirements also affect VOM emission sources 

within the Chicago ozone NAA. These include Maximum Achievable Control 

Technology (MACT), federal New Source Performance Standards (NSPS), and National 

Emission Standards for Hazardous Air Pollutants (NESHAPS). These programs satisfy 

the RACT requirements for specific source categories because these rules are more 

stringent than RACT. It is concluded from this review that Illinois’ existing VOM RACT 

rules fulfill U.S. EPA’s RACT requirements for VOM sources in the NAA.

As mentioned previously, the RACT requirement for NOx was previously waived under 

the 1-hour ozone NAAQS. With respect to the 8-hour ozone NAAQS, the Illinois 

Pollution Control Board (Illinois PCB) is now considering two regulatory proposals

prepared by the Illinois EPA. The Illinois EPA will submit Illinois’ NOx RACT rules as a 

SIP revision once these requirements have been adopted by the Illinois PCB. It should be 

noted however that the attainment demonstration for the Chicago NAA for the 1997 

ozone NAAQS does not rely on emission reductions from the Illinois EPA’s NOx RACT 

proposal. The reductions resulting from this program, when implemented, will help the 
22

area to maintain the NAAQS in future years.

5.4 Controls to Remain in Effect

Illinois will maintain all of the control measures listed in this Section to ensure 

maintenance of the 8-hour ozone NAAQS. Any revisions to the control measures 

included as part of the Maintenance Plan will be submitted as a SIP revision to U.S. EPA 

for approval, and will be accompanied by a showing that such changes will not interfere 

with maintenance of the NAAQS.

Illinois EPA has the necessary resources to enforce any violations of its rules or permit 

provisions. After redesignation, it intends to continue enforcing all rules that relate to the 

emission of ozone precursors in the Chicago nonattainment area.

5.5 Provisions for Permitting New or Modified Emission Sources

Illinois has longstanding and fully implemented programs for the review of new major 

sources and significant modifications of existing sources. The Prevention of Significant 

Deterioration (PSD) program, which includes requirements for Best Available Control 

Technology (BACT) on major new sources or significant modifications of existing 

sources, will be applicable in the Chicago area once the area has been redesignated to 

attainment. Illinois has been delegated full authority to implement the PSD program by 

U.S. EPA.

5.6 Transportation Conformity

The purpose of this section is to describe and establish the Chicago nonattainment area 

motor vehicle emissions budgets associated with the 8-hour ozone Maintenance Plan SIP.

Average summer weekday motor vehicle emissions budgets are being proposed for the 

final year of the Maintenance Plan, 2020, and for the precursor pollutants VOM and NOx. 

These budgets were developed consistent with the motor vehicle activity assumptions 

and emissions control strategies incorporated into the 8-hour ozone attainment 

demonstration analysis. The budgets reflect an emissions level determined using motor 

vehicle VMT and fleet mix provided by the Chicago Metropolitan Agency for Planning 

(CMAP) and are consistent with the emission levels used in the attainment 

demonstration. 

A motor vehicle emissions budget is that portion of the total allowable emissions 

allocated to highway and transit vehicle use that are defined in the SIP for a certain year. 

The rules governing transportation conformity require certain transportation activities to 

be consistent with motor vehicle emissions budgets contained in control strategy 

implementation plans (40 CFR § 93.118). Section 93.101 of the rule defines a ―control 

strategy [State] implementation plan revision‖ as a ―plan which contains specific 

strategies for controlling the emissions and reducing ambient levels of pollutants in order 

to satisfy CAA requirements of reasonable further progress and attainment.‖ In order to 
23

demonstrate conformity to the motor vehicle emissions budget, emissions from the 

implementation of a transportation plan or a transportation improvement program must be 

less than or equal to the budget level (40 CFR § 93.118(a)).

The motor vehicle emissions budgets established and described herein were developed 

consistent with the methodology and control strategy assumptions used in the 8-hour 

ozone attainment demonstration. The effects of motor vehicle control measures are 

incorporated into the emissions factors produced by the U.S. EPA’s MOBILE6 model. 

These control measures include motor vehicle emissions standards, the operation of a 

vehicle inspection and maintenance (I/M) program, and the required use of reformulated 

gasoline and low sulfur gasoline and diesel fuel.

The budgets also incorporate responses to comments raised during the public comment 

period. These comments concerned the use of an updated vehicle registration distribution 

dataset and the incorporation of a ―safety margin‖ into the year 2020 motor vehicle 

emissions budgets. Discussion of these comments is included in Appendix B of this 

report as well as the Responsiveness Summary prepared by the Illinois EPA subsequent 

to the public hearing and comment period. The motor vehicle emissions budgets, which 

reflect the VMT and control program assumptions and methodology described here, are 

listed in Table 5.1.

Table 5.1

Proposed Chicago NAA Year 2020 Motor Vehicle Emissions Budgets

For the 1997 8-Hour Ozone NAAQS

(tons per ozone season weekday) 

VOM 73.68

NOx 88.17

Complete details on the derivation of the motor vehicle emissions budgets, including 

discussion of the MOBILE6 model inputs and assumptions are included in Appendix B of 

this report.
24

6.0 CONTINGENCY MEASURES

6.1 Contingency Measures

Section 175(A) of the CAA specifies the requirements for maintenance plans, including 

provisions for contingency measures that will be implemented if violations of the 8-hour

ozone NAAQS are measured after redesignation to attainment. A list of potential 

contingency measures that would be implemented in such an event should also be 

included in the Maintenance Plan. Finally, the plan should provide a commitment to 

submit a revised maintenance plan eight years after redesignation to ensure continued 

maintenance for the next ten-year maintenance period.

Contingency measures are intended to provide further emission reductions in the event 

that violations of the 8-hour ozone NAAQS occur after redesignation to attainment. 

While these measures do not need to be fully adopted by the IPCB prior to the occurrence 

of NAAQS violations, the contingency plan should ensure that the contingency measures 

are adopted expeditiously once they are triggered. The Maintenance Plan must identify 

the triggers that determine when contingency measures will be adopted, and the measures 

that the state will consider.

Illinois EPA’s contingency plan for the Chicago NAA is described in Table 6.1. 

Consistent with this plan, Illinois agrees to adopt and implement, as expeditiously as is 

practicable, the necessary corrective actions in the event that violations of the 8-hour

ozone NAAQS occur within the Chicago maintenance area after redesignation to 

attainment. Further, Illinois commits to continue to implement the control measures 

identified in the attainment demonstration and RFP demonstration. As described in 

Section 5.0 of this report, Illinois has adopted and is continuing to implement a range of 

control measures that will greatly reduce precursor emissions, both locally and statewide.

The contingency plan anticipates that these emission reductions will be sufficient to 

mitigate exceedances or violations of the NAAQS that may occur in the coming years 

without further regulatory action. 

The contingency plan provides for different levels of corrective responses should ambient

8-hour ozone levels exceed the NAAQS in any year, if emissions in the NAA increase 

significantly above current attainment levels, or if the NAAQS is violated. A Level I 

response would occur in the event that: 1) the fourth highest 8-hour ozone concentration

at any monitoring site in the Chicago NAA exceeds 84 ppb in any year, or 2) if VOM or 

NOx emissions increase more than 5% above the levels contained in the attainment year 

(2006) emissions inventory. It should be noted that U.S. EPA does not require a state to 

implement contingency measures when occasional exceedances are recorded. IEPA’s 

voluntary commitment to initiate a Level I response is intended to prevent future 

violations of the NAAQS from ever occurring.

Illinois commits to compiling VOM and NOx emissions inventories every three years for 

the duration of the Maintenance Plan to facilitate the emissions trends analysis included 
25

Table 6.1

Contingency Plan for the Chicago 8-Hour Ozone Nonattainment Area

 

Contingency Measure 

Trigger Action to be Taken List of Potential Contingency Measures

Level I Trigger

Fourth highest 

monitored 8-hour 

average ozone 

concentration 

exceeding 84 ppb in 

any year at any 

monitoring station in 

the Chicago 

maintenance area.

The Chicago 

maintenance area’s 

NOx or VOM 

emissions inventories 

increase more than 

5% above the levels 

included in the 2006 

emissions inventories.

IL will evaluate air quality, or 

determine if adverse emissions trends 

are likely to continue. If so, IL will 

determine what and where controls may 

be required, as well as level of 

emissions reductions needed, to avoid a 

violation of the NAAQS. The study 

shall be completed within 9 months. If 

necessary, control measures shall be 

adopted within 18 months of 

determination and implemented as 

expeditiously as practicable, taking into 

consideration the ease of 

implementation and the technical and 

economic feasibility of the selected 

measures. 

Point Source Measures

IL Multi-Pollutant Program for 

electric generating units

Reinstate requirements for Offsets 

and/or LAER

Apply RACT to smaller existing 

sources

Tighten RACT for existing 

sources covered by US EPA 

CTGs.

