1

Technical Support Document for the

Removal of Stage II Vapor Recovery Requirements in 

Middle Tennessee

I. Background and Purpose

Tennessee Air Pollution Control Regulations (TAPCR) rule 1200-03-18-.24, Gasoline Dispensing 

Facilities, Stage I and Stage II Vapor Recovery regulates the emissions of Volatile Organic Compounds 

(VOCs) from the petroleum product storage and distribution network. This rule was submitted to EPA on 

July 6, 1993 and approved by EPA on February 9, 1995. Revisions to this rule were approved by EPA on 

April 14, 1997, and August 26, 2005. 

TAPCR 1200-03-18-.24 includes requirements for control of VOC emissions from motor vehicle 

refueling in the 5-county Middle Tennessee area (Davidson, Rutherford, Sumner, Williamson, and Wilson 

Counties) using Stage II vapor recovery systems. Stage II systems capture displaced vapors from vehicle 

fuel tanks during refueling and return the vapors to the underground storage tanks at the gasoline 

dispensing facility. The Stage II requirements were promulgated in the late 1980s and were incorporated 

into Tennessee’s State Implementation Plan (SIP) as part of the control strategies for the one-hour ozone 

National Ambient Air Quality Standard (NAAQS)1. Tennessee is proposing to remove the Stage II vapor 

recovery requirements from TAPCR 1200-03-18-.242.

Onboard Refueling Vapor Recovery (ORVR) is an alternative method of controlling the vapor displaced 

during motor vehicle refueling. The displaced vapors are captured before they exit the vehicle fill pipe 

and are stored in activated carbon canisters onboard the vehicle. When the vehicle’s engine is started, the 

vapors are purged from the activated carbon into the engine where they are burned as fuel. EPA adopted 

ORVR requirements in 1994 pursuant to CAA §202(a)(6)3. ORVR has been phased in for new passenger 

vehicles beginning with model year 1998, and since 2001 for light-duty trucks and most heavy-duty 

gasoline-powered vehicles. ORVR equipment has been installed on nearly all (~99%) new gasolinepowered light-duty vehicles, light-duty trucks and heavy-duty vehicles since 20064,5

.

Stage II and ORVR systems each use a vacuum system to draw captured VOC back to the underground 

storage tanks and the motor vehicle, respectively. When both Stage II and ORVR are in use during 

fueling, the two vacuum systems compete against each other6, and the efficiency of both systems is 

 

1 CAA §182(b)(3) requires each State with Moderate ozone nonattainment areas to submit SIP revisions requiring owners or of operators certain 

gasoline dispensing systems to install and operate a system for gasoline vapor recovery of emissions from the fueling of motor vehicles. 

2 Tennessee is also proposing to revise the Stage I vapor recovery requirements in TAPCR 1200-03-18-.24. Changes to Stage I requirements are 

addressed in a separate document.

3 Within 1 year after November 15, 1990, the Administrator shall, after consultation with the Secretary of Transportation regarding the safety of

vehicle-based (“onboard”) systems for the control of vehicle refueling emissions, promulgate standards under this section requiring that new 

light-duty vehicles manufactured beginning in the fourth model year after the model year in which the standards are promulgated and thereafter 

shall be equipped with such systems. The standards required under this paragraph shall apply to a percentage of each manufacturer’s fleet of new 

light-duty vehicles beginning with the fourth model year after the model year in which the standards are promulgated... 

4 Guidance on Removing State II Gasoline Vapor control Programs from State Implementation Plans and Assessing Comparable Measures. 

USEPA. EPA-457/B-142-001. August 7, 2012.

5 Currently, more than 75% of gasoline refueling nationwide occurs with ORVR-equipped vehicles.

6 Essentially, the ORVR and Stage II systems are pulling the gasoline vapors in opposite directions.
2

reduced. Congress recognized that ORVR and Stage II were redundant technologies and provided EPA 

the authority to allow states to remove Stage II from SIPs after EPA finds that ORVR is “in widespread 

use.”7 

On May 9, 2012, the Administrator signed a notice of final rulemaking determining that onboard 

refueling vapor recovery (ORVR) systems are in widespread nationwide use for control of gasoline 

emissions during refueling of vehicles at gasoline dispensing facilities (GDFs)8. EPA’s determination 

allows States to remove Stage II requirements from their SIPs if States demonstrate that use of ORVR

controls in lieu of Stage II will not adversely affect air quality and satisfies all CAA requirements for 

removal of control measures from a SIP. 

In the 5-county Middle Tennessee area, historical fleet data indicates that about 85% of the fleet will be 

equipped with ORVR in 2016. Tennessee’s analysis, performed in accordance with EPA’s guidance, 

demonstrates that continuation of Stage II will become a dis-benefit to the area after 2016, and Stage II 

systems should be decommissioned to minimize emissions from refueling. This approach will maintain 

the overall downward trend in VOC emission as older vehicles leave the fleet.

II. Anti-Backsliding Requirements

Section 110(l) of the Clean Air Act (CAA) prohibits revision of a SIP that would interfere with attainment 

or maintenance of a NAAQS, reasonable further progress toward attainment of a NAAQS, or any other 

applicable requirement of the CAA. Since Stage II controls are part of Tennessee’s SIP, the requirements 

of CAA §110(l) must be satisfied before removing Stage II controls in the Middle Tennessee area.

This Technical Support Document (TSD) serves as the analysis of the emissions impact of eliminating 

Stage II requirements from the 5-county Middle Tennessee area. The TSD demonstrates the removal of 

Stage II controls will not adversely affect the air quality in the Middle Tennessee area and satisfies all

CAA requirements for removal of control measures from a SIP. In fact, this document demonstrates that 

VOC emissions will increase due to the wider use of ORVR if Stage II controls are not decommissioned.

