United States

Environmental Protection

Agency

Air and Radiation EPA420-R-00-007

April 2000

IM240 & Evap

Technical Guidance

 Printed on Recycled Paper
EPA420-R-00-007

April 2000

IM240 & Evap Technical Guidance

Transportation and Regional Programs Division

Office of Transportation and Air Quality

U.S. Environmental Protection Agency

NOTICE

This technical report does not necessarily represent final EPA decisions or positions.

It is intended to present technical analysis of issues using data which are currently available.

The purpose in the release of such reports is to facilitate the exchange of

technical information and to inform the public of technical developments which

may form the basis for a final EPA decision, position, or regulatory action.
Introduction

§85.2205 Test Standards .................................................................................................................. 1

(a) IM240 Emission Standards .............................................................................................. 1

(b) Transient Test Score Calculations .................................................................................... 5

(c) Evaporative System Pressure Test Standards ................................................................. 10

(d) Gas Cap Test Standards .................................................................................................. 10

§85.2221 IM240 Test Procedures .................................................................................................. 12

(a) General Requirements .................................................................................................... 12

(b) Pre-inspection and Preparation ....................................................................................... 12

(c) Equipment Positioning and Settings ............................................................................... 13

(d) Vehicle Conditioning ...................................................................................................... 14

(e) Vehicle Emission Test Sequence .................................................................................... 15

(f) Emission Measurements ................................................................................................. 18

§85.2222 Evaporative System Pressure and Gas Cap Test Procedures ......................................... 19

(a) General Requirements .................................................................................................... 19

(b) Pre-inspection and Preparation ....................................................................................... 19

(c) Fuel Inlet Pressure Test .................................................................................................. 19

(d) Gas Cap Test .................................................................................................................. 20

§85.2226 IM240 Equipment Specifications ................................................................................... 21

(a) Dynamometer Specifications .......................................................................................... 21

(b) Constant Volume Sampler .............................................................................................. 25

(c) Analytical Instruments .................................................................................................... 27

§85.2227 Evaporative System Equipment Specifications .............................................................. 29

(a) General Requirements .................................................................................................... 29

(b) Evaporative System Pressure Test Equipment ............................................................... 29

(c) Gas Cap Test Equipment ................................................................................................ 29

§85.2234 IM240 Test Quality Control Requirements .................................................................... 31

(a) General Requirements .................................................................................................... 31

(b) Dynamometer ................................................................................................................. 31

(c) Constant Volume Sampler .............................................................................................. 33

(d) Analysis System ............................................................................................................. 34

(e) Gases .............................................................................................................................. 36

(f) Overall System Performance .......................................................................................... 37

(g) Control Charts ................................................................................................................ 37

§85.2235 Evaporative Test Quality Control Requirements ............................................................ 39

(a) General Requirements .................................................................................................... 39

(b) Evaporative Pressure Checks ......................................................................................... 39

(c) Evaporative Gas Cap Checks ......................................................................................... 39

§85.2239 Test Report ..................................................................................................................... 40

(a) General Test Report Information .................................................................................... 40
(b) Tests and Results ............................................................................................................ 40

(c) Recommended IM240 Second-By-Second Emissions Report ....................................... 41

§85.2241 Terms .............................................................................................................................. 43

Appendix A

Guidance on the Use of Fast-Pass IM240 Standards .................................................................... 44

Appendix B

Alternative Fast-Pass IM240 Standards ........................................................................................ 50

Appendix C

Fast Pass IM240 Standards Developed for Wisconsin ................................................................. 66

Appendix D

Fast Pass IM240 Standards: Modal Regression Technique .......................................................... 73

Appendix E

Calculation of Raw Emission Scores from Dilute Measurements ................................................ 82

Appendix F

Modal Analysis of Second-by-Second Data Preconditioning Guidelines ................................... 87

Appendix G

Full and Fast-Pass IM240 Positive Kinetic Energy Speed Variation Limits ................................ 91

Appendix H

Derivation of TRLHP Coefficients ............................................................................................. 100

Appendix I

Derivation of TRLHP Coefficients ............................................................................................ 103
Introduction

This document is the successor to the August 1998 version of the EPA “IM240 & Evap Technical Guidance” and

incorporates changes made since its publication. The following changes have been incorporated in this release of

the EPA I/M technical guidance:

1) All references to the EPA evaporative emission purge test have been removed. Standards, procedures,

specifications, and quality control practices are described in the August 1998 technical guidance.

2) A spreadsheet and example for usage of the Modal Fast Pass concept have been posted with the IM240 & Evap

Technical Guidance on the EPA I/M web site..

3) K1 and K2 coefficients have been changed in 85.2205(b)(3)(iv)(E) to make them technically correct.

4) The exponent in the humidity correction factor in 85.2205(b)(3)(xi)(F) has been corrected for a typographical

error.

5) References to procedures for treatment of OBD II evaporative emission controlled vehicles have been revised to

state that guidance for these vehicles will be published in a separate document, not a revision of the IM240 & Evap

Technical Guidance.

6) The standard for the fuel inlet pressure test, 85.2205(d)(2)(i) has corrected a typographical error. The value “8"

has been changed to “6.”

7) 85.2222(a)(2) has added a sentence stating fuel volatility is also a factor contributing to test variability when

conducting the fuel inlet pressure test.

8) 85.2226(a)(3)(iii) has been revised to specify response time measurements at 2000, base inertia, and 5500

pounds of inertia.

9) 85.2227(b)(1)(i) has been added to specifically permit the use of flow based leak detection methods, but no

standards have been proposed at present.

10) The text in 85.2227(c)(1)(iv) has been revised to clarify the term “automated.” The new wording states

automatic operation means automated measurement of the pass/fail condition and a requirement for a real time data

link.

11) Paragraphs (ii) and (iii) of 85.2234 have been modified to provide more flexible load settings at 50 and 20 mph

to achieve longer and more measurable coast down times. The 22 to 18 mph coastdown limit has been changed to

± 6 seconds.

12) The 0.4% of point tolerance in 85.2234(d)(3) has been revised to ± 2% of point of a specific analyzer range,

and the first sentence is modified to state its intent is to apply to the initial setting of a span point.

13) Paragraph 4 of 85.2234(g)(4) has been revised to state that driving trace quality is an example of how control

charts for individual inspectors may used.

14) An equation has been added to 85.2239(b)(6) to define how “gpme” is calculated.
15) Appendix I, Derivation of GTRL Coefficients has been revised to clarify its content, and make it more

compatible with terms and equations provided by Sierra Research in the supporting documentation when the EPA

I/M Look-up Table is revised. 
1

§85.2205 Test Standards

(a) IM240 Emission Standards

(1) Two Ways to Pass Standards. If the corrected, composite emission rates calculated in

§85.2205(b) exceed the standards for any exhaust component, additional analysis of test results

shall look at the second phase of the driving cycle separately. Phase 2 shall include second 94

through second 239. Second-by-second emission rates in grams, and composite emission rates

in grams per mile for Phase 2 and for the entire test shall be recorded for each gas. If the

composite emission level is equal to or below the composite standard, or if the Phase 2 grams

per mile emission level is equal to or below the applicable Phase 2 standard, then the vehicle

shall pass the test for that exhaust component.

(2) Start-up Standards. Start-up standards should be used during the first two years of program

operation. Tier 1 standards are recommended for 1996 and newer vehicles and may be used for

1994 and newer vehicles certified to Tier 1 standards as well. The following exhaust emissions

standards, in grams per mile, are recommended:

(i) Light Duty Vehicles.

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1996+ 0.80 0.50 15.0 12.0 2.0 2.0

1991-1995 1.20 0.75 20.0 16.0 2.5 2.5

1983-1990 2.00 1.25 30.0 24.0 3.0 3.0

1981-1982 2.00 1.25 60.0 48.0 3.0 3.0

1980 2.00 1.25 60.0 48.0 6.0 6.0

1977-1979 7.50 5.00 90.0 72.0 6.0 6.0

1975-1976 7.50 5.00 90.0 72.0 9.0 9.0

1973-1974 10.0 6.00 150 120 9.0 9.0

1968-1972 10.0 6.00 150 120 10.0 10.0

(ii) High-Altitude Light Duty Vehicles.

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1983-1984 2.00 1.25 60.0 48.0 3.0 3.0

1982 2.00 1.25 75.0 60.0 3.0 3.0

(iii) Light Duty Trucks (0 - 6000 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1996+

(<3750 LVW) 0.80 0.50 15.0 12.0 2.0 2.0

(>3750 LVW) 1.00 0.63 20.0 16.0 2.5 2.5

1991-1995 2.40 1.50 60.0 48.0 3.0 3.0

1988-1990 3.20 2.00 80.0 64.0 3.5 3.5

1984-1987 3.20 2.00 80.0 64.0 7.0 7.0

1979-1983 7.50 5.00 100 80.0 7.0 7.0
1

The heavy-duty truck standards provided here were calculated using new vehicle certification standards and

have not been subjected to field testing. This document provides no other guidance on heavy duty truck testing. 

Thus, anyone interested in performing IM240 tests on heavy-duty trucks should proceed with appropriate caution.

2

1975-1978 8.00 5.00 120 96.0 9.0 9.0

1973-1974 10.0 6.00 150 120 9.0 9.0

1968-1972 10.0 6.00 150 120 10.0 10.0

(iv) High-Altitude Light Duty Trucks (0 - 6000 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1991+ 3.00 2.00 70.0 56.0 3.0 3.0

1988-1990 4.00 2.50 90.0 72.0 3.5 3.5

1984-1987 4.00 2.50 90.0 72.0 7.0 7.0

1982-1983 8.00 5.00 130 104 7.0 7.0

(v) Light Duty Trucks (6001 - 8500 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 CompositePhase 2

1996+

(<5750 ALVW) 1.00 0.63 20.0 16.0 2.5 2.5

(>5750 ALVW) 2.40 1.50 60.0 48.0 4.0 4.0

1991-1995 2.40 1.50 60.0 48.0 4.5 4.5

1988-1990 3.20 2.00 80.0 64.0 5.0 5.0

1984-1987 3.20 2.00 80.0 64.0 7.0 7.0

1979-1983 7.50 5.00 100 80.0 7.0 7.0

1975-1978 8.00 5.00 120 96.0 9.0 9.0

1973-1974 10.0 6.00 150 120 9.0 9.0

1968-1972 10.0 6.00 150 120 10.0 10.0

(vi) High-Altitude Light Duty Trucks (6001 - 8500 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1991+ 3.00 2.00 70.0 56.0 4.5 4.5

1988-1990 4.00 2.50 90.0 72.0 5.0 5.0

1984-1987 4.00 2.50 90.0 72.0 7.0 7.0

1982-1983 8.00 5.00 130 104 7.0 7.0

(vii) Heavy-Duty Trucks (greater than 8500 pounds GVWR).

1

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1998+ 2.00 1.30 30.0 24.0 4.0 4.0

1991-1997 3.00 1.90 60.0 48.0 6.0 6.0

1987-1990 3.00 1.90 60.0 48.0 8.0 8.0
3

1985-1986 5.00 3.10 75.0 60.0 8.0 8.0

1979-1984 6.00 3.80 100.0 80.0 8.0 8.0

1974-1978 10.0 6.30 150.0 120.0 10.0 10.0

1970-1973 10.0 6.30 175.0 140.0 10.0 10.0

pre-1970 20.0 12.50 200.0 160.0 15.0 15.0

(3) Final Standards. The following exhaust emissions standards, in grams per mile, are

recommended for vehicles tested in the calendar years 1997 and later. Tier 1 standards are

recommended for all 1996 and newer vehicles but may be used for 1994 and newer vehicles.

(i) Light Duty Vehicles.

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1996+ 0.60 0.40 10.0 8.0 1.5 1.5

1983-1995 0.80 0.50 15.0 12.0 2.0 2.0

1981-1982 0.80 0.50 30.0 24.0 2.0 2.0

1980 0.80 0.50 30.0 24.0 4.0 4.0

1977-1979 3.00 2.00 65.0 52.0 4.0 4.0

1975-1976 3.00 2.00 65.0 52.0 6.0 6.0

1973-1974 7.00 4.50 120 96.0 6.0 6.0

1968-1972 7.00 4.50 120 96.0 7.0 7.0

(ii) High-Altitude Light Duty Vehicles.

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1983-1984 1.20 0.75 30.0 24.0 2.0 2.0

1982 1.20 0.75 45.0 36.0 2.0 2.0

(iii) Light Duty Trucks (0 - 6000 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1996+

(<3750 LVW) 0.60 0.40 10.0 8.0 1.5 1.5

(>3750 LVW) 0.80 0.50 13.0 10.0 1.8 1.8

1988-1995 1.60 1.00 40.0 32.0 2.5 2.5

1984-1987 1.60 1.00 40.0 32.0 4.5 4.5

1979-1983 3.40 2.00 70.0 56.0 4.5 4.5

1975-1978 4.00 2.50 80.0 64.0 6.0 6.0

1973-1974 7.00 4.50 120 96.0 6.0 6.0

1968-1972 7.00 4.50 120 96.0 7.0 7.0

(iv) High-Altitude Light Duty Trucks (0 - 6000 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1988+ 2.00 1.25 60.0 48.0 2.5 2.5

1984-1987 2.00 1.25 60.0 48.0 4.5 4.5
4

1982-1983 4.00 2.50 90.0 72.0 4.5 4.5

(v) Light Duty Trucks (6001 - 8500 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1996+ 

(<5750 ALVW) 0.80 0.50 13.0 10.0 1.8 1.8

(>5750 ALVW) 0.80 0.50 15.0 12.0 2.0 2.0

1988-1995 1.60 1.00 40.0 32.0 3.5 3.5

1984-1987 1.60 1.00 40.0 32.0 4.5 4.5

1979-1983 3.40 2.00 70.0 56.0 4.5 4.5

1975-1978 4.00 2.50 80.0 64.0 6.0 6.0

1973-1974 7.00 4.50 120 96.0 6.0 6.0

1968-1972 7.00 4.50 120 96.0 7.0 7.0

(vi) High-Altitude Light Duty Trucks (6001 - 8500 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1988+ 2.00 1.25 60.0 48.0 3.5 3.5

1984-1987 2.00 1.25 60.0 48.0 4.5 4.5

1982-1983 4.00 2.50 90.0 72.0 4.5 4.5

(vii) Heavy-Duty Trucks (greater than 8500 pounds GVWR).

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen

Composite Phase 2 Composite Phase 2 Composite Phase 2

1998+ 2.00 1.30 30.0 24.0 4.0 4.0

1991-1997 2.00 1.30 40.0 32.0 5.0 5.0

1987-1990 2.00 1.30 40.0 32.0 6.0 6.0

1985-1986 3.00 1.90 50.0 40.0 6.0 6.0

1979-1984 5.00 3.10 75.0 60.0 6.0 6.0

1974-1978 10.0 6.30 150.0 120.0 10.0 10.0

1970-1973 10.0 6.30 175.0 140.0 10.0 10.0

pre-1970 20.0 12.50 200.0 160.0 15.0 15.0

(4) Fast-Pass. Vehicles may be fast-passed using the following algorithm.

(i) Fast-Pass Algorithm. Beginning at second 30 of the driving cycle, cumulative secondby-second emission levels for each second, calculated from the start of the cycle in

grams, shall be compared to the cumulative fast-pass emission standards for the second

under consideration. For exhaust components subject to Phase 2 standards, cumulative

second-by-second emission levels calculated in grams from second 109 forward shall

be compared to cumulative second-by-second fast-pass Phase 2 emission standards for

the second under consideration.

(ii) Fast-Pass Standards. A vehicle shall pass the IM240 for a given exhaust component if

either of the following conditions occur:
5

(A) cumulative emissions of each exhaust are below the full cycle fast-pass

standard for the second under consideration; or,

(B) at second 109 and later, (if the exhaust component is subject to Phase 2

standards) cumulative Phase 2 emissions of each exhaust component

are below the Phase 2 fast-pass standards for the second under

consideration;

(iii) Fast-Pass End of Test. Testing may be terminated when fast-pass criteria are met for

all subject exhaust components.

(iv) Applicability of Fast-Pass Standards. If a fast-pass determination cannot be made for

all subject exhaust components before the driving cycle ends, the pass/fail

determination for each component shall be based on composite or Phase 2 emissions

over the full driving cycle as described in §85.2205(a)(1).

(v) Fast-Pass Algorithms. Vehicles may be fast-passed using other approaches if they are

approved by the Administrator. States are encouraged to develop and use equations to

define fast-pass standards for each composite emission standard rather than using

tabular standards for each second of the test. 

EPA-developed, tabular, fast-passed standards are included in Appendix A. 

Fast-pass standards developed by Radian for Colorado are included in Appendix B. 

Appendix C contains fast-pass standards generated by EPA for Wisconsin at the state's

request. This was done to allow the state to move toward implementing final IM240

standards. 

Appendix D contains fast-pass guidelines and 0.8 g/mi HC composite standards along

with 0.5 g/mi HC Phase 2 cut points developed by Sierra Research under contract 68-

C4-0056 Work Assignment 2-04. A complete listing of the modal regression

coefficients would be too large to print in an appendix; however, the description in

Appendix D is intended to provide background information and the rational behind this

methodology. A complete series of coefficients are available on EPA's web site.

(b) Transient Test Score Calculations

(1) Composite Scores. The composite scores for the test shall be determined by dividing the sum of

the mass of each exhaust component obtained in each second of the test by the number of miles

driven in the test. The first data point is the sample taken from t=0 to t=1. The composite test

value shall be calculated by the equation in §85.2205(b)(1)(i):
6

(i) Composite gpm = 

emissions(g)

distance(m iles)

s=0

s

s=0

s

∑

∑

Where: s = duration of test in seconds for fast pass

= 239 seconds for complete IM240

(2) Second-by-Second Mass Calculations. The mass of each exhaust component shall be calculated

to five significant digits for each second of the test using the following equations:

(i) Hydrocarbon mass: HCmass = Vmix * DensityHC * 

H C

1,000,000

conc

(ii) Carbon Monoxide mass: COmass = Vmix * DensityCO * 

C O

1,000,000

conc

(iii) Oxides of Nitrogen mass: NOxmass = Vmix * DensityNO2 * KH * 

N O

1,000,000

conc

(iv) Carbon Dioxide mass: CO2mass = Vmix * DensityCO2 * 

CO2

100

conc

(3) Meaning of Terms.

(i) Vmix = The CVS flow rate in cubic feet per second corrected to standard

temperature and pressure.
7

(ii) HCmass = Hydrocarbon emissions in grams per second.

(iii) DensityHC = Density of hydrocarbons is 16.33 grams per cubic foot assuming an

average carbon to hydrogen ratio of 1:1.85 at 68°F and 760 mm Hg

pressure.

(iv) HCconc = Average hydrocarbon concentration per second of the dilute exhaust

sample corrected for background, in ppm carbon equivalent, i.e.,

equivalent propane * 3.

(A) HCconc = HCe - HCd (1 - ) Where:

1

D F

(B) HCe = Hydrocarbon concentration of the dilute exhaust sample, in

ppm carbon equivalent.

(C) HCd = Background hydrocarbon concentration of the dilution air, in

ppm carbon equivalent.

(D) DF = 

13.4

C O 2 (H C C O ) * 1 0 ee e

4 + + −

This is calculated on a second-by-second basis, where CO2 is measured in

% and HC and CO are measured in ppm. Note this DF does not account

for pollutants in the background air and becomes less accurate as the airfuel ratio of the vehicle deviates from stoichiometric.

(E) ( ) ()

( )( ) D F 100 K CO K CO K (HC )

K CO CO K CO CO K (HC HC ) alt

1 2d 2 d 3 d

1 2e 2d 2 e d 3 e d

= − −−

− + −+ −

This method of calculating DF is also done on a second-by-second basis and

accounts for pollutants in the background air as well as being more accurate

than the method in (D) above when the vehicle deviates from stoichiometric

operation. All concentrations are expressed in volume percent and the values of

the constants for gasoline fuel are: K1 = 7.4806, K2 = 5.5936, and K3 =

57.0945. Appendix E contains additional information on this subject.

If raw emission scores are being determined from dilute measurements, EPA

recommends the use of this method for calculating DF.

(v) COmass = Carbon monoxide emissions in grams per second.

(vi) DensityCO = Density of carbon monoxide is 32.97 grams per cubic foot at 68°F and

760 mm Hg pressure.
8

(vii) COconc = Average carbon monoxide concentration per second of the dilute

exhaust sample, corrected for background, water vapor, and CO2

extraction, in ppm.

(A) COconc = COe - COd (1 - )

1

D F

(B) COe = Carbon monoxide concentration of the dilute exhaust, in ppm.

(C) COd = Background carbon monoxide concentration of the dilution air, in

ppm.

(viii) NOxmass = Oxides of nitrogen emissions in grams per second.

(ix) DensityNO2 = Density of oxides of nitrogen is 54.16 grams per cubic foot assuming

they are in the form of nitrogen dioxide at 68°F and 760 mm Hg

pressure.

(x) NOxconc = Average concentration of oxides of nitrogen per second of the dilute

exhaust sample, corrected for background in ppm.

(A) NOxconc = NOxe - NOxd (1 - )

1

D F

(B) NOxe = Oxides of nitrogen concentration of the dilute exhaust sample,

in ppm.

(C) NOxd = Background oxides of nitrogen concentration of the dilution air,

in ppm.

(xi) KH = humidity correction factor 

(A) Standard Method

KH = 1.0

1.0 0.0047 * (H 75.0) − −

(B) H = Absolute humidity in grains of water per pound of dry air.

= 43.478 * R * P

P (P *

R

100 )

a d

b d

a −

(C) Ra = Relative humidity of the ambient air, percent.
2

This revised method for calculating KH as a function of both T and H is based on work performed by Sierra

Research under contract 68-C4-0056, Work Assignment 2-04. If the calculated value of KH exceeds 2.19, the

value of KH shall be set to 2.19. This analysis used the same MY69, 5-vehicle sample employed for the original

KH factor study that resulted in the current CFR standard KH calculation method (listed in (xi)(A) above). 

However, in many cases IM testing occurs outside the temperature limits set by the CFR for the standard method;

therefore, at this time EPA recommends using the revised method when testing above 86(F.

9

(D) Pd = Saturated vapor pressure, mm Hg at the ambient dry bulb

temperature.

(E) Pb = Barometric pressure, mm Hg.

(F) Revised method2

KH = e[0.004977(H 75) .004447(T 75)] −− −

(G) H = Absolute humidity in grains of water per pound of dry air.

(H) T = Temperature in °F.

NOTE: If the calculated KH using either method of calculation is greater than 2.19, the

value of KH shall be set at 2.19.

(xiii) CO2mass = Carbon dioxide emissions in grams per second.

(xiv) DensityCO2 = Density of carbon dioxide is 51.81 grams per cubic foot at 68°F and

760 mm Hg.

(xv) CO2conc = Average carbon dioxide concentration per second of the dilute exhaust

sample, corrected for background, in percent.

(A) CO2conc = CO2e - CO2d (1 - )

1

D F

(B) CO2d = Background carbon dioxide concentration of the dilution air, in

percent.

(4) Negative Values. Negative gram per second readings shall be integrated as zero and recorded

as such. Negative values measured for ambient background concentrations (HCd, COd, CO2d,

and NOxd) used in 85.2205(b)(3) shall be calculated as zero and recorded as such.

(5) Determination of Raw Exhaust Concentrations from IM240 Results. Although the IM240 is a

mass-based test, it is possible to estimate tailpipe concentrations from the dilute measurements

for those vehicles only required to undergo an idle test. One method for performing this
10

calculation can be found in SAE manuscript 980678. Additional clarification on this can be

found in Appendix E.

