Appendix C, Exhibit 3

Emissions Modeli ng Assumptions Used to Develop Motor Vehicl e Emission Budgets for the Atlanta Eight-Hour Ozone 15% R easonable Further Progress Plan and Attainment Demonstration On April 30, 2004, the United States Envir onmental Protection Agency designated 20 counties within the metropolitan Atlanta ar ea as a "marginal" nonattainment under the eight-hour ozone standard. The eight-hour ozone nonattainment area encompasses the previous 13-county one-hour ozone nonattainme nt area plus seven additional "ring" counties: Barrow, Bartow, Carroll, Hall, Newton, Spalding, and Walton. With an attainment deadline of June 15, 2007, marginal 8-hour ozone areas were required to attain the National Ambient Air Quality Standard (NAAQS) by the 2006 ozone season. Because monitoring data from the 2006 ozone season indicated that Atlanta had not attained the NAAQS, the area was reclassifi ed to "moderate"). Regional emissions inventories for the 20-county eight-hour ozone nonattainment area are needed to develop Motor Vehicle Emission Budgets (MVEB) fo r NOx and VOC as part of the State Implementation Plan (SIP) revisions that wi ll demonstrate reasonabl e further progress towards attainment and modeled attainment of th e eight-hour ozone standa rd in Atlanta. In ozone nonattainment areas with air quality classified as "moderate" or worse, the reasonable further progress (RFP) requirement established in Secti on 182(b) of the CAA prescribes emission reductions from the base line totaling 15% within six years of the base year (i.e., by the end of 2008 for the 8-hour ozone NAAQS). MVEB are being established for the year 2 008, the RFP milestone year. Separate MVEB are being established for 2009, the last full ozone season before the June 15, 2010, "maximum attainment date" for a moderate ozone area. Be low is a detailed listing of the procedures and planning assumptions that were used for the regional emissions inventories to support MVEB development. This document was submitted to the Interagency Consultation Group, in accordance with Section 93.105(b) of the Transportation Conformity Rule and Sections 106(g) and 106(h) of Georgia's tr ansportation conformity SIP, all of which require interagency consultation for SIP development, on October 28, 2008.

Section 1: General Meth ods and Assumptions

• Regional emissions inventories completed to establish MVEB fo r Atlanta Eight-Hour Ozone 15% RFP Plan and Attainment Demonstration

• Emissions Modeling Methodology o Eight-Hour Ozone Nonattainment Area:  Existing ARC link-level travel demand and emissions modeling process for 20-county Atlanta ozone nonattainment areaSection 2: Travel Demand Modeling Assumptions

• Calibration Year: 2000

• Project Listing: o As approved in Envision6 2030 RTP a nd 2008-2013 TIP; adopted by the ARC Board September 26, 2007; and received a positive conformity determination from USDOT October 10, 2007 o As approved in 2030 LRTP and 2008-2013 TIP; adopted by GHMPO Board August 14, 2007; and received a positive c onformity determination from USDOT October 10, 2007 o Project coding for network years 2005 and 2010 reviewed by state and local project sponsors in March and Apr il 2007 as part of Envision6 2030 RTP/FY 2008-2013 TIP development  Year 2008 and 2009 networks needed fo r budget inventories derived from 2010 travel model network

• Travel demand model refinements implemen ted as part of model expansion to 20 counties, from the previous 13-county platform: o Mode choice model updated to improve performance of suburban intra-county trips o Attraction share model incorporated into four-step modeling process o New commercial vehicle and truck m odel developed to improve traffic assignment for both passenger vehicles and truck traffic

• Demographic Data: See "Demographic Da ta Used to Develop Motor Vehicle Emissions Budgets for the Atlant a Attainment Demonstrations"

• Speed Data: Free-flow Speed by Ar ea Type and Facility Type Note: Within the ARC travel demand a nd emission modeling process, free flow speeds are adjusted to refl ect the increase in delay a nd travel time on a roadway segment as traffic volumes build and c ongestion levels increase. Link-level congested flow speeds are used to estimate mobile source emissions, consistent with the requirements of Sections 93.122(b)(1)( iv) and 93.122(b)(2) of the Transportation Conformity Rule.