III. Demonstration

A. EPA Guidance

On August 7, 2012, EPA released guidance for States that wish to remove Stage II requirements from 

their SIP titled Guidance on Removing Stage II Gasoline Vapor Control Programs from State 

Implementation Plans and Assessing Comparable Measures9. EPA’s guidance presents the methodology 

and information needed for an emissions analysis related to phasing out an existing Stage II program. To 

comply with CAA §110(l), the guidance recommends computing the incremental emission control from 

Stage II installations as ORVR technology is phased into the motor vehicle fleet. The guidance also 

presents a method to quantify the impact on area-wide VOC emissions inventory from incremental 

emissions that result from the removal of Stage II vapor recovery systems.

 

7 CAA §202(a)(6) states that the requirements of §182(b)(3) for Moderate ozone nonattainment areas shall not apply after promulgation of ORVR 

standards, and the Administrator may revise or waive Stage II requirements for Serious, Severe, or Extreme ozone nonattainment areas after the 

Administrator determines that onboard emissions control systems are in widespread use throughout the motor vehicle fleet.

8

77 FR 28772 

9 Unless specifically noted otherwise, all references herein to EPA guidance reference the August 7, 2012 document.
3

B. Input Parameters for the Equations in EPA’s Guidance Document

The equations in the EPA guidance require area-specific values for the penetration of ORVR in the motor 

vehicle fleet and in-use efficiencies of ORVR and Stage II systems. Other factors include the proportion 

of gasoline dispensed by facilities equipped with Stage II controls, the projected gasoline consumption for 

the area, the time periods of interest, and the uncontrolled displacement refueling emission factor.

The values of the individual parameters for the Middle Tennessee area are:

1. Penetration of ORVR in the Motor Vehicle Fleet, VMTORVR and QORVR

QORVR represents the proportion of annual gallons of highway motor gasoline dispensed to ORVRequipped vehicles. Table A-1 of the EPA guidance (Appendix A) shows nationwide values for the 

percentage of ORVR-equipped vehicles, the percentage of vehicle miles traveled by ORVR-equipped 

vehicles, and the percentage of gasoline dispensed into ORVR-equipped vehicles. As stated in section 

3.3.3 of the EPA guidance, the nationwide values in Table A-1 may be adjusted to obtain area-specific 

values by comparing the area-specific fleet age to the national fleet age.

An area-specific vehicle age and fleet composition was developed for the 5-county Middle Tennessee 

area as follows:

1. The I/M program testing numbers for calendar years 2007-2012 were obtained (Appendix B, 

Table B-1).

2. The composition of the vehicle fleet (by passenger cars, passenger trucks, and light commercial 

vehicles) for Nashville/Davidson County in calendar year 2011 was obtained (Appendix B, Table 

B-2). This was the best fleet composition data available, and it was assumed that this would be 

representative of the 5-county fleet composition over the time period of the calculations.

3. The percentages of each vehicle category required to undergo I/M testing were estimated 

(Appendix B, Table B-3). Past analysis of Davidson County’s I/M program, which requires 

testing of all gasoline-powered cars and trucks up to 10,500 lb GVWR, has shown these 

percentages to be reasonable.

4. The 1994 ORVR phase-in rule10 set minimum percentages of new vehicles to be equipped with 

ORVR between 1998 and 2006 (Appendix B, Table B-4). For this analysis, “light duty trucks” 

were assumed to be equivalent to passenger trucks and “medium duty trucks” were assumed to be

equivalent to light commercial trucks.

5. The data above were used to calculate the total fleet population and the fraction of vehicles 

equipped with ORVR. The total number of vehicles tested by model year (Table B-1) was 

multiplied by the percentages in Table B-2 to get the number of passenger cars, passenger trucks, 

and light commercial trucks in the fleet. These numbers of vehicles were then adjusted by the 

percentages undergoing I/M testing from Table B-3 to get estimates of the total vehicle 

populations by model year (Appendix B, Tables B-5, B-6, and B-7). 

 

10 59 FR 16262, April 6, 1994
4

6. Finally, using the ORVR phase-in percentages from Table B-4, the total population of ORVRequipped vehicles and the ORVR percentage of the gasoline-powered fleet for calendar years 

2007-2012 were calculated (Appendix B, Table B-8).

Table B-8 shows that the calculated ORVR percentages for the 5-county Middle Tennessee area are very 

close to the values from the EPA guidance. These calculated percentages were used for calendar years 

2007-2012. A regression equation was developed using the 2007-2012 values, assuming an endpoint of 

92 percent for calendar year 202011, and the regression equation was used to calculate values for 2013-

2019.

2. In-use control efficiency of ORVR, ORVR

ORVR represents the in-use control efficiency of ORVR systems. Section 3.3.3 of the EPA guidance 

recommends using 98% for this control efficiency.

3. In-use control efficiency of Stage II vapor recovery systems, iuSII

iuSII represents the in-use control efficiency of Stage II vapor recovery systems. Section 3.3.3 of the EPA 

guidance recommends using a value consistent with field test data and advises against relying on prior 

EPA guidance, new system certification efficiency, or state regulation claims regarding efficiency. Since 

Tennessee’s inspection of Stage II-equipped installations does not include calculation of in-use efficiency, 

other test data must be used to establish the control efficiency.