(c) Evaporative System Pressure Test Standards

The methods described below are applicable to pre OBD II evaporative emission controlled

vehicles. OBD II vehicles equipped with evaporative control monitors and certified to the

enhanced evaporative emission standards are being phased-in with the 1996 through 1998

model years. Those vehicles must be tested using either OBD II scan tools, by measuring

pressure loss through an evaporative emission "service port," or by following vehicle

manufacturer specific instruction to avoid damaging rigid vapor lines which are prevalent on

many vehicles equipped with enhanced evaporative emission control systems. Procedures for

using OBD II scan tools will be published in a separate document.

All I/M programs conducting a pressure test must perform a leak check on the gas cap and

provide a unique test result.

(1) Visual Check. The vehicle shall fail the evaporative system visual check if any part of the

system is missing, damaged, improperly connected, or disconnected as described in

§85.2222(b).

(2) Fuel Inlet Pressure Test. 

(i) Pressure Test Method. A vehicle shall fail the pressure test if the fuel vapor control

system isolated between the fuel inlet and a clamp on the line between the fuel tank

and the canister, (located as close to the canister as possible) loses more than 6 inches

of water pressure over a period of 120 seconds starting from a stabilized pressure of

14±1 inch of water.

(ii) Fast-Pass. Fast-pass determinations for the pressure test may be made anytime during

the pressure decay between 20 and 120 seconds if the measured pressure exceeds:

 Pm = P (

0.33 * P 

120 )*t i

i − + 133 .

Where: Pm = Measured pressure in inches of water

Pi = Initial pressure in inches of water

t = Time in seconds

(d) Gas Cap Test Standards

The methods described below are applicable to pre OBD II evaporative emission controlled

vehicles. OBD II vehicles equipped with evaporative control monitors and certified to the

enhanced evaporative emission standards are being phased-in with the 1996 through 1998

model years. Procedures for OBD vehicles will be published in a separate document.
11

Pressure decay methods using a 1 liter head space are currently permitted under the June 1996

version of the IM240 technical guidance. As this method has been widely used in IM240

testing it will continue to be allowed. The pressure decay loss of 6 inches of WC from a

starting pressure of 28 in. WC referenced to 70F and 1 atm and assuming a 1 liter head space,

equates to a flow rate of about 80 cc/min.

(1) Visual Check. The vehicle shall fail the gas cap visual check if the cap is missing, obviously

defective, or the wrong style cap for the vehicle. An example of a wrong style includes a cam

lock cap installed on fill pipe which requires a threaded cap. States conducting cap testing

should work with OEM suppliers to develop a user friendly method of identifying wrong style

gas caps.

(2) Pressure Decay Test Standard. For pressure decay methods using a 1 liter head space and the

June 1996 IM240 technical guidance, the fuel cap shall fail the pressure test if it loses more

than 6 inches of water column (WC) pressure over a period of 10 seconds from a starting

pressure of 28±1 inch WC.

(3) 60 cc/min Flow Standard. The gas cap leak rate may be determined by pressure loss

measurement, direct flow measurement, or flow comparison methods and shall be compared to

a pass/fail flow rate standard of 60 cubic centimeters per minute of air at 30 inches of water

column. The flow rate methods shall be referenced to standard conditions of 70(F and 1 atm. 

If the leak rate exceeds 60 cc/min at a pressure of 30 inches of water column, the cap shall fail

the test. 
12

§85.2221 IM240 Test Procedures

(a) General Requirements

(1) Test Parameters. The following information shall be determined for the vehicle being tested

and used to automatically select the dynamometer inertia, power absorption settings, and

evaporative emission test parameters.

(i) Model Year

(ii) Manufacturer

(iii) Model name

(iv) Body style

(v) Number of cylinders

(vi) Engine displacement

Alternative computerized methods of selecting dynamometer test conditions, such as VIN decoding, may be used.

(2) Ambient Conditions. The ambient temperature, absolute humidity, and barometric pressure

shall be recorded continuously during the transient test, or as a single set of readings if taken

less than 4 minutes prior to the transient driving cycle.

(3) Restart. If shut off, the vehicle shall be restarted as soon as possible before the test and shall be

running at least 30 seconds prior to the transient driving cycle.

(b) Pre-inspection and Preparation

(1) Accessories. All accessories (air conditioning, heat, defogger, radio, automatic traction control

if switchable, etc.) shall be turned off by the inspector, if necessary. 

(2) Traction Control and Four-Wheel Drive (4WD). Vehicles with traction control systems that

cannot be turned off shall not be tested on two wheel drive dynamometers. Vehicles with 4WD

that cannot be turned off shall only be tested on 4WD dynamometers. If the 4WD function can

be disabled, then 4WD vehicles may be tested on two wheel drive dynamometers.

(3) Leaks. The vehicle shall be inspected for exhaust leaks. Audio assessment while blocking

exhaust flow, or measurement of carbon dioxide or other gases, shall be acceptable. Vehicles

with leaking exhaust systems shall be rejected from testing.

(4) Operating Temperature. The vehicle temperature gauge, if equipped and operating, shall be

checked to assess temperature. If the temperature gauge indicates that the engine is well below

(less than 180(F) normal operating temperature, the vehicle shall not be fast-failed and shall get

a second-chance emission test if it fails the initial test for any criteria exhaust component. 

Vehicles in overheated condition shall be rejected from testing.

(5) Tire Condition. Vehicles shall be rejected from testing if tire cords, bubbles, cuts, or other

damage are visible. Vehicles shall be rejected that have space-saver spare tires, or unreasonably

sized tires on the drive axle. Vehicle tires shall be visually checked for adequate pressure level. 

Drive wheel tires that appear low shall be inflated to approximately 30 psi, or to tire side wall
13

pressure, or manufacturer's recommendation. The tires of vehicles being tested for the purposes

of program evaluation under §51.353(c) shall have their tires inflated to tire side wall pressure.

(6) Ambient Background. Background concentrations of hydrocarbons, carbon monoxide, oxides

of nitrogen, and carbon dioxide (HC, CO, NOx, and CO2, respectively) shall be sampled as

specified in §85.2226(b)(2)(iv) to determine background concentration of dilution air. The

sample shall be taken for a minimum of 15 seconds within 120 seconds of the start of the

transient driving cycle, using the same analyzers used to measure tailpipe emissions except as

provided in §85.2226(c)(4)(iv). Average readings over the 15 seconds for each gas shall be

recorded in the test record. Testing shall be prevented until the average ambient background

levels are less than 20 ppmC HC, 30 ppm CO, and 2 ppm NOx, or outside ambient air levels

(not influenced by station exhaust), whichever are greater.

Other methods that do not employ a fixed analysis time of 15 seconds may be used, if approved

by the Administrator. 

(7) Sample System Purge. While a lane is in operation, the CVS shall continuously purge the CVS

hose between tests. The blower may be turned off if the CVS is not in operation, but the system

shall be purged for 2 minutes prior to the start of a test if the blower has been turned off. The

off time shall be computer monitored and recorded to a history file for quality assurance.

(c) Equipment Positioning and Settings

(1) Roll Rotation. The vehicle shall be maneuvered onto the dynamometer with the drive wheels

positioned on the dynamometer rolls. Prior to test initiation, the rolls shall be rotated until the

vehicle laterally stabilizes on the dynamometer. Drive wheel tires shall be dried if necessary to

prevent slippage during the initial acceleration.

(2) Cooling System. The use of a cooling system is optional when testing at temperatures below

50(F. Furthermore, the hood may be opened at the state's discretion. If a cooling system is in

use, testing shall not begin until the cooling system is positioned and activated. The cooling

system shall be positioned to direct air to the vehicle cooling system, but shall not be directed at

the catalytic converter.

(3) Vehicle Restraint. Testing shall not begin until the vehicle is restrained. Any restraint system

shall meet the requirements of §85.2226(a)(5)(vii). The parking brake shall be set for front

wheel drive vehicles prior to the start of the test. The parking brake need not be set for vehicles

that release the parking brake automatically when the transmission is put in gear.

(4) Dynamometer Settings. Dynamometer power absorption and inertia weight settings shall be

automatically chosen from an EPA-supplied electronic look-up table which will be referenced

based upon the vehicle identification information obtained in 85.2221(a)(1). Vehicles not listed

shall be tested using default power absorption and inertia settings in the latest version of the

EPA I/M Look-up Table, as posted on EPA's web site: www.epa.gov/orcdizux/im.htm

(5) Exhaust Collection System. The exhaust collection system shall be positioned to insure

complete capture of the entire exhaust stream from the tailpipe during the transient driving

cycle. The system shall meet the requirements of §85.2226(b)(2).
14

(d) Vehicle Conditioning

(1) Queuing Time. When the vehicle queue exceeds 20 minutes, a vehicle shall get a secondchance emission test if it fails the initial test and all criteria exhaust components are at or below

1.5 times the standard. At the state’s discretion, second-chance testing may be granted if

criteria exhaust components exceed any preset level above the standard.

(2) Program Evaluation. Vehicles being tested for the purpose of program evaluation under

§51.353(c) shall receive two full transient emission tests (i.e., a full 240 seconds each). Results

from both tests and the test order shall be separately recorded in the test record. Emission

scores and results provided to the motorist may be from either test.

(3) Discretionary Preconditioning. 

(i) Any vehicle may be preconditioned by maneuvering the vehicle on to the dynamometer

and driving the 94 to 239 second segment of the transient cycle in 85.2221(e)(1). This

method has been demonstrated to adequately precondition the vast majority of vehicles

(SAE 962091).

Other preconditioning cycles may be developed and used if approved by the

Administrator.

(ii) Alternatively, modal analysis of the failing second-by-second test data may be

performed to identify vehicles that would benefit from additional pre-conditioning. 

Appendix F provides retest criteria developed by Sierra Research under EPA contract

68-C4-0056 Work Assignment 2-04.
15

(e) Vehicle Emission Test Sequence

(1) Transient Driving Cycle. The vehicle shall be driven over the following cycle:

Time

second

Speed

mph

Time

second

Speed

mph

Time

second

Speed

mph

Time

second

Speed

mph

Time

second

Speed

mph

0 0 48 25.7 96 0 144 24.6 192 54.6

1 0 49 26.1 97 0 145 24.6 193 54.8

2 0 50 26.7 98 3.3 146 25.1 194 55.1

3 0 51 27.5 99 6.6 147 25.6 195 55.5

4 0 52 28.6 100 9.9 148 25.7 196 55.7

5 3 53 29.3 101 13.2 149 25.4 197 56.1

6 5.9 54 29.8 102 16.5 150 24.9 198 56.3

7 8.6 55 30.1 103 19.8 151 25 199 56.6

8 11.5 56 30.4 104 22.2 152 25.4 200 56.7

9 14.3 57 30.7 105 24.3 153 26 201 56.7

10 16.9 58 30.7 106 25.8 154 26 202 56.3

11 17.3 59 30.5 107 26.4 155 25.7 203 56

12 18.1 60 30.4 108 25.7 156 26.1 204 55

13 20.7 61 30.3 109 25.1 157 26.7 205 53.4

14 21.7 62 30.4 110 24.7 158 27.3 206 51.6

15 22.4 63 30.8 111 25.2 159 30.5 207 51.8

16 22.5 64 30.4 112 25.4 160 33.5 208 52.1

17 22.1 65 29.9 113 27.2 161 36.2 209 52.5

18 21.5 66 29.5 114 26.5 162 37.3 210 53

19 20.9 67 29.8 115 24 163 39.3 211 53.5

20 20.4 68 30.3 116 22.7 164 40.5 212 54

21 19.8 69 30.7 117 19.4 165 42.1 213 54.9

22 17 70 30.9 118 17.7 166 43.5 214 55.4

23 14.9 71 31 119 17.2 167 45.1 215 55.6

24 14.9 72 30.9 120 18.1 168 46 216 56

25 15.2 73 30.4 121 18.6 169 46.8 217 56

26 15.5 74 29.8 122 20 170 47.5 218 55.8

27 16 75 29.9 123 20.7 171 47.5 219 55.2

28 17.1 76 30.2 124 21.7 172 47.3 220 54.5

29 19.1 77 30.7 125 22.4 173 47.2 221 53.6

30 21.1 78 31.2 126 22.5 174 47.2 222 52.5

31 22.7 79 31.8 127 22.1 175 47.4 223 51.5

32 22.9 80 32.2 128 21.5 176 47.9 224 50.5

33 22.7 81 32.4 129 20.9 177 48.5 225 48

34 22.6 82 32.2 130 20.4 178 49.1 226 44.5

35 21.3 83 31.7 131 19.8 179 49.5 227 41

36 19 84 28.6 132 17 180 50 228 37.5

37 17.1 85 25.1 133 17.1 181 50.6 229 34

38 15.8 86 21.6 134 15.8 182 51 230 30.5

39 15.8 87 18.1 135 15.8 183 51.5 231 27

40 17.7 88 14.6 136 17.7 184 52.2 232 23.5

41 19.8 89 11.1 137 19.8 185 53.2 233 20

42 21.6 90 7.6 138 21.6 186 54.1 234 16.5
16

43 23.2 91 4.1 139 22.2 187 54.6 235 13

44 24.2 92 0.6 140 24.5 188 54.9 236 9.5

45 24.6 93 0 141 24.7 189 55 237 6

46 24.9 94 0 142 24.8 190 54.9 238 2.5

47 25 95 0 143 24.7 191 54.6 239 0

(2) Driving Trace. The inspector shall follow an electronic, visual depiction of the time/speed

relationship of the transient driving cycle, or trace. The visual depiction of the trace shall be of

sufficient magnification and adequate detail to allow accurate tracking by the driver and shall

permit the driver to anticipate upcoming speed changes. The trace shall also clearly indicate

gear shifts as specified in §85.2221(e)(3).

(3) Shift Schedule. For vehicles with manual transmissions, inspectors shall shift gears according

to the following shift schedule:

Shift Sequence

(gear)

Speed

 (miles per hour)

 Nominal Cycle Time

(seconds)

 1 - 2 15 9.3

 2 - 3 25 47.0

 De-clutch 15 87.9

 1 - 2 15 101.6

 2 - 3 25 105.5

 3 - 2 17 119.0

 2 - 3 25 145.8

 3 - 4 40 163.6

 4 - 5 45 167.0

 5 - 6 50 180.0

 De-clutch 15 234.5

Gear shifts shall occur at the points in the driving cycle where the specified speeds are obtained. 

For vehicles with fewer than six forward gears the same schedule shall be followed while

disregarding shifts above the highest gear.

(4) Speed Excursion Limits. Speed excursion limits shall apply as follows:

(i) Upper Limit. The upper limit is 2 mph higher than the highest point on the trace within

1 second of the given time.

(ii) Lower Limit. The lower limit is 2 mph lower than the lowest point on the trace within

1 second of the given time.

(iii) Speed Variations. Speed variations greater than the tolerances (such as may occur

during gear changes) are acceptable provided they occur for no more than 2 seconds on

any occasion.

(iv) Underpowered Vehicles. Speeds lower than those prescribed during accelerations are

acceptable provided the vehicle is operated at maximum available power during such

accelerations until the vehicle speed is within the excursion limits. If the vehicle is

underpowered and unable to adequately follow the trace, it may at the State’s

discretion be rejected from testing or given an idle test.
17

(v) Exceedances. Exceedances of the limits in §85.2221(5)(ii) through §85.2221(5)(iii)

shall automatically result in a void test. The station manager can override the

automatic void of a test if the manager determines that the conditions specified in

§85.2221(e)(4)(iv) occurred.

(5) Speed Variation Limits.

(i) Limits. Based on work performed under contract 68-C4-0056, Work Assignment 2-04

the following Positive Kinetic Energy limits were developed by Sierra Research. 

These results are based on an analysis of 16,581 IM240 tests conducted in AZ.

(ii) PKE = 

P P

d x

t

t 0

t

x 0

x =

=

∑

∫

where: PPt = V2

t - V2(t-1) mi2/hr2 for Vt > V(t-1)

PPt = 0 for Vt = V(t-1) 

x = distance (mi)

(iii) PKE Limits. Full Test PKE Limits:

Upper Limit 3456 mi/hr2

Lower Limit 3082 mi/hr2

NOTE: The test cycle shall be invalid for a pass/fail determination if the PKE value is

below the lower limit for a passing vehicle or above the upper limit for a failing

vehicle. PKE values alone should not be used to make an early pass/fail

determination.

Test cycles with PKE values outside the lower and upper limits shall be valid for

preconditioning provided that all other requirements are met.

(iv) Second-by-Second Limits. Second-by-Second PKE upper and lower limits are listed in

Appendix G.

(6) Distance Criteria. The actual distance traveled for the transient driving shall be measured. If

the absolute difference between the measured distance and the theoretical distance for the actual

test exceeds 0.05 miles, the test shall be void.

(7) Vehicle Stalls. Vehicle stalls during the test shall void the test and result in a new test. More

than 3 stalls shall result in rejecting the vehicle from testing.
18

(8) Inertia Weight Selection. The inertia weight selected for the vehicle shall be verified as

specified in §85.2226(a)(1)(i). For systems employing electrical inertia simulation, an

algorithm identifying the actual inertia force applied during the transient driving cycle shall be

used to determine proper inertia simulation.

(9) CVS Operation. The CVS operation shall be verified for each test for a CFV-type CVS by

measuring either the absolute pressure difference across the venturi or measuring the blower

vacuum behind the venturi for minimum levels needed to maintain choke flow for the venturi

design. The operation of an SSV-type CVS shall be verified throughout the test by monitoring

the difference in pressure between upstream and throat pressure. The minimum values shall be

determined from system calibrations. Monitored pressure differences below the minimum

values shall void the test.

(f) Emission Measurements

(1) Exhaust Measurement. The emission analysis system shall sample and record dilute exhaust

HC, CO, CO2, and NOx during the transient driving cycle as described in §85.2226(c).
19

§85.2222 Evaporative System Pressure and Gas Cap Test Procedures

(a) General Requirements

(1) Pressure Test. The on-vehicle pressure tests described in §85.2222(c) shall be performed after

any tailpipe emission test. Vehicles receiving a pressure test specified in §85.2222(c) should

also be given a gas cap leak test specified in §§85.2222(d).

(2) Controlling Test Variability. The pressure test shall be conducted in a manner that minimizes

changes in temperature, since pressure measurements are affected by changes in the vapor space

temperature. Volume compensation for the pressure test is not required, but the vapor space

volume will affect the pressure decay measurement. Excessive fuel vapor pressure, although

not controllable at the time of test, may affect the accuracy and repeatability of the result.

(3) Gas Cap Test Requirement. A gas cap test described in §85.2222(d) may be performed before

or after the tailpipe emission test.

(4) Alternative Techniques. Alternative gas cap or pressure test procedures may be used if they are

shown to be equivalent or better than those described below.

(b) Pre-inspection and Preparation

(1) Visual Inspection - Canister. The evaporative canister(s) shall be visually checked to the degree

practical. A missing or obviously damaged canister(s) shall fail the visual evaporative system

check.

(2) Visual Inspection - System. The evaporative system hoses shall be visually inspected for the

appearance of proper routing, connection, and condition, to the degree practical. If any

evaporative system hose is misrouted, disconnected, or damaged, the vehicle shall fail the visual

evaporative system check.

(3) Visual Inspection - Gas Cap. If the gas cap is missing, obviously defective, or the wrong style

cap for the vehicle, the vehicle shall fail the visual inspection.

(c) Fuel Inlet Pressure Test

(1) Equipment Set-up. The vapor vent line(s) from the gas tank to the canister(s) shall be clamped

off as close to the canister(s) as practical without damaging evaporative system hardware. Dual

fuel tanks shall be checked individually if the complete vapor control system can not be

accessed by pressurizing from the fill pipe interface of only one fuel tank. The proper adapter,

as specified in §85.2227(c)(2)(i) shall be selected.

(2) Starting Pressure. The gas tank shall be pressurized to 14±1 inch of WC, or a vehicle specific

pressure as identified in the I/M Look-up Table.

(3) Stability. Pressure stability shall be monitored for a period of 10 seconds prior to the start of

the pressure decay measurement. One definition of stability is a loss of no more than 5 inches

WC over a 10 second period when the initial pressure is 14±1 inch WC. If the loss of pressure

in 10 seconds exceeds this value, two more attempts shall be made to reach stability. Failure to

achieve stability likely indicates the presence of a large leak and therefore failure of the pressure

test. Alternate definitions of stability may be proposed by the State and approved by the

Administrator. Stability criteria for flow comparator or direct flow measurement methods do

not apply. 
20

(4) Volume Compensation. Pressure decay measurements are affected by the vapor volume in the

fuel tank. Volume-compensated pressure decay measurements are presently not required. By

design, flow comparator or flow measurement methods do not require volume corrections.

(5) Pressure Monitoring. Close the pressure source and measure the loss in pressure over a 120

second interval. Fast-pass determinations may be made using the equations in

§85.2205(d)(2)(ii).

(6) Clamp Removal. Remove the clamp on the vapor line and carefully relieve pressure and

remove the adapter used to supply pressure to the vapor space.

(d) Gas Cap Test

(1) Cap Installation. The fuel cap, or caps, shall be removed from the fuel inlet(s) and installed on

a portable or bench test rig using the adapter appropriate for the gas cap as specified in

§85.2227(d)(1)(ii).

(2) Leak Measurement. The gas cap leak rate shall be measured and compared against a 60 cc/min

at 30 in. WC flow standard. Pressure decay measurement using instruments with a 1 liter head

space shall be made from an initial pressure of 28 in. WC and be compared against a loss of 6

in. WC in 10 seconds.

(3) Cap Replacement. The fuel cap(s) shall be replaced on the fuel inlet and tightened

appropriately.
21

§85.2226 IM240 Equipment Specifications

(a) Dynamometer Specifications

(1) General Requirements.

(i) Capacity. The dynamometer structure (e.g., bearings, rollers, pit plates, etc.) shall

accommodate all light-duty vehicles and light-duty trucks up to 8500 pounds GVWR. 

(ii) Test Parameters. Road load horsepower and inertia simulation shall be automatically

selected from the EPA I/M Look-up Table, or equivalent data base, based on the

vehicle parameters in the test record.

(iii) Alternative Designs. Alternative dynamometer specifications, designs, and error

checking methods may be used if the alternative provides proper dynamometer loading

over the IM240 driving cycle.

(iv) Units. Specifications in this section are generally expressed in units of horsepower. 

System designs using equivalent units of force, English or SI, are permissible.

(v) Ambient Range. The dynamometer shall be designed to meet specifications at an

ambient temperature range of 35 to 110°F, and at absolute humidity values

representative of the IM240 testing location. 

(2) Power Absorption.

(i) Power Absorber Design. The power absorber unit shall be an electric AC or DC

motor/absorber design. Eddy current designs may be approved if proven equivalent to

other designs in terms of inertia response time, total load, and emissions performance

over an IM240 driving cycle.

(ii) Range.

(A) Mechanical Inertia Dynamometers. Dynamometers using clutchable flywheels

shall have sufficient power absorber capacity to accommodate the TRLHP

values in the EPA I/M Look-up Table.

(B) Electric Inertia Dynamometers. Dynamometers using a combination of

mechanical base inertia and supplemental electrical inertia shall have sufficient

power absorber capacity to accommodate the sum of the TRLHP values in the

EPA I/M Look-up Table plus the power absorbed from accelerating a vehicle at

3.3 mph/sec at the equivalent test weight (ETW) specified in the I/M Look-up

Table.

(iii) Accuracy. The power absorber shall be adjustable across the required horsepower

range at 50 mph in 0.1 horsepower increments. The accuracy of the power absorber or

power exchange unit, for road load simulation only, shall be ±0.25 horsepower or ±3%

of point, whichever is greater.

(iv) Indicated Horsepower. At constant velocity, the power absorber shall load the vehicle

according the following equations:

IHP = TRLHP - PLHP - GTRL

Where: IHP is the dynamometer indicated, or set, horsepower.
22

TRLHP is the track, or total, horsepower for a particular vehicle.

PLHP is the dynamometer parasitic loss horsepower.

GTRL is the generic tire/roll loss of a vehicle on the dynamometer.