C3-2Free Flow Speed by Area Type and Facility Type Area Type

Facility Type Urban Very High Density Urban High Density Urban Medium Density Urban Low Density Suburban Ex urban Rural Metered Ramps 0 Zone Centroid Connectors 7 11 11 11 11 14 14
1 Interstate / Freeway Free Flow 55 58 58 61 61 63 65 2 Parkway 50 50 55 55 57 60 60 3 HOV Buffer Separated 55 58 58 61 61 63 65 4 HOV Barrier Separated 55 58 58 61 61 63 65
5 High Speed Ramp / CD Road 50 50 55 55 57 60 60 15 6 Medium Speed Ramp 50 50 50 50 50 50 50 10 7 Low Speed Ramp 40 40 40 40 40 40 40 10 8 Loop Ramp 30 30 30 30 30 30 30 10 9 Off Ramp w/ Intersection 25 25 25 25 25 25 25 10 On Ramp w/ Intersection 40 40 40 40 40 40 40 5 11 Expressway 40 42 45 48 52 55 60 12 Principal Arterial - Class I 26 30 33 36 42 46 55 13 Principal Arterial - Class II 24 27 30 34 40 44 48 14 Minor Arterial - Class I 22 25 28 31 38 42 45 15 Minor Arterial - Class II 20 23 26 29 34 38 42 16 HOV - Arterial (all classes) 20 27 30 33 36 39 42 17 Major Collector 18 22 25 28 31 34 38 18 Minor Collector 15 18 21 24 27 30 35
19 Planned Ramps w/ Intersections 30 30 30 30 30 30 30 5 20 Planned Directional Ramps 45 45 45 45 45 45 45 10

• Transit Modeling o Model recalibrated to 2000 transit ridership estimates, provided by transit operators o Reflects results from Transit On Board Survey o Routes updated to reflect current operating plans o Transit mode split is estimated using the mode choice model  Estimates individual modal trips from th e person trip movements developed in the trip distribution model.  Composed of three nested logit models: • Home based work trips, which incl udes home based university trips; • Home based other trips, which include home based other, home based shopping and home based grade school; and • Non-home based trips.  The mode choice models is organized in terms of seven characteristics: • Mathematical structure; • Trip purposes and choice sets; • Limitations on choice sets; • Analysis of transit access; • Treatment of HOV lanes;

C3-3• Stratification by income groups; and • Analysis of alternative transit paths. o Transit Fare Modeling  Fare structure and operating plans su pplied by the local transit operators • Fares remain constant over time, across all network years • Fares reflect current transit operating plans  Transit fare structure uses a fare ma trix on a zone to zone level with a universal fare structure (flat fare) for all bus and rail lines • Changes to the existing fare struct ure and service frequency are coded directly into the model • Current fare values in the model are weighted according to the percentage of riders using a discounted fare pass; changes to these assumptions can be incorporated directly into the model • Peak and off-peak fares are equivalent

Section 3: Emissions Modeling Assumptions

• Emission Factor Model: MOBILE6.2.03

• MOBILE6.2.03 Inputs (13-county portion) o Average hourly temperature, humidity, and average barometric pressure for the 10 highest ozone days during 2000-2002 o Stage II refueling  Started in 1992  Three phase in years  81% efficiency o Anti-tampering program  Started in 1982  Covers model years 1975 – 1995  All LDG vehicle types are covered  Annual program  97% compliance  Catalyst removal only o I/M Program  Exhaust and Evaporative (OBD and gas cap pressure test) for 1996 and newer vehicles • Began in 1982 • Annual inspection required • Computerized test and repair OBD – Exhaust • Computerized test and repair OBD & GC - Evaporative • Applies to all LDG vehicle types • Three year grace period • 3% waiver rate for all vehicles – Exhaust test • 0% waiver rate for all ve hicles – Evaporative test • 97% compliance