The EPA guidance states that “typical” values of iuSII are 0.60-0.75. The San Diego Air Pollution Control 

District’s Performance of Balance Vapor Recovery Systems at Gasoline Dispensing Facilities12 studied 

balance vapor recovery systems in four air districts in California and used field tests and engineering 

calculations to estimate the in-use efficiency. This report concluded that “American vacuum assist and 

balance vapor recovery systems averaged about 75% overall, with balance systems having the worst 

performance with efficiencies ranging from 63 to 68%.” The majority of the Stage II vapor recovery 

systems in the 5-county Middle Tennessee area are of the vacuum assist type and have a required testing 

once every 5 years. From discussions with EPA, the lower value was suggested to be used to give an inuse control efficiency of 60% (iuSII = 0.60).

4. Compatibility factor of vacuum-assisted Stage II vapor recovery systems with onboard ORVR 

systems, CFi

This is an increase in UST vent pipe emissions over the normal breathing/emptying loss emissions. The 

compatibility factor may be calculated using either the VMT fraction of ORVR-equipped vehicles or the 

fraction of gasoline dispensed to ORVR-equipped vehicles13:

Equation 1

Equation 2

For completeness, the compatibility factor was calculated using both VMTORVRi and QORVRi (Appendix C).

The calculations produce nearly identical results, with the second approach producing fractionally lower 

 

11 i. e., the same endpoint assumed in Table A-1 of the EPA guidance.

12 Released May 2000.

13 These equations were obtained from pages 11 and 12 of the EPA guidance.
5

values. To be more conservative, the CF used in these calculations was calculated with Equation 2 (using 

QORVRi).

5. Proportion of gasoline throughput covered by Stage II vapor recovery systems, QSII and by Stage 

II vapor recovery systems with vacuum assist, QSIIva

QSII represents the proportion of gasoline throughput dispensed by gasoline distribution facilities with 

Stage II vapor recovery systems, and QSIIva represents the proportion of gasoline throughput dispensed by 

facilities with vacuum-assisted Stage II vapor recovery systems.

The total gasoline throughput for the 5-county Middle Tennessee area was determined from 2011 annual 

throughput reports for Davidson County and from maximum permitted throughputs for the remaining 4 

counties. The fractions of gasoline dispensed from stations equipped with Stage II and with vacuumassisted Stage II were calculated from the throughputs (Appendix D).

6. Projected gasoline consumption for the area and time periods of interest, GCi

GCi represents the gasoline consumption for the 5-county Middle Tennessee area for the time periods 

used in this demonstration. The actual reported/permitted gasoline throughputs were used for 2011, and

gasoline consumption for the remaining years (2010 through 2020) were calculated from the nationwide 

fuel usage 14 and a calculated growth factor (Appendix E, Table E-1). The growth factor was applied to 

the 2011 consumption to calculate the annual fuel usages. To estimates the 5-month ozone season fuel 

consumption, the annual numbers were multiplied by 5/12 (Appendix E, Table E-2).

7. Uncontrolled Displacement Refueling Emission Factor, EF

EF represents the uncontrolled displacement refueling emission factor. This emission factor depends on 

the Reid Vapor Pressure (RVP) of the fuel, the dispensed fuel temperature, and the difference between the 

tank fuel temperature and the dispensed fuel temperature. The 5-county Middle Tennessee area uses 

gasoline which meets the RVP requirements in Appendix F of this document. The RVP for motor vehicle 

gasoline sold in the 5-county Middle Tennessee area is restricted to a maximum of 9.0 psi for the month 

of May and 7.8 psi for the months of June through September. Thus, the average RVP is 8.04 psi for the 

5-month ozone season (May-September).

Td is the dispensed fuel temperature and is presented in Table A-2 of the EPA guidance (Appendix G). 

The mean temperature for the 5-county Middle Tennessee area (Region 2 from EPA’s table) is 81° F 

annually and 86° F for the 5-month ozone season.

T is the difference between the tank fuel temperature and the dispensed fuel temperature and is found in 

Table A-3 of the EPA guidance (Appendix H). For the annual average, the temperature difference is 4.0 

°F. For the 5-month ozone season (May-September), the temperature difference is 7.5 °F. EF is calculated 

from the above parameters using the equation from section 3.5.1 of the EPA guidance (Equation 3):

EF(grams⁄gallon) = e

[-1.2798-0.0049(T)+0.0203(Td)+0.1315(RVP)] Equation 3

Using the above values for RVP, Td, and ΔT, the uncontrolled displacement refueling emission factor, 

EF, for the 5-county Middle Tennessee area is 4.4216 grams of VOC per gallon of fuel dispensed for the 

5-month ozone season.

 

14 AEO 2013, Early Release: http://www.eia.gov/oiaf/aeo/tablebrowser/#release=AEO2013ER&subject=0-AEO2013ER&table=11-

AEO2013ER®ion=0-0&cases=full2012-d020112c,early2013-d102312a
6

C. Section 110(l) Demonstration

This section demonstrates, pursuant to CAA §110(l), that the requested SIP revision will not interfere 

with any applicable requirement concerning attainment and reasonable further progress, or any other 

applicable requirement of the Federal Act.

§110(l) requirements may be met by calculating the incremental emission control15 from Stage II systems 

as ORVR technology is phased in and demonstrating that any incremental emissions from the removal of 

Stage II systems will not interfere with attainment, maintenance, or progress toward attainment of any air 

quality standard. Section 3.3.1 of the EPA guidance recommends calculating the incremental emission 

control for Stage II systems using the following equation:

Incrementi = (QSII)(1-QORVRi)(iuSII)-(QSIIva)(CFi) Equation 4

Where:

- Incrementiis the incremental emission control for Stage II systems for year I;

- QSII is the fraction of gasoline throughput covered by Stage II vapor recovery systems;

- QORVRi is the fraction of annual gallons of highway motor gasoline dispensed to ORVR-equipped 

vehicles for year I;

- ηiuSII is the in-use Stage II control efficiency;

- QSIIva is the fraction of gasoline throughput covered by traditional vacuum assist Stage II vapor

recovery systems; and

- CFiis the compatibility factor for the increase in underground storage tank emissions over the 

normal breathing/emptying loss emissions when using vacuum assist Stage II vapor recovery 

systems for year i.