TRLHP, PLHP, GTRL, and therefore IHP, are all expressed as three term polynomials of

the type:

HP = A*Obmph + B*Obmph2 + C*Obmph3

Where: HP represents individual expressions relating IHP, TRLHP, PLHP,

or GTRL as a function of velocity.

A, B, or C represent horsepower coefficients for the individual

expressions relating IHP, TRLHP, PLHP, or GTRL as a function of

velocity.

Obmph is the velocity in miles per hour.

Expressions for TRLHP, and GTRL are found in Appendices H and I. 

(3) Inertia.

(i) Range. The dynamometer shall provide inertia simulation capability of 2000 to 5500

pounds for light duty vehicles and trucks less than or equal to 5500 pounds ETW. 

Dynamometers used for testing light duty vehicles and trucks over 5500 ETW shall

have inertia simulation capability to set the inertia at the correct value as referenced in

the EPA I/M Look-up Table.

(ii) Mechanical Inertia Simulation. The dynamometer shall be equipped with clutchable

mechanical flywheels with inertia selectable to a 250 pound sensitivity. The tolerance

on the base inertia weight and the flywheels shall be within 1% of the specified test

weights. The test system shall be equipped with a method, independent from the

flywheel selection system, that identifies which flywheels are actually rotating during

the transient driving cycle.

(iii) Electric Inertia Simulation. Electric inertia simulation, or a combination of electric and

mechanical simulation may be used in lieu of mechanical flywheels, provided that the

performance of the electrically simulated inertia complies with the following

specifications.

(A) System Response. The torque response to a step change shall be at least 90% of

the command value within 200 milliseconds, and shall be within 2 percent of the

commanded torque by 300 milliseconds after the command is issued. Any

overshoot of the commanded torque value shall not exceed 25 percent of the

torque value. Response time measurements shall be performed at 2000, base

inertia, and 5500 pounds of inertia.

(B) Simulation Error. An inertia simulation error (ISE) shall be continuously

calculated any time the actual dynamometer speed is between 10 and 60 mph.

The average positive ISE over the driving cycle shall be calculated by the

equation in §85.2226(a)(3)(iii)(C), and shall not exceed 2 percent of the inertia

weight selected (IWs) for the vehicle under test.
23

(C) ISE 

IW - I

IW

s t

s

= 



 



 *100

Where: ISE = Inertia simulation error expressed in percent.

IWs = Total inertia desired, or selected, in pounds mass.

It

 = Total inertia being simulated by the dynamometer in 

pounds mass.

(D) I I

32.2

V (F F )dt t m m rl

t 0

t

=+ −

=

∫

Where: It = Total inertia being simulated by the dynamometer in pounds mass. 

Im = Base mechanical inertia of the dynamometer in pounds mass.

32.2 = Gravitational constant, (ft)(lbm)/(lbf)(sec2

).

V = Measured roll speed in feet/second.

Fm = Force measured by the load cell converted to force at the roll

surface in pounds. 

Frl = Dynamometer road load expressed as a three term polynomial in

pounds force at the measured roll speed.

t = Time in seconds.

(4) Dynamometer Parasitic Loss

(i) Friction Curves. The dynamometer internal friction curves, typically bearing and

windage friction expressed as a function of velocity, shall be capable of being

automatically measured, stored, and accurately accounted for over the IM240 driving

cycle.

(ii) Friction Curve Definition. Parasitic loss friction shall be expressed in a tabular format

as a function of velocity, or as a polynomial of the type: 

PLHP = Ap*Obmph + BpObmph2 + CpObmph3

Where: PLHP represents the dynamometer parasitic friction, expressed in

horsepower.

Ap, Bp, and Cp are coefficients relating a least squares fit of

dynamometer friction and velocity.

Obmph is dynamometer roll surface velocity in miles per hour.
24

(5) Rolls.

(i) Size and Type. The dynamometer shall be equipped with twin rolls. The rolls shall be

coupled side to side. In addition, the front and rear rolls shall be coupled. The

dynamometer roll diameter shall be between 8.5 and 21.0 inches. The spacing between

the roll centers shall comply with the equation in §85.2226(a)(5)(iii). The

dynamometer rolls shall accommodate an inside track width of 30 inches and an

outside track width of at least 100 inches.

(ii) Roll Installation. Rolls shall be installed in the floor such that vehicles will be within

±5 degrees of horizontal.

(iii) Roll Spacing. The spacing between the roll centers shall comply with the following

equation to within +0.5 inches and -0.25 inches.

Roll Spacing = (24.375 + D) * Sin 31.5(

Where: Roll Spacing is the distance between the roll centerlines in inches.

D = Roll diameter in inches

(iv) Roll Surface. The surface finish and hardness shall be such that tire slippage is

minimized when testing vehicles using the inertia weight and horsepower settings

found in the EPA I/M Look-up Table while following the IM240 driving schedule, and

that tire wear and noise are minimized. Knurled roll surfaces are acceptable.

(v) Test Distance and Vehicle Speed. The total number of dynamometer roll revolutions

shall be used to calculate the distance traveled. Pulse counters may be used to

calculate the distance directly if there are at least 16 pulses per revolution. The

measurement of the actual roll distance for the composite and each phase of the

transient driving cycle shall be accurate to within ±0.01 mile. The measurement of the

roll speed shall be accurate to within ±0.1 mph over the IM240 driving schedule.

(vi) Vehicle Lift. A vehicle lift system located between the dynamometer rolls shall be

provided to facilitate drive axle positioning and vehicle egress from the dynamometer.

(vii) Vehicle Restraint System. The dynamometer shall include a system of safely

restraining the forward and side-to-side motion of front wheel drive vehicles, and the

forward motion of rear wheel drive vehicles during the IM240 driving schedule, while

allowing unobstructed ingress and egress from the dynamometer.

(6) Load Cell.

(i) Torque Measurement. The dynamometer shall have a torque measurement system

accurate to within ±2% of full scale.

(ii) Dead Weights. Dead weights used to calibrate a torque meter or load cell shall be

traceable to NIST and be accurate to within ±0.5%.

(iii) Dynamic Calibrations. Designs using an F = MA method for calibrating the load cell

are also acceptable. 

(7) Driver's Aid.
25

(i) Video Display. The dynamometer shall be equipped with a video display device able

to be easily positioned to accommodate all test vehicles while clearly visible to the

driver. The display shall have a method that allows the driver to accurately and

smoothly follow the desired driving cycle.

(ii) Remote Capabilities. The dynamometer shall have a means of allowing the driver to

start the test, perform an emergency stop, and perform other necessary and convenient

functions related to the test while inside the vehicle. 

(8) Other.

(i) Augmented Braking. Augmented braking shall be used during vehicle decelerations

on the driving cycle. Augmented braking shall be actuated only when the negative

force applied by the vehicle at the roll surface is greater than 110 pounds. If the

augmented braking is not linked to driver braking, the driver shall be signaled to not

accelerate during this period.

(ii) Cooling Fan. The cooling fan capacity shall be 5400 ±300 SCFM, positioned within

12 inches of the intake to the vehicle's cooling system, and avoid unrepresentative

cooling of the engine and exhaust control system.

(9) All Wheel Drive Dynamometers.

(i) Design. The dynamometer shall meet the requirements for two wheel drive vehicles

and be capable of testing traction control and all wheel drive vehicles in a safe manner

without damaging the vehicle. 

(ii) Wheelbase. The all wheel drive dynamometer shall be capable of testing vehicles

having a wheelbase between 84 and 125 inches, or as necessary to meet the wheelbase

values in the I/M Look-up Table. The system shall provide a locking mechanism to

secure the roll at the desired wheelbase.

(iii) Speed Synchronization. Front and rear wheels shall maintain speed synchronization

within ±0.1 mph.

(b) Constant Volume Sampler

(1) General Design Requirements.

(i) Venturi Type. A constant volume sampling (CVS) system of the critical flow venturi

(CFV) or the sub-sonic venturi (SSV) type shall be used to collect vehicle exhaust

samples. The CVS system and components shall generally conform to the

specifications in §86.109-90.

(ii) CVS Flow Size. The CVS system shall be sized in a manner that prevents

condensation in the dilute sample over the range of ambient conditions to be

encountered during testing. A 700 SCFM system is assumed to satisfy this

requirement. The range of ambient conditions may require the use of heated sample

lines. Should heated sample lines be used , the lines and components shall be heated to

a minimum of 120(F and a maximum of 250(F, which shall be monitored during the

driving cycle.

(iii) CVS Compressor. The CVS compressor flow capacity shall be sufficient to maintain

proper flow in the main CVS venturi with an adequate margin. For CFV CVSs the
26

margin shall be sufficient to maintain choke flow. The capacity of the blower relative

to the CFV flow capacity shall not be so large as to create a limited surge margin.

(iv) Materials. All materials in contact with exhaust gas shall be unaffected by and shall

not affect the sample (i.e., the materials shall not react with the sample, and neither

shall they taint the sample as a result of out gassing). Acceptable materials include

stainless steel, Teflon®, silicon rubber, and Tedlar®.

(v) Alternative Designs. Alternative CVS specifications, materials, or designs may be

allowed upon a determination by the Administrator, that for the purpose of properly

conducting an approved short test, the evidence supporting such deviations will not

significantly affect the proper measurement of emissions.

(2) Sample System.

(i) Sample Probe. The sample probe within the CVS shall be designed such that a

continuous and adequate volume of sample is collected for analysis. The system shall

have a method for determining if the sample collection system has deteriorated or

malfunctioned such that an adequate sample is not being collected, or that the response

time has deteriorated such that the time correlation for each emission constituent is no

longer valid.

(ii) CVS Mixing Tee.

(A) Design and Effect. The mixing tee for diluting the vehicle exhaust with

ambient air shall be at the vehicle tailpipe exit as in §86.109-90(a)(2)(iv). The

dilution mixing tee shall be capable of collecting exhaust from all light-duty

vehicle and light-duty truck exhaust systems. The design used shall not cause

static pressure in the tailpipe to change such that the emission levels are

significantly affected. A change of ±1.0 inch of water or less, as measured at

the tailpipe, shall be acceptable.

(B) Locating Device. The mixing tee shall have a device for positively locating

the tee relative to the tailpipe with respect to distance from the tailpipe, and

with respect to positioning the exhaust stream from the tailpipe(s) in the

center of the mixing tee flow area. The locating device, or the size of the

entrance to the tee shall be such that if a vehicle moves laterally from one

extreme position on the dynamometer to the other extreme, that mixing tee

will collect all of the exhaust sample.

(iii) Dual Exhaust. For dual exhaust systems, the design used shall insure that each leg of

the sample collection system maintains equal flow. Equal flow will be assumed if the

design of the "Tee" intersection for the dual CVS hoses is a "Y" that minimizes the

flow loss from each leg of the "Y," if each leg of the dual exhaust collection system is

approximately equal in length (± 1 foot), and if the dilution area at the end of each leg

is approximately equal. In addition, the CVS flow capacity shall be such that the

entrance flow velocity for each leg of the dual exhaust system is sufficient to entrain

all of the vehicle's exhaust from each tailpipe.

(iv) Background Sample. The mixing tee shall be used to collect the background sample.

The position of the mixing tee for taking the background sample shall be within 12

lateral and 12 longitudinal feet of the position during the transient driving cycle, and

approximately 4 vertical feet from the floor.
27

(v) Integrated Sample. A continuous dilute sample shall be provided for integration by the

analytical instruments in a manner similar to the method for collecting bag samples as

described in §86.109-90.

(c) Analytical Instruments

(1) General Requirements.

(i) Instrument Specifications. The emission analysis system shall automatically sample,

integrate, and record the specified emission values for HC, CO, CO2, and NOx. 

Performance of the analytical instruments with respect to accuracy and precision, drift,

interferences, noise, etc. shall be similar to instruments used for testing under §86

Subparts B, D, and N. Analytical instruments shall perform in this manner in the full

range of operating conditions in the lane environment.

(ii) Alternative Designs. Alternative analytic equipment specifications, materials, designs,

or detection methods may be allowed upon a determination by the Administrator, that

for the purpose of properly conducting an approved short test, the evidence supporting

such deviations will not significantly affect the proper measurement of emissions.

(2) Detection Methods and Instrument Ranges

(i) Total Hydrocarbon Analysis. Total hydrocarbon analysis shall be determined by a

flame ionization detector. If a 700 SCFM CVS is used, the analyzer calibration curve

shall cover at least the range of 0 ppmC to 2,000 ppmC. Use of a different CVS flow

capacity shall require an adjustment to these ranges. Appropriate documentation

supporting any adjustment in ranges shall be available. The calibration curve must

comply with the quality control specifications in §85.2234(d) for calibration curve

generation.

(ii) Carbon Monoxide Analysis. CO analysis shall be determined using a non-dispersive

infrared analyzer. If a 700 SCFM CVS is used, CO analysis shall cover at least the

range of 0 ppm to 10,000 ppm (1%). In order to meet the calibration curve

requirements, two CO analyzers may be required - one from 0 to 1000 or 2000 ppm,

and one from 0 to 1% CO. Use of a different CVS flow capacity shall require an

adjustment to these ranges. Appropriate documentation supporting any adjustment in

ranges shall be available. The calibration curve requirements and the quality control

specifications in §85.2234(d) apply to both analyzers.

(iii) Carbon Dioxide Analysis. CO2 analysis shall be determined using an NDIR analyzer. 

If a 700 SCFM CVS is used, CO2 analysis shall cover at least the range of 0 ppm to

40,000 ppm (4%). Use of a different CVS flow capacity shall require an adjustment to

these ranges. Appropriate documentation supporting any adjustment in ranges shall be

available. The calibration curve must comply with the quality control specifications in

§85.2234(d) for calibration curve generation.

(iv) Oxides of Nitrogen Analysis. NOx analysis shall be determined using

chemiluminescence. The NOx measurement shall be the sum of nitrogen oxide and

nitrogen dioxide. Alternatively, NOx measurements may be made by re-calibrating the

chemiluminescence analyzer in NO only mode, then running the analyzer in NO only

mode and multiplying the result by 1.03. This will eliminate the need for the converter

and flow balance checks in §85.2234(d)(5) and §85.2234(d)(6).

If a 700 SCFM CVS is used, the NOx analysis shall cover at least the range of 0 ppm

to 500 ppm. Use of a different CVS flow capacity shall require an adjustment to these
28

ranges. Appropriate documentation supporting any adjustment in ranges shall be

available. The calibration curve must comply with the quality control specifications in

§85.2234(d) for calibration curve generation.

(3) System Response Requirements. Historically, continuously integrated emission analyzers have

been required to have a response time of 1.5 seconds or less to 90% of a step change, where a

step change was 60% of full scale or better. System response times between a step change at

the probe and reading 90% of the change shall be less than 10 seconds.

(4) Integration Requirements.

(i) Sampling Frequency. The analyzer voltage responses, CVS pressure(s), CVS

temperature(s), dynamometer speed, and dynamometer power shall be sampled at a

frequency of no less than 5 Hertz, and the voltage levels shall be averaged over 1

second intervals.

(ii) Time Alignment. The system shall properly time correlate each analyzer signal and the

CVS signals to the driving trace.

(iii) Engineering Units. The one-second average analyzer voltage levels shall be converted

to concentrations by the analyzer calibration curves. Corrected concentrations for each

gas shall be derived by subtracting the pre-test background concentrations from the

measured concentrations, according to the method in §85.2205(b). The corrected

concentrations shall be converted to grams, for each second, using the equations

specified in §85.2205(b) to combine the concentrations with the CVS flow over the

same interval. The grams of emissions per test phase shall be determined using the

equations in §85.2205(b).

(iv) Multiple Analyzers. When multiple analyzers are used for any constituent, the

integration system shall simultaneously integrate both analyzers. The integrated values

for the lowest analyzer in range shall be used for each second.

(v) Background Samples. For all constituents, the background concentration levels from

the lowest range shall be used, including the case where multiple analyzers may have

been used.

(5) Analytical System Design.

(i) Materials. All materials in contact with exhaust gas prior to and throughout the

measurement portion of the system shall be unaffected by and shall not affect the

sample (i.e., the materials shall not react with the sample, and neither shall they taint

the sample as a result of out gassing). Acceptable materials include stainless steel,

Teflon, silicon rubber, and Tedlar®.

(ii) System Filters. The sample system shall have an easily replaceable filter element to

prevent particulate matter from reducing the reliability of the analytical system. The

filter element shall provide for reliable sealing after filter element changes. If the

sample line is heated, the filter system shall also be heated.

(iii) Availability of Intermediate Calculation Variables. Upon request prior to a test, all

intermediate calculation variables shall be available to be downloaded to electronic

files or hard copy. These variables shall include those that calculate the vehicle

emission test results, perform emission analyzer and dynamometer function checks,

and perform quality assurance and quality control measurements.
29

§85.2227 Evaporative System Equipment Specifications

(a) General Requirements

(1) Equipment Design. Automated and computerized test systems shall be used for the evaporative

system tests wherever they are appropriate. Pass/fail decisions shall be made automatically. 

The systems shall be tamper resistant and designed to avoid damage to the vehicle during

installation, testing, and removal.

(2) Alternative Systems. Alternative purge, pressure, or gas cap test equipment specifications or

designs may be proposed by a State if they are supported by data and approved in advance by

the Administrator.

(b) Evaporative System Pressure Test Equipment

(1) General Requirements.

(i) Alternative Designs. Flow measurement or flow comparator leak detection methods

are acceptable if supported by data and approved in advance by the Administrator. 

Standards for flow based methods have not been established.

(ii) Pressurizing Gas. Nitrogen, or an equivalent non-toxic, non-greenhouse, inert gas,

shall be used for pressurizing the evaporative system. Air should only be used if the

pressurized vapor space is outside the combustible limits for the vehicle fuel type.

(iii) Automatic Operation. The process for filling the vapor space, monitoring compliance,

recording data, and making a pass/fail decision shall be automatic. After the

determination that the evaporative system has been filled to the specified pressure

level, and upon initiation of the test, the pressure level in the evaporative system shall

be recorded at a frequency of no less than 1 Hertz until the conclusion of the test.

(iv) Test Abort. The system shall be equipped with an abort system that positively shuts

off and relieves pressure. The abort system shall be capable of being activated quickly

and conveniently by the inspector should the need arise.

(v) Grounding. A fillpipe pressure test must be designed to prevent electrostatic discharge

that would pose a flammability risk during the test.

(2) Adapters and Clamps.

(i) Fuel Inlet Adapters. Adapters attached to the fuel fillpipe inlet shall be used to supply 

pressurized gas into the fuel tank. Adapters shall be available for at least 95 percent of

the fuel inlets that are used on U.S. light duty vehicles and light duty trucks for the

model years covered by the program.

(ii) Hose Clamp. The hose clamp used for the fuel inlet pressure test shall be designed to

apply only enough pressure to close the flexible vent line between the fuel tank and

canister without damaging it. The nose of the clamp shall be smooth-surfaced or

otherwise designed to avoid damage to the vent line.

(3) Pressure Gauge. The device for measuring pressure shall have a minimum range of 0 to 28

inches of water and an accuracy of +0.3 inches of water, or 2% of point, whichever is greater.

(c) Gas Cap Test Equipment 
30

(1) General Requirements.

(i) Alternative Designs. Leak testers failing gas caps with a test standard below 60 cc/min

at 30 in. WC are permissible provided they do not falsely fail gas caps designed to

meet vehicle manufacturer OEM specifications, are repeatable and accurate in a

centralized I/M environment, and demonstrate quantifiable reductions in real world

mass emissions. OEM leak rates for individual manufacturers are proprietary. 

Information submitted to EPA shows some vehicle manufacturers had maximum leak

rates up to 20 cc/min at 30 inches of WC.

(ii) Gas Cap Adapters. The gas cap tester shall accommodate at least 95 percent of the gas

caps that are used on U.S. light duty vehicles and trucks for the model years covered

by the gas cap test program.

(iii) Pressurizing Gas. Air, Nitrogen, or an equivalent non-toxic, non-greenhouse, inert gas,

shall be used for pressurizing the gas cap tester.

(iv) Automatic Operation. The process for making a pass/fail decision shall be automated. 

The gas cap tester shall provide for automated pass/fail determination and automated

transfer of the pass/fail result to a host computer, i.e. a real-time data link.

(v) Over-Pressurization. The tester shall control the supply pressure of the gas used for

pressure decay, direct flow measurement, or flow comparison methods and prevent

over-pressurization.

(2) Gas Cap Tester. Gas cap testers employing internal reference orifices, or pressure measurement

devices, shall be traceable to NIST flow or pressure measurement standards.

(i) Range. The tester shall identify passing gas caps with a leak rate equal to or less than

60 cc/min of air at 30 inches of WC, and failing caps with leak rates more than 60

cc/min at 30 inches of WC at reference conditions of 70F and 1 atm. 

(ii) Filter. A serviceable air filter shall be incorporated upstream of flow orifices.

(iii) Power Supply. Battery powered testers shall be equipped with an automatic shutoff

and a low-battery indicator.

(iv) Accuracy. Pressure decay, direct flow measurement, or flow comparison methods

shall be accurate to ±3 cc/min at the 60 cc/min flow standard.

(v) Reference Caps and Orifices. NIST traceable reference passing fuel caps or orifices of

nominal 52-56 cc/min, and NIST traceable reference failing fuel caps or orifices of

nominal 64-68 cc/min shall be supplied with the tester for daily verification tests.

(vi) Head Space. Pressure decay methods shall employ a head space sized to produce

correct results at the 60 cc/min at 30 in. WC standard.
31

§85.2234 IM240 Test Quality Control Requirements

(a) General Requirements

(1) Manufacturers' Recommendations. Manufacturers' recommendations for equipment

installation, calibration, and maintenance, shall be followed.

(2) Statistical Process Control. SPC tracking methods shall be established for appropriate

equipment checks and custom diagnostic or verification tests.

(3) Modifications to Quality Control Requirements. Changes to the type or frequency of the quality

checks are permitted provided they are based on SPC analysis, or data from experimental

studies.

(b) Dynamometer

(1) Dynamometer Manufacturer Recommendations

(i) Minimum Requirements. The dynamometer manufacturer's requirements for periodic

diagnostic checks, calibration, scheduled maintenance, and recommended quality

control monitoring shall be followed.

(ii) Warm-up Requirements. The dynamometer manufacturer's procedure for insuring

proper warm-up over a 35 to 110°F temperature range shall be followed.

(2) Coast Down Testing

(i) Frequency. Dynamometers with electric and mechanical inertia simulation shall

receive a daily unloaded (vehicle off the dynamometer) coast down check over the

range of 60 to 10 mph. This daily check shall be run at alternating combinations of

inertia and road load settings. Dynamometers using only mechanical flywheels for

inertia simulation shall also receive additional weekly coast down checks to properly

characterize the friction at other combinations of flywheel weights. The number of

these coast downs shall be established based on the dynamometer design and quality

control monitoring. 

(ii) Load Settings. Inertia and power absorber settings shall be representative of vehicle

test conditions, and shall result in nominal coast down times of 15-20 seconds when

time is measured between 55 and 45 mph, and 22-33 seconds when time is measured

between 22 and 18 mph. Inertia settings for clutchable flywheel dynamometers are

discretionary but should attempt to be above and below the base inertia of the

dynamometer and represent high and low inertia weight vehicles.

(iii) Quality Control Limits. Actual control limits for the coast down tests shall be

established by statistical process control practices. The 55 to 45 mph and 22 to 18 mph

coastdown times shall be within ±1 second, and ± 6 seconds, respectively, of the

theoretical coast down times. These ±1 and ±6 second limits are based on the 15-20

and 22-33 second coastdown times in the preceding paragraph. Theoretical coastdown

time is based on the following equation: 

( ) t 

0.5 * ETW

32.2 * (V V )

550* HP

I

2

F

2

= −

Where: t = The coastdown time in seconds
32

ETW = The Equivalent Test Weight in pounds

VI = The initial roll velocity in feet/second

VF = The final roll velocity in feet/second

IHP = The dynamometer indicated horsepower

An alternative to the ±1 or ±6 second limits is to perform an unloaded coastdown from

60 to 10 mph and reduce the speed/time data to produce a polynomial relationship

between horsepower (or force) versus time. The measured horsepower curve shall be

within ±0.25 horsepower or ±3% of point, whichever is greatest.