Expanded geographic coverage of 

NOx RACT 

MACT controls for industrial 

sources

Other measures to be identified

Mobile Source Measures

Tier 2 Vehicle Standards and Low 

Sulfur Fuel

Heavy Duty Diesel Standards and 

Low Sulfur Diesel Fuel

High-enhanced I/M (OBDII)

California Engine Standards

Other measures to be identified

Area Source Measures

Architectural/Industrial 

Maintenance (AIM) Coatings

Commercial and Consumer 

Products

Aerosol coatings

Broader geographic applicability 

of existing measures

Other measures to be identified

Level II Trigger

A violation of the 

NAAQS at any 

monitoring station in 

the Chicago

maintenance area.

IL will conduct a thorough analysis to 

determine appropriate measures to 

address the cause of the violation. 

Analysis shall be completed within 6 

months. Selected measures shall be 

implemented within 18 months of a 

violation.

in the contingency plan under Level I. Illinois will coordinate with LADCO and other 

Lake Michigan states to evaluate the causes of high ozone levels or the emissions trends 

and to determine appropriate control measures needed to assure continued attainment of 

8-hour ozone NAAQS. Under Level I, measures that could be implemented in a short 

time would be selected so as to be in place quickly after the Illinois EPA is aware that 

corrective measures have been triggered. Control measures selected under Level I will be 

adopted in most cases within 18 months after a determination is made, and implemented, 

generally, within 24 months of adoption by the IPCB. 
26

A Level II response would be implemented in the event that a violation of the 8-hour 

ozone NAAQS were to be measured at a monitoring site within the Chicago maintenance 

area. In order to select appropriate corrective measures, Illinois will work with LADCO 

and other Lake Michigan States to conduct a comprehensive study to determine the 

causes of the violation and the control measures necessary to mitigate the problem. The 

analysis will examine the following factors:

the number, location, and severity of the ambient ozone concentrations;

the weather patterns contributing to ozone levels;

potential, contributing emissions sources;

the geographic applicability of possible contingency measures;

emissions trends, including timeliness of implementation of scheduled control 

measures;

current and recently identified control technologies;

air quality contributions from outside the maintenance area.

Contingency measures will be selected from those listed in Table 6.1 or from any other 

measure deemed appropriate and effective at the time the selection is made. This list of 

contingency measures is comprehensive, and it is expected that only a few of these 

measures would be required. The selection between measures will be based upon costeffectiveness, emission reduction potential, economic and social considerations, ease and 

timing of implementation, or other appropriate factors. Implementation of necessary 

controls in response to a Level II trigger will take place as expeditiously as possible, but 

in no event later than 18 months after Illinois makes a determination, based on qualityassured ambient data, that a violation of the NAAQS has occurred.

Adoption of additional control measures is subject to necessary administrative and legal 

processes. Illinois EPA will solicit input from all interested and affected persons in the 

area prior to selecting appropriate control measures. No contingency measure will be 

implemented without providing the opportunity for full public participation. This process 

will include publication of notices, an opportunity for public hearing, and other measures 

required by Illinois law.

6.2 Commitment to Revise Plan

As noted in Section 4.5 above, Illinois commits to review its Maintenance Plan eight 

years after redesignation, as required by Section 175(A) of the CAA. The Maintenance 

Plan revision is intended to ensure continued attainment of the 8-hour ozone NAAQS for 

an additional ten-year period.

6.3 Public Participation

In accordance with Section 110(a)(2) of the CAA, Illinois is required to hold a public 

hearing prior to adoption of this Maintenance Plan and submittal to U.S. EPA. Public 

participation in the SIP process is provided for as follows:
27

Notice of availability of the Maintenance Plan document and the time and date of 

the public hearing was published in the local papers for the Chicago 

nonattainment area on November 15, 2008.

The public hearing to receive comments on the Maintenance Plan was held on

December 16, 2008. 

A 30-day public comment period was also available after the public hearing to 

receive comments on the Maintenance Plan. A summary of the comments 

received and Illinois EPA’s responses thereto is included as part of the submittal 

to U.S. EPA.

6.4 Legal Authority to Implement and Enforce

The Maintenance Plan must contain a demonstration that the State of Illinois has the 

necessary legal authority to implement and enforce the measures relied upon to attain and 

maintain the NAAQS. Illinois has the legal authority to implement and enforce the 

requirements of this SIP submittal pursuant to the Illinois Environmental Protection Act.
28

7.0 CONCLUSIONS

The Chicago nonattainment area has attained the 8-hour ozone NAAQS established in 

1997 and has complied with the applicable provisions of the Clean Air Act required of 

moderate ozone nonattainment areas. Illinois has submitted an attainment demonstration 

that was based on air quality modeling and contains enforceable control measures. 

Illinois has performed an analysis that demonstrates that the Chicago NAA has attained 

the 1997 8-hour ozone NAAQS and believes the air quality improvements are due to 

permanent and enforceable control measures. Supporting documentation is contained 

herein.

Illinois has prepared a Maintenance Plan that meets the requirement of the Clean Air Act. 

This Maintenance Plan provides for the continued attainment of the 1997 8-hour ozone

NAAQS for a period of ten years after U.S. EPA has formally redesignated the area to 

attainment. This Maintenance Plan provides adequate contingency measures for 

potential, additional emission reductions in the event that future violations of the 8-hour

ozone NAAQS are observed in the area. 

Illinois has prepared a comprehensive emission inventory of the precursors of ozone 

completed for the ―attainment‖ year 2006, and has prepared a projection of the emission 

inventory to a year at least 10 years following redesignation. These projections indicate 

that emissions levels in the Chicago nonattainment area will continue to decrease, thereby 

maintaining the ozone NAAQS in future years. Illinois commits to continue to operate an 

appropriate monitoring network to verify the maintenance of the attainment status once 

the area has been redesignated. Illinois EPA has the legal authority to implement and 

enforce all control measures.

Finally, the Maintenance Plan includes on-road motor vehicle emissions budgets for use 

in transportation conformity determinations to assure that any increases in emissions from 

this sector do not jeopardize continued attainment of the 8-hour ozone standard during the 

ten-year maintenance period. This Maintenance Plan has been prepared in accordance 

with the requirements specified in U.S. EPA’s guidance document, and additional 

guidance received from U.S. EPA staff.
29

APPENDIX A

Summary of Ambient Air Monitoring Data 

(2006-2008)
30

Table A.1

2006-2008 8-hour Ozone Design Values 

for Monitors in the Lake Michigan Region

State of Illinois

County AQS Code Site Name Design Value 4th High 2006 4th High 2007 4th High 2008

Cook 170310001 Alsip 76 78 85 66

Cook 170310032 Chicago (SWFP) 74 75 82 67

Cook 170310064 Chicago (U. of Chicago) 70 70 79 63

Cook 170310072 Chicago (Jardine) 67 65 75 63

Cook 170310076 Chicago (ComED) 73 75 80 66

Cook 170311003 Chicago (Taft) 73 77 79 64

Cook 170311601 Lemont 75 70 85 71

Cook 170314002 Cicero 62 60 68 60

Cook 170314007 Des Plaines 66 65 78 57

Cook 170314201 Northbrook 69 68 76 65

Cook 170317002 Evanston 70 72 80 58

DuPage 170436001 Lisle 63 62 72 57

Kane 170890005 Elgin 66 62 75 61

Lake 170971002 Waukegan 71 71 81 63

Lake 170971007 Zion 72 68 80 69

McHenry 171110001 Cary 65 57 74 65

Will 171971011 Braidwood 66 68 71 60

State of Indiana

County AQS Code Site Name Design Value 4th High 2006 4th High 2007 4th High 2008

Elkhart 180390007 Bristol 72 67 82 68

Lake 180890022 Gary 73 73 85 62

Lake 180890030 Whiting 77 81 88 62

Lake 180892008 Hammond 73 75 77 68

La Porte 180910005 Michigan City 69 75 73 59

La Porte 180910010 La Porte 70 69 78 65

Porter 181270026 Valparaiso 70 71 80 61

St. Joseph 181410010 Potato Creek St Park 69 69 75 63

St. Joseph 181410015 South Bend 61 58 67 58

St. Joseph 181411007 Granger 73 70 82 69

 
31

State of Michigan

County AQS Code Site Name Design Value 4th High 2006 4th High 2007 4th High 2008

Allegan 260050003 Holland 86 91 94 73

Benzie 260190003 Frankfort/Benzonia 76 80 82 66

Berrien 260210014 Coloma 78 76 86 73

Cass 260270003 Cassopolis 75 73 83 71

Kalamazoo 260770008 Kalamazoo 73 68 81 70

Kent 260810020 Grand Rapids 77 82 84 66

Kent 260810022 Evans/Oakfield 78 81 85 69

Leelanau 260890001 Peshawbestown 71 73 79 62

Manistee 261010922 Manistee 77 83 83 65

Mason 261050007 Scottville 75 76 83 68

Missaukee 261130001 Houghton Lake 71 73 76 66

Muskegon 261210039 Muskegon 82 90 86 72

Ottawa 261390005 Jenison 79 83 88 67

Schoolcraft 261530001 Seney 75 76 85 64

State of Wisconsin

County AQS Code Site Name Design Value 4th High 2006 4th High 2007 4th High 2008

Brown 550090026 Green Bay 70 66 82 63

Door 550290004 Newport Beach 80 79 92 69

Kenosha 550590019 Chiwaukee 78 79 85 72

Kewaunee 550610002 Kewaunee 75 77 85 65

Manitowoc 550710007 Manitowoc (Two Rivers) 75 78 85 64

Milwaukee 550790010 Milwaukee (16th St.) 63 64 67 60

Milwaukee 550790026 DNR SE Region 68 68 75 63

Milwaukee 550790041 Milwaukee (UWM-North) 72 73 78 65

Milwaukee 550790085 Milwaukee (Bayside) 75 73 83 69

Ozaukee 550890008 Grafton 72 71 82 64

Ozaukee 550890009 Harrington Beach 74 72 84 67

Racine 551010017 Racine 71 71 77 65

Sheboygan 551170006 Sheboygan 82 83 88 75

Walworth 551270005 Lake Geneva 70 72 75 64

Washington 551310009 Slinger 65 66 71 60

Waukesha 551330027 Waukesha 66 67 72 60
32

APPENDIX B

Transportation Conformity
33

TRANSPORTATION CONFORMITY

This section describes the development of the Chicago nonattainment area motor vehicle 

emissions budgets associated with the Maintenance Plan for the 1997 8-hour NAAQS. 