Table 1 shows the Increment for 2010 through 2020 calculated using Equation 4:

Table 1: Incremental Emissions Control for Stage II

In-use Stage II Efficiency (iuSII) = 0.60

End of: QSII QORVR iuSII QSIIva CF Increment

2010 0.963 0.715 0.60 0.9465 0.0555 0.1123

2011 0.963 0.749 0.60 0.9465 0.0582 0.0899

2012 0.963 0.790 0.60 0.9465 0.0614 0.0635

2013 0.963 0.824 0.60 0.9465 0.0640 0.0414

2014 0.963 0.851 0.60 0.9465 0.0661 0.0237

2015 0.963 0.874 0.60 0.9465 0.0679 0.0086

2016 0.963 0.894 0.60 0.9465 0.0695 -0.0046

2017 0.963 0.910 0.60 0.9465 0.0707 -0.0152

2018 0.963 0.925 0.60 0.9465 0.0718 -0.0245

2019 0.963 0.936 0.60 0.9465 0.0727 -0.0317

2020 0.963 0.942 0.60 0.9465 0.0732 -0.0361

 

15 The incremental emission control, or increment, is the amount of emission control that is gained from Stage II controls as ORVR technology is 

phased in. If the increment is a positive value, then there is a net emissions decrease resulting from Stage II controls. If the increment is a 

negative value, then the number of vehicles with ORVR is high enough that the competition between ORVR and Stage II controls results in a net 

emission increase.
7

The increment shows that the additional emissions control for Stage II over ORVR diminishes over time 

as ORVR becomes more prevalent in the motor vehicle fleet. In 2016 the increment becomes negative, 

which indicates that incompatibility between Stage II and ORVR will increase VOC emissions. Thus, in 

2016, Stage II controls can be removed without causing any increase in refueling VOC emissions. 

The increase or decrease in VOC emissions resulting from Stage II controls may be calculated using the 

equation presented in section 3.5 of the EPA guidance:

Tonsi = (Incrementi)(GCi)(EF) Equation 5

Where:

- Tonsiis the overall effect of removing Stage II (tons) for year I;

- Incrementiis the incremental emissions gain from removal of Stage II systems for year I;

- GCiis the projected gasoline consumption (gallons) for year I; and

- EF is the uncontrolled displacement refueling emission factor (grams/gallon).

Table 2 shows the calculated tons of VOC emissions for the 5-month ozone season using Equation 5.

The overall increment identifies the annual area-wide emission control gain from Stage II installations at 

GDFs as ORVR technology phases in. Thus, it also indicates the emission reduction potential loss (in 

year l) from removing Stage II.

Table 2: 5-County Middle Tennessee Incremental VOC Emissions per Ozone Season

End of:

Increment 

(from Table 1)

GC Mid-TN 

5-Month 

(gallons)

EF 

(grams/gallon)

VOC Emissions 

Reduction from 

Stage II 

Controls

(tons/year)**

VOC Emissions 

Reduction from 

Stage II 

Controls

(avg. tons/day)

2010 0.1123 391,033,685

4.4216

510.60 1.40

2011 0.0899 380,159,556 397.39 1.09

2012 0.0635 381,899,417 281.97 0.77

2013 0.0414 391,468,651 188.45 0.52

2014 0.0237 389,293,825 107.28 0.29

2015 0.0086 386,249,069 38.62 0.11

2016 -0.0046 383,204,313 -20.50 -0.06

2017 -0.0152 380,159,556 -67.19 -0.18

2018 -0.0245 374,939,974 -106.81 -0.29

2019 -0.0317 372,330,183 -137.24 -0.38

2020 -0.0361 368,850,462 -154.83 -0.42

**Calculated with Equation 5

Table 2 shows that removal of Stage II vapor recovery systems in the 5-county Middle Tennessee area 

starting in 2016 will result in a VOC emissions decrease, with emission reduction benefits increasing over 

time. Conversely, if Stage II requirements are kept in place, an increase in VOC emissions will occur 

beyond 2015, and it will become detrimental to air quality in the 5-county Middle Tennessee area to keep

Stage II systems in operation.
8

D. Other Criteria Pollutants 

The affected sources covered by Tennessee’s Stage II vapor recovery requirements are sources of volatile 

organic compounds. Other criteria pollutants (carbon monoxide, sulfur dioxide, nitrogen dioxide, 

particulate matter, and lead) are not emitted by gasoline dispensing facilities and will not be affected by 

removal of Stage II controls. 

IV. Decommissioning Schedule and Procedures

The proposed revisions to TAPCR 1200-03-18-.24 proposed the following schedule for GDF located in 

Davidson, Rutherford, Sumner, Williamson, and Wilson counties: 

(a) Any GDF with an existing Stage II vapor recovery system shall decommission and remove the 

system no later than January 1, 2019 and no GDF shall install a Stage II vapor recovery system 

on or after such date.

(b) On and after January 1, 2016, until December 31, 2018, no GDF shall be required to install a 

Stage II vapor recovery system and a GDF may decommission and remove the GDF’s existing 

Stage II vapor recovery system. 