Dynamometers which exceed specific SPC limits or the coast down limits presented

above, shall be removed from service until corrective action is taken to assure the

dynamometer is performing satisfactorily.

 (3) Parasitic Loss Checks

(i) Frequency. Checks of the parasitic loss curve shall be conducted at a frequency 

recommended by the dynamometer manufacturer, as required by inspection of quality

control data, or as necessary following service to the dynamometer.

(ii) Quality Control Limits. Parasitic loss measurements shall be measured between 10

and 60 mph. Identification of outlier data shall be established by examination of

quality control data.

Dynamometers which exceed dynamometer specific SPC limits for parasitic loss

checks shall be removed from service until corrective action is taken to ensure the

dynamometer is performing satisfactorily.

(4) Roll Speed. 

(i) Frequency. Weekly checks of the roll speed measurement system shall be made, or at

intervals recommended by the dynamometer manufacturer, or as required by

inspection of quality control data, or as necessary following service to the

dynamometer.

(ii) Quality Control Limits. If roll speed checks are conducted, the measured roll speed

shall agree to within ±0.1 mph of the calibration standard. Dynamometers which

exceed the 0.1 mph limit shall be removed from service until corrective action is taken

to ensure the dynamometer is performing satisfactorily.

(5) Acceptance Criteria

(i) General. Prior to dynamometer acceptance, the dynamometer shall demonstrate

compliance with the design criteria for the load cell accuracy, power absorber curve

accuracy, roll geometry, dynamometer simulation error, electric inertia response time,

and parasitic loss measurement. These criteria are specified in §85.2226(a).

(ii) Base Inertia Verification. The base inertia of dynamometers shall be verified before

dynamometer acceptance. The base inertia weight plus individual prime weights shall

be verified for dynamometers which simulate inertia with mechanical flywheels. The
33

specified base inertia shall agree with acceptance testing measurements within ±10

pounds.

(iii) Independent Speed and Distance Verification. An independent method of verifying

dynamometer roll speed and distance measurement accuracy shall be performed before

dynamometer acceptance to ensure compliance with the specifications in

§85.2226(a)(5)(v).

(c) Constant Volume Sampler

(1) Flow Calibration. The flow of the CVS shall be calibrated at six flow rates upon initial

installation, 6 months following installation, and every 12 months thereafter. SPC tracer gas

injection data may be used to verify CVS flow in lieu of the annual calibration requirement. 

This data shall be made available to EPA upon request. The flow rates shall include the

nominal rated flow-rate and a rate below the rated flow-rate for both critical flow venturis and

subsonic venturis, and a flow-rate above the rated flow for sub-sonic venturis. The flow

calibration points shall cover the range of variation in flow that typically occurs when testing. 

A complete calibration shall be performed following repairs to the CVS that could affect flow.

(2) System Check. CVS flow calibration at the nominal CVS design flow shall be checked once

per day using a procedure equivalent to that in §86.119(c). Deviations greater than ±4% shall

result in automatic lockout of official testing until corrected. At the State’s discretion, the

frequency of this may be reduced to weekly.

(3) Cleaning Flow Passages. The sample probe shall be checked at least once per month, and

cleaned if necessary in order to maintain proper sample flow. CVS venturi passages shall be

checked once per year and cleaned if necessary.

(4) Probe Flow. The indicator identifying the presence of proper probe flow for the system design

(e.g., proportional flow for CFV systems, minimum flow for time correlation of different

analyzers) shall be checked on a daily basis. Lack of proper flow shall require corrective action.

(5) Leak Check. The vacuum portion of the sample system shall be checked for leaks on a daily

basis and each time the system is serviced.

(6) System Response Time Check. The response time of each analyzer shall be checked upon

initial installation and after each repair or modification to the flow system that would reasonably

be expected to affect the response time, and at least once per week. The check shall include the

complete sample system from the sample probe to the analyzer. Statistical process control shall

be used to monitor compliance and establish quality control limits. At a minimum, response

time measurements that deviate significantly from the average response time for all CVS

systems designed to the same specification in the program shall require corrective action before

testing may resume.

(7) Mixing Tee Acceptance Test.

(i) Static Pressure Requirement. The design of the mixing tee shall be evaluated by

running the transient driving cycle on at least two vehicles, representing the high and

low ends of engine displacement and inertia. Changes in the static tailpipe pressure

with and without CVS, measured on a second-by-second basis within 3 inches of the

end of the tailpipe, shall not exceed ±1.0 inch of water.

(ii) Single Exhaust System. The ability of the mixing tee design to capture all of the

exhaust as a vehicle moves laterally from one extreme position on the dynamometer to

the other extreme shall be evaluated with back-to-back testing of three vehicles,
34

representing the high and low ends of engine displacement and inertia. The back-toback testing shall be done with the mixing tee at the tailpipe and with an airtight

connection to the tailpipe (i.e., the mixing tee will be effectively moved downstream,

as in typical FTP testing). The difference in carbon-balance fuel economy between the

mixing tee located at the vehicle and the positive connection shall be no greater than

5%.

(iii) Dual Exhaust System. The design of the dual exhaust system shall be evaluated with

back-to-back testing of three vehicles, representing the high and low ends of engine

displacement and inertia, with an airtight connection to the tailpipe (i.e., the mixing tee

will be effectively moved downstream, as in typical FTP testing, for these qualification

tests). The difference in carbon-balance fuel economy between the two methods shall

be no greater than 5%.

(d) Analysis System

(1) Calibration Curve Generation. 

(i) Initial Installation Calibration. Upon initial installation, calibration curves shall be

generated for each analyzer. If an analyzer has more than one measurement

transducer, each transducer shall be considered as a separate analyzer in the analysis

system for the purposes of curve generation and analysis system checks.

(ii) Complete Range Calibration. The calibration curve shall consider the entire range of

the analyzer as one curve.

(iii) Calibration Point Spacing. When both a low range analyzer and a high range analyzer

are used for a single gas (e.g., CO), the high range analyzer shall use at least 5

calibration points plus zero in the lower portion of the high range scale corresponding

to approximately 100% of the full-scale value of the low range analyzer. For all

analyzers, at least 5 calibration points shall be used to define the calibration curve

above the 5 lower calibration points. The calibration zero gas shall be used to set the

analyzer to zero.

Alternatively, gas dividers may be used to generate a 10-point calibration curve

employing equally spaced points. 

(iv) Calibration Curve Fits. The calibration curves generated shall be a polynomial of the

best fit and no greater than 4th order, and shall fit the data within ±2.0% at each

calibration point as specified in §86.120-90, §86.122-78, §86.123-78, and §86.124-78.

(v) Mid-scale Verification. Each curve shall be verified for each analyzer with a

confirming calibration standard between 30-60% of full scale that is not used for curve

generation. Each confirming standard shall be measured by the curve within 2.5%.

(2) Spanning Frequency. The zero and up-scale span points shall be checked at 3 hour intervals

following the daily mid-scale curve check specified in §85.2234(d)(4) and adjusted if necessary. 

If the up-scale span point drifts by more than 2.0% from the previous check official testing shall

be prevented and corrective action shall be taken to bring the system into compliance. If the

zero point drifts by more than 2 ppmC HC, 1 ppm NOx, 10 ppm CO, or 40 ppm CO2, official

testing shall be prevented and corrective action shall be taken to bring the system into

compliance, or the unit may be zeroed prior to each test.

(3) Limit Check. The tolerance on the initial adjustment of a change in the up-scale span point

shall be ± 2% of point on the appropriate analyzer range. A software algorithm to perform the

zero and span adjustment and subsequent calibration curve adjustment shall be used. 
35

Cumulative software up-scale zero and span adjustments greater than ± 10% from the latest

calibration curve shall cause official testing to be prevented and corrective action shall be taken

to bring the system into compliance. Zero and span potentiometers on the analyzer may be used

between calibrations to minimize software corrections; however, a zero and span check shall be

performed after any adjustment of a potentiometer. 

(4) Daily Calibration Checks. The curve for each analyzer shall be checked and adjusted to

correctly read zero using a working zero gas, and an up-scale span gas within the tolerance in

§85.2234(d)(3), and then by reading a mid-scale span gas within 2.5% of point, on each

operating day prior to vehicle testing. If the analyzer does not read the mid-scale span point

within 2.5% of point, the analyzer shall automatically be prevented from official testing. The

up-scale span gas concentration for each analyzer may be up to 90% of full scale, and the midpoint concentration shall correspond to approximately 15% of full scale.

(5) Monthly NOx Converter Checks. The converter efficiency of the NO2 to NO converter shall

be checked on a monthly basis. The check shall be equivalent to §86.123-78 (for reference see

TSD Form 305-01) except that the concentration of the NO gas shall be in the range of 75-400

ppm. Alternative methods may be used if approved by the Administrator.

This check is not required if the measurements of NO only are being performed per

85.2226(c)(2)(iv) with the NOx analyzer run in NO only mode.

(6) Monthly NO/NOx Flow Balance. The flow balance between the NO and NOx test modes shall

be checked monthly. The check may be combined with the NOx converter check as illustrated

in EPA NVFEL test laboratory Form 305-01.

This check is not required if the measurements of NO only are being performed per

85.2226(c)(2)(iv) with the NOx analyzer run in NO only mode.

(7) Monthly Calibration Checks. The basic calibration curve shall be verified monthly by the same

procedure used to generate the curve in §85.2234(d)(1), and to the same tolerances.

(8) FID Check.

(i) FID Optimization. Upon initial operation, and after maintenance to the detector, each

FID shall be checked, and adjusted if necessary, for proper peaking and

characterization using the procedures described in SAE Paper No. 770141 or by

analyzer manufacturer recommended procedures.

(ii) Methane Response. The response of each FID to a methane concentration of

approximately 50 ppm CH4 shall be checked once per month. If the response is

outside of the range of 1.00 to 1.30, corrective action shall be taken to bring the FID

response within this range. The response shall be computed by the equation in

§85.2234(d)(8)(iii). The frequency of this check may be reduced by providing 1 year

of data for each analyzer that demonstrates less frequent checks are acceptable. If less

frequent checks are used, the response check data shall be made available to EPA upon

request.

(iii) Methane Response Definition. Ratio of Methane Response = FID response to CH4

gas in ppmC /ppm CH4 in the cylinder.

(9) Mid-Span or Cross-Checks. On a quarterly basis, and whenever gas bottles are changed, each

analyzer in a given facility shall analyze a sample of a test gas. The test gas used for these cross

checks shall be a 1% NIST traceable mid-span bottle and the same bottle shall be used for all
36

analyzers at a given facility. The analyzer shall read this mid-span gas within 2.5% of the

labeled value or the analyzer shall be taken out of service.

Alternatively, all gas bottles entering a facility shall be verified using a master bench and NIST

traceable SRM, CRM, NTRM, or RGM gases. Quarterly checks would then be performed on

each analyzer using three points at 25%, 50%, and 75% of full scale.

(10) Interference Test. The CO analyzer shall be checked for water vapor interference prior to initial

service. The interference limits in this paragraph shall apply to analyzers used with a CVS of

700 SCFM or greater. For analyzers used with lower flow rate CVS units, the allowable

interference response shall be proportionately adjusted downward.

(i) CO Analyzer. A CO instrument will be considered to be essentially free of CO2 and

water vapor interference if its response to a mixture of 3% CO2 in N2 which has been

bubbled through water at 20°C produces an equivalent CO response, as measured on

the most sensitive CO range, which is less than 1% of full scale.

(e) Gases

(1) General Requirements. Gas blends may contain up to three of any of the following

components: HC, CO, CO2, and NO. The HC component shall be propane. The diluent for

blends containing HC shall be air. The diluent for blends containing NO shall be N2. CO and

CO2 may be used with either air or N2 as the diluent. Blends containing four interest

components may be used only if approved by the Administrator. Blends containing NO2 shall

also require approval by the Administrator prior to use, except if used to perform the NOx

converter check specified in §85.2234(d)(5). Any interference effects between components in a

gas blend shall be addressed in the quality control and quality assurance process. When a gas

audit of the analytical system is performed, the auditor shall indicate whether CO2 is present in

the audit gas mixture prior to performing the audit.

(2) Calibration Gases. Gases used to generate and check calibration curves shall be traceable to a

NIST SRM, CRM, NTRM, or RGM and have a stated uncertainty to within 1% of the standard

by gas comparison methods. Calibration zero gas shall be used when using a gas divider to

generate intermediary calibration gases.

(3) Span Gases. Gases used for up-scale span adjustment, cross-checks, and for mid-scale span

checks shall be traceable to NIST SRM, CRM, NTRM, or RGM and have a stated uncertainty

to within 2% of the standard by gas comparison methods. Span gas concentrations shall be

verified immediately after a monthly calibration curve check and before being put into service. 

If the reading on the span gases exceeds 2.5% of the label value, the system or gases shall be

taken out of service until corrective action is taken. When a gas divider is used to generate span

gases, the diluent gas shall not have impurities any greater than the working zero gas.

(4) Calibration Zero Gas. The impurities in the calibration zero gas shall not exceed 0.1 ppmC, 0.5

ppm CO, 1 ppm CO2, and 0.1 ppm NO. Calibration zero grade air shall be used for the FID

zero calibration gas. Calibration zero grade nitrogen or calibration zero grade air shall be used

for CO, CO2, and NOx zero calibration gases.

(5) Working Zero Gas. The impurities in working zero grade gases shall not exceed 1 ppmC, 2

ppm CO, 400 ppm CO2, and 0.3 ppm NOx. Working zero grade air or calibration zero grade

air shall be used for the FID zero span gas. Working or calibration zero grade nitrogen or air

shall be used for CO, CO2, and NOx zero span gases.
37

(6) FID Fuel. The fuel for the FID shall consist of a mixture of 40% (+2%) hydrogen, and the

balance helium. The FID oxidizer shall be zero grade air, which can consist of artificial air

containing 18 to 21 mole percent of oxygen.

(7) Gas Naming Protocol. Gases used for calibration or auditing shall be named according to a

written established practice that has been approved by the Administrator. An accepted gas

naming procedure for I/M test purposes is the IM240 Gas Certification Protocol dated 10/27/94,

or its latest revision. Copies of the 10/27/94 document are available upon request from EPA.

(f) Overall System Performance

(1) Emission Levels. For each test lane, the average, median, 10th percentile and 90th percentile of

the composite emissions (HC, CO, CO2, and NOx) measured shall be monitored on a monthly

basis. Differences in the monthly average of greater than ±10% by any one lane from the

facility-average or combined facility-average, or by any one facility from the combined facilityaverage shall require an investigation to determine whether the single lane or facility has a

systematic equipment or operating error or difference. Where it can be determined that the

averages from one facility (or facilities) are offset from the average of the other facilities based

on the mix of vehicles tested, the ±10% limit shall be compared to the expected offset. If

systematic equipment or operating errors or differences causing the offset are found, such errors

shall be corrected. The sample period may be adjusted to assure that a reasonably random

sample of vehicles was tested in each lane.

(2) Pass/Fail Status. The average number of passing vehicles and the average number of failing

vehicles shall be monitored monthly for each test lane. Differences in the monthly average of

greater than ±15% by any one lane from the facility-average or combined facility-average, or by

any one facility from the combined facility-average shall require an investigation to determine

whether the single lane or facility has a systematic equipment or operating error or difference. 

Where it can be determined that the averages from one facility (or facilities) are offset from the

average of the other facilities based on the mix of vehicles tested, the ±15% limit shall be

compared to the expected offset. If systematic equipment or operating errors or differences

causing the offset are found, such errors shall be corrected. The sample period may be adjusted

to assure that a reasonably random sample of vehicles was tested in each lane.

(g) Control Charts

(1) General Requirements. Control charts and Statistical Process Control theory shall be used to

determine, forecast, and maintain performance of each test lane, each facility, and all facilities

in a given network. The control charts shall cover the performance of key parameters in the test

system. When key parameters approach control chart limits, close monitoring of such systems

shall be initiated and corrective actions shall be taken when needed to prevent such systems

from exceeding control chart limits. If any key parameter exceeds the control chart limits,

corrective action shall be taken to bring the system into compliance. The control chart limits

specified are those values listed for the test procedures, the equipment specifications, and the

quality control specifications that cause a test to be voided or require equipment to be removed

from service. These values are "fit for use" limits, unlike a strict interpretation of SPC control

chart theory which may use tighter limits to define the process. The test facility is encouraged

to apply SPC strict control chart theory to determine when equipment or processes could be

improved. No action shall be required until the equipment or process exceeds the "fit for use

limits" specified in this section.

(2) Control Charts for Individual Test Lanes. In general, control charts for individual test lanes

shall include parameters that will allow the cause for abnormal performance of a test lane to be

pinpointed to individual systems or components. Test lane control charts shall include at a

minimum:
38

(i) Difference between theoretical and measured coast-down times

(ii) Difference between theoretical and measured CVS flow

(iii) Up-scale span change from last up-scale span (not required if software corrections are

tracked)

(iv) Mathematical or software correction to the calibration curve as a result of an up-scale

span change (if used)

(v) Difference between the analyzer response to the daily cross-check, and the test gas

concentration

(vi) The system response time

(vii) FID CH4 response ratio

(viii) Difference between theoretical or measured values for other parameters measured

during quality assurance procedures

(3) Control Charts for Individual Facilities. Control charts for individual facilities shall consist of

the test lane control charts for each test lane at the facility.

(4) Control Charts of Individual Inspectors. Control charts for individual inspectors shall include

parameters that will allow the cause for abnormal performance to be evaluated, such as

technician IM240 driving quality.
39

§85.2235 Evaporative Test Quality Control Requirements

(a) General Requirements

(1) Manufacturers' Recommendations. Manufacturers' recommendations for equipment

installation, calibration, and maintenance shall be followed.

(2) Statistical Process Control. SPC tracking methods shall be established for appropriate

equipment checks and custom diagnostic or verification tests.

(3) Modifications to Quality Control Requirements. Changes to the type or frequency of the quality

checks are permitted provided they are based on SPC analysis, or data from experimental

studies.

(b) Evaporative System Pressure Checks

(1) Daily Checks. The pressure check system shall be pressurized to 28±1 inch of WC and

monitored for a loss of pressure. Pressure testing shall be stopped and corrective action shall be

taken to repair the system if a loss of pressure of more than 0.4 inches of WC is observed over a

15 second period.

(2) Bi-Weekly Check. Pressure gauges or measurement devices shall be checked on a bi-weekly

basis against a reference gauge or device equal to or better than the specified performance

requirements. Deviations exceeding the specified accuracy shall require corrective action.

(c) Evaporative System Gas Cap Checks

(1) Gas Cap Tester. 

(i) Daily Checks. The tester shall be verified daily by testing and correctly identifying

passing and failing reference gas caps or flow orifices as specified in

§85.2227(d)(2)(v). Reference caps and orifices shall be stored in a dirt and dust free

manner to prevent clogging and changes in flow rates. Reference caps and orifices

shall be stored at the same temperature as the cap tester to provide accurate flow

reference.

(ii) Corrective Action. Gas cap testing shall be stopped and corrective action taken to

repair the tester if passing and failing reference gas caps or flow orifices cannot be

correctly identified.

(iii) Reference Caps or Orifices - Flow Checks. Independent flow bench verification of the

reference gas caps and flow orifices shall be conducted before initial usage, and at six

month intervals, or as recommended by the cap tester manufacturer or as suggested by

analysis of quality control data. The bench flow verification results shall be traceable

to NIST.

(iv) Comparator Orifices - Flow Checks. Internal flow standard orifices for direct flow

measurement methods, or flow comparator methods, shall be traceable to a NIST

reference.

(2) Gas Cap Adapters.

(i) Leak Checks. The gas cap adapters shall be checked for visual damage daily and leak

checked weekly, or by following the recommendations of the gas cap adapters supplier.
40

§85.2239 Test Report

(a) General Test Report Information

(1) Vehicle Description.

(i) License plate number

(ii) Vehicle identification number

(iii) Weight class

(iv) Odometer reading

(2) Date and Time. Date and end time of the tailpipe emission measurement test.

(3) Identification Information. Name or identification number of the individual performing the test

and the location of the test station and lane.

(4) Warranty Provisions. For failed vehicles, a statement indicating the availability of warranty

coverage as provided in Section 207 of the Clean Air Act.

(5) Certification. A statement certifying that the short tests were performed in accordance with

applicable regulations.

(b) Tests and Results

(1) Test Types and Standards. The test report shall indicate the types of tests performed on the

vehicle and the test standards for each. Test standards shall be displayed to the appropriate

number of significant digits as in §85.2205(a). For the IM240 the reported standards shall be

the composite test standards.

(2) Test Scores. The test report shall show the scores for each test performed. Test scores shall be

displayed to the same number of significant digits as the standards.

(3) IM240 Scores. The reported score for the IM240 shall be in units of grams per mile and shall

be selected based upon the following:

(i) Passing Scores - Composite IM240. If the emissions of any exhaust component on the

composite IM240 are below the applicable standard in §85.2205(a), then the vehicle

shall pass for that constituent and the composite score shall be reported.

(ii) Passing Scores - Phase 2. If the emissions of any exhaust component on the composite

IM240 exceed the applicable standard in §85.2205(a) but are below the Phase 2

standard, then the vehicle shall pass for that component and the Phase 2 score shall be

reported.

(iii) Failing Scores. If the emissions of any exhaust component on the composite IM240

exceed the applicable standard in §85.2205(a)(2) through §85.2205(a)(4) and exceed

the Two Ways to Pass Standard as described in §85.2205(a)(1), then the vehicle shall

fail for that component and the composite score shall be reported.

(iv) Emission Reporting. If a passing decision is made for all three exhaust components on

the IM240 before the end of the full driving cycle according to the criteria described in

§85.2205(a)(4), the passing results and reported emissions levels shall be those

obtained at the time the test is terminated. Emission levels for the IM240 shall be

reported in grams per mile calculated using the full IM240 mileage (not actual
41

mileage). The emission standards reported shall be the composite standards (i.e., not

the fast-pass standards).

(4) Pressure Test Scores. The score(s) for the pressure test(s) shall be reported as a change in

pressure expressed in inches of water.

(5) Test Results. The test report shall indicate the pass/fail result for each test performed and the

overall result. In the case of exhaust emission tests, the report shall indicate the pass/fail status

for each component for which standards apply. 