An average summer weekday motor vehicle emissions budget is being proposed for the 

year 2020 for the precursor pollutants VOM and NOx. These budgets were developed 

consistent with the motor vehicle activity assumptions (e.g., fleet mix, registration 

distribution,...) and emissions control strategies incorporated into the 8-hour ozone 

attainment demonstration analysis. 

Background

Section 176(c)(4) of the Clean Air Act Amendments of 1990 requires that transportation 

plans, programs, and projects which are funded or approved under Title 23 USC must be 

determined to conform with State or Federal air implementation plans. A motor vehicle 

emissions budget is that portion of the total allowable emissions allocated to highway and 

transit vehicle use that are defined in the SIP for a certain year. Section 93.101 of the rule 

defines a ―control strategy [State] implementation plan revision‖ as a ―plan which 

contains specific strategies for controlling the emissions and reducing ambient levels of 

pollutants in order to satisfy Clean Air Act (―CAA‖) requirements of reasonable further 

progress and attainment.‖ In order to demonstrate conformity to the motor vehicle 

emissions budget, emissions from the implementation of a transportation plan or a 

transportation improvement program (―TIP‖) must be less than or equal to the budget 

level (40 CFR § 93.118(a)).

Transportation conformity will be based on these submitted on road motor vehicle 

emissions budgets after the U.S. Environmental Protection Agency (―U.S. EPA‖) 

determines that the budgets meet the adequacy criteria of the transportation conformity 

rule under §93.118(e). The motor vehicle emissions budgets in this submittal are 

adequate as each of the six criteria under §93.118(e) is satisfied. These six criteria 

include:

1. 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.

2. Before the control strategy implementation plan or maintenance plan was submitted to 

U.S. EPA, consultation among federal, State, and local agencies occurred; full 

implementation plan documentation was provided to U.S. EPA; and U.S. EPA’s 

stated concerns, if any, were addressed;

3. The motor vehicle emissions budgets(s) is clearly identified and precisely quantified;
34

4. The motor vehicle emissions budget(s), when considered together with all other 

emission sources, is consistent with all applicable requirements for reasonable further 

progress, attainment, or maintenance (whichever is relevant to the given 

implementation plan submission);

5. 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

6. Revisions to previously submitted control strategy implementation 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; and 

reasons for the changes (including the basis for any changes related to emission 

factors or estimates of vehicle miles traveled).

This State Implementation Plan and the associated motor vehicle emissions budgets have 

been developed by the Illinois Environmental Protection Agency (Illinois EPA), the 

designated air quality agency for the State of Illinois. The required public hearing to 

accept public comment on the proposed motor vehicle emissions inventory was held on 

December 16, 2008 in Room 9-031 of the James R. Thompson Center in downtown 

Chicago. Notification of this hearing was printed in the Chicago Sun Times on 

November 15, 2008. Comments on the proposed attainment demonstration and motor 

vehicle emissions budgets were accepted for 30 days after the public hearing. A 

―Responsiveness Summary‖ which addresses the written comments received has been

prepared and is included in the final submission. 

Two comments pertinent to the proposed motor vehicle emissions budgets were received 

after the public hearing. The first comment, from the Chicago Metropolitan Agency for 

Planning (CMAP), pointed out that that the vehicle Registration dataset incorporated into 

the proposed budgets was from the 2003-2004 time frame and recommended that it be 

updated in order to comply with the transportation conformity requirement for the use of 

―updated planning assumptions.‖ An updated vehicle registration distribution dataset, 

representative of the Chicago area’s 2008 vehicle fleet was developed and has been 

incorporated into the motor vehicle emissions budgets estimation. The CMAP also 

requested the inclusion of a ―safety margin‖ within the Maintenance Plan’s motor vehicle 

emissions budgets. As the total emissions for the region were well below the attainment 

year emissions level, an additional 10% of the total of both the 2020 VOM and NOx 

emissions was included. 

In compliance with criterion #2 above, a Tier 2 Conformity Consultation Team meeting 
35

was held on January 30, 2009 to discuss the proposed Maintenance Plan and associated 

motor vehicle emissions budgets. The Consultation Team includes representatives from 

the Federal Highway Administration, Federal Transit Authority, U.S. EPA, Chicago 

Metropolitan Agency for Planning, Illinois Department of Transportation, Regional 

Transportation Authority, and the Illinois EPA. In addition, the development of the 

Maintenance Plan was discussed at length by the LADCO Project Team, which includes a 

representative from the U.S. EPA Region V office. The draft Maintenance Plan was also 

forwarded to the Region V representative for his review and comment.

The motor vehicle emissions budgets established and described herein were developed 

consistent with the methodology and control strategy assumptions used in the 1997 8-

hour ozone attainment demonstration as well as the 8-hour ozone RFP plan . The effects 

of these controls are incorporated into the emissions factors produced by the U.S. EPA’s 

MOBILE6 model. Following is a discussion of the inputs and assumptions incorporated 

into the development of the proposed Maintenance Plan motor vehicle emissions budgets.

Vehicle Miles Traveled

The RFP plan described in attainment demonstration incorporates county-level base year 

2002 average daily vehicle miles traveled (ADVMT) levels from the Illinois Department 

of Transportation (IDOT). The 2002 ADVMT total for the 6-county-3-township Chicago 

NAA was approximately 160.8 million miles. This total was projected to the modeled 

attainment year, 2009, using an area-wide vehicle miles traveled (VMT) growth rate of 

1.27 percent per year, determined through consultation between the Illinois EPA, CMAP, 

and LADCO. This growth rate has also been applied to project year 2020 VMT. Using 

this growth rate, the projected 2020 ADVMT level for the Chicago NAA was 201.8

million miles. To account for ozone season weekday traffic, the average daily VMT 

estimates were multiplied by Chicago area and facility type -specific Average-Daily-toAverage Summer Weekday conversion factors supplied by IDOT. Applying these factors 

resulted in an average summer weekday VMT *(ASWVMT) that is 11.3 percent greater 

than the average daily VMT. Applying this 11.3 percent factor yields a year 2020 

ASWVMT total of 224.6 million. Following is a summary of the information and 

MOBILE6 model assumptions used included in the development of the draft motor 

vehicle emissions budgets.

Year: VMT estimates and motor vehicle emissions factors were developed 

representative of summer 2020

Typical Ozone Season Weekday: The 2002 Chicago NAA ozone emissions inventory, 

which established the baseline for the CAA-required RFP emissions reductions, is based 

on activity on a typical ozone season weekday. The primary parameters affected by this 

choice of temporal time frame are the temperature and the adjustment of VMT to account 

for increased travel during the summer. 

Temperature: U.S. EPA guidance for the use of the MOBILE6 model calls for 

the use of representative summer daily temperatures. For future years, the representative 
36

summer temperatures are the climatological average minimum and maximum 

temperatures at Chicago’s O’Hare Airport for the summer months of June, July, and 

August. Those are 61 o F and 81 o F, respectively.

Absolute Humidity: U.S. EPA guidance calls for the use of the lowest absolute 

humidity on days corresponding to the summer climatological temperatures in the region 

as calculated from local climatological data published by the National Weather Service. 

A climatological average summer weekday absolute humidity value of 97 grains of water 

(vapor) per pound of dry air was calculated for O’Hare Airport.

Motor Vehicle Emission Controls: The primary motor vehicle emission control 

programs that will be in place in the Chicago NAA in 2020 are (1) an OBD-II-based 

vehicle emissions testing program, and the requirement that gasoline sold in the area be 

―reformulated gasoline‖, which is specially formulated to reduce emissions.

Inspection and Maintenance (I/M): The I/M program in effect since 2007 

requires biennial On-Board Diagnostics (OBD) testing on all model year (MY) 

1996 and newer (MY96+) light duty gasoline vehicles, and biennial exhaust idle 

and gas cap testing on MY96+ heavy duty gasoline vehicles including gasolinepowered buses, registered in the I/M area (the ―testable area‖). The program 

includes a 4 year grace period for new vehicles. This post-2007 I/M program was 

established after the Illinois legislature amended the Illinois Vehicle Inspection 

law in 2005 to (a) drop dynamometer testing of vehicles, (b) require an OBDbased program beginning in February 2007, and (c) remove the requirement for 

testing compliant pre-MY-1996 vehicles. (Motorcycles and diesel vehicles are 

not subject to I/M.)