(c) Any GDF that decommissions and removes a Stage II vapor recovery system shall conduct the 

decommissioning and removal in accordance with Petroleum Equipment Institute (PEI) guidance, 

“Recommended Practices for Installation and Testing of Vapor Recovery Systems at Vehicle 

Fueling Sites, PEI/RP300-09” for removal, notification, and certification. 

Because the final rule will not be State-effective on January 1, 2016, Tennessee has amended the final 

version to allow decommissioning to begin on the effective date of the rule, which should be in the first 

quarter of 2016. Affected facilities will be required to complete the decommissioning process no later 

than three years after the effective date of the rule. Tennessee is planning another rulemaking action to 

add specific dates, once the effective dates of the final rule are known.

V. Request for SIP Revision

Tennessee requests that EPA approve a SIP revision removing the Stage II vapor recovery requirements 

(TAPCR 1200-03-18-.24) from Tennessee’s SIP. Tennessee requests this change because the preceding 

calculations demonstrate that VOC emissions will increase after 2015 if affected sources are required to 

continue the operation of existing Stage II systems or to install new systems.

VI. Conclusion.

This document demonstrates that penetration of ORVR systems in the motor vehicle fleet will continue to 

increase, but ORVR systems will eventually conflict with existing Stage II vapor recovery systems.

Section III of this document demonstrates that no VOC emissions increases would result from Stage II 

removal, and there would be no impact on the maintenance of the 5-county Middle Tennessee area in 

attainment with the ozone NAAQS. 

The requested SIP revision will not interfere with attainment or maintenance of a NAAQS, reasonable 

further progress toward attainment of a NAAQS, or any other applicable requirement of the Clean Air 

Act. Therefore, the requirements of section 110(l) of the CAA are satisfied for all years analyzed in the 

demonstration.
9

APPENDIX A

Table A-1 – Projected Penetration of ORVR in the National Gasoline Fueled Vehicle Fleet by 

Year, Based on MOVES 2010(a)

1 2 3 4

End of Calendar 

Year

Vehicle Population 

Percentage VMT Percentage

Gasoline Dispensed 

Percentage

2006 42.6% 51.2% 49.2%

2007 48.4% 57.3% 55.5%

2008 53.3% 62.3% 60.5%

2009 57.7% 66.8% 64.8%

2010 62.4% 71.6% 69.5%

2011 67.1% 76.0% 73.9%

2012 71.4% 80.0% 77.7%

2013 75.3% 83.4% 81.0%

2014 78.7% 86.3% 84.0%

2015 81.8% 88.8% 86.5%

2016 84.5% 90.9% 88.6%

2017 86.8% 92.5% 90.3%

2018 88.8% 93.9% 91.9%

2019 90.5% 95.0% 93.2%

2020 92.0% 95.9% 94.3%

See EPA Memorandum “Updated data for ORVR Widespread Use Assessment” February 29, 2012, in docket (number 

EPA-HQ-OAR-2010-1076) addressing details on values in this table and providing more calendar years. 

Note: In this table, the columns have the following meaning. 

1. Calendar year that corresponds to the percentages in the row associated with the year. 

2. Percentage of the gasoline-powered highway vehicle fleet that have ORVR. 

3. Percentage of gasoline-fueled vehicle miles traveled (VMT) by vehicles equipped with ORVR. 

4. Amount of gasoline dispensed into ORVR-equipped vehicles as a percentage of all gasoline dispensed to highway motor 

vehicles. 
10

APPENDIX B

Table B-1: Davidson County I/M Program Testing Numbers 2007-2012

Model Year Number of Vehicles Tested

2007 2008 2009 2010 2011 2012

1975 171 135 126 103 77 71

1976 279 218 212 184 156 150

1977 419 333 307 254 220 196

1978 561 443 413 359 298 261

1979 650 559 496 416 343 293

1980 299 302 243 237 196 180

1981 416 345 311 267 226 200

1982 583 465 422 349 300 258

1983 931 772 659 539 490 425

1984 1,568 1,388 1170 996 810 675

1985 2,166 1,799 1538 1,273 1,128 989

1986 2,916 2,376 2083 1,845 1,531 1,290

1987 3,526 2,886 2435 2,092 1,738 1,475

1988 4,963 4,042 3375 2,852 2,380 2,044

1989 6,259 5,204 4332 3,604 3,068 2,606

1990 7,302 5,951 5076 4,277 3,527 2,951

1991 9,303 7,744 6447 5,375 4,471 3,810

1992 12,026 10,226 8631 7,408 6,180 5,197

1993 16,066 13,590 11567 9,819 8,239 7,157

1994 20,256 17,692 15398 13,475 11,631 10,071

1995 25,888 22,607 20023 17,545 15,279 13,353

1996 24,085 21,497 18911 16,837 14,634 13,028

1997 30,449 27,368 24712 22,287 20,003 17,880

1998 34,029 30,988 27885 25,453 23,056 20,952

1999 38,094 35,985 33119 30,366 27,868 25,746

2000 41,084 39,311 36853 34,441 31,851 30,198

2001 37,977 37,143 35137 33,350 31,197 29,594

2002 38,435 37,893 36733 35,507 34,016 32,632

2003 38,188 37,661 36780 36,124 35,285 34,409

2004 36,438 39,088 38221 38,008 37,598 37,295

2005 37,274 38,761 38000 38,230 38,401 38,638

2006 31,625 34,238 36249 36,858 37,166 37,890

2007 12,715 31,765 33493 38,011 37,992 38,848

2008 308 10,016 27098 31,004 34,409 34,689

2009 5 260 6501 19,117 20,060 23,106

2010 0 0 241 7,573 22,595 26,058

2011 0 0 0 259 7,609 25,826

2012 0 0 0 0 245 9,412

2013 0 0 0 0 0 284

Total 517,254 521,051 515,197 516,694 516,273 530,137
11

Table B-2: Davidson County 2011 Fleet Composition

Vehicle Classification Number Percentage

Passenger Car 285,845 55.37%

Passenger Truck 178,052 34.49%

Light Commercial Truck 52,376 10.15%

Total: 516,273 100.00%

Table B-3: Davidson County I/M Testing Percentages

Vehicle Classification Percentage

Passenger Car 100%

Passenger Truck 98%

Light Commercial Truck 75%

Table B-4: ORVR Phase-in Percentages by Model Year

(59 FR 16262, April 6, 1994)