(6) Second-by-Second Measurements. For vehicles failing the IM240, a graph showing the secondby-second emission levels (see following example), for each exhaust component in grams per

mile equivalent. The plots of HC, CO, NOx, and CO2 are expressed in units of “gram per mile

equivalent,” or:

Y = (X)*(239 seconds)/(1.959 miles)

Where: Y = Grams per mile equivalent calculated on a second by second basis

X = Grams of HC, CO, NOx, or CO2 calculated during the one second interval

(c) Recommended IM240 Second-By-Second Emissions Report

Test Number 4719

Model Year 1988 Test Weight 3000 Emission Actual Cut

point

Make XXXX TRLHP 14.7 HC (gpm) 2.45 0.80

Model YYYY Traction Control No CO (gpm) 23.1 15.0

Cylinders 4 ABS No NOx (gpm) 0.71 2.00

Transmission Auto Gas Cap Test Yes CO2 (gpm) 279 n/a

Vehicle Type LDGV Press Test Yes

The following figures provide illustrations of the recommended second-by-second emissions output.
42

0.0 

1.0 

2.0 

3.0 

4.0 

5.0 

6.0 

0 

15

30

45

60

0 

2 

4 

6 

8 

10

12

Seconds 

0 20 40 60 80 100 120 140 160 180 200 220 240 

2000

1500

1000

500 

0 

0 

10

20

30

40

50

60

mph 

0 

10

20

30

40

50

60

mph 

0 

10

20

30

40

50

60

mph 

0 

10

20

30

40

50

60

mph 

HC

gpme

CO

gpme

NOx 

gpme

CO2 

gpme
43

§85.2241 Terms

(1) ALVW: Adjusted Loaded Vehicle Weight: (VCW + GVWR)/2

(2) CFV: Critical Flow Venturi

(3) CH4: Methane

(4) CO2: Carbon dioxide

(5) CO: Carbon monoxide

(6) CRM: Certified Reference Material

(7) CVS: Constant Volume Sampler

(8) ETW: Equivalent Test Weight

(9) FID: Flame Ionization Detector

(10) gpm: Grams per mile

(11) GVWR: Gross Vehicle Weight Rating

(12) HC: Hydrocarbons

(13) HDGT: Heavy-Duty Gasoline-powered Truck greater than 8500 pounds GVWR

(14) hp: Horsepower

(15) Hz: Cycles per Second (Hertz)

(16) I/M: Inspection and Maintenance

(17) IW: Inertia Weight

(18) LDGV: Light-Duty Gasoline-powered Vehicle

(19) LVW: Loaded Vehicle Weight: VCW + 300 pounds

(20) mph: Miles per hour

(21) NDIR: Non-Dispersive Infrared 

(22) NIST: National Institute for Standards and Technology

(23) NO2: Nitrogen Dioxide

(24) NO: Nitrogen Oxide

(25) NOx: Oxides of Nitrogen

(26) NVFEL: National Vehicle and Fuel Emissions Laboratory

(27) Obmph: Observed dynamometer speed in mph of the loading roller, if rolls are not coupled

(28) PLHP: Parasitic horsepower loss at the observed dynamometer speed in mph

(29) ppm: parts per million by volume

(30) ppmC: parts per million, carbon

(31) psi: Pounds per square inch

(32) RFP: Request for Proposal

(33) RLHP Road Load Horsepower

(34) rpm: revolutions per minute

(35) SCFM: Standard cubic feet per minute

(36) SPC: Statistical Process Control

(37) SRM: Standard Reference Material

(38) SSV: Subsonic venturi

(39) TRLHP: Track Road-Load Horsepower

(40) VCW: Vehicle Curb Weight: Actual vehicle weight with standard equipment and 100%

fuel fill

(41) WC: Pressure in inches of water column
44

Appendix A

Guidance on the Use of Fast-Pass IM240 Standards
45

Guidance on the Use of Fast-Pass IM240 Standards

A fast-pass decision is made by measuring the vehicle's cumulative emissions of each pollutant in each second, and

comparing them to cumulative emission fast-pass standards for each pollutant for the second of the test under consideration. 

In general, if the vehicle's cumulative emissions are below a given level for all pollutants the vehicle passes. Testing

continues until decisions are made for each pollutant. Measurements of all constituents shall continue to be taken as long as

the test continues, including those constituents for which a decision has already been made.

These fast-pass standards are derived from an Arizona IM240 data set which included 3,718 tests. Fast-pass

standards for each second represent the tenth lowest cumulative emission levels in that second obtained for vehicles failing

the IM240 using the two-ways-to-pass criteria. Hence, vehicles that fall below this level are showing lower cumulative

emissions at that point in the test than the cleanest vehicles failing the full test and therefore pass. Fast-pass determinations

begin at second 30 of the IM240 cycle.

Beginning at second 109, fast pass decisions for HC and CO are based upon analysis of cumulative emissions in

phase 2, the portion of the test beginning at second 94, as well as emission levels accumulated from the beginning of the test

(the "composite" test). Fast-pass standards are derived for phase 2 of the test as described above. Since the phase 2

standards for NOx are the same as the composite, the phase 2 NOx fast-pass standards are also the same as the composite.

Scores

HCt = cumulative composite HC at time = t seconds

COt = cumulative composite CO at time = t seconds

NOxt = cumulative composite NOx at time = t seconds

HCbt = cumulative Phase 2 HC at time = t seconds

CObt = cumulative Phase 2 CO at time = t seconds

NOxbt = cumulative Phase 2 NOx at time = t seconds

Cumulative composite scores represent the cumulative grams of emissions from t = 0 seconds

Cumulative Phase 2 scores represent the cumulative grams of emissions from t = 109 seconds

Fast-Pass Standards

HCpt = composite HC fast-pass standard at time = t seconds

COpt = composite CO fast-pass standard at time = t seconds

NOxpt = composite NOx fast-pass standard for failing vehicles at time = t seconds

HCpbt = Phase 2 HC fast-pass standard at time = t seconds

COpbt = Phase 2 CO fast-pass standard at time = t seconds

NOxpbt = Phase 2 NOx fast-pass standard at time = t seconds

Fast-Pass Conditions

For t > 30 seconds, the vehicle shall pass if:

HCt < HCpt and COt < COpt, NOxt < NOxpt;

additionally, for t > 109 seconds, the vehicle shall pass if:

HCbt < HCpbt and CObt < COpbt and NOxbt < NOxpbt or

HCt < HCpt and CObt < COpbt and NOxbt < NOxpbt or

HCt < HCpt and COt < COpt and NOxbt < NOxpbt or

HCbt < HCpbt and COt < COpt and NOxbt <NOxpbt or

HCbt < HCpbt and COt < COpt and NOxt < NOxpt or

HCbt < HCpbt and CObt < COpbt and NOxt < NOxpt
46

IM240 FAST-PASS EMISSION STANDARDS

(grams)

Hydrocarbons Carbon Monoxide Oxides of

Nitrogen

Sec Composite Phase

2

Composite Phase

2

Composite Phase

2

Composite Phase

2 

Composite Phase

2 

Composite Phase

2

0.80 0.50 1.25 0.75 2.00 1.25 15.0 12.0 20.0 16.0 30.0 24.0 2.0 2.5 3.0

30 0.124 n/a 0.247 n/a 0.407 n/a 0.693 n/a 1.502 n/a 3.804 n/a 0.167 0.262 0.419

31 0.126 n/a 0.253 n/a 0.415 n/a 0.773 n/a 1.546 n/a 3.985 n/a 0.177 0.275 0.425

32 0.129 n/a 0.258 n/a 0.423 n/a 0.837 n/a 1.568 n/a 4.215 n/a 0.188 0.301 0.431

33 0.135 n/a 0.263 n/a 0.436 n/a 0.851 n/a 1.582 n/a 4.440 n/a 0.214 0.317 0.449

34 0.140 n/a 0.268 n/a 0.451 n/a 0.853 n/a 1.593 n/a 4.579 n/a 0.232 0.327 0.476

35 0.146 n/a 0.277 n/a 0.464 n/a 0.857 n/a 1.602 n/a 4.688 n/a 0.240 0.330 0.497

36 0.150 n/a 0.283 n/a 0.468 n/a 0.900 n/a 1.621 n/a 4.749 n/a 0.243 0.332 0.515

37 0.153 n/a 0.293 n/a 0.475 n/a 0.960 n/a 1.631 n/a 4.783 n/a 0.245 0.334 0.516

38 0.156 n/a 0.297 n/a 0.487 n/a 1.034 n/a 1.702 n/a 4.813 n/a 0.246 0.336 0.519

39 0.160 n/a 0.298 n/a 0.506 n/a 1.070 n/a 1.784 n/a 4.876 n/a 0.246 0.337 0.527

40 0.165 n/a 0.313 n/a 0.530 n/a 1.076 n/a 1.879 n/a 5.104 n/a 0.250 0.354 0.542

41 0.169 n/a 0.320 n/a 0.549 n/a 1.083 n/a 2.162 n/a 5.217 n/a 0.260 0.366 0.560

42 0.172 n/a 0.327 n/a 0.569 n/a 1.102 n/a 2.307 n/a 5.383 n/a 0.277 0.410 0.598

43 0.173 n/a 0.342 n/a 0.588 n/a 1.111 n/a 2.343 n/a 5.571 n/a 0.311 0.414 0.616

44 0.177 n/a 0.360 n/a 0.609 n/a 1.114 n/a 2.376 n/a 5.888 n/a 0.328 0.438 0.645

45 0.197 n/a 0.376 n/a 0.621 n/a 1.157 n/a 2.406 n/a 6.199 n/a 0.343 0.477 0.670

46 0.200 n/a 0.389 n/a 0.636 n/a 1.344 n/a 2.433 n/a 6.245 n/a 0.359 0.506 0.691

47 0.208 n/a 0.408 n/a 0.649 n/a 1.482 n/a 2.458 n/a 6.318 n/a 0.373 0.518 0.716

48 0.221 n/a 0.423 n/a 0.666 n/a 1.530 n/a 2.483 n/a 6.418 n/a 0.383 0.522 0.735

49 0.232 n/a 0.434 n/a 0.679 n/a 1.542 n/a 2.774 n/a 6.540 n/a 0.385 0.526 0.765

50 0.235 n/a 0.444 n/a 0.696 n/a 1.553 n/a 2.844 n/a 6.690 n/a 0.400 0.554 0.802

51 0.238 n/a 0.454 n/a 0.712 n/a 1.571 n/a 2.900 n/a 6.875 n/a 0.410 0.574 0.836

52 0.240 n/a 0.465 n/a 0.727 n/a 1.595 n/a 2.936 n/a 7.029 n/a 0.434 0.587 0.868

53 0.242 n/a 0.472 n/a 0.745 n/a 1.633 n/a 3.133 n/a 7.129 n/a 0.464 0.601 0.890

54 0.246 n/a 0.478 n/a 0.760 n/a 1.685 n/a 3.304 n/a 7.359 n/a 0.472 0.615 0.918

55 0.249 n/a 0.485 n/a 0.776 n/a 1.689 n/a 3.407 n/a 7.722 n/a 0.480 0.629 0.936

56 0.252 n/a 0.493 n/a 0.797 n/a 1.693 n/a 3.456 n/a 8.017 n/a 0.491 0.643 0.947

57 0.261 n/a 0.500 n/a 0.814 n/a 1.700 n/a 3.480 n/a 8.249 n/a 0.500 0.667 0.958

58 0.271 n/a 0.505 n/a 0.826 n/a 1.723 n/a 3.518 n/a 8.425 n/a 0.506 0.678 0.970

59 0.276 n/a 0.514 n/a 0.837 n/a 1.852 n/a 3.560 n/a 8.563 n/a 0.509 0.683 0.982

60 0.278 n/a 0.537 n/a 0.849 n/a 1.872 n/a 3.593 n/a 8.686 n/a 0.512 0.686 0.994

61 0.280 n/a 0.540 n/a 0.862 n/a 1.872 n/a 3.628 n/a 8.804 n/a 0.516 0.693 1.019

62 0.282 n/a 0.543 n/a 0.872 n/a 1.872 n/a 3.641 n/a 8.916 n/a 0.519 0.699 1.042

63 0.283 n/a 0.546 n/a 0.887 n/a 1.900 n/a 3.655 n/a 9.025 n/a 0.523 0.703 1.049

64 0.284 n/a 0.551 n/a 0.895 n/a 1.917 n/a 3.680 n/a 9.138 n/a 0.529 0.707 1.058

65 0.285 n/a 0.559 n/a 0.903 n/a 1.944 n/a 3.700 n/a 9.250 n/a 0.533 0.711 1.062

66 0.286 n/a 0.567 n/a 0.925 n/a 2.000 n/a 3.728 n/a 9.354 n/a 0.535 0.716 1.064

67 0.288 n/a 0.575 n/a 0.933 n/a 2.060 n/a 3.857 n/a 9.457 n/a 0.540 0.721 1.070

68 0.291 n/a 0.588 n/a 0.945 n/a 2.064 n/a 3.894 n/a 9.575 n/a 0.551 0.726 1.077

69 0.294 n/a 0.595 n/a 0.959 n/a 2.076 n/a 3.943 n/a 9.728 n/a 0.563 0.742 1.085

70 0.296 n/a 0.601 n/a 0.970 n/a 2.104 n/a 3.983 n/a 9.938 n/a 0.575 0.759 1.092

71 0.298 n/a 0.606 n/a 0.980 n/a 2.117 n/a 4.009 n/a 10.140 n/a 0.588 0.773 1.101

72 0.300 n/a 0.610 n/a 0.988 n/a 2.125 n/a 4.023 n/a 10.222 n/a 0.600 0.784 1.111

73 0.302 n/a 0.617 n/a 0.997 n/a 2.130 n/a 4.023 n/a 10.261 n/a 0.603 0.790 1.121

74 0.304 n/a 0.631 n/a 1.022 n/a 2.138 n/a 4.053 n/a 10.278 n/a 0.604 0.794 1.131
47

75 0.307 n/a 0.643 n/a 1.037 n/a 2.152 n/a 4.063 n/a 10.290 n/a 0.613 0.799 1.141

76 0.308 n/a 0.651 n/a 1.051 n/a 2.170 n/a 4.077 n/a 10.715 n/a 0.624 0.809 1.159

77 0.308 n/a 0.659 n/a 1.064 n/a 2.188 n/a 4.225 n/a 10.790 n/a 0.646 0.821 1.164

78 0.308 n/a 0.667 n/a 1.075 n/a 2.200 n/a 4.243 n/a 10.844 n/a 0.651 0.833 1.186

79 0.314 n/a 0.676 n/a 1.087 n/a 2.212 n/a 4.260 n/a 10.921 n/a 0.659 0.839 1.221

80 0.320 n/a 0.681 n/a 1.097 n/a 2.212 n/a 4.282 n/a 11.010 n/a 0.673 0.844 1.260

81 0.324 n/a 0.685 n/a 1.105 n/a 2.221 n/a 4.322 n/a 11.090 n/a 0.696 0.857 1.268

82 0.327 n/a 0.689 n/a 1.114 n/a 2.222 n/a 4.398 n/a 11.136 n/a 0.706 0.870 1.272

83 0.329 n/a 0.694 n/a 1.136 n/a 2.227 n/a 4.482 n/a 11.136 n/a 0.715 0.883 1.277

84 0.333 n/a 0.700 n/a 1.160 n/a 2.236 n/a 4.515 n/a 11.165 n/a 0.724 0.894 1.288

85 0.336 n/a 0.705 n/a 1.182 n/a 2.243 n/a 4.518 n/a 11.191 n/a 0.737 0.902 1.310

86 0.339 n/a 0.709 n/a 1.201 n/a 2.262 n/a 4.520 n/a 11.205 n/a 0.747 0.907 1.319

87 0.343 n/a 0.713 n/a 1.217 n/a 2.271 n/a 4.522 n/a 11.211 n/a 0.748 0.910 1.320

88 0.347 n/a 0.717 n/a 1.233 n/a 2.284 n/a 4.522 n/a 11.211 n/a 0.748 0.912 1.337

89 0.350 n/a 0.721 n/a 1.248 n/a 2.299 n/a 4.523 n/a 11.211 n/a 0.748 0.913 1.348

90 0.356 n/a 0.724 n/a 1.262 n/a 2.308 n/a 4.526 n/a 11.211 n/a 0.748 0.914 1.361

91 0.358 n/a 0.727 n/a 1.271 n/a 2.326 n/a 4.527 n/a 11.220 n/a 0.748 0.915 1.366

92 0.360 n/a 0.729 n/a 1.279 n/a 2.330 n/a 4.527 n/a 11.294 n/a 0.748 0.916 1.369

93 0.363 n/a 0.731 n/a 1.287 n/a 2.331 n/a 4.528 n/a 11.332 n/a 0.748 0.917 1.373

94 0.367 n/a 0.734 n/a 1.295 n/a 2.344 n/a 4.528 n/a 11.355 n/a 0.748 0.918 1.375

95 0.370 n/a 0.740 n/a 1.302 n/a 2.347 n/a 4.528 n/a 11.383 n/a 0.748 0.919 1.377

96 0.372 n/a 0.748 n/a 1.309 n/a 2.355 n/a 4.529 n/a 11.410 n/a 0.748 0.920 1.379

97 0.376 n/a 0.759 n/a 1.316 n/a 2.395 n/a 4.575 n/a 11.433 n/a 0.748 0.921 1.381

98 0.388 n/a 0.771 n/a 1.325 n/a 2.451 n/a 4.703 n/a 11.516 n/a 0.748 0.922 1.383

99 0.396 n/a 0.783 n/a 1.339 n/a 2.508 n/a 4.805 n/a 11.820 n/a 0.751 0.924 1.385

100 0.405 n/a 0.793 n/a 1.356 n/a 2.590 n/a 4.886 n/a 12.104 n/a 0.764 0.929 1.399

101 0.410 n/a 0.810 n/a 1.365 n/a 2.660 n/a 4.957 n/a 12.344 n/a 0.789 0.941 1.405

102 0.411 n/a 0.823 n/a 1.378 n/a 2.749 n/a 5.104 n/a 12.781 n/a 0.822 0.970 1.466

103 0.412 n/a 0.836 n/a 1.397 n/a 2.913 n/a 5.340 n/a 13.472 n/a 0.867 1.027 1.485

104 0.413 n/a 0.853 n/a 1.420 n/a 3.162 n/a 5.496 n/a 14.405 n/a 0.905 1.093 1.546

105 0.421 n/a 0.871 n/a 1.445 n/a 3.170 n/a 5.625 n/a 14.808 n/a 0.925 1.155 1.623

106 0.428 n/a 0.887 n/a 1.470 n/a 3.197 n/a 5.815 n/a 14.965 n/a 0.955 1.234 1.699

107 0.430 n/a 0.899 n/a 1.491 n/a 3.288 n/a 6.473 n/a 15.121 n/a 0.985 1.275 1.760

108 0.455 n/a 0.931 n/a 1.506 n/a 3.419 n/a 7.037 n/a 15.372 n/a 0.993 1.305 1.788

109 0.459 0.015 0.947 0.040 1.517 0.151 3.587 0.168 7.419 0.246 15.530 1.113 0.995 1.320 1.798

110 0.462 0.017 0.957 0.047 1.528 0.159 3.595 0.173 7.643 0.257 15.687 1.213 0.996 1.332 1.842

111 0.464 0.021 0.965 0.052 1.542 0.172 3.640 0.237 7.759 0.286 16.018 1.344 1.010 1.346 1.864

112 0.466 0.024 0.971 0.056 1.559 0.186 3.740 0.266 7.824 0.379 16.527 1.399 1.028 1.358 1.888

113 0.468 0.024 0.977 0.061 1.578 0.199 3.868 0.280 7.889 0.425 16.810 1.520 1.034 1.378 1.905

114 0.471 0.025 0.983 0.064 1.594 0.207 3.877 0.291 7.960 0.457 16.961 1.640 1.044 1.406 1.920

115 0.488 0.026 1.003 0.072 1.605 0.216 3.934 0.314 8.024 0.477 17.120 1.684 1.059 1.426 1.926

116 0.513 0.029 1.030 0.081 1.615 0.229 4.015 0.331 8.076 0.494 17.135 1.693 1.075 1.438 1.939

117 0.538 0.032 1.041 0.082 1.625 0.235 4.061 0.345 8.111 0.504 17.249 1.786 1.080 1.448 1.958

118 0.561 0.035 1.050 0.083 1.642 0.240 4.063 0.350 8.130 0.512 17.451 2.007 1.080 1.460 1.972

119 0.577 0.035 1.052 0.092 1.670 0.245 4.079 0.356 8.148 0.519 17.509 2.084 1.081 1.462 1.981

120 0.580 0.036 1.055 0.094 1.694 0.261 4.140 0.367 8.211 0.529 17.605 2.179 1.091 1.467 1.987

121 0.586 0.038 1.061 0.097 1.705 0.267 4.185 0.388 8.478 0.529 17.734 2.264 1.096 1.476 1.991

122 0.594 0.040 1.071 0.100 1.717 0.277 4.199 0.407 8.548 0.530 18.049 2.328 1.111 1.494 1.996

123 0.603 0.041 1.081 0.103 1.732 0.287 4.205 0.463 8.561 0.531 18.447 2.375 1.122 1.505 2.012

124 0.610 0.042 1.091 0.106 1.747 0.298 4.212 0.480 8.568 0.532 18.592 2.437 1.135 1.517 2.040

125 0.615 0.042 1.102 0.108 1.763 0.308 4.232 0.506 8.572 0.533 18.657 2.543 1.138 1.546 2.060

126 0.624 0.042 1.110 0.110 1.779 0.316 4.298 0.518 8.584 0.548 18.796 2.593 1.139 1.569 2.069

127 0.628 0.045 1.116 0.112 1.795 0.322 4.344 0.522 8.592 0.610 18.952 2.641 1.139 1.586 2.092
48

128 0.632 0.046 1.121 0.114 1.810 0.329 4.361 0.525 8.596 0.614 19.137 2.663 1.139 1.596 2.114

129 0.637 0.046 1.125 0.116 1.823 0.338 4.366 0.528 8.597 0.622 19.329 2.672 1.139 1.603 2.132

130 0.641 0.049 1.128 0.118 1.835 0.346 4.369 0.530 8.601 0.631 19.519 2.676 1.139 1.605 2.144

131 0.643 0.050 1.130 0.120 1.845 0.354 4.372 0.530 8.605 0.640 19.707 2.683 1.139 1.606 2.152

132 0.644 0.052 1.132 0.122 1.854 0.356 4.435 0.534 8.608 0.646 19.882 2.817 1.139 1.607 2.157

133 0.645 0.054 1.134 0.123 1.862 0.357 4.523 0.550 8.626 0.650 19.905 2.992 1.139 1.607 2.160

134 0.647 0.054 1.135 0.124 1.870 0.359 4.524 0.554 8.650 0.652 20.049 3.111 1.139 1.608 2.163

135 0.651 0.054 1.143 0.127 1.883 0.362 4.525 0.590 8.660 0.738 20.460 3.234 1.139 1.614 2.165

136 0.658 0.055 1.147 0.130 1.888 0.364 4.531 0.616 8.767 0.754 20.746 3.304 1.160 1.616 2.168

137 0.663 0.055 1.156 0.134 1.896 0.368 4.534 0.639 9.029 0.780 21.068 3.310 1.174 1.631 2.171

138 0.666 0.056 1.163 0.139 1.911 0.378 4.542 0.653 9.238 0.795 21.380 3.320 1.183 1.643 2.186

139 0.668 0.059 1.186 0.146 1.928 0.391 4.553 0.662 9.389 0.804 21.748 3.354 1.197 1.656 2.235

140 0.670 0.061 1.253 0.149 1.949 0.402 4.554 0.683 9.493 0.810 22.046 3.436 1.223 1.673 2.298

141 0.672 0.061 1.262 0.151 1.969 0.408 4.554 0.696 9.583 0.815 22.348 3.443 1.255 1.703 2.333

142 0.675 0.061 1.271 0.153 1.982 0.422 4.554 0.708 9.626 0.818 22.397 3.452 1.272 1.739 2.373

143 0.678 0.063 1.277 0.155 1.999 0.428 4.554 0.721 9.669 0.821 22.407 3.490 1.286 1.767 2.406

144 0.681 0.064 1.283 0.157 2.011 0.432 4.554 0.739 9.716 0.825 22.417 3.552 1.304 1.774 2.416

145 0.684 0.065 1.291 0.162 2.022 0.434 4.554 0.742 9.763 0.840 22.922 3.588 1.307 1.785 2.420

146 0.686 0.066 1.294 0.164 2.035 0.439 4.554 0.743 9.809 0.847 22.951 3.600 1.312 1.806 2.424

147 0.688 0.067 1.296 0.166 2.043 0.450 4.554 0.745 9.852 0.855 22.976 3.616 1.317 1.830 2.435

148 0.690 0.068 1.298 0.168 2.049 0.460 4.554 0.748 9.885 0.865 23.017 3.627 1.321 1.844 2.455

149 0.692 0.069 1.303 0.169 2.063 0.467 4.554 0.751 9.932 0.874 23.073 3.636 1.325 1.845 2.471

150 0.694 0.070 1.316 0.170 2.085 0.472 4.554 0.762 9.986 0.891 23.161 3.676 1.328 1.846 2.484