The Chicago testable area is based upon urbanized areas and includes all of Cook, 

DuPage, and Lake Counties, and parts of Kane, McHenry, Will, and Kendall 

Counties. Some of the VMT in the Chicago testable area is generated by vehicles 

that come from outside the testable area and are therefore not required to undergo 

I/M testing. Conversely, some VMT in an area without I/M (such as Grundy 

County’s NAA townships) may be generated by I/M vehicles from a neighboring 

testable area. The VMT estimates used when calculating I/M emission credits for 

a county or township must be adjusted to reflect VMT from vehicles subject to 

I/M only. This is done using I/M coverage factors derived ultimately from 

transportation modeling outputs. (I/M Credits are subtracted from emissions 

calculated assuming no I/M to give Net Emissions with I/M.) The coverage 

factors are 98% for Cook and DuPage Counties (that is, 98% of the gasolinevehicle VMT in the county is from vehicles subject to I/M) , 95% for Lake 

County, 81% for Kendall County’s NAA township, 65% for Will County, 60% for 

Kane County, 50% for McHenry County, and 25% for Grundy County’s NAA 

townships. 
37

Fuels: Reformulated gasoline (RFG) has been required in the Chicago NAA since 

1995. The attainment demonstration and RFP plan both assume all gasoline sold in the 

Chicago NAA since 1995 is ―Northern‖ RFG, and that this will continue through and 

beyond 2008 and 2009. Although a small amount of non-RFG fuel comes into the NAA 

in the fuel tanks of vehicles from outside the area, it is assumed that the use of nonreformulated gasoline fuel in the Chicago area is negligible. 

Gasoline Sulfur: Gasoline sulfur levels were assumed to be 30 parts per million 

(ppm) in 2020 in accordance with the federal Tier 2 gasoline regulations which 

required the 30 ppm level beginning in 2006. 

Diesel Sulfur: Diesel sulfur levels were assumed to be 15 parts per million in 

2020 in accordance with the U.S. EPA’s Highway Diesel Rule which was 

finalized in January 2001. This regulation required the sale of on-road diesel fuel 

with no greater than 15 ppm of sulfur beginning in June 2006.

Speeds: For the Chicago area, the Illinois EPA assumed an area-specific vehicle 

speed distribution that appears in the VMT-by-Speed-Bin external file SVMTCH07.DEF, 

which is described in more detail later in this document. The speed distribution in this 

file is for freeways and arterials only (local roads and ramps have a fixed speed in 

MOBILE6), and was based on transportation model output (modeled speeds on links of 

various classes of roads by modeling period) from CMAP (CATS) for the year 2007 (the 

most recent available). This speed distribution is assumed valid for 2020 as well. 

VMT Mix: The regional VMT mix inputs used for 2020 were based on Chicago-areaspecific 2005 VMT-by-vehicle-type data supplied by IDOT, modified to reflect expected 

changes in the ratio of cars to light trucks. This information is used in the MOBILE 

model to compute the average emission factors for certain combined vehicle classes, and 

the all-vehicle emission rate. 

Registration Distribution: A Chicago-area-specific vehicle registration distribution 

profile based upon 2008 information data was developed by Illinois EPA’s Division of 

Mobile Source Programs from data provided by the Illinois Secretary of State’s 

Department of Motor Vehicles. 

Emissions Computation: Illinois EPA calculates emissions budgets using the following 

formula: 

1. No-I/M County Emissions by vehicle type (VT) and functional class (FC) 

= (County ASWVMT by FC) * (VMT Mix by VT and FC) * No-I/M emission factors 

(EF) by pollutant, VT, and FC) * 1.102 (grams to ton conversion factor). For areas 

without I/M, this is the only calculation.

2. I/M Credits by VT and FC = (County ASWVMT by FC) * (VMT Mix by 
38

VT and FC) * (No-I/M EF – I/M EF [both by pollutant, VT, and FC]) * I/M coverage 

factor * 1.102. This is for areas with I/M only.

3. Net County Emissions by VT and FC = (I/M County Emissions by VT and 

FC) – ( I/M Credits by VT and FC). This is for areas with I/M only.

The Illinois EPA performs these above calculations on a multi-page spreadsheet which 

automatically calculates emissions and I/M credits by county or township for each 

pollutant, VT, and FC, sums them by VT and FC, and aggregates them into area totals. 

Attachment A of this section provides additional details on the MOBILE6 model inputs 

used in the development of the 2020 Chicago NAA motor vehicle emissions budgets.

Motor Vehicle Emissions Budgets

Using the above VMT and control program assumptions and methodology, following are 

the 8-hour ozone motor vehicle emissions budgets for the Chicago area for use in 

determining transportation conformity. 

Proposed Chicago Area Maintenance Plan 

2020 Motor Vehicle Emissions Budgets

(tons per ozone season weekday)

Pollutant Emissions

VOM 73.68

NOx 88.17
39

Transportation Conformity

External MOBILE6.2 Inputs: 

In the examples of external files shown below, the actual command lines are boldfaced; 

the unbolded lines represent comments. The actual text files have no such distinction in 

typefaces. The unbolded lines have been ―commented out‖ and have no effect on the 

MOBILE model. They may therefore be omitted, but it is suggested that they remain in 

the files for documentation, and to make the files easier for the user to read and 

understand. 

The comments and other text in the External Files have been shown in the Courier 

New typeface. Actual command lines—the inputs that MOBILE actually uses—are 

shown in Courier New Bold

In certain cases (especially the VMT-by-Speed-Bin files) the typeface has been reduced in 

size so that the lines would fit within the margins of the page. This makes them easier to 

read. 

Vehicle Inspection and Maintenance (I/M) Program 

The External I/M files giving the inputs used in the MOBILE6 model in this exercise 

were ILLOBDIM.D (for 2002 and through 2006) and IM07ON.D (for 2007 and later 

years). When evaluating I/M credits for 2008, the residual effect of the ILLOBDIM 

program in the summer of ’08 is taken into account by assuming that 75% of the vehicle 

fleet subject to I/M has been tested under the IM07ON program by that time, and that the 

other 25% have been tested under the ILLOBDIM in late 2006 and have not yet come up 

for retesting under IM07ON by summer 2008 (both programs are biennial). By summer 

2009, all vehicles subject to I/M will have been tested under IM07ON, so this question 

does not arise: the I/M emission rate is simply that for the IM07ON program.

The IM07ON.D File, used for the 2020 target year inventory

The external I/M file IM07ON.D is described below. It represents an I/M program with 

four components, chief of which is an OBD (on-board diagnostics) test for vehicles of 

model year (MY) 1996 and newer. The order in which the components appear in the 

external file is not significant, but they must be numbered consecutively. Illinois EPA 

begins IM07ON.D with identifying comments, and adds other comment lines or blank 

lines to make the file easier to read and understand. Programs after the first need 

comparatively few comments because the commands are largely self-descriptive.
40

* ILLINOIS ENHANCED I/M DESCRIPTION 

* Filename: IM07ON.D

* External input file for Illinois' OBD-only I/M program 

* from 2007 on.

* OBD-only applies to light-duty vehicles only; HDVs still get 

* an Idle Test & Gas Cap Check.

* All program start years set to 1986 per U.S. EPA guidance in 

* "Frequently Asked Questions on MOBILE6" from U.S. EPA/OTAQ.

* This represents the NEW I/M program in which only 1996 & 

* newer vehicles are tested with an OBD test; and the OBD test 

* applies only to LDVs. 

* This program came into effect in February 2007.

*-------------------------------------------------

* Program description for post MY'96 LDV OBD I/M 

*=================================================

* FIRST I/M program--"Evaporative]" OBD for MY 1996+ LDVs 

*-------------------------------------------------

I/M PROGRAM : 1 1986 2050 2 T/O EVAP OBD

I/M MODEL YEARS : 1 1996 2050

I/M VEHICLES : 1 22222 11111111 1

I/M STRINGENCY : 1 20.0

I/M COMPLIANCE : 1 95.0

I/M WAIVER RATES : 1 0.5 2.2 '01 data

I/M EXEMPTION AGE : 1 25

I/M GRACE PERIOD : 1 4

In each case, the first number after the colon refers to the I/M program’s 

component number. 

I/M PROGRAM : 1 1986 2050 2 T/O EVAP OBD

Testing began in 1986 and runs into the indefinite future (2050). The program is

a biennial test-only (2 T/O, here and in other program components) program, in 

this case an Evaporative On-Board Diagnostics (OBD) test. The On-Board 

Diagnostic program in a vehicle’s engine computer records information from 

sensors in the engine and fuel system. Indications of malfunctions or out-ofspecification operations of the engine or fuel and evaporative emission control 

systems are stored in the engine computer as ―fault codes‖. An OBD test 

consists of plugging a special scanner into an output jack from vehicle’s engine 

computer. The scanner queries the computer and records any fault codes that 

the computer’s OBD system has saved. OBD tests are quick, dependable, and 

clean, and, if a vehicle fails an OBD test, the fault codes that the scanner 

displays help mechanics diagnose the problem. 
41

I/M MODEL YEARS : 1 1996 2050

This program component covers only vehicles manufactured between model year 

(MY) 1996 (start year) and the indefinite future (MY 2050, the end year). More 

and more vehicles are becoming subject to this test as new vehicles are bought 

and older (pre-MY-1996) ones are scrapped vehicles. 