Vehicle Classification

Minimum ORVR Percentage

40% 80% 100%

Passenger Car 1998 1999 2000

Light-Duty Trucks* 2001 2002 2003

Medium-Duty Trucks** 2004 2005 2006

For comparison of Tables B-3 and B-4, assume that: Light-Duty Trucks = Passenger Trucks and Medium-Duty 

Trucks = Light Commercial Trucks
12

Table B-5: Total Davidson County Passenger Cars, 2007-2012

MY* 2007 2008 2009 2010 2011 2012

1975 95 75 70 57 43 39

1976 154 121 117 102 86 83

1977 232 184 170 141 122 109

1978 311 245 229 199 165 145

1979 360 310 275 230 190 162

1980 166 167 135 131 109 100

1981 230 191 172 148 125 111

1982 323 257 234 193 166 143

1983 515 427 365 298 271 235

1984 868 768 648 551 448 374

1985 1,199 996 852 705 625 548

1986 1,615 1,316 1,153 1,022 848 714

1987 1,952 1,598 1,348 1,158 962 817

1988 2,748 2,238 1,869 1,579 1,318 1,132

1989 3,465 2,881 2,398 1,995 1,699 1,443

1990 4,043 3,295 2,810 2,368 1,953 1,634

1991 5,151 4,288 3,570 2,976 2,475 2,109

1992 6,658 5,662 4,779 4,102 3,422 2,877

1993 8,895 7,524 6,404 5,436 4,562 3,963

1994 11,215 9,796 8,525 7,461 6,440 5,576

1995 14,333 12,517 11,086 9,714 8,460 7,393

1996 13,335 11,902 10,470 9,322 8,102 7,213

1997 16,859 15,153 13,682 12,340 11,075 9,900

1998 18,841 17,157 15,439 14,093 12,765 11,600

1999 21,092 19,924 18,337 16,813 15,430 14,255

2000 22,747 21,765 20,404 19,069 17,635 16,720

2001 21,027 20,565 19,454 18,465 17,273 16,385

2002 21,280 20,980 20,338 19,659 18,834 18,067

2003 21,144 20,852 20,364 20,001 19,536 19,051

2004 20,175 21,642 21,162 21,044 20,817 20,649

2005 20,638 21,461 21,039 21,167 21,261 21,393

2006 17,510 18,957 20,070 20,407 20,578 20,979

2007 7,040 17,587 18,544 21,046 21,035 21,509

2008 171 5,546 15,003 17,166 19,051 19,206

2009 3 144 3,599 10,585 11,107 12,793

2010 0 0 133 4,193 12,510 14,428

2011 0 0 0 143 4,213 14,299

2012 0 0 0 0 136 5,211

2013 0 0 0 0 0 157

Total 286,388 288,490 285,249 286,078 285,845 293,521
13

Table B-6: Total Davidson County Passenger Trucks, 2007-2012

MY* 2007 2008 2009 2010 2011 2012

1975 60 48 44 36 27 25

1976 98 77 75 65 55 53

1977 147 117 108 89 77 69

1978 197 156 145 126 105 92

1979 229 197 175 146 121 103

1980 105 106 86 83 69 63

1981 146 121 109 94 80 70

1982 205 164 149 123 106 91

1983 328 272 232 190 172 150

1984 552 488 412 351 285 238

1985 762 633 541 448 397 348

1986 1,026 836 733 649 539 454

1987 1,241 1,016 857 736 612 519

1988 1,747 1,422 1,188 1,004 838 719

1989 2,203 1,831 1,525 1,268 1,080 917

1990 2,570 2,094 1,786 1,505 1,241 1,039

1991 3,274 2,725 2,269 1,892 1,573 1,341

1992 4,232 3,599 3,037 2,607 2,175 1,829

1993 5,654 4,783 4,071 3,455 2,899 2,519

1994 7,128 6,226 5,419 4,742 4,093 3,544

1995 9,110 7,956 7,046 6,174 5,377 4,699

1996 8,476 7,565 6,655 5,925 5,150 4,585

1997 10,716 9,631 8,697 7,843 7,039 6,292

1998 11,975 10,905 9,813 8,957 8,114 7,373

1999 13,406 12,664 11,655 10,686 9,807 9,060

2000 14,458 13,834 12,969 12,120 11,209 10,627

2001 13,365 13,071 12,365 11,736 10,979 10,415

2002 13,526 13,335 12,927 12,496 11,971 11,484

2003 13,439 13,254 12,944 12,713 12,417 12,109

2004 12,823 13,756 13,451 13,376 13,231 13,125

2005 13,117 13,641 13,373 13,454 13,514 13,597

2006 11,129 12,049 12,757 12,971 13,079 13,334

2007 4,475 11,179 11,787 13,377 13,370 13,671

2008 108 3,525 9,536 10,911 12,109 12,208

2009 2 91 2,288 6,728 7,059 8,131

2010 0 0 85 2,665 7,952 9,170

2011 0 0 0 91 2,678 9,089

2012 0 0 0 0 86 3,312

2013 0 0 0 0 0 100

Total 182,031 183,367 181,307 181,834 181,685 186,564

Table B-7: Total Davidson County Lt. Commercial Trucks, 2007-2012
14