151 0.696 0.071 1.330 0.171 2.104 0.480 4.556 0.789 10.039 0.914 23.218 3.882 1.332 1.852 2.495

152 0.698 0.072 1.342 0.172 2.117 0.491 4.556 0.790 10.072 0.929 23.253 4.011 1.338 1.868 2.509

153 0.700 0.073 1.348 0.173 2.127 0.503 4.565 0.794 10.090 0.937 23.337 4.047 1.344 1.877 2.522

154 0.702 0.073 1.353 0.175 2.138 0.505 4.612 0.799 10.105 0.942 23.425 4.067 1.350 1.879 2.533

155 0.704 0.074 1.362 0.178 2.152 0.515 4.834 0.805 10.146 0.949 23.534 4.081 1.357 1.886 2.541

156 0.706 0.077 1.365 0.180 2.168 0.522 5.702 0.842 10.245 1.375 23.652 4.116 1.365 1.900 2.552

157 0.708 0.079 1.366 0.189 2.186 0.527 5.841 0.990 10.397 1.576 23.739 4.251 1.379 1.910 2.589

158 0.710 0.082 1.373 0.198 2.205 0.537 6.170 1.038 10.923 1.943 24.606 5.099 1.414 1.936 2.631

159 0.712 0.082 1.397 0.203 2.224 0.549 6.670 1.357 11.970 2.820 25.615 5.383 1.466 1.954 2.704

160 0.716 0.086 1.423 0.207 2.242 0.568 7.425 1.455 13.421 3.281 26.073 6.362 1.514 1.986 2.758

161 0.750 0.095 1.440 0.214 2.268 0.586 8.379 1.546 15.289 3.483 28.496 7.926 1.559 2.050 2.802

162 0.784 0.107 1.452 0.221 2.308 0.610 9.648 1.824 15.912 3.620 29.772 8.429 1.591 2.131 2.904

163 0.805 0.115 1.465 0.229 2.352 0.648 10.918 2.746 16.530 4.168 31.056 9.201 1.641 2.235 2.960

164 0.840 0.122 1.509 0.247 2.406 0.677 12.157 3.073 17.622 4.338 33.351 10.825 1.719 2.320 3.027

165 0.853 0.127 1.533 0.274 2.421 0.699 12.731 3.633 18.366 4.682 34.890 12.291 1.777 2.395 3.127

166 0.874 0.159 1.555 0.309 2.435 0.720 12.831 4.505 19.869 5.633 35.937 13.366 1.832 2.488 3.187

167 0.903 0.186 1.576 0.318 2.470 0.738 12.892 4.952 20.711 6.137 37.012 14.428 1.919 2.563 3.306

168 0.910 0.189 1.598 0.322 2.501 0.767 12.932 5.254 22.319 6.853 37.892 15.318 1.972 2.645 3.384

169 0.914 0.200 1.618 0.333 2.537 0.828 13.702 5.730 23.751 7.136 39.028 15.699 2.013 2.746 3.467

170 0.916 0.220 1.636 0.343 2.571 0.855 14.139 6.051 24.842 7.320 40.406 16.073 2.100 2.778 3.565

171 0.919 0.236 1.666 0.356 2.625 0.869 14.964 6.333 25.410 7.685 41.379 16.475 2.200 2.792 3.640

172 0.931 0.247 1.685 0.385 2.657 0.885 15.704 6.490 25.798 8.052 42.033 17.158 2.251 2.810 3.718

173 0.948 0.257 1.726 0.409 2.683 0.900 16.253 6.796 26.122 8.344 42.432 17.532 2.270 2.847 3.781

174 0.983 0.267 1.742 0.433 2.701 0.941 16.907 7.205 26.353 8.602 42.742 17.965 2.301 2.874 3.827

175 1.018 0.283 1.756 0.453 2.717 0.979 17.655 8.151 26.638 8.898 43.399 18.242 2.318 2.905 3.852

176 1.027 0.295 1.769 0.463 2.732 1.002 18.020 8.230 27.219 9.251 43.895 18.283 2.335 2.950 3.903

177 1.035 0.312 1.784 0.507 2.756 1.025 18.349 8.584 27.279 10.253 44.227 18.480 2.349 3.001 3.930

178 1.051 0.318 1.802 0.523 2.781 1.047 18.671 8.800 27.320 10.828 44.926 19.576 2.387 3.047 3.970

179 1.074 0.323 1.822 0.528 2.811 1.065 18.972 8.847 27.352 10.933 45.256 20.015 2.423 3.104 4.015

180 1.084 0.337 1.843 0.541 2.853 1.089 19.228 8.913 27.822 11.060 45.553 20.203 2.462 3.173 4.074
49

181 1.099 0.345 1.864 0.549 2.898 1.109 20.123 9.122 28.763 11.188 45.753 20.433 2.503 3.238 4.159

182 1.121 0.350 1.884 0.559 2.946 1.133 20.405 9.532 29.402 11.345 46.210 21.025 2.545 3.302 4.230

183 1.132 0.359 1.896 0.571 2.988 1.158 20.754 10.256 29.971 11.733 47.017 21.882 2.586 3.372 4.286

184 1.152 0.387 1.915 0.584 3.023 1.184 21.684 10.862 30.276 12.598 48.185 22.204 2.627 3.452 4.334

185 1.161 0.398 1.940 0.598 3.057 1.209 21.955 10.996 30.988 12.953 48.741 22.859 2.673 3.545 4.388

186 1.168 0.400 1.958 0.613 3.076 1.222 22.650 11.206 31.095 13.213 49.462 23.533 2.749 3.648 4.447

187 1.175 0.402 1.972 0.624 3.101 1.231 22.989 11.514 31.314 14.131 50.313 24.281 2.804 3.701 4.505

188 1.181 0.405 1.985 0.629 3.120 1.239 23.535 11.894 31.833 14.839 51.285 25.078 2.851 3.759 4.561

189 1.188 0.418 1.991 0.629 3.136 1.254 23.876 12.019 32.239 15.137 52.076 25.276 2.894 3.821 4.625

190 1.203 0.429 1.993 0.638 3.151 1.278 24.018 12.170 32.547 15.138 52.857 25.578 2.931 3.870 4.696

191 1.219 0.442 1.995 0.648 3.163 1.300 24.464 12.517 32.855 15.141 52.876 25.859 2.971 3.892 4.731

192 1.233 0.457 2.001 0.659 3.209 1.313 24.685 12.598 33.153 15.595 53.067 25.985 3.020 3.914 4.780

193 1.251 0.473 2.015 0.663 3.223 1.324 24.931 12.625 33.444 15.658 53.777 26.153 3.077 3.955 4.837

194 1.255 0.487 2.031 0.671 3.237 1.340 25.188 12.653 33.482 15.704 54.242 26.582 3.132 3.997 4.876

195 1.258 0.501 2.047 0.681 3.263 1.367 25.468 12.777 33.516 15.729 54.489 27.067 3.185 4.035 4.928

196 1.265 0.510 2.063 0.693 3.302 1.387 25.627 12.906 33.549 16.058 54.601 27.456 3.219 4.089 4.972

197 1.280 0.512 2.079 0.709 3.338 1.402 25.746 12.989 33.653 16.987 54.912 27.805 3.268 4.146 5.025

198 1.293 0.514 2.094 0.725 3.372 1.417 25.850 13.060 33.973 17.064 55.588 28.070 3.299 4.206 5.104

199 1.301 0.516 2.109 0.740 3.390 1.432 25.974 13.165 34.159 17.073 56.266 28.590 3.350 4.243 5.189

200 1.313 0.518 2.122 0.754 3.428 1.446 26.141 13.242 34.191 17.153 56.617 28.914 3.406 4.295 5.275

201 1.324 0.527 2.130 0.767 3.470 1.460 26.225 13.412 34.250 17.332 56.863 29.063 3.466 4.351 5.336

202 1.332 0.540 2.137 0.775 3.493 1.477 26.338 13.662 34.469 17.406 57.204 29.502 3.497 4.398 5.366

203 1.341 0.547 2.157 0.787 3.509 1.492 26.547 13.773 34.716 17.641 57.371 29.697 3.514 4.410 5.387

204 1.357 0.553 2.172 0.795 3.522 1.501 26.818 13.942 34.969 17.922 57.487 29.713 3.517 4.419 5.427

205 1.375 0.559 2.194 0.803 3.533 1.510 27.052 14.090 35.144 18.484 57.728 29.783 3.519 4.426 5.444

206 1.392 0.563 2.222 0.854 3.550 1.522 27.393 14.224 35.418 18.553 58.097 29.942 3.523 4.429 5.447

207 1.408 0.567 2.245 0.859 3.578 1.561 27.501 14.426 35.766 18.658 58.572 30.284 3.545 4.453 5.477

208 1.422 0.571 2.268 0.872 3.607 1.585 27.632 14.498 35.949 18.953 59.024 30.755 3.570 4.486 5.520

209 1.433 0.575 2.279 0.892 3.630 1.597 27.803 14.776 36.010 19.266 59.321 31.287 3.600 4.542 5.560

210 1.443 0.579 2.288 0.896 3.658 1.607 27.953 14.907 36.548 19.309 59.715 31.549 3.619 4.598 5.603

211 1.453 0.595 2.301 0.903 3.701 1.627 28.205 14.916 37.179 19.731 60.045 31.820 3.639 4.638 5.657

212 1.463 0.605 2.316 0.924 3.745 1.645 28.543 15.014 37.651 19.902 60.453 32.250 3.686 4.715 5.698

213 1.468 0.614 2.332 0.938 3.778 1.656 28.997 15.221 38.041 20.012 60.935 32.546 3.732 4.774 5.762

214 1.470 0.622 2.345 0.941 3.814 1.663 29.000 15.472 38.591 20.260 61.307 32.808 3.791 4.829 5.827

215 1.474 0.627 2.354 0.951 3.825 1.669 29.005 15.555 38.852 20.739 61.666 33.060 3.833 4.872 5.849

216 1.478 0.638 2.362 0.966 3.835 1.674 29.081 15.652 38.861 21.346 62.148 33.204 3.890 4.931 5.884

217 1.481 0.643 2.368 0.979 3.844 1.685 29.281 15.969 38.926 21.810 62.532 33.341 3.932 4.960 5.908

218 1.484 0.643 2.376 0.980 3.853 1.700 29.483 16.028 39.194 22.001 62.546 33.414 3.960 4.963 5.921

219 1.487 0.645 2.384 0.981 3.864 1.704 29.734 16.375 39.474 22.290 62.559 33.514 3.997 4.965 5.931

220 1.490 0.651 2.391 1.005 3.874 1.706 29.803 16.487 39.668 22.324 62.570 33.640 4.013 4.968 5.939

221 1.493 0.655 2.395 1.016 3.891 1.709 29.821 16.524 39.781 22.343 62.846 33.692 4.035 4.971 5.947

222 1.504 0.663 2.400 1.022 3.928 1.711 29.847 16.578 39.890 22.522 63.097 33.711 4.038 4.974 5.952

223 1.522 0.671 2.405 1.028 3.966 1.714 29.862 16.684 39.954 22.661 63.150 33.733 4.050 4.977 5.955

224 1.547 0.675 2.409 1.035 4.008 1.718 29.873 16.755 39.984 22.666 63.150 33.770 4.066 4.979 5.957

225 1.549 0.684 2.413 1.041 4.010 1.721 30.008 16.770 39.989 22.667 63.150 33.796 4.070 4.980 5.959

226 1.562 0.694 2.415 1.045 4.012 1.723 30.126 16.805 39.990 22.668 63.150 33.810 4.072 4.981 5.961

227 1.574 0.701 2.417 1.051 4.016 1.726 30.127 16.865 39.990 22.669 63.150 33.821 4.072 4.982 5.963

228 1.579 0.702 2.419 1.055 4.019 1.729 30.127 16.960 39.990 22.670 63.150 33.839 4.073 4.983 5.966

229 1.584 0.708 2.420 1.059 4.057 1.731 30.208 16.960 39.991 22.671 63.150 33.865 4.073 4.984 5.971

230 1.589 0.708 2.421 1.062 4.065 1.733 30.314 16.962 40.012 22.671 63.150 33.894 4.073 4.985 5.977

231 1.590 0.709 2.423 1.063 4.071 1.735 30.323 16.988 40.061 22.672 63.150 33.918 4.073 4.986 5.984

232 1.596 0.710 2.425 1.063 4.073 1.743 30.325 17.072 40.116 22.673 63.150 33.944 4.074 4.987 5.990

233 1.598 0.710 2.427 1.063 4.075 1.749 30.368 17.094 40.249 22.673 63.150 33.985 4.074 4.988 5.997
50

234 1.604 0.711 2.429 1.064 4.077 1.753 30.411 17.184 40.253 22.673 63.153 34.014 4.075 4.989 6.004

235 1.610 0.712 2.430 1.064 4.079 1.757 30.416 17.187 40.290 22.674 63.159 34.032 4.075 4.990 6.012

236 1.612 0.712 2.431 1.066 4.081 1.762 30.428 17.188 40.385 22.675 63.173 34.051 4.076 4.991 6.024

237 1.613 0.712 2.432 1.069 4.083 1.767 30.430 17.189 40.488 22.675 63.193 34.067 4.076 4.992 6.037

238 1.614 0.713 2.433 1.072 4.084 1.772 30.452 17.241 40.720 22.675 63.214 34.079 4.076 4.993 6.049

239 1.615 0.716 2.434 1.075 4.085 1.776 30.488 17.370 40.763 22.677 63.233 34.085 4.076 4.994 6.060
51

Appendix B

Alternative Fast-Pass IM240 Standards
52

Alternative Fast-Pass IM240 Standards

Corresponding to Composite Start-up Emission Standards

in §85.2205(a)(2)(i) and §85.2205(a)(2)(ii)