I/M VEHICLES : 1 22222 11111111 1

Only the five light-duty vehicle types (cars [LDGVs], and light trucks [LDGTs 1, 

2, 3, and 4]) are covered by this program component (22222). Heavy-duty 

gasoline trucks (eight types) and gasoline buses are not covered by this program 

component (11111111 1), but rather by Programs 3 and 4, described below.

I/M STRINGENCY : 1 20.0

Stringency (exhaust inspection failure rate) is 20%. A Stringency entry is necessary for 

an Exhaust test, but not an Evaporative test, so this entry can be omitted or ―commented 

out‖. In this Evap test case, it will be ignored by the model, but is included for 

reference.

I/M COMPLIANCE : 1 95.0

Compliance rate (tested vehicles as percent of all vehicles subject to I/M) is 95%

I/M WAIVER RATES : 1 0.5 2.2 '01 data

The Waiver Rate is the fraction of tested vehicles that get a waiver—i.e., do not 

pass the I/M test but, because repairs cost more than a specified amount, get a 

certificate of compliance. Waiver rate is 0.5% for MY 1980 and earlier vehicles 

(irrelevant now that pre-MY-96 vehicles are not tested), and 2.2% for MY 1981 

and later vehicles. These figures are from VIM’s actual 2001 waiver statistics, 

and have been representative of the last few years.

I/M EXEMPTION AGE : 1 25

Vehicles older than 25 years are not subject to this program. This will not 

happen until at least 2021. The default is 25, and the model does not calculate 

benefits for vehicles older than 25 years, so in essence this command has no 

effect. It could be omitted, but is included for completeness. 

I/M GRACE PERIOD : 1 4

Vehicles less than 4 model years old are exempt from I/M testing. 

Most of the inputs to the second and subsequent program components are the 

same as those for the first program, so the description of the components will be 

abbreviated and summarized as below, rather than after each command line as 

above.

* Second I/M program--"Exhaust" OBD for MY 1996+ LDVs
42

*----------------------------------------------------

I/M PROGRAM : 2 1986 2050 2 T/O OBD I/M

I/M MODEL YEARS : 2 1996 2050

I/M VEHICLES : 2 22222 11111111 1

I/M STRINGENCY : 2 20.0

I/M COMPLIANCE : 2 95.0

I/M WAIVER RATES : 2 0.5 2.2 '01 data

I/M EXEMPTION AGE : 2 25

I/M GRACE PERIOD : 2 4

*

The second program component is a biennial, test-only Exhaust OBD test for 

MY 1996 and later LDGVs and LDGTs. In this OBD test, the scanner queries 

the vehicle’s computer for fault codes concerning exhaust emissions. 

Stringency, Compliance, Waiver Rates, Exemption Age, and Grace Period are 

the same as in the first program. An entry for I/M STRINGENCY (20%) is 

required for an Exhaust I/M program.

*------------------------------------------------------

* Program description for post MY'96 HDV Idle & GC I/M

*======================================================

* Third I/M program--HDV IDLE for MY 1996+ HDVs

*------------------------------------------------

I/M PROGRAM : 3 1986 2050 2 T/O IDLE

I/M MODEL YEARS : 3 1996 2050

I/M VEHICLES : 3 11111 22222222 2

I/M STRINGENCY : 3 20.0

I/M COMPLIANCE : 3 95.0

I/M WAIVER RATES : 3 1.2 1.5 '01 data

I/M EXEMPTION AGE : 3 25

I/M GRACE PERIOD : 3 4

The third program component is a biennial, test-only Idle test for MY 1996 and 

later HDGVs and Gas Buses (22222222 2). Light-duty vehicles are not subject 

to this component (11111), but rather to components 1 and 2. Stringency,

Compliance, Exemption Age, and Grace Period are the same as in component 1, 

but the pre- and post-MY 1981 Waiver Rates (1.2% and 1.5%, respectively), are 

slightly different from those in components 1 and 2. HDGVs are few in 

number, and most of them are commercial vehicles. 

* Fourth I/M program--Gas Cap Check for MY 1996+ HDVs

*----------------------------------------------------

I/M PROGRAM : 4 1986 2050 2 T/O GC

I/M MODEL YEARS : 4 1996 2050
43

I/M VEHICLES : 4 11111 22222222 2

I/M COMPLIANCE : 4 95.0

I/M WAIVER RATES : 4 1.2 1.5 '01 data

I/M EXEMPTION AGE : 4 25

I/M GRACE PERIOD : 4 4

The fourth program component is a biennial, test-only Gas Cap Check for MY 

1996 and later HDVs. Compliance, Waiver Rates, Exemption Age, and Grace 

Period are the same as in the third program. Since a Gas Cap Check is an 

evaporative I/M test, the I/M STRINGENCY command is not necessary and is 

not included here.

Illinois EPA includes further notes and comments in the I/M file to document it 

further, as shown below:

* NOTES

* This is a standard Illinois I/M input, describing the I/M

* program with OBD Only as it is supposed to exist after

* January 2007. It is the file to be used for regular M6

* I/M runs for 2007 and future years. 

*

* This file was originally SB397.D, supplied 24.viij.05.

* Original SB397.D has been slightly revised by

* the addition of comments such as this one. The actual 

* inputs have not been changed. This was done to put the two 

* LDV OBD programs (exhaust and evaporative) together, and the 

* two HDV programs together too. The order of the programs in 

* the I/M file is not significant and has no effect in M6, but 

* the programs must be numbered sequentially.

* DVIM verified that this file as shown is correctly describes the 

* I/M program planned for introduction in January '07.

* ----------------

* COMPARISON WITH ILLOBDIM.D:

* The first three programs in ILLOBDIM.D, covering the idle

* test for MY'68-'81 LDVs, IM240 for '81-'95 LDVs, and gas

* cap check for MY'68-'95 LDVs have been eliminated from 

* IM07ON; and the two HDV programs now refer only to MY'96

* and later. 

There is no ―MYCUTS.D‖ file associated with IM07ON.D, as there was in the previous 

ILLOBDIM.D file. The old ILLOBDIM.D file is not included here.

The Registration Distribution (RD) for a vehicle type is an indication of the fraction of 

the vehicle fleet of that type that is made up of vehicles of a given age.

The following is based on 2008 registration data from the Illinois Secretary of State’s 

office (ISOS). It and its contents are described in detail in the comments to the file. This 

file contains data (commented out so not used) from the 2001 RD file (CHIRD01) for 

historical and reference purposes. As noted above, those data may be deleted. 
44

REG DIST

* CNAA M6 LDV RD = SOSLDV (Light-duty Vehicles--passenger cars) RD from 

* 08VADbyCounty.xls for Chicago omitting '09 counts & '08 = 75% of '07

1 0.0550 0.0733 0.0675 0.0656 0.0649 0.0666 0.0698 0.0665 0.0680 

0.0598

 0.0524 0.0500 0.0415 0.0421 0.0325 0.0263 0.0218 0.0166 0.0134 

0.0103

 0.0074 0.0057 0.0043 0.0033 0.0154

* CNAA M6 LDT1 RD = SOSLDT1 (ISOS "light" or type 1 LD trucks) RD from

* 08VADbyCounty.xls for Chicago omitting '09 counts & '08 = 75% of '07

2 0.0526 0.0702 0.0769 0.0872 0.0796 0.0729 0.0835 0.0670 0.0669 

0.0586

 0.0583 0.0478 0.0385 0.0342 0.0294 0.0219 0.0148 0.0118 0.0076 

0.0065

 0.0051 0.0031 0.0020 0.0012 0.0024

 

* CNAA M6 LDT2 RD = Same as M6 LDT1 RD; see above. 

3 0.0526 0.0702 0.0769 0.0872 0.0796 0.0729 0.0835 0.0670 0.0669 

0.0586

 0.0583 0.0478 0.0385 0.0342 0.0294 0.0219 0.0148 0.0118 0.0076 

0.0065

 0.0051 0.0031 0.0020 0.0012 0.0024

 

* CNAA M6 LDT3 = SOSLDT21 (ISOS "heavy" or type 2 LD trucks) RD from

* 08VADbyCounty.xls for Chicago omitting '09 counts & '08 = 75% of '07

4 0.0457 0.0609 0.0635 0.0720 0.0854 0.0843 0.0729 0.0689 0.0705 

0.0800

 0.0517 0.0472 0.0349 0.0375 0.0294 0.0203 0.0162 0.0095 0.0104 

0.0099

 0.0075 0.0049 0.0041 0.003 0.0094

 

* CNAA M6 LDT4 = same as LDT3 RDs; see above.