MY* 2007 2008 2009 2010 2011 2012

1975 23 18 17 14 10 10

1976 38 29 29 25 21 20

1977 57 45 42 34 30 27

1978 76 60 56 49 40 35

1979 88 76 67 56 46 40

1980 40 41 33 32 27 24

1981 56 47 42 36 31 27

1982 79 63 57 47 41 35

1983 126 104 89 73 66 57

1984 212 188 158 135 110 91

1985 293 243 208 172 153 134

1986 394 321 282 250 207 174

1987 477 390 329 283 235 200

1988 671 547 457 386 322 276

1989 847 704 586 488 415 353

1990 988 805 687 579 477 399

1991 1,258 1,048 872 727 605 515

1992 1,627 1,383 1,167 1,002 836 703

1993 2,173 1,838 1,565 1,328 1,114 968

1994 2,740 2,393 2,083 1,823 1,573 1,362

1995 3,502 3,058 2,708 2,373 2,067 1,806

1996 3,258 2,908 2,558 2,278 1,980 1,762

1997 4,119 3,702 3,343 3,015 2,706 2,419

1998 4,603 4,192 3,772 3,443 3,119 2,834

1999 5,153 4,868 4,480 4,108 3,770 3,483

2000 5,557 5,318 4,985 4,659 4,308 4,085

2001 5,137 5,024 4,753 4,511 4,220 4,003

2002 5,199 5,126 4,969 4,803 4,601 4,414

2003 5,166 5,094 4,975 4,886 4,773 4,654

2004 4,929 5,287 5,170 5,141 5,086 5,045

2005 5,042 5,243 5,140 5,171 5,194 5,226

2006 4,278 4,631 4,903 4,986 5,027 5,125

2007 1,720 4,297 4,531 5,142 5,139 5,255

2008 42 1,355 3,665 4,194 4,654 4,692

2009 1 35 879 2,586 2,713 3,125

2010 0 0 33 1,024 3,056 3,525

2011 0 0 0 35 1,029 3,493

2012 0 0 0 0 33 1,273

2013 0 38

Total 69,968 70,481 69,689 69,892 69,835 71,710

Table B-8: ORVR Percentages for 2007-2020
15

Year ORVR %*

VMT % / Veh Pop 

% VMT % VMTORVR QORVR

2007 49.2 1.18 58.2 0.582 0.572

2008 54.9 1.17 64.2 0.642 0.631

2009 59.2 1.16 68.6 0.686 0.674

2010 63.4 1.15 72.7 0.727 0.715

2011 67.3 1.13 76.2 0.762 0.749

2012 71.7 1.12 80.4 0.804 0.790

2013 75.7 1.11 83.8 0.838 0.824

2014 79.0 1.10 86.6 0.866 0.851

2015 81.9 1.09 88.9 0.889 0.874

2016 84.6 1.08 91.0 0.910 0.894

2017 86.9 1.07 92.7 0.927 0.910

2018 89.0 1.06 94.1 0.941 0.925

2019 90.7 1.05 95.2 0.952 0.936

2020 92.0 1.04 95.9 0.959 0.942

* ORVR Percentages for 2007-2012 were calculated from actual ORVR values for the 5-county middle 

 Tennessee area.

 The ORVR Percentage for 2020 is the value from the EPA Guidance

 For 2013 through 2019, the ORVR% was calculated using a regression equation:

 ORVR% = (-0.154)x2+ (623.437)x – 630,869, where x is equal to the year

VMT% / Veh. Pop % was calculated by dividing the values in Table A-1, Column 3 of the EPA Guidance by 

the values in Table A-1, Column 2 

 These ratios were used to calculate VMT %, VMTORVR, and QORVR, using the equations from Table 2 of the 

EPA 

 Guidance
16

APPENDIX C

Table C-1

Calculation of Compatibility Factor

Year CF1st Way CF2nd Way

2007 0.0445 0.0445

2008 0.0491 0.0490

2009 0.0524 0.0524

2010 0.0556 0.0555

2011 0.0583 0.0582

2012 0.0614 0.0614

2013 0.0641 0.0640

2014 0.0662 0.0661

2015 0.0680 0.0679

2016 0.0696 0.0695

2017 0.0708 0.0707

2018 0.0719 0.0718

2019 0.0728 0.0727

2020 0.0733 0.0732
17

APPENDIX D

Total Stage I and Stage II Vacuum-Assisted Gasoline Throughputs, 2011

Rutherford Sumner Williamson Wilson Total (4 County) Total Yearly (4 County) Davidson (yearly) Combined

Number of Facilities (have facility ID) 147 97 84 70 398 379 777

Number with Stage II 117 63 63 55 298 335 633

Number with known type of Stage II 87 40 37 39 203 335 538

Number with Stage II Vacuum Assist 84 40 36 36 196 328 524

Throughput 18,566,563 11,382,633 12,027,256 8,236,708 50,213,160 602,557,920 309,825,015 912,382,935

Throughput with Stage II 17,619,129 10,765,633 11,179,144 7,919,802 47,483,708 569,804,496 308,778,947 878,583,443

% Throughput with Stage II 94.90% 94.58% 92.95% 96.15% 94.56% 94.56% 99.66% 96.30%