Light Duty Vehicles

Low Altitude Low Altitude Low Altitude High Altitude

Sec 1981-1982 1983-1990 1991-1995 1982

HC CO NOx HC CO NOx HC CO NOx HC CO NOx

30 0.330 4.189 0.250 0.330 1.941 0.251 0.174 1.307 0.222 0.330 7.391 0.250

31 0.342 4.278 0.267 0.342 1.983 0.268 0.179 1.329 0.246 0.342 7.667 0.267

32 0.353 4.366 0.283 0.353 2.025 0.285 0.184 1.350 0.270 0.353 7.944 0.283

33 0.364 4.455 0.300 0.365 2.067 0.302 0.189 1.372 0.294 0.364 8.220 0.300

34 0.375 4.544 0.316 0.376 2.108 0.320 0.194 1.394 0.318 0.375 8.497 0.316

35 0.386 4.633 0.333 0.388 2.150 0.337 0.199 1.416 0.342 0.386 8.773 0.333

36 0.398 4.728 0.336 0.399 2.230 0.339 0.201 1.453 0.345 0.398 9.011 0.336

37 0.409 4.823 0.339 0.410 2.310 0.342 0.203 1.490 0.348 0.409 9.249 0.339

38 0.420 4.917 0.342 0.420 2.390 0.344 0.205 1.527 0.350 0.420 9.488 0.342

39 0.431 5.012 0.345 0.431 2.471 0.347 0.207 1.565 0.353 0.431 9.726 0.345

40 0.443 5.107 0.348 0.442 2.551 0.349 0.209 1.602 0.356 0.443 9.964 0.348

41 0.458 5.429 0.371 0.458 2.738 0.373 0.214 1.642 0.373 0.458 10.527 0.371

42 0.474 5.751 0.394 0.473 2.926 0.397 0.219 1.682 0.390 0.474 11.090 0.394

43 0.489 6.073 0.418 0.489 3.114 0.422 0.224 1.722 0.407 0.489 11.652 0.418

44 0.505 6.395 0.441 0.505 3.302 0.446 0.228 1.763 0.425 0.505 12.215 0.441

45 0.521 6.717 0.465 0.520 3.489 0.470 0.233 1.803 0.442 0.521 12.778 0.465

46 0.535 6.985 0.480 0.536 3.589 0.486 0.238 1.867 0.465 0.535 13.265 0.480

47 0.550 7.254 0.496 0.552 3.688 0.501 0.244 1.932 0.487 0.550 13.751 0.496

48 0.565 7.522 0.512 0.568 3.787 0.517 0.250 1.997 0.510 0.565 14.238 0.512

49 0.580 7.791 0.527 0.584 3.887 0.533 0.255 2.061 0.533 0.580 14.724 0.527

50 0.594 8.060 0.543 0.600 3.986 0.549 0.261 2.126 0.555 0.594 15.211 0.543

51 0.611 8.511 0.567 0.617 4.029 0.571 0.268 2.152 0.573 0.611 15.550 0.567

52 0.628 8.962 0.590 0.633 4.072 0.594 0.275 2.179 0.590 0.628 15.889 0.590

53 0.644 9.413 0.613 0.649 4.115 0.616 0.282 2.205 0.608 0.644 16.228 0.613

54 0.661 9.865 0.637 0.665 4.157 0.638 0.290 2.232 0.625 0.661 16.567 0.637

55 0.678 10.316 0.660 0.681 4.200 0.661 0.297 2.258 0.643 0.678 16.907 0.660

56 0.691 10.818 0.675 0.696 4.263 0.676 0.302 2.348 0.654 0.691 17.199 0.675

57 0.705 11.320 0.689 0.710 4.326 0.691 0.306 2.437 0.666 0.705 17.492 0.689

58 0.718 11.822 0.703 0.725 4.388 0.707 0.311 2.526 0.677 0.718 17.785 0.703

59 0.731 12.325 0.718 0.740 4.451 0.722 0.316 2.616 0.688 0.731 18.078 0.718

60 0.745 12.827 0.732 0.754 4.514 0.737 0.320 2.705 0.700 0.745 18.371 0.732

61 0.758 13.228 0.743 0.767 4.589 0.748 0.323 2.726 0.707 0.758 18.609 0.743

62 0.772 13.629 0.754 0.780 4.664 0.758 0.326 2.746 0.714 0.772 18.847 0.754

63 0.786 14.029 0.764 0.794 4.740 0.769 0.329 2.767 0.722 0.786 19.085 0.764

64 0.799 14.430 0.775 0.807 4.815 0.780 0.332 2.787 0.729 0.799 19.323 0.775

65 0.813 14.831 0.786 0.820 4.891 0.790 0.335 2.808 0.736 0.813 19.562 0.786

66 0.827 15.046 0.794 0.833 4.945 0.799 0.340 2.812 0.742 0.827 19.887 0.794

67 0.841 15.261 0.803 0.846 4.999 0.808 0.345 2.816 0.747 0.841 20.213 0.803
53

68 0.855 15.476 0.811 0.859 5.053 0.817 0.350 2.820 0.753 0.855 20.539 0.811

69 0.869 15.692 0.820 0.872 5.107 0.826 0.355 2.825 0.758 0.869 20.865 0.820

70 0.883 15.907 0.828 0.885 5.162 0.835 0.360 2.829 0.764 0.883 21.191 0.828

71 0.894 16.118 0.838 0.896 5.226 0.846 0.364 2.847 0.783 0.894 21.396 0.838

72 0.905 16.330 0.848 0.906 5.291 0.857 0.367 2.865 0.802 0.905 21.602 0.848

73 0.917 16.542 0.858 0.917 5.356 0.868 0.371 2.884 0.822 0.917 21.808 0.858

74 0.928 16.753 0.868 0.928 5.421 0.878 0.375 2.902 0.841 0.928 22.013 0.868

75 0.939 16.965 0.878 0.939 5.486 0.889 0.378 2.921 0.860 0.939 22.219 0.878

76 0.953 17.199 0.891 0.952 5.553 0.900 0.387 2.982 0.874 0.953 22.685 0.891

77 0.967 17.432 0.904 0.965 5.620 0.911 0.396 3.044 0.888 0.967 23.151 0.904

78 0.981 17.666 0.917 0.978 5.687 0.922 0.405 3.106 0.902 0.981 23.617 0.917

79 0.994 17.900 0.930 0.991 5.754 0.933 0.414 3.167 0.916 0.994 24.083 0.930

80 1.008 18.133 0.944 1.004 5.821 0.944 0.423 3.229 0.930 1.008 24.549 0.944

81 1.019 18.182 0.951 1.015 5.842 0.951 0.428 3.240 0.945 1.019 24.570 0.951

82 1.031 18.231 0.958 1.026 5.863 0.959 0.432 3.250 0.959 1.031 24.591 0.958

83 1.042 18.280 0.965 1.037 5.883 0.966 0.437 3.261 0.973 1.042 24.612 0.965

84 1.053 18.329 0.972 1.048 5.904 0.973 0.441 3.271 0.987 1.053 24.633 0.972

85 1.065 18.378 0.979 1.059 5.925 0.980 0.445 3.281 1.002 1.065 24.654 0.979

86 1.072 18.393 0.980 1.067 5.970 0.981 0.448 3.290 1.003 1.072 24.666 0.980

87 1.079 18.408 0.981 1.075 6.015 0.982 0.452 3.298 1.004 1.079 24.678 0.981

88 1.086 18.423 0.982 1.083 6.060 0.982 0.455 3.306 1.005 1.086 24.690 0.982

89 1.093 18.438 0.983 1.091 6.105 0.983 0.458 3.315 1.006 1.093 24.703 0.983

90 1.099 18.453 0.983 1.099 6.151 0.984 0.462 3.323 1.007 1.099 24.715 0.983

91 1.107 18.467 0.984 1.106 6.185 0.985 0.463 3.360 1.008 1.107 24.737 0.984

92 1.114 18.481 0.985 1.114 6.219 0.986 0.464 3.397 1.008 1.114 24.758 0.985

93 1.121 18.495 0.985 1.122 6.253 0.986 0.465 3.434 1.009 1.121 24.780 0.985

94 1.128 18.509 0.986 1.129 6.287 0.987 0.466 3.470 1.009 1.128 24.801 0.986

95 1.135 18.523 0.986 1.137 6.321 0.988 0.468 3.507 1.010 1.135 24.823 0.986

96 1.149 18.681 0.992 1.150 6.489 0.993 0.472 3.536 1.011 1.149 25.193 0.992

97 1.162 18.840 0.997 1.163 6.657 0.999 0.477 3.565 1.012 1.162 25.563 0.997

98 1.176 18.998 1.002 1.176 6.825 1.004 0.481 3.594 1.013 1.176 25.933 1.002

99 1.189 19.157 1.008 1.189 6.992 1.009 0.486 3.623 1.014 1.189 26.303 1.008

100 1.203 19.315 1.013 1.202 7.160 1.014 0.490 3.651 1.015 1.203 26.672 1.013

101 1.223 20.090 1.049 1.224 7.269 1.049 0.499 3.685 1.042 1.223 27.821 1.049

102 1.244 20.864 1.085 1.245 7.378 1.084 0.509 3.719 1.069 1.244 28.969 1.085

103 1.264 21.639 1.121 1.266 7.487 1.119 0.518 3.753 1.097 1.264 30.117 1.121

104 1.285 22.414 1.157 1.287 7.596 1.154 0.527 3.787 1.124 1.285 31.265 1.157

105 1.305 23.189 1.193 1.309 7.705 1.189 0.537 3.821 1.151 1.305 32.414 1.193

106 1.319 23.461 1.224 1.323 7.835 1.215 0.541 3.842 1.194 1.319 33.103 1.224

107 1.333 23.733 1.255 1.338 7.965 1.241 0.545 3.863 1.237 1.333 33.792 1.255

108 1.346 24.006 1.286 1.352 8.095 1.267 0.548 3.884 1.280 1.346 34.481 1.286

109 1.360 24.278 1.317 1.367 8.225 1.293 0.552 3.904 1.323 1.360 35.170 1.317

110 1.374 24.550 1.348 1.382 8.355 1.319 0.556 3.925 1.366 1.374 35.859 1.348

111 1.385 24.846 1.356 1.394 8.414 1.327 0.562 3.931 1.368 1.385 36.177 1.356

112 1.396 25.141 1.363 1.406 8.472 1.336 0.568 3.937 1.371 1.396 36.495 1.363
54

113 1.407 25.437 1.371 1.418 8.531 1.345 0.574 3.943 1.374 1.407 36.813 1.371

114 1.417 25.732 1.378 1.430 8.590 1.354 0.580 3.949 1.377 1.417 37.132 1.378

115 1.428 26.028 1.386 1.442 8.649 1.363 0.586 3.956 1.380 1.428 37.450 1.386

116 1.437 26.045 1.388 1.451 8.735 1.364 0.590 3.975 1.380 1.437 37.554 1.388

117 1.446 26.062 1.389 1.460 8.821 1.365 0.593 3.995 1.381 1.446 37.658 1.389

118 1.455 26.079 1.391 1.469 8.907 1.366 0.597 4.015 1.382 1.455 37.761 1.391

119 1.464 26.096 1.393 1.479 8.992 1.368 0.600 4.035 1.383 1.464 37.865 1.393

120 1.472 26.114 1.394 1.488 9.078 1.369 0.604 4.055 1.383 1.472 37.969 1.394

121 1.488 26.293 1.408 1.501 9.152 1.385 0.610 4.152 1.400 1.488 38.310 1.408

122 1.503 26.472 1.422 1.514 9.227 1.401 0.615 4.250 1.417 1.503 38.650 1.422

123 1.518 26.651 1.435 1.527 9.301 1.417 0.621 4.348 1.433 1.518 38.990 1.435

124 1.534 26.830 1.449 1.540 9.375 1.434 0.627 4.445 1.450 1.534 39.330 1.449

125 1.549 27.010 1.463 1.553 9.449 1.450 0.632 4.543 1.466 1.549 39.671 1.463

126 1.559 27.151 1.471 1.563 9.519 1.458 0.636 4.567 1.470 1.559 39.865 1.471

127 1.569 27.292 1.479 1.572 9.590 1.467 0.639 4.592 1.473 1.569 40.059 1.479

128 1.579 27.433 1.487 1.582 9.661 1.475 0.642 4.617 1.476 1.579 40.254 1.487

129 1.590 27.575 1.495 1.592 9.731 1.484 0.645 4.641 1.479 1.590 40.448 1.495

130 1.600 27.716 1.502 1.601 9.802 1.492 0.648 4.666 1.482 1.600 40.642 1.502

131 1.612 27.878 1.506 1.615 9.849 1.496 0.653 4.685 1.483 1.612 40.790 1.506

132 1.624 28.040 1.509 1.628 9.895 1.500 0.657 4.704 1.485 1.624 40.937 1.509

133 1.635 28.202 1.512 1.642 9.942 1.504 0.661 4.724 1.486 1.635 41.084 1.512

134 1.647 28.365 1.515 1.655 9.989 1.508 0.666 4.743 1.488 1.647 41.231 1.515

135 1.659 28.527 1.519 1.669 10.035 1.512 0.670 4.762 1.489 1.659 41.379 1.519

136 1.676 28.833 1.542 1.685 10.104 1.534 0.678 4.785 1.507 1.676 42.023 1.542

137 1.693 29.140 1.566 1.700 10.173 1.557 0.685 4.807 1.524 1.693 42.668 1.566

138 1.709 29.446 1.589 1.716 10.241 1.580 0.693 4.830 1.541 1.709 43.312 1.589

139 1.726 29.753 1.613 1.732 10.310 1.603 0.700 4.853 1.559 1.726 43.957 1.613

140 1.743 30.060 1.636 1.747 10.378 1.626 0.708 4.875 1.576 1.743 44.602 1.636

141 1.756 30.160 1.651 1.762 10.506 1.640 0.716 4.886 1.592 1.756 45.010 1.651

142 1.770 30.260 1.666 1.777 10.633 1.655 0.723 4.897 1.608 1.770 45.419 1.666

143 1.783 30.361 1.681 1.791 10.761 1.669 0.731 4.908 1.624 1.783 45.828 1.681

144 1.797 30.461 1.696 1.806 10.888 1.684 0.738 4.918 1.640 1.797 46.237 1.696

145 1.810 30.562 1.711 1.821 11.016 1.699 0.746 4.929 1.656 1.810 46.646 1.711

146 1.822 30.592 1.720 1.830 11.101 1.709 0.751 4.954 1.663 1.822 46.945 1.720

147 1.834 30.622 1.730 1.840 11.187 1.720 0.755 4.979 1.671 1.834 47.244 1.730

148 1.846 30.653 1.740 1.850 11.273 1.730 0.760 5.004 1.679 1.846 47.544 1.740

149 1.858 30.683 1.750 1.860 11.359 1.741 0.765 5.029 1.687 1.858 47.843 1.750

150 1.869 30.713 1.760 1.869 11.445 1.752 0.770 5.054 1.694 1.869 48.143 1.760

151 1.880 30.741 1.767 1.879 11.504 1.759 0.775 5.060 1.711 1.880 48.423 1.767

152 1.890 30.768 1.775 1.890 11.564 1.767 0.780 5.065 1.727 1.890 48.704 1.775

153 1.900 30.796 1.783 1.900 11.624 1.775 0.785 5.070 1.743 1.900 48.984 1.783

154 1.910 30.823 1.791 1.910 11.683 1.783 0.791 5.075 1.760 1.910 49.265 1.791

155 1.920 30.850 1.798 1.920 11.743 1.790 0.796 5.080 1.776 1.920 49.545 1.798

156 1.949 32.415 1.828 1.945 12.434 1.821 0.819 5.150 1.813 1.949 50.517 1.828

157 1.977 33.980 1.858 1.971 13.125 1.852 0.842 5.220 1.850 1.977 51.489 1.858
55

158 2.006 35.545 1.888 1.996 13.816 1.883 0.865 5.290 1.887 2.006 52.461 1.888

159 2.034 37.110 1.918 2.022 14.507 1.913 0.888 5.360 1.924 2.034 53.433 1.918

160 2.063 38.674 1.948 2.047 15.198 1.944 0.911 5.430 1.961 2.063 54.406 1.948

161 2.105 41.040 2.043 2.092 16.627 2.038 0.951 7.045 2.030 2.105 56.279 2.043

162 2.147 43.405 2.138 2.137 18.056 2.133 0.992 8.661 2.099 2.147 58.152 2.138

163 2.190 45.770 2.234 2.182 19.485 2.227 1.032 10.276 2.168 2.190 60.026 2.234

164 2.232 48.136 2.329 2.227 20.914 2.321 1.073 11.891 2.237 2.232 61.899 2.329

165 2.275 50.501 2.424 2.272 22.343 2.415 1.113 13.506 2.306 2.275 63.773 2.424

166 2.304 52.979 2.509 2.300 23.672 2.502 1.163 14.131 2.357 2.304 65.726 2.509

167 2.333 55.458 2.593 2.328 25.002 2.589 1.213 14.755 2.409 2.333 67.678 2.593

168 2.362 57.937 2.678 2.356 26.331 2.676 1.263 15.380 2.460 2.362 69.631 2.678

169 2.391 60.415 2.762 2.385 27.660 2.763 1.313 16.004 2.512 2.391 71.584 2.762

170 2.420 62.894 2.847 2.413 28.989 2.849 1.363 16.628 2.564 2.420 73.536 2.847

171 2.451 63.874 2.890 2.442 29.484 2.892 1.386 16.692 2.603 2.451 75.553 2.890

172 2.481 64.855 2.933 2.472 29.978 2.934 1.410 16.756 2.643 2.481 77.570 2.933

173 2.512 65.835 2.976 2.502 30.473 2.976 1.433 16.820 2.683 2.512 79.587 2.976

174 2.542 66.815 3.019 2.532 30.967 3.019 1.457 16.883 2.723 2.542 81.604 3.019

175 2.573 67.796 3.062 2.562 31.462 3.061 1.480 16.947 2.762 2.573 83.621 3.062

176 2.598 68.919 3.122 2.588 32.216 3.119 1.494 17.044 2.809 2.598 85.074 3.122

177 2.623 70.042 3.181 2.615 32.970 3.178 1.508 17.141 2.856 2.623 86.528 3.181

178 2.648 71.165 3.240 2.641 33.725 3.236 1.522 17.238 2.903 2.648 87.981 3.240

179 2.674 72.287 3.300 2.668 34.479 3.295 1.536 17.335 2.949 2.674 89.434 3.300

180 2.699 73.410 3.359 2.694 35.233 3.353 1.550 17.431 2.996 2.699 90.888 3.359

181 2.726 74.714 3.432 2.718 35.950 3.424 1.565 17.453 3.040 2.726 92.421 3.432

182 2.753 76.017 3.504 2.743 36.666 3.495 1.580 17.475 3.084 2.753 93.953 3.504

183 2.780 77.320 3.576 2.767 37.382 3.567 1.595 17.497 3.129 2.780 95.486 3.576

184 2.807 78.623 3.648 2.791 38.099 3.638 1.610 17.519 3.173 2.807 97.019 3.648

185 2.834 79.927 3.720 2.816 38.815 3.709 1.624 17.540 3.217 2.834 98.552 3.720

186 2.861 81.488 3.804 2.843 39.562 3.795 1.639 17.816 3.277 2.861 100.583 3.804

187 2.888 83.049 3.889 2.869 40.309 3.880 1.654 18.091 3.337 2.888 102.615 3.889

188 2.915 84.611 3.973 2.896 41.056 3.965 1.668 18.366 3.397 2.915 104.646 3.973

189 2.942 86.172 4.057 2.923 41.803 4.051 1.683 18.641 3.457 2.942 106.677 4.057

190 2.969 87.733 4.141 2.950 42.550 4.136 1.697 18.916 3.518 2.969 108.709 4.141

191 2.994 88.668 4.196 2.975 43.279 4.190 1.711 19.891 3.565 2.994 110.057 4.196

192 3.019 89.603 4.250 3.001 44.008 4.243 1.724 20.866 3.612 3.019 111.405 4.250

193 3.044 90.538 4.304 3.027 44.737 4.297 1.737 21.840 3.658 3.044 112.753 4.304

194 3.070 91.473 4.358 3.052 45.466 4.351 1.750 22.815 3.705 3.070 114.101 4.358

195 3.095 92.407 4.412 3.078 46.195 4.404 1.763 23.790 3.752 3.095 115.449 4.412

196 3.120 93.768 4.485 3.105 46.747 4.477 1.778 24.992 3.794 3.120 116.561 4.485

197 3.145 95.129 4.558 3.132 47.299 4.549 1.793 26.194 3.836 3.145 117.674 4.558

198 3.169 96.490 4.630 3.159 47.852 4.622 1.808 27.396 3.877 3.169 118.786 4.630

199 3.194 97.851 4.703 3.186 48.404 4.694 1.823 28.597 3.919 3.194 119.899 4.703

200 3.219 99.212 4.775 3.213 48.957 4.767 1.838 29.799 3.960 3.219 121.011 4.775

201 3.242 99.878 4.821 3.234 49.204 4.812 1.858 29.975 4.004 3.242 121.695 4.821

202 3.266 100.544 4.867 3.255 49.451 4.858 1.877 30.152 4.047 3.266 122.378 4.867
56

203 3.289 101.210 4.914 3.277 49.698 4.904 1.897 30.328 4.090 3.289 123.062 4.914

204 3.312 101.876 4.960 3.298 49.945 4.950 1.916 30.504 4.133 3.312 123.745 4.960

205 3.335 102.542 5.006 3.320 50.192 4.996 1.936 30.680 4.176 3.335 124.429 5.006

206 3.362 103.507 5.037 3.346 50.698 5.029 1.948 30.747 4.193 3.362 125.599 5.037

207 3.388 104.472 5.069 3.373 51.205 5.063 1.961 30.813 4.209 3.388 126.769 5.069

208 3.415 105.437 5.101 3.399 51.711 5.097 1.973 30.879 4.225 3.415 127.939 5.101

209 3.441 106.402 5.132 3.426 52.218 5.130 1.986 30.946 4.241 3.441 129.109 5.132

210 3.468 107.366 5.164 3.452 52.724 5.164 1.998 31.012 4.257 3.468 130.279 5.164

211 3.488 108.519 5.234 3.472 53.327 5.233 2.006 32.744 4.311 3.488 132.009 5.234

212 3.509 109.671 5.304 3.492 53.931 5.303 2.015 34.476 4.365 3.509 133.740 5.304

213 3.530 110.823 5.374 3.513 54.534 5.372 2.023 36.207 4.419 3.530 135.470 5.374

214 3.550 111.976 5.444 3.533 55.137 5.442 2.031 37.939 4.473 3.550 137.201 5.444

215 3.571 113.128 5.514 3.553 55.740 5.511 2.039 39.671 4.527 3.571 138.931 5.514

216 3.591 113.763 5.564 3.571 56.057 5.559 2.044 39.822 4.565 3.591 140.070 5.564

217 3.612 114.398 5.613 3.589 56.373 5.606 2.048 39.973 4.602 3.612 141.208 5.613

218 3.632 115.033 5.663 3.608 56.689 5.654 2.053 40.125 4.640 3.632 142.347 5.663

219 3.652 115.668 5.713 3.626 57.005 5.701 2.058 40.276 4.677 3.652 143.485 5.713

220 3.672 116.304 5.763 3.644 57.321 5.749 2.062 40.427 4.715 3.672 144.624 5.763

221 3.693 116.644 5.775 3.669 57.474 5.761 2.076 40.526 4.724 3.693 144.903 5.775

222 3.714 116.984 5.787 3.693 57.626 5.773 2.089 40.626 4.732 3.714 145.182 5.787

223 3.736 117.324 5.799 3.717 57.779 5.785 2.103 40.725 4.741 3.736 145.462 5.799

224 3.757 117.663 5.811 3.741 57.931 5.797 2.117 40.825 4.750 3.757 145.741 5.811

225 3.778 118.003 5.823 3.766 58.084 5.809 2.130 40.924 4.759 3.778 146.020 5.823

226 3.795 118.158 5.828 3.782 58.158 5.814 2.160 40.962 4.764 3.795 146.177 5.828

227 3.811 118.312 5.833 3.798 58.232 5.820 2.190 41.000 4.770 3.811 146.334 5.833

228 3.828 118.466 5.838 3.815 58.307 5.825 2.219 41.038 4.775 3.828 146.491 5.838

229 3.845 118.621 5.842 3.831 58.381 5.830 2.249 41.076 4.781 3.845 146.648 5.842

230 3.862 118.775 5.847 3.848 58.455 5.835 2.278 41.114 4.786 3.862 146.805 5.847

231 3.873 118.885 5.852 3.858 58.534 5.840 2.285 41.142 4.790 3.873 147.057 5.852

232 3.884 118.995 5.856 3.868 58.612 5.845 2.292 41.171 4.794 3.884 147.308 5.856

233 3.896 119.105 5.860 3.879 58.690 5.850 2.299 41.199 4.797 3.896 147.560 5.860

234 3.907 119.215 5.865 3.889 58.769 5.855 2.306 41.228 4.801 3.907 147.812 5.865

235 3.918 119.325 5.869 3.900 58.847 5.860 2.313 41.256 4.805 3.918 148.064 5.869

236 3.924 119.407 5.874 3.907 58.990 5.865 2.315 41.285 4.808 3.924 148.450 5.874

237 3.930 119.488 5.878 3.913 59.132 5.869 2.318 41.313 4.812 3.930 148.837 5.878

238 3.935 119.570 5.883 3.920 59.275 5.874 2.320 41.341 4.815 3.935 149.223 5.883

239 3.941 119.651 5.887 3.927 59.418 5.878 2.322 41.369 4.818 3.941 149.609 5.887

240 3.947 119.733 5.892 3.934 59.560 5.883 2.325 41.397 4.822 3.947 149.996 5.892
57

Alternative Fast-Pass IM240 Standards

Corresponding to Composite Start-up Emission Standards in §85.2205(a)(2)(iv)

Light Duty Truck 1&2

1982-1983 1984-1987 1988-1990 1991

Sec HC CO NOx HC CO NOx HC CO NOx HC CO NOx

30 1.064 14.776 0.562 0.585 10.661 0.513 0.585 10.661 0.298 0.477 5.069 0.254

31 1.091 15.338 0.610 0.609 11.033 0.551 0.609 11.033 0.319 0.494 5.129 0.270

32 1.118 15.900 0.657 0.633 11.405 0.590 0.633 11.405 0.340 0.512 5.189 0.285

33 1.145 16.462 0.705 0.657 11.777 0.629 0.657 11.777 0.361 0.529 5.249 0.300

34 1.172 17.023 0.752 0.681 12.149 0.667 0.681 12.149 0.382 0.547 5.309 0.316

35 1.199 17.585 0.800 0.705 12.521 0.706 0.705 12.521 0.403 0.564 5.369 0.331

36 1.237 17.834 0.804 0.730 12.895 0.711 0.730 12.895 0.407 0.582 5.562 0.334

37 1.275 18.084 0.808 0.754 13.269 0.716 0.754 13.269 0.410 0.601 5.755 0.336

38 1.313 18.333 0.813 0.779 13.643 0.721 0.779 13.643 0.414 0.619 5.948 0.339

39 1.351 18.582 0.817 0.803 14.018 0.727 0.803 14.018 0.418 0.637 6.142 0.341

40 1.389 18.832 0.822 0.828 14.392 0.732 0.828 14.392 0.422 0.656 6.335 0.344

41 1.459 19.867 0.869 0.854 15.098 0.796 0.854 15.098 0.451 0.681 6.890 0.368

42 1.529 20.902 0.915 0.880 15.805 0.861 0.880 15.805 0.479 0.707 7.445 0.392

43 1.599 21.937 0.962 0.907 16.511 0.925 0.907 16.511 0.508 0.732 7.999 0.416

44 1.669 22.972 1.009 0.933 17.217 0.989 0.933 17.217 0.536 0.758 8.554 0.440

45 1.738 24.008 1.056 0.959 17.924 1.053 0.959 17.924 0.565 0.783 9.109 0.464

46 1.784 24.572 1.098 0.989 18.458 1.096 0.989 18.458 0.587 0.799 9.593 0.480

47 1.830 25.136 1.140 1.019 18.992 1.138 1.019 18.992 0.609 0.816 10.076 0.496

48 1.876 25.701 1.182 1.050 19.526 1.180 1.050 19.526 0.631 0.832 10.560 0.512

49 1.922 26.265 1.224 1.080 20.060 1.223 1.080 20.060 0.652 0.848 11.044 0.528

50 1.968 26.830 1.266 1.110 20.594 1.265 1.110 20.594 0.674 0.864 11.527 0.543

51 2.020 27.642 1.305 1.146 21.719 1.294 1.146 21.719 0.701 0.891 12.038 0.563

52 2.072 28.454 1.343 1.182 22.845 1.324 1.182 22.845 0.728 0.917 12.549 0.582

53 2.124 29.266 1.381 1.218 23.970 1.353 1.218 23.970 0.755 0.943 13.059 0.601

54 2.176 30.079 1.420 1.254 25.095 1.382 1.254 25.095 0.782 0.969 13.570 0.621

55 2.228 30.891 1.458 1.290 26.221 1.411 1.290 26.221 0.809 0.995 14.081 0.640

56 2.265 31.485 1.490 1.310 26.449 1.449 1.310 26.449 0.826 1.015 14.438 0.653

57 2.302 32.078 1.522 1.330 26.677 1.486 1.330 26.677 0.842 1.035 14.796 0.666

58 2.340 32.672 1.555 1.350 26.905 1.523 1.350 26.905 0.859 1.055 15.154 0.679

59 2.377 33.266 1.587 1.370 27.133 1.560 1.370 27.133 0.876 1.075 15.512 0.692

60 2.415 33.860 1.619 1.390 27.361 1.597 1.390 27.361 0.892 1.095 15.870 0.705

61 2.451 34.449 1.637 1.405 27.372 1.611 1.405 27.372 0.903 1.109 16.268 0.714

62 2.487 35.037 1.656 1.420 27.383 1.625 1.420 27.383 0.915 1.124 16.667 0.723

63 2.523 35.626 1.674 1.434 27.393 1.639 1.434 27.393 0.926 1.138 17.066 0.732

64 2.559 36.215 1.693 1.449 27.404 1.653 1.449 27.404 0.938 1.153 17.465 0.741

65 2.595 36.804 1.711 1.464 27.415 1.667 1.464 27.415 0.949 1.167 17.863 0.750

66 2.639 37.463 1.737 1.497 28.054 1.699 1.497 28.054 0.960 1.182 18.249 0.759

67 2.683 38.122 1.763 1.530 28.694 1.732 1.530 28.694 0.972 1.196 18.635 0.768

68 2.728 38.782 1.789 1.563 29.333 1.765 1.563 29.333 0.983 1.211 19.020 0.777
58

69 2.772 39.441 1.815 1.596 29.972 1.797 1.596 29.972 0.994 1.225 19.406 0.786

70 2.817 40.100 1.841 1.629 30.612 1.830 1.629 30.612 1.005 1.239 19.792 0.795

71 2.859 40.631 1.862 1.650 31.097 1.854 1.650 31.097 1.016 1.255 19.906 0.805

72 2.901 41.161 1.884 1.672 31.583 1.878 1.672 31.583 1.028 1.271 20.020 0.815

73 2.943 41.692 1.906 1.694 32.068 1.902 1.694 32.068 1.039 1.287 20.134 0.825

74 2.985 42.222 1.928 1.715 32.554 1.925 1.715 32.554 1.051 1.303 20.248 0.835

75 3.027 42.753 1.950 1.737 33.039 1.949 1.737 33.039 1.062 1.318 20.362 0.845

76 3.061 43.694 1.978 1.760 33.193 1.977 1.760 33.193 1.074 1.331 20.782 0.859

77 3.096 44.636 2.007 1.782 33.347 2.005 1.782 33.347 1.085 1.344 21.202 0.874

78 3.130 45.577 2.035 1.805 33.501 2.033 1.805 33.501 1.096 1.357 21.623 0.888

79 3.165 46.519 2.063 1.828 33.655 2.061 1.828 33.655 1.108 1.370 22.043 0.902

80 3.200 47.461 2.092 1.851 33.809 2.089 1.851 33.809 1.119 1.382 22.463 0.916

81 3.237 47.831 2.111 1.872 34.035 2.111 1.872 34.035 1.131 1.407 22.571 0.925

82 3.275 48.201 2.130 1.894 34.261 2.132 1.894 34.261 1.144 1.431 22.678 0.934

83 3.313 48.571 2.149 1.915 34.488 2.154 1.915 34.488 1.156 1.455 22.786 0.942

84 3.351 48.941 2.168 1.937 34.714 2.175 1.937 34.714 1.169 1.480 22.894 0.951

85 3.389 49.311 2.187 1.958 34.941 2.197 1.958 34.941 1.181 1.504 23.001 0.960

86 3.432 49.503 2.189 1.973 35.115 2.200 1.973 35.115 1.182 1.531 23.112 0.961

87 3.475 49.694 2.192 1.988 35.289 2.203 1.988 35.289 1.182 1.558 23.223 0.963

88 3.518 49.886 2.194 2.002 35.463 2.206 2.002 35.463 1.183 1.586 23.334 0.964

89 3.562 50.077 2.197 2.017 35.637 2.209 2.017 35.637 1.184 1.613 23.445 0.966

90 3.605 50.269 2.199 2.032 35.811 2.212 2.032 35.811 1.185 1.640 23.556 0.967

91 3.645 50.447 2.200 2.044 35.968 2.213 2.044 35.968 1.186 1.654 23.558 0.968

92 3.686 50.626 2.201 2.056 36.125 2.214 2.056 36.125 1.187 1.668 23.560 0.968

93 3.727 50.805 2.202 2.068 36.282 2.215 2.068 36.282 1.188 1.682 23.562 0.968

94 3.767 50.984 2.203 2.081 36.440 2.216 2.081 36.440 1.189 1.696 23.564 0.969

95 3.808 51.162 2.204 2.093 36.597 2.217 2.093 36.597 1.190 1.710 23.567 0.969

96 3.853 51.779 2.212 2.111 36.968 2.227 2.111 36.968 1.195 1.727 23.924 0.978

97 3.898 52.395 2.219 2.129 37.339 2.236 2.129 37.339 1.201 1.744 24.282 0.987

98 3.943 53.012 2.227 2.147 37.710 2.245 2.147 37.710 1.207 1.762 24.639 0.996

99 3.988 53.628 2.234 2.165 38.081 2.254 2.165 38.081 1.213 1.779 24.997 1.004

100 4.033 54.245 2.242 2.183 38.453 2.263 2.183 38.453 1.218 1.796 25.355 1.013

101 4.081 55.131 2.322 2.221 40.429 2.342 2.221 40.429 1.259 1.819 25.871 1.045

102 4.128 56.016 2.403 2.258 42.405 2.420 2.258 42.405 1.299 1.842 26.387 1.076

103 4.175 56.902 2.484 2.295 44.382 2.498 2.295 44.382 1.340 1.865 26.903 1.107

104 4.223 57.788 2.565 2.333 46.358 2.576 2.333 46.358 1.380 1.887 27.419 1.139

105 4.270 58.674 2.646 2.370 48.335 2.654 2.370 48.335 1.421 1.910 27.935 1.170

106 4.300 59.222 2.721 2.404 49.060 2.740 2.404 49.060 1.458 1.936 28.221 1.201

107 4.331 59.771 2.797 2.437 49.785 2.826 2.437 49.785 1.495 1.962 28.506 1.232

108 4.361 60.319 2.872 2.471 50.511 2.912 2.471 50.511 1.531 1.988 28.792 1.263

109 4.391 60.868 2.948 2.504 51.236 2.998 2.504 51.236 1.568 2.014 29.077 1.294

110 4.421 61.416 3.023 2.538 51.962 3.084 2.538 51.962 1.605 2.040 29.363 1.325

111 4.449 61.935 3.038 2.560 52.113 3.101 2.560 52.113 1.615 2.057 29.405 1.332

112 4.476 62.455 3.053 2.582 52.265 3.118 2.582 52.265 1.624 2.074 29.447 1.338

113 4.503 62.974 3.067 2.604 52.417 3.136 2.604 52.417 1.634 2.090 29.489 1.344
59