5 0.0457 0.0609 0.0635 0.0720 0.0854 0.0843 0.0729 0.0689 0.0705 

0.0800

 0.0517 0.0472 0.0349 0.0375 0.0294 0.0203 0.0162 0.0095 0.0104 

0.0099

 0.0075 0.0049 0.0041 0.003 0.0094

* Above from 2008 Chicago-area data from DVIM (Gebhardt), as modified by 

* OTAQ (16.j.09) from SL's CRD08X09.d file, & renamed CHRD08AA.d. 

*

* Heavy-Duty & MC RDs below are all assumed same as M6 default RD.

* 

* HDV2B (Heavy-duty vehicles 2B--M6 Default RDs)

6 0.0503 0.0916 0.0833 0.0758 0.0690 0.0627 0.0571 0.0519 0.0472 0.0430

 0.0391 0.0356 0.0324 0.0294 0.0268 0.0244 0.0222 0.0202 0.0184 0.0167

 0.0152 0.0138 0.0126 0.0114 0.0499

* HDV3 (Heavy-duty vehicles3, same RD as HDV2B, M6 Default RDs)

7 0.0503 0.0916 0.0833 0.0758 0.0690 0.0627 0.0571 0.0519 0.0472 0.0430

 0.0391 0.0356 0.0324 0.0294 0.0268 0.0244 0.0222 0.0202 0.0184 0.0167

 0.0152 0.0138 0.0126 0.0114 0.0499

* HDV4 (Heavy-duty vehicles 4, M6 default RDs)

8 0.0388 0.0726 0.0679 0.0635 0.0594 0.0556 0.0520 0.0486 0.0455 0.0425

 0.0398 0.0372 0.0348 0.0326 0.0304 0.0285 0.0266 0.0249 0.0233 0.0218

 0.0204 0.0191 0.0178 0.0167 0.0797

* HDV5 (Heavy-duty vehicles 5, same RD as HDV4, M6 Default)
45

9 0.0388 0.0726 0.0679 0.0635 0.0594 0.0556 0.0520 0.0486 0.0455 0.0425

 0.0398 0.0372 0.0348 0.0326 0.0304 0.0285 0.0266 0.0249 0.0233 0.0218

 0.0204 0.0191 0.0178 0.0167 0.0797

* HDV6 (Heavy-duty vehicles 6, same RD as HDV4, M6 Default)

10 0.0388 0.0726 0.0679 0.0635 0.0594 0.0556 0.0520 0.0486 0.0455 0.0425

 0.0398 0.0372 0.0348 0.0326 0.0304 0.0285 0.0266 0.0249 0.0233 0.0218

 0.0204 0.0191 0.0178 0.0167 0.0797

* HDV7 (Heavy-duty vehicles 7, same RD as HDV4, M6 Default)

11 0.0388 0.0726 0.0679 0.0635 0.0594 0.0556 0.0520 0.0486 0.0455 0.0425

 0.0398 0.0372 0.0348 0.0326 0.0304 0.0285 0.0266 0.0249 0.0233 0.0218

 0.0204 0.0191 0.0178 0.0167 0.0797

* HDV8A (Heavy-duty vehicles 8A same RD as HDV4, M6 Default)

12 0.0388 0.0726 0.0679 0.0635 0.0594 0.0556 0.0520 0.0486 0.0455 0.0425

 0.0398 0.0372 0.0348 0.0326 0.0304 0.0285 0.0266 0.0249 0.0233 0.0218

 0.0204 0.0191 0.0178 0.0167 0.0797

* HDV8B (Heavy-duty vehicles 8B,same RD as HDV4, M6 Default)

13 0.0388 0.0726 0.0679 0.0635 0.0594 0.0556 0.0520 0.0486 0.0455 0.0425

 0.0398 0.0372 0.0348 0.0326 0.0304 0.0285 0.0266 0.0249 0.0233 0.0218

 0.0204 0.0191 0.0178 0.0167 0.0797

* HDBS (HDV School buses; this M6 RD default is assumed)

14 0.0393 0.0734 0.0686 0.0641 0.0599 0.0559 0.0522 0.0488 0.0456 0.0426

 0.0398 0.0372 0.0347 0.0324 0.0303 0.0283 0.0264 0.0247 0.0231 0.0216

 0.0201 0.0188 0.0176 0.0165 0.0781

* HDBT (HDV Transit buses; this M6 RD default is assumed)

15 0.0307 0.0614 0.0614 0.0614 0.0614 0.0614 0.0614 0.0614 0.0614 0.0613

 0.0611 0.0607 0.0595 0.0568 0.0511 0.0406 0.0254 0.0121 0.0099 0.0081

 0.0066 0.0054 0.0044 0.0037 0.0114

* MC (Motorcycles; this M6 default RD is assumed)

16 0.1440 0.1680 0.1350 0.1090 0.0880 0.0700 0.0560 0.0450 0.0360 0.0290

 0.0230 0.0970 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

 0.0000 0.0000 0.0000 0.0000 0.0000

This CHRD08AA.d file is derived ultimately from REGDATA.D, the default MOBILE6 

RD file, but more immediately derived from an original CHIRD08.D file calculated using 

2008 registration counts by age for light-duty vehicles (LDVs) supplied to SL by Chuck 

Gebhardt (IEPA/BOA/DMSP) in his spreadsheet VehicleAgeDistributionByCounty.xls

and rendered into RD form in SL's spreadsheet 08VADbyCounty.xls, with counts for 

MY'09 vehicles omitted as non-representative, and counts for MY’08 vehicles set to 75% 

of those for MY’07 vehicles, in accordance with USEPA practice as given in MOBILE6 

training materials available from OTAQ on line. This file was created in January 2009.

This data is ultimately derived from ISOS registration data for LDVs subject to I/M in the 

Chicago-area counties. Since more than 90% of the light-duty gasoline vehicles in the 

Chicago NAA are subject to I/M, we assume the RD for Chicago-area LDVs subject to 

I/M is representative of that for all Chicago-area LDVs.

The ISOS data were counts for what ISOS calls "LDVs", LDT1s", and "LDT2s" by model 

year (MY). Those appear below as SLDV, SLDT1, and SLDT2 to distinguish them from 

M6 vehicle types. 

SLDVs correspond to passenger cars, so SLDVs = M6 LDVs.

SLDT1s correspond to M6 LDT1s and LDT2s. ISOS data do not distinguish 

between the two M6 categories. For this reason, the RDs for M6 LDT1 and LDT2 

are assumed to be the same. 
46

Similarly, SLDT2s correspond to M6 LDT3s and LDT4s, and ISOS data don't 

distinguish between those two M6 categories either. Therefore, the RDs for M6 

LDT3 and LDT4 are also assumed to be the same.

Of course the SLDT1 (LDT12) and SLDT2 (LDT34) RDs are not the same. 

The age distribution fractions have been rounded to 4 decimal places, and where the 

rounded fractions do not add up to 1.0000 exactly, RD fractions for old (age 22 to 24 

years) have at times been modified by +/- 0.0001 so as to make the RDs add up to 1.0000. 

(This is a requirement of the MOBILE6 model.) 

See the default M6 RD file REGDATA.D and especially the M6 Users Guide Section 

2.8.7.1 (p. 63 ff) for more detailed information about RD files. See also the actual 

MOBILE6 source code \SOURCE\BD20.FOR and IEPA’s previous local-area RDs (e.g., 

CHIRD03.D and CHIRD01.D) for further information.

In this RD file, the first number in each distribution is an integer that indicates which of 

the 16 M6 vehicle classes are represented by the RD in question. That number is 

followed by 25 age fractions arranged in two rows of 10 values followed by a third row 

with the last 5 values. (This is similar to the format used in M5b for RDs, and is the same 

format as the default REGDATA.D file.) 

RDs for all vehicle classes are given in this file. This is for completeness even though 

only those vehicle classes whose RDs were changed from the REGDATA defaults need 

to be included in this file. Those RDs that were not changed from default values are so 

noted.

It is assumed that the RDs for diesel vehicles are the same as the RDs for the 

corresponding gasoline vehicles; in particular, LDDV and LDDT RDs are assumed the 

same as LDGV and LDGT RDs. Since the (default) HDV RDs are based more on diesel 

vehicles to start with, and HDGVs are many fewer than HDDVs, especially in the higher 

weight classes, we feel the default HDV RDs represent both HDGV and HDDV 

reasonably well.

Default RDs are assumed for the various HDV classes. Good area-specific HDV age 

distribution data are lacking—the ISOS data covered only light-duty vehicles subject to 

I/M—and besides, much Chicago-area HDV VMT is from vehicles registered outside the 

Chicago area and just passing through. The best choice, then, was to go with the HDV 

defaults. Similarly, accurate local-area registration data for motorcycles are lacking, so 

the default MC RD is used.

External MOBILE6.2 Activity File Inputs: VMT by Facility Type, VMT 

by Hour, VMT by Speed Bin. 
47

The following files were used in the 2002 base year and the 2008 and 2009 future year 

estimates. 