C3-4 Exhaust and Evaporative test for 1975 – 1995 vehicles • Began in 1982 • Annual inspection required • Computerized test and repair ASM 2525/5015 Phase-in – Exhaust • Computerized test and re pair GC – Evaporative • Applies to all LDG vehicle types • 3% waiver rate for all vehicles – Exhaust • 0% waiver rate for all vehicles – Evaporative • 97% compliance • 25 year and older model years are exempt o Fuel 1  Low Sulfur, Low RVP Geor gia Gasoline Phase 2 • 100% market share of 10% ethano l-blend gasoline (E10) assumed • volatility waiver for E10 allows 8.0 psi RVP o 2002 regional fleet age distribution  Derived from R.L. Polk & Co. re gistration data for 13-county area  Applied to 15 of the 16 MOBILE6.2.03 composite vehicle classifications - LDV, LDT1, LDT2, LDT3, LDT4, HDV2B, HDV3, HDV4, HDV5, HDV6, HDV7, HDV8A, HDBS, HDBT, MC • Default for HDV8B o Default VMT fractions

• MOBILE6.2.03 Inputs (7-county portion) o Same temperature, humidity, and barometr ic pressure inputs as 13-county area o No Stage II refueling o No anti-tampering program o No I/M program o Fuel  Same as 13-county area o 2002 regional fleet age distribution  Derived from R.L. Polk & Co. re gistration data for 7-county area  Applied to 15 of the 16 MOBILE6.2.03 composite vehicle classifications - LDV, LDT1, LDT2, LDT3, LDT4, HDV2B, HDV3, HDV4, HDV5, HDV6, HDV7, HDV8A, HDBS, HDBT, MC • Default for HDV8B o Default VMT fractions

• VMT adjustment factors o Adjusts link-level VMT produced by trav el model for ozone precursor emissions modeling:

C3-5 1 In 1999, Georgia's two-phase gasoline sulfur control program limited average sulfur in gasoline sold in the 13-county Atlanta area and in 12 surrounding counties to 150 parts per million (ppm). In addition, there is a seasonal (June 1 to September 15) 7.0 pounds per square inch (psi) Reid vapor pressure (RVP) cap on gasoline sold in this Phase 1 area. In 2003, Phase 2 of Geor gia's gasoline rule reduced average sulfur to 30 ppm and added 20 additional counties outside the 20-county ozone nonattainment area to the sulfur and RVP control program. HPMS adjustment in base year of calibration, year 2000, in accordance with Section 93.122(b)(3) of the Trans portation Conformity Rule which recommends that HPMS adjustment fact ors be developed to reconcile travel model estimates of VMT in base year of calibration to HPMS estimates for the same period 2  Summer (seasonal) adjustment to c onvert from average annual VMT to summer-season VMT 3  Factors applied to VMT estimates gene rated by ARC travel demand model for 13-county and 7-county portions of 20-c ounty nonattainment area, separately VMT Adjustment Factors – 13 County Portion Functional Class Name Factor Rural Interstate 0.67 Rural Prin. Arterial 1.02 Rural Min. Arterial 1.16 Rural Major Collector 0.88 Rural Minor Collector 1.07 Rural Local 0.64 Urb. Interstate 1.05 Urb. Other Fwy 2.44 Urb. Prin. Arterial 0.67 Urb. Min. Arterial 1.21 Urbanized Collector 1.21

Urbanized Local 0.95 VMT Adjustment Factors – 7 County Portion Functional Class Name Factor Rural Interstate 0.89 Rural Prin. Arterial 0.99 Rural Min. Arterial 0.98 Rural Major Collector 1.81 Rural Minor Collector 1.81 Rural Local 1.10 Urb. Interstate 0.86 Urb. Other Fwy 0.85 Urb. Prin. Arterial 0.97 Urb. Min. Arterial 0.96 Urbanized Collector 1.80

Urbanized Local 1.06

• Off-Model Calculations o The Senior I/M Exemption emissions de bit calculated for 2002 was considered conservatively high and was also added to the 2008 and 2009 budget year inventories

2 40 CFR Part 93.122(b)(3) 3 Procedures for Emission Inventory Preparation, Volume IV: Mobile Sources , Section 3.4.2.6, EPA420-R92-009, USEPA Office of Air and Radiation, Office of Mobile Sources, 1992.

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