Throughput with Stage I only 947,434 617,000 848,112 316,906 2,729,452 32,753,424 1,046,068 33,799,492

% Throughput Stage I only 5.10% 5.42% 7.05% 3.85% 5.44% 5.44% 0.34% 3.70%

Throughput of known type of Stage II 11,119,002 7,333,280 7,060,539 4,939,230 30,452,051 365,424,612 308,778,947 674,203,559

Throughput with known Stage II Vacuum Assist 10,793,496 7,333,280 7,038,201 4,643,885 29,808,862 357,706,344 305,828,272 663,534,616

% of Throughput known to be Stage II Vacuum Assist 97.07% 100.00% 99.68% 94.02% 97.89% 97.89% 99.04% 98.42%

Throughput of Stage II Vacuum Assist 17,103,333 10,765,633 11,143,776 7,446,231 46,480,787 557,769,445 305,828,272 863,597,717

% of Throughput with Stage II Vacuum Assist 92.12% 94.58% 92.65% 90.40% 92.57% 92.57% 98.71% 94.65%

% Stage I facilities 20.41% 35.05% 25.00% 21.43% 25.13% 11.61% 18.53%
18

APPENDIX E

Table E-1: Calculation of Growth Factor in 

Gasoline Usage

Year MMbbl/day Growth Factor

2010 8.99 --

2011 8.74 -0.027808676

2012 8.78 0.004576659

2013 9.00 0.025056948

2014 8.95 -0.005555556

2015 8.88 -0.007821229

2016 8.81 -0.007882883

2017 8.74 -0.007945516

2018 8.62 -0.013729977

2019 8.56 -0.006960557

2020 8.48 -0.009345794

* Source of usage: AEO 2012, Early Release –

Data for Motor Gasoline

Table E-2: Growth Factor Adjustments to 2011 5-County Middle TN Gasoline 

Consumption

Usage (gallons)

Year Annual 5-month O3 Season

2010 938,480,845 391,033,685

2011* 912,382,935 380,159,556

2012 916,558,601 381,899,417

2013 939,524,761 391,468,650

2014 934,305,179 389,293,824

2015 926,997,765 386,249,069

2016 919,690,350 383,204,313

2017 912,382,935 380,159,556

2018 899,855,938 374,939,974

2019 893,592,440 372,330,183

2020 885,241,109 368,850,462

* 2011 usage is based on actual reported/permitted throughputs. Other years are calculated from 

the growth factor
19

APPENDIX F

Gasoline RVP Requirements for the 5-County Middle Tennessee Area

Month RVP

January, December 15.0

February, March, April, October, November 13.5

May 9.0

June, July, August, September 7.8

APPENDIX G

Table A-2 - Monthly Average Dispensed Liquid Temperature

Dispensed liquid temperature (°F)

Summer Winter Annual

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec (Apr-Sep) (Oct-Mar) Average

National 

Average

51 54 54 58 69 76 82 81 76 70 62 54 74 58 66

Region 1 43 45 48 53 66 74 78 78 72 66 59 46 70 51 61

Region 2 69 74 73 80 84 87 90 91 78 85 83 73 85 76 81

Region 3 54 57 61 67 76 82 83 84 79 76 67 54 79 62 70

Region 4 50 51 41 47 63 74 88 85 83 75 63 52 74 56 65

Region 5 54 NA NA NA 72 77 83 83 79 74 67 58 79 63 72

Region 6 NA 48 49 53 59 63 NA 73 71 60 49 42 64 50 57

Regional Boundaries 

Region 1: ME, VT, NH, MA, CT, RI, NY, NJ, PA, DE, MD,VA,WV,DC, KY, OH, IN, IL, MI, WI 

Region 2: NC, SC, GA, FL, AL, MS, AR, LA, TN 

Region 3: OK, TX, NM, AZ 

Region 4: MN, IA, MO, ND, SD, NE, KS, MT, WY, CO 

Region 5: CA, NV, UT 

Region 6: WA, OR, ID 

Source: McNally Michael and Dickerman J.C., "Summary and Analysis of Data from Gasoline Temperature 

Survey," conducted by API, Radian Corporation, May, 1976. 
20

APPENDIX H

Table A-3 - Seasonal Variation In Temperature Difference Between Vehicle Fuel Tank and 

Dispensed Fuel

Temperature Difference

Average 

Annual

Summer

(Apr – Sep)

Winter

(Oct – Mar)

5-Month 

Ozone Season

(May – Sep)

2-Month Ozone 

Season

(Jul – Aug)

National 

Average 

4.4 8.8 -0.8 9.44 9.9

Region 1 5.7 10.7 -0.3 11.5 12.5

Region 2 4.0 6.8 0.9 7.5 8.2

Region 3 3.7 7.6 -0.4 7.1 7.0

Region 4 5.5 11.7 -2.4 12.1 13.3

Region 5 0.1 3.9 -4.4 5.1 3.2

Region 6 Use Region 4 data 

Regional Boundaries 

Region 1: ME, VT, NH, MA, CT, RI, NY, NJ, PA, DE, MD,VA,WV,DC, KY, OH, IN, IL, MI, WI 

Region 2: NC, SC, GA, FL, AL, MS, AR, LA, TN 

Region 3: OK, TX, NM, AZ 

Region 4: MN, IA, MO, ND, SD, NE, KS, MT, WY, CO 

Region 5: CA, NV, UT 

Region 6: WA, OR, ID 

Source: Rothman, Dale and Johnson, Robert, Technical Report, “Refueling Emissions from 

Uncontrolled Vehicles,” EPA.OMS, EPA-AA-SDSB-85-6. June 1985.