VMT by Facility Type

The M6.2 default file is FVMT.D, provided with the MOBILE6 model. The Chicagoarea-specific VMT-by-facility-type file is FVMTCH07.D, shown below. It based on the 

most recent complete data from CMAP on VMT by hour by vehicle class. This is a very 

long file —about 750 lines—so for the purposes of this Appendix, only the data for 

vehicle types 1, 6, 11, 13, 24 (LDGV, HDGV2b, HDGV7, HDGV13, and MC) are 

shown; the others are omitted. See the second paragraph of the introduction to the file.

VMT BY FACILITY

*

* This is [F:\]AREASPEC\CHNAA\FVMTCH07.DEF, an FVMT file, which was 

* developed from CATS 2007 transportation model output

* as given in his MF13.XLS file as sent to and recalculated by

* SL. 13.xj.02. 

* 

* VMT fractions are listed for 28 vehicle classes for each hour of 

* the day starting at 6AM, as follows 

* Classes 1-5 (LDGV, LDGT1, LDGT2, LDGT3, and LDGT4), and 

* Classes 14, 15, and 28 (LDDV, LDDT12, LDDT34) were all assumed 

* to have the "Light-duty Vehicle" distribution on page "SL VMT 

* by vehicle type reedited" of the MF13 file. 

* Classes 6-10 and 16-20 (HDGV2b-HDGV6 and HDDV2b-HDDV6) were assumed

* to have the "LTRK" (light HDV) distribution on that page.

* Classes 11 & 12 and 21 & 22 (HDGV7 & HDGV8a, and HDDV7 & HDDV8a) were

* assumed to have the "MTRK" (medium HDV) distribution on that page.

* Classes 13 and 23 (HDGV8b and HDDV8b) were assumed to have the 

* "HTRK" (heavy HDV) distribution on that page

* Classes 24 and 25-27 (Motorcycles and the three bus classes [HDGB,

* HDDBT and HDDBS]) were assumed to have the default distribution

* for those types in FVMT.DEF. 

*

* The four values in each line represent the VMT distribution on

* freeway, arterial, local and ramps--in that order--as shown.

*

* See M6UG 2.8.5.1.f., p. 49, or CLASLIST.TXT for further info.

* (The CLASLIST file describes the vehicle classes.)

* 

* Veh Int& Arts& Local

*Class Fwys Colls Rd/St Ramps

*----- ---- ----- ----- -----

* 

 1 0.3341 0.5393 0.1105 0.0161 

 0.2604 0.6106 0.1160 0.0130 

 0.2604 0.6106 0.1160 0.0130 

 0.2669 0.5831 0.1365 0.0135 

 0.2576 0.5823 0.1468 0.0133 

 0.2576 0.5823 0.1468 0.0133 

 0.2576 0.5823 0.1468 0.0133 

 0.2576 0.5823 0.1468 0.0133 

 0.2683 0.5830 0.1354 0.0133 

 0.2683 0.5830 0.1354 0.0133 

 0.2646 0.5911 0.1315 0.0128 
48

 0.2646 0.5911 0.1315 0.0128 

 0.2825 0.5568 0.1468 0.0139 

 0.2825 0.5568 0.1468 0.0139 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

 0.3363 0.5122 0.1358 0.0157 

.

[Data for Vehicle Types 2 through 5 omitted]

.

 6 0.3836 0.5157 0.0827 0.0180

 0.3045 0.5985 0.0822 0.0148

 0.3045 0.5985 0.0822 0.0148

 0.3589 0.5412 0.0829 0.0170

 0.3791 0.5203 0.0826 0.0180

 0.3791 0.5203 0.0826 0.0180

 0.3791 0.5203 0.0826 0.0180

 0.3791 0.5203 0.0826 0.0180

 0.3606 0.5397 0.0827 0.0170

 0.3606 0.5397 0.0827 0.0170

 0.3581 0.5432 0.0816 0.0171

 0.3581 0.5432 0.0816 0.0171

 0.4101 0.4884 0.0815 0.0200

 0.4101 0.4884 0.0815 0.0200

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

 0.4312 0.4663 0.0818 0.0207

.

[Data for Vehicle Types 7 through 11 omitted]

.

 11 0.4158 0.4904 0.0752 0.0186

 0.3337 0.5763 0.0749 0.0151

 0.3337 0.5763 0.0749 0.0151

 0.3905 0.5165 0.0755 0.0175

 0.4111 0.4952 0.0752 0.0185

 0.4111 0.4952 0.0752 0.0185

 0.4111 0.4952 0.0752 0.0185

 0.4111 0.4952 0.0752 0.0185

 0.3928 0.5144 0.0753 0.0175

 0.3928 0.5144 0.0753 0.0175

 0.3896 0.5185 0.0742 0.0177

 0.3896 0.5185 0.0742 0.0177

 0.4423 0.4630 0.0743 0.0204

 0.4423 0.4630 0.0743 0.0204

 0.4619 0.4425 0.0745 0.0211

 0.4619 0.4425 0.0745 0.0211

 0.4619 0.4425 0.0745 0.0211

 0.4619 0.4425 0.0745 0.0211

 0.4619 0.4425 0.0745 0.0211
49

 0.4619 0.4425 0.0745 0.0211

 0.4619 0.4425 0.0745 0.0211

 0.4619 0.4425 0.0745 0.0211

 0.4619 0.4425 0.0745 0.0211

 0.4619 0.4425 0.0745 0.0211

.

[Data for Vehicle Types 7 through 12 omitted]

.

 13 0.6106 0.3299 0.0430 0.0165

 0.5563 0.3937 0.0367 0.0133

 0.5563 0.3937 0.0367 0.0133

 0.6241 0.3235 0.0376 0.0148

 0.6260 0.3178 0.0403 0.0159

 0.6260 0.3178 0.0403 0.0159

 0.6260 0.3178 0.0403 0.0159

 0.6260 0.3178 0.0403 0.0159

 0.6561 0.2957 0.0340 0.0142

 0.6561 0.2957 0.0340 0.0142

 0.6029 0.3414 0.0401 0.0156

 0.6029 0.3414 0.0401 0.0156

 0.5776 0.3523 0.0508 0.0193

 0.5776 0.3523 0.0508 0.0193

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

 0.5737 0.3512 0.0547 0.0204

.

[Data for Vehicle Types 14 through 23 omitted]

.

 24 0.392 0.457 0.117 0.034

 0.344 0.497 0.129 0.030

 0.338 0.497 0.135 0.029

 0.349 0.492 0.129 0.030

 0.346 0.497 0.127 0.030

 0.333 0.509 0.129 0.029

 0.324 0.516 0.132 0.028

 0.334 0.506 0.131 0.029

 0.334 0.506 0.131 0.029

 0.320 0.519 0.134 0.028

 0.330 0.506 0.135 0.029

 0.312 0.521 0.140 0.027

 0.295 0.538 0.141 0.026

 0.310 0.527 0.137 0.027

 0.329 0.510 0.133 0.029

 0.343 0.497 0.131 0.030

 0.381 0.460 0.126 0.033

 0.405 0.437 0.123 0.035

 0.426 0.418 0.118 0.037

 0.443 0.403 0.115 0.039

 0.457 0.394 0.110 0.040

 0.461 0.391 0.107 0.040

 0.453 0.400 0.108 0.039

 0.418 0.434 0.112 0.036

[Data for Vehicle Types 25 through 28 omitted; the file ends after Vehicle Type 28.]
50

VMT by Hour of the Day

The MOBILE6.2 default file is HVMT.D. The most current Chicago-area-specific file is 

HVMTCH7R.SL, shown below, derived from 2007 modeling output from CMAP. 

Again, this file contains ―commented-out‖ data from previous files for comparison 

purposes. 

VMT BY HOUR

* Fraction of all vehicle miles traveled by hour of the day. 

* First hour is 6 a.m. These data are for the Chicago NAA for 

* 2007, derived from CMAP VbyHr07.def file based 

* upon his run iepa07 300_20070830, VMT for 2007.

*

* This file is HVMTCH7R.SL representing SL's estimate of VMT by hour. 

* IEPA estimates are based on CMAP data, but assume VMT in multi-hour 

* modeling periods is distributed as the default is distributed across 

* the hours in question. Calculations made from VbyHr07.def 

* in accordance with USEPA guidance on the subject. See M6 Technical Guidance

* Document (Jan '02) Section 4.3.3 for details.

0.03358 0.07039 0.06240 0.07658 0.05870 0.06327

0.06609 0.06207 0.06693 0.07118 0.07991 0.07507

0.05924 0.04599 0.02160 0.01851 0.01360 0.01010

0.00757 0.00603 0.00568 0.00561 0.00687 0.01304

 

* Here are RP's original fractions from VbyHr07.def 

* 0.033579 0.066392 0.066392 0.076578 0.062532 0.062532

* 0.062532 0.062532 0.069056 0.069056 0.077490 0.077490

* 0.052616 0.052616 0.010861 0.010861 0.010861 0.010861

* 0.010861 0.010861 0.010861 0.010861 0.010861 0.010861

* These following are the default values from HVMT.DEF

* supplied for comparison.

* 0.0569 0.0740 0.0655 0.0555 0.0540 0.0582

* 0.0608 0.0571 0.0598 0.0636 0.0777 0.0730

* 0.0501 0.0389 0.0308 0.0264 0.0194 0.0144

* 0.0108 0.0086 0.0081 0.0080 0.0098 0.0186

*

* Following are SL's original HVMTCH07 fractions based upon DE's '07 model

* runs made in 2002 (for information).

* 0.0443 0.0851 0.0755 0.0577 0.0541 0.0583

* 0.0609 0.0572 0.0659 0.0701 0.0818 0.0769

* 0.0576 0.0447 0.0219 0.0188 0.0138 0.0102

* 0.0077 0.0061 0.0058 0.0057 0.0070 0.0132

All these Hourly-VMT files show similar profiles, with morning and afternoon peaks, a 

noontime dip, and a minimum about 3AM - 4AM, which is to be expected.

VMT by Speed Bin
51

The MOBILE6.2 default file is SVMT.D. The Chicago-area-specific Speed-bin file is 

SVMTCH07.DEF, shown below. It represents 2007 CMAP transportation model output. 

SPEED VMT

 1 1 0.0053 0.0044 0.0088 0.0299 0.0300 0.0484 0.0641 0.0632 0.0709 0.0801 0.0981 0.2160 0.1953 

0.0857

 1 2 0.0135 0.0570 0.0859 0.0790 0.0766 0.0954 0.0681 0.0704 0.0722 0.1018 0.0761 0.1084 0.0524 

0.0432

 1 3 0.0135 0.0570 0.0859 0.0790 0.0766 0.0954 0.0681 0.0704 0.0722 0.1018 0.0761 0.1084 0.0524 

0.0432

 1 4 0.0017 0.0054 0.0027 0.0159 0.0331 0.0451 0.0702 0.0761 0.0892 0.1259 0.1164 0.2390 0.0989 

0.0805

 1 5 0.0017 0.0047 0.0109 0.0329 0.0238 0.0300 0.0439 0.0582 0.0740 0.1160 0.1244 0.2584 0.1237 

0.0975

 1 6 0.0017 0.0047 0.0109 0.0329 0.0238 0.0300 0.0439 0.0582 0.0740 0.1160 0.1244 0.2584 0.1237 

0.0975

 1 7 0.0017 0.0047 0.0109 0.0329 0.0238 0.0300 0.0439 0.0582 0.0740 0.1160 0.1244 0.2584 0.1237 

0.0975

 1 8 0.0017 0.0047 0.0109 0.0329 0.0238 0.0300 0.0439 0.0582 0.0740 0.1160 0.1244 0.2584 0.1237 

0.0975

 1 9 0.0072 0.0093 0.0142 0.0382 0.0420 0.0478 0.0654 0.0898 0.0849 0.1104 0.1195 0.2126 0.0722 

0.0866

 1 10 0.0072 0.0093 0.0142 0.0382 0.0420 0.0478 0.0654 0.0898 0.0849 0.1104 0.1195 0.2126 0.0722 

0.0866

 1 11 0.0081 0.0325 0.0434 0.0683 0.0493 0.0530 0.0780 0.0803 0.0773 0.0953 0.1179 0.1443 0.0875 

0.0648

 1 12 0.0081 0.0325 0.0434 0.0683 0.0493 0.0530 0.0780 0.0803 0.0773 0.0953 0.1179 0.1443 0.0875 

0.0648

 1 13 0.0016 0.0013 0.0059 0.0137 0.0237 0.0247 0.0391 0.0556 0.0479 0.0729 0.0904 0.2202 0.2979 

0.1049

 1 14 0.0016 0.0013 0.0059 0.0137 0.0237 0.0247 0.0391 0.0556 0.0479 0.0729 0.0904 0.2202 0.2979 

0.1049

 1 15 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 16 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 17 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 18 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 19 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 20 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 21 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 22 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 23 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 1 24 0.0011 0.0002 0.0000 0.0000 0.0000 0.0038 0.0101 0.0178 0.0386 0.0660 0.0981 0.1509 0.5215 

0.0919

 2 1 0.0000 0.0004 0.0017 0.0041 0.0160 0.0461 0.1311 0.1952 0.1835 0.2385 0.0665 0.1170 0.0000 

0.0000

 2 2 0.0021 0.0328 0.0517 0.0618 0.0924 0.1181 0.1447 0.1449 0.1170 0.1185 0.0457 0.0704 0.0000 

0.0000

 2 3 0.0021 0.0328 0.0517 0.0618 0.0924 0.1181 0.1447 0.1449 0.1170 0.1185 0.0457 0.0704 0.0000 

0.0000

 2 4 0.0001 0.0007 0.0025 0.0068 0.0232 0.0572 0.1470 0.2077 0.1791 0.2034 0.0682 0.1041 0.0000 

0.0000

 2 5 0.0000 0.0008 0.0029 0.0074 0.0224 0.0565 0.1435 0.1985 0.1862 0.2044 0.0681 0.1093 0.0000 

0.0000

 2 6 0.0000 0.0008 0.0029 0.0074 0.0224 0.0565 0.1435 0.1985 0.1862 0.2044 0.0681 0.1093 0.0000 

0.0000

 2 7 0.0000 0.0008 0.0029 0.0074 0.0224 0.0565 0.1435 0.1985 0.1862 0.2044 0.0681 0.1093 0.0000 

0.0000

 2 8 0.0000 0.0008 0.0029 0.0074 0.0224 0.0565 0.1435 0.1985 0.1862 0.2044 0.0681 0.1093 0.0000 

0.0000

 2 9 0.0002 0.0028 0.0064 0.0149 0.0423 0.0779 0.1620 0.1879 0.1732 0.1734 0.0644 0.0947 0.0000 

0.0000

 2 10 0.0002 0.0028 0.0064 0.0149 0.0423 0.0779 0.1620 0.1879 0.1732 0.1734 0.0644 0.0947 0.0000 

0.0000

 2 11 0.0017 0.0151 0.0292 0.0423 0.0720 0.1030 0.1538 0.1654 0.1429 0.1415 0.0511 0.0821 0.0000 

0.0000

 2 12 0.0017 0.0151 0.0292 0.0423 0.0720 0.1030 0.1538 0.1654 0.1429 0.1415 0.0511 0.0821 0.0000 

0.0000

 2 13 0.0000 0.0003 0.0018 0.0039 0.0140 0.0369 0.1146 0.1939 0.1865 0.2383 0.0751 0.1348 0.0000 
52

0.0000

 2 14 0.0000 0.0003 0.0018 0.0039 0.0140 0.0369 0.1146 0.1939 0.1865 0.2383 0.0751 0.1348 0.0000 

0.0000

 2 15 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 16 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 17 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 18 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 19 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 20 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 21 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 22 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 23 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

 2 24 0.0003 0.0000 0.0002 0.0008 0.0008 0.0042 0.0749 0.1565 0.1661 0.3285 0.0786 0.1890 0.0000 

0.0000

* 

 

* Speed Bins: 

 

* 2.5 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 

45.0 50.0 55.0 60.0 65.0+

*

* Speed bins extend 2.5 mph on either side of the bin name (i.e., the 

30 mph speed bin encompasses speeds from 27.5 to 32.5 mph), except for 

the 2.5 mph bin (0 to 2.5 mph) and the 65+ mph bin (62.5 mph or above) 

 

 

*

* This is SVMTCH07.DEF.

*

* These data come from a spreadsheet page titled "[DE] spdvmt" in the 

Excel file MF13.XLS, supplied to IEPA by CATS, in October '02, being VMT

output from CATS's transportation model aggregated into the 

various speed bins by county and M6 road type for the 8 CATS time 

periods. SL 

* slightly modified and reformatted the page, and verified that DE's 

vmt-by-speed-bin calculations were correct. See also CATS's file 

titled VBYSPD.DEF

* 

* The information in this file strictly speaking represents a speed 

distribution for 2007, but this is assumed (after discussion with 

CATS) reasonably valid throughout the 2000-2020 period. 

* 

* The above data are for the Chicago NAA, and for Freeways and 

Arterials only. 

*

* See M6 User's Guide Sec. 2.8.8.2.c and Appendix B, Table 5: "Average 

Speed Ranges for Speed Bins 

* (SPEED VMT Command)" for further information about this file and its

use. 

*

* The first number in each line is roadway type: 1 = Freeways; 2 = 

Arterials. Locals and Ramps have a fixed speed in M6, and therefore are

not affected by this file. 

* The second number is the hour of the day, hour 1 being [hour 

beginning at] 6 AM, and hour 24 being [hour beginning at] 5 AM the next 

day. 

* The third and subsequent numbers are the fractions of VMT in that 

hour that occur within the specified speed bins. These fractions were 

calculated from DE's file, which gave estimates of VMT assigned to each 
53

of the 8 CATS modeling periods. 

 

*

* Note that, for Freeways, most VMT is in the 45-50-55-60-mph speed 

bins, with lower speeds more common during Peak hours (which is 

reasonable). Much the same holds for Arterials, where most VMT is in 

the 30-35-40-45 mph speed bins (also reasonable). 

 

*

* See also the default VMT-by-speed file SVMT.DEF for more information 

and comments. 

* 

 

* --SL, 25.xj.02 

* Revisions:

* 7.ix.06...Small changes made to text of these comments by SL; 

no changes to numerical data.