114 4.531 63.493 3.082 2.625 52.569 3.153 2.625 52.569 1.644 2.107 29.531 1.350

115 4.558 64.013 3.097 2.647 52.721 3.170 2.647 52.721 1.653 2.124 29.573 1.357

116 4.600 64.559 3.099 2.673 52.723 3.173 2.673 52.723 1.656 2.152 29.865 1.359

117 4.642 65.105 3.102 2.698 52.724 3.175 2.698 52.724 1.658 2.179 30.157 1.361

118 4.684 65.651 3.105 2.723 52.726 3.178 2.723 52.726 1.661 2.207 30.449 1.363

119 4.726 66.197 3.108 2.749 52.728 3.181 2.749 52.728 1.663 2.234 30.741 1.365

120 4.768 66.743 3.111 2.774 52.729 3.184 2.774 52.729 1.666 2.262 31.033 1.368

121 4.804 67.600 3.134 2.799 53.168 3.206 2.799 53.168 1.684 2.276 31.230 1.383

122 4.840 68.458 3.156 2.824 53.606 3.229 2.824 53.606 1.703 2.290 31.428 1.399

123 4.876 69.315 3.179 2.850 54.044 3.251 2.850 54.044 1.722 2.304 31.625 1.415

124 4.911 70.173 3.202 2.875 54.483 3.274 2.875 54.483 1.741 2.318 31.823 1.431

125 4.947 71.030 3.224 2.900 54.921 3.296 2.900 54.921 1.759 2.332 32.020 1.446

126 4.983 71.729 3.241 2.920 55.078 3.310 2.920 55.078 1.770 2.355 32.099 1.453

127 5.019 72.427 3.257 2.941 55.236 3.323 2.941 55.236 1.780 2.377 32.178 1.460

128 5.055 73.126 3.274 2.961 55.393 3.337 2.961 55.393 1.790 2.399 32.256 1.468

129 5.091 73.825 3.290 2.981 55.551 3.350 2.981 55.551 1.800 2.422 32.335 1.475

130 5.126 74.523 3.307 3.001 55.708 3.364 3.001 55.708 1.811 2.444 32.413 1.482

131 5.178 75.331 3.311 3.027 55.921 3.370 3.027 55.921 1.813 2.464 32.638 1.484

132 5.230 76.139 3.316 3.052 56.134 3.376 3.052 56.134 1.816 2.485 32.862 1.487

133 5.282 76.947 3.321 3.078 56.346 3.382 3.078 56.346 1.819 2.505 33.086 1.490

134 5.334 77.755 3.326 3.103 56.559 3.388 3.103 56.559 1.822 2.525 33.310 1.492

135 5.386 78.563 3.331 3.129 56.771 3.394 3.129 56.771 1.825 2.545 33.534 1.495

136 5.468 79.372 3.365 3.167 57.854 3.432 3.167 57.854 1.851 2.573 34.147 1.520

137 5.549 80.181 3.398 3.206 58.937 3.469 3.206 58.937 1.877 2.600 34.760 1.546

138 5.630 80.990 3.431 3.244 60.020 3.507 3.244 60.020 1.903 2.628 35.373 1.571

139 5.712 81.798 3.464 3.283 61.102 3.544 3.283 61.102 1.929 2.655 35.985 1.596

140 5.793 82.607 3.498 3.322 62.185 3.582 3.322 62.185 1.955 2.682 36.598 1.622

141 5.825 83.486 3.536 3.342 62.366 3.639 3.342 62.366 1.977 2.702 36.880 1.639

142 5.856 84.365 3.575 3.363 62.548 3.697 3.363 62.548 1.999 2.722 37.162 1.656

143 5.888 85.245 3.613 3.383 62.729 3.754 3.383 62.729 2.021 2.742 37.444 1.673

144 5.920 86.124 3.652 3.404 62.910 3.811 3.404 62.910 2.043 2.762 37.727 1.691

145 5.951 87.003 3.690 3.425 63.091 3.869 3.425 63.091 2.065 2.782 38.009 1.708

146 5.975 87.915 3.718 3.453 63.539 3.892 3.453 63.539 2.074 2.797 38.632 1.717

147 5.998 88.827 3.745 3.482 63.987 3.916 3.482 63.987 2.082 2.811 39.255 1.726

148 6.022 89.739 3.772 3.510 64.435 3.939 3.510 64.435 2.090 2.825 39.878 1.735

149 6.046 90.652 3.800 3.539 64.883 3.963 3.539 64.883 2.098 2.839 40.501 1.743

150 6.069 91.564 3.827 3.568 65.331 3.986 3.568 65.331 2.106 2.853 41.124 1.752

151 6.099 92.475 3.852 3.595 65.704 4.000 3.595 65.704 2.117 2.868 41.450 1.765

152 6.129 93.387 3.877 3.623 66.077 4.014 3.623 66.077 2.129 2.883 41.776 1.778

153 6.159 94.298 3.901 3.650 66.450 4.029 3.650 66.450 2.141 2.898 42.102 1.791

154 6.189 95.209 3.926 3.677 66.823 4.043 3.677 66.823 2.152 2.913 42.428 1.803

155 6.219 96.121 3.951 3.705 67.197 4.057 3.705 67.197 2.164 2.927 42.754 1.816

156 6.313 97.599 4.030 3.767 69.206 4.117 3.767 69.206 2.205 2.969 44.233 1.849

157 6.407 99.077 4.110 3.829 71.215 4.176 3.829 71.215 2.247 3.011 45.712 1.882

158 6.501 100.555 4.190 3.891 73.225 4.236 3.891 73.225 2.289 3.053 47.191 1.915
60

159 6.595 102.033 4.269 3.953 75.234 4.295 3.953 75.234 2.330 3.095 48.670 1.948

160 6.689 103.511 4.349 4.015 77.243 4.355 4.015 77.243 2.372 3.136 50.149 1.981

161 7.010 107.552 4.542 4.078 79.985 4.551 4.078 79.985 2.472 3.182 51.569 2.071

162 7.331 111.593 4.736 4.142 82.727 4.747 4.142 82.727 2.571 3.227 52.988 2.162

163 7.652 115.634 4.930 4.205 85.469 4.943 4.205 85.469 2.671 3.272 54.408 2.252

164 7.972 119.676 5.123 4.268 88.211 5.139 4.268 88.211 2.770 3.318 55.828 2.343

165 8.293 123.717 5.317 4.332 90.953 5.335 4.332 90.953 2.870 3.363 57.247 2.434

166 8.576 125.252 5.496 4.380 93.266 5.516 4.380 93.266 2.961 3.410 58.958 2.509

167 8.859 126.786 5.676 4.428 95.579 5.696 4.428 95.579 3.053 3.458 60.670 2.584

168 9.142 128.321 5.855 4.477 97.892 5.876 4.477 97.892 3.144 3.505 62.381 2.659

169 9.425 129.855 6.034 4.525 100.205 6.056 4.525 100.205 3.235 3.552 64.092 2.735

170 9.708 131.390 6.213 4.573 102.517 6.237 4.573 102.517 3.327 3.600 65.804 2.810

171 9.788 132.095 6.318 4.618 103.813 6.345 4.618 103.813 3.373 3.644 66.939 2.863

172 9.868 132.801 6.422 4.664 105.109 6.452 4.664 105.109 3.420 3.688 68.075 2.916

173 9.948 133.506 6.527 4.709 106.404 6.560 4.709 106.404 3.467 3.732 69.210 2.969

174 10.028 134.211 6.632 4.754 107.700 6.668 4.754 107.700 3.513 3.776 70.345 3.022

175 10.107 134.917 6.736 4.799 108.995 6.776 4.799 108.995 3.560 3.821 71.481 3.075

176 10.174 137.703 6.876 4.858 110.733 6.910 4.858 110.733 3.626 3.856 73.077 3.130

177 10.242 140.490 7.016 4.917 112.471 7.045 4.917 112.471 3.692 3.891 74.674 3.185

178 10.309 143.276 7.155 4.977 114.209 7.179 4.977 114.209 3.758 3.927 76.271 3.240

179 10.376 146.063 7.295 5.036 115.946 7.313 5.036 115.946 3.824 3.962 77.867 3.295

180 10.443 148.849 7.435 5.095 117.684 7.447 5.095 117.684 3.889 3.997 79.464 3.350

181 10.506 152.900 7.603 5.158 119.775 7.621 5.158 119.775 3.979 4.024 81.282 3.430

182 10.570 156.950 7.772 5.221 121.866 7.795 5.221 121.866 4.069 4.050 83.100 3.509

183 10.634 161.001 7.941 5.284 123.956 7.969 5.284 123.956 4.159 4.077 84.919 3.589

184 10.698 165.051 8.110 5.347 126.047 8.143 5.347 126.047 4.248 4.104 86.737 3.668

185 10.761 169.102 8.279 5.411 128.138 8.318 5.411 128.138 4.338 4.131 88.555 3.748

186 10.836 171.850 8.477 5.428 129.673 8.499 5.428 129.673 4.443 4.154 90.333 3.841

187 10.911 174.598 8.675 5.446 131.209 8.681 5.446 131.209 4.547 4.178 92.110 3.934

188 10.986 177.345 8.873 5.463 132.745 8.862 5.463 132.745 4.652 4.202 93.888 4.026

189 11.061 180.093 9.071 5.481 134.281 9.043 5.481 134.281 4.756 4.225 95.665 4.119

190 11.136 182.841 9.269 5.499 135.816 9.225 5.499 135.816 4.861 4.249 97.442 4.212

191 11.307 184.591 9.422 5.561 137.198 9.386 5.561 137.198 4.932 4.285 98.856 4.274

192 11.477 186.341 9.576 5.623 138.580 9.547 5.623 138.580 5.003 4.321 100.271 4.336

193 11.648 188.091 9.730 5.686 139.961 9.708 5.686 139.961 5.074 4.357 101.685 4.398

194 11.819 189.841 9.884 5.748 141.343 9.869 5.748 141.343 5.146 4.393 103.099 4.459

195 11.990 191.591 10.038 5.810 142.724 10.030 5.810 142.724 5.217 4.430 104.513 4.521

196 12.067 194.037 10.193 5.828 144.052 10.188 5.828 144.052 5.301 4.460 106.134 4.589

197 12.144 196.482 10.348 5.845 145.381 10.346 5.845 145.381 5.385 4.490 107.755 4.658

198 12.221 198.927 10.503 5.863 146.709 10.504 5.863 146.709 5.469 4.520 109.376 4.726

199 12.298 201.373 10.658 5.880 148.037 10.662 5.880 148.037 5.553 4.550 110.997 4.795

200 12.376 203.818 10.813 5.898 149.365 10.820 5.898 149.365 5.637 4.580 112.617 4.863

201 12.463 204.868 10.912 5.942 150.214 10.948 5.942 150.214 5.692 4.623 113.207 4.906

202 12.551 205.918 11.012 5.986 151.063 11.075 5.986 151.063 5.746 4.666 113.796 4.949

203 12.639 206.967 11.111 6.029 151.912 11.203 6.029 151.912 5.801 4.709 114.385 4.993
61

204 12.726 208.017 11.211 6.073 152.760 11.330 6.073 152.760 5.856 4.752 114.974 5.036

205 12.814 209.067 11.310 6.117 153.609 11.458 6.117 153.609 5.911 4.795 115.563 5.079

206 12.891 211.915 11.381 6.174 154.888 11.530 6.174 154.888 5.951 4.848 116.847 5.119

207 12.969 214.764 11.452 6.231 156.166 11.601 6.231 156.166 5.990 4.901 118.131 5.160

208 13.046 217.612 11.523 6.288 157.445 11.673 6.288 157.445 6.030 4.955 119.415 5.201

209 13.124 220.460 11.594 6.345 158.724 11.745 6.345 158.724 6.070 5.008 120.699 5.241

210 13.201 223.309 11.665 6.401 160.002 11.817 6.401 160.002 6.110 5.061 121.983 5.282

211 13.243 226.365 11.862 6.451 161.606 11.984 6.451 161.606 6.194 5.090 123.498 5.355

212 13.285 229.421 12.060 6.500 163.210 12.152 6.500 163.210 6.278 5.119 125.012 5.429

213 13.327 232.478 12.257 6.550 164.814 12.319 6.550 164.814 6.362 5.147 126.526 5.502

214 13.370 235.534 12.455 6.599 166.418 12.486 6.599 166.418 6.446 5.176 128.040 5.576

215 13.412 238.591 12.653 6.649 168.022 12.653 6.649 168.022 6.530 5.204 129.554 5.649

216 13.470 240.891 12.778 6.693 168.948 12.780 6.693 168.948 6.585 5.240 130.345 5.695

217 13.528 243.191 12.904 6.737 169.874 12.906 6.737 169.874 6.640 5.275 131.136 5.741

218 13.586 245.492 13.030 6.782 170.800 13.032 6.782 170.800 6.695 5.310 131.928 5.787

219 13.645 247.792 13.156 6.826 171.726 13.159 6.826 171.726 6.750 5.345 132.719 5.833

220 13.703 250.092 13.282 6.870 172.653 13.285 6.870 172.653 6.804 5.380 133.510 5.879

221 13.896 250.710 13.307 6.946 173.200 13.314 6.946 173.200 6.818 5.436 133.899 5.888

222 14.088 251.329 13.332 7.022 173.748 13.343 7.022 173.748 6.831 5.492 134.287 5.896

223 14.281 251.947 13.358 7.098 174.295 13.371 7.098 174.295 6.844 5.548 134.676 5.905

224 14.474 252.565 13.383 7.173 174.843 13.400 7.173 174.843 6.857 5.604 135.064 5.913

225 14.667 253.184 13.409 7.249 175.391 13.429 7.249 175.391 6.870 5.660 135.453 5.922

226 14.845 253.888 13.422 7.334 175.611 13.440 7.334 175.611 6.877 5.699 135.633 5.927

227 15.023 254.593 13.436 7.419 175.831 13.452 7.419 175.831 6.884 5.738 135.814 5.931

228 15.201 255.297 13.450 7.504 176.051 13.464 7.504 176.051 6.891 5.776 135.995 5.936

229 15.379 256.002 13.464 7.589 176.271 13.475 7.589 176.271 6.897 5.815 136.176 5.941

230 15.557 256.706 13.478 7.674 176.491 13.487 7.674 176.491 6.904 5.854 136.356 5.946

231 15.658 257.286 13.488 7.710 176.612 13.498 7.710 176.612 6.910 5.875 136.581 5.951

232 15.759 257.866 13.499 7.746 176.732 13.508 7.746 176.732 6.916 5.897 136.806 5.956

233 15.861 258.445 13.510 7.782 176.853 13.519 7.782 176.853 6.922 5.918 137.031 5.962

234 15.962 259.025 13.521 7.818 176.974 13.530 7.818 176.974 6.928 5.940 137.256 5.967

235 16.063 259.605 13.531 7.853 177.095 13.540 7.853 177.095 6.934 5.961 137.482 5.972

236 16.104 259.940 13.543 7.867 177.463 13.551 7.867 177.463 6.940 5.977 137.680 5.978

237 16.144 260.276 13.554 7.881 177.830 13.561 7.881 177.830 6.946 5.994 137.879 5.983

238 16.185 260.612 13.566 7.894 178.198 13.572 7.894 178.198 6.951 6.010 138.078 5.989

239 16.225 260.947 13.577 7.908 178.566 13.582 7.908 178.566 6.957 6.026 138.277 5.994

240 16.265 261.283 13.589 7.922 178.933 13.592 7.922 178.933 6.962 6.042 138.476 6.000
62

Alternative Fast-Pass IM240 Standards

Corresponding to Composite Start-up Emission Standards in §85.2205(a)(2)(vi)

Light Duty Truck 3&4

1982-1983 1984-1987 1988-1990 1991

Sec HC CO NOx HC CO NOx HC CO NOx HC CO NOx

30 1.064 14.776 0.513 0.585 10.661 0.513 0.585 10.661 0.436 0.477 5.069 0.395

31 1.091 15.338 0.551 0.609 11.033 0.551 0.609 11.033 0.463 0.494 5.129 0.420

32 1.118 15.900 0.590 0.633 11.405 0.590 0.633 11.405 0.490 0.512 5.189 0.445

33 1.145 16.462 0.629 0.657 11.777 0.629 0.657 11.777 0.517 0.529 5.249 0.470

34 1.172 17.023 0.667 0.681 12.149 0.667 0.681 12.149 0.544 0.547 5.309 0.495

35 1.199 17.585 0.706 0.705 12.521 0.706 0.705 12.521 0.572 0.564 5.369 0.520

36 1.237 17.834 0.711 0.730 12.895 0.711 0.730 12.895 0.576 0.582 5.562 0.524

37 1.275 18.084 0.716 0.754 13.269 0.716 0.754 13.269 0.580 0.601 5.755 0.527

38 1.313 18.333 0.721 0.779 13.643 0.721 0.779 13.643 0.584 0.619 5.948 0.531

39 1.351 18.582 0.727 0.803 14.018 0.727 0.803 14.018 0.588 0.637 6.142 0.535

40 1.389 18.832 0.732 0.828 14.392 0.732 0.828 14.392 0.592 0.656 6.335 0.539

41 1.459 19.867 0.796 0.854 15.098 0.796 0.854 15.098 0.636 0.681 6.890 0.578

42 1.529 20.902 0.861 0.880 15.805 0.861 0.880 15.805 0.681 0.707 7.445 0.617

43 1.599 21.937 0.925 0.907 16.511 0.925 0.907 16.511 0.726 0.732 7.999 0.657

44 1.669 22.972 0.989 0.933 17.217 0.989 0.933 17.217 0.771 0.758 8.554 0.696

45 1.738 24.008 1.053 0.959 17.924 1.053 0.959 17.924 0.815 0.783 9.109 0.735

46 1.784 24.572 1.096 0.989 18.458 1.096 0.989 18.458 0.840 0.799 9.593 0.760

47 1.830 25.136 1.138 1.019 18.992 1.138 1.019 18.992 0.866 0.816 10.076 0.785

48 1.876 25.701 1.180 1.050 19.526 1.180 1.050 19.526 0.891 0.832 10.560 0.810

49 1.922 26.265 1.223 1.080 20.060 1.223 1.080 20.060 0.916 0.848 11.044 0.835

50 1.968 26.830 1.265 1.110 20.594 1.265 1.110 20.594 0.941 0.864 11.527 0.860

51 2.020 27.642 1.294 1.146 21.719 1.294 1.146 21.719 0.978 0.891 12.038 0.893

52 2.072 28.454 1.324 1.182 22.845 1.324 1.182 22.845 1.016 0.917 12.549 0.926

53 2.124 29.266 1.353 1.218 23.970 1.353 1.218 23.970 1.053 0.943 13.059 0.959

54 2.176 30.079 1.382 1.254 25.095 1.382 1.254 25.095 1.090 0.969 13.570 0.992

55 2.228 30.891 1.411 1.290 26.221 1.411 1.290 26.221 1.128 0.995 14.081 1.026

56 2.265 31.485 1.449 1.310 26.449 1.449 1.310 26.449 1.160 1.015 14.438 1.051

57 2.302 32.078 1.486 1.330 26.677 1.486 1.330 26.677 1.192 1.035 14.796 1.077

58 2.340 32.672 1.523 1.350 26.905 1.523 1.350 26.905 1.224 1.055 15.154 1.103

59 2.377 33.266 1.560 1.370 27.133 1.560 1.370 27.133 1.256 1.075 15.512 1.129

60 2.415 33.860 1.597 1.390 27.361 1.597 1.390 27.361 1.288 1.095 15.870 1.155

61 2.451 34.487 1.611 1.405 27.372 1.611 1.405 27.372 1.301 1.109 16.268 1.166

62 2.487 35.113 1.625 1.420 27.383 1.625 1.420 27.383 1.313 1.124 16.667 1.177

63 2.523 35.740 1.639 1.434 27.393 1.639 1.434 27.393 1.326 1.138 17.066 1.188

64 2.559 36.367 1.653 1.449 27.404 1.653 1.449 27.404 1.338 1.153 17.465 1.200

65 2.595 36.994 1.667 1.464 27.415 1.667 1.464 27.415 1.351 1.167 17.863 1.211

66 2.639 37.728 1.699 1.497 28.054 1.699 1.497 28.054 1.366 1.182 18.249 1.230

67 2.683 38.462 1.732 1.530 28.694 1.732 1.530 28.694 1.382 1.196 18.635 1.250

68 2.728 39.197 1.765 1.563 29.333 1.765 1.563 29.333 1.397 1.211 19.020 1.269
63

69 2.772 39.931 1.797 1.596 29.972 1.797 1.596 29.972 1.412 1.225 19.406 1.289

70 2.817 40.666 1.830 1.629 30.612 1.830 1.629 30.612 1.427 1.239 19.792 1.308

71 2.859 41.083 1.854 1.650 31.097 1.854 1.650 31.097 1.443 1.255 19.906 1.321

72 2.901 41.500 1.878 1.672 31.583 1.878 1.672 31.583 1.459 1.271 20.020 1.334

73 2.943 41.918 1.902 1.694 32.068 1.902 1.694 32.068 1.475 1.287 20.134 1.347

74 2.985 42.335 1.925 1.715 32.554 1.925 1.715 32.554 1.491 1.303 20.248 1.361

75 3.027 42.753 1.949 1.737 33.039 1.949 1.737 33.039 1.507 1.318 20.362 1.374

76 3.061 43.705 1.977 1.760 33.193 1.977 1.760 33.193 1.528 1.331 20.782 1.391

77 3.096 44.657 2.005 1.782 33.347 2.005 1.782 33.347 1.550 1.344 21.202 1.409

78 3.130 45.609 2.033 1.805 33.501 2.033 1.805 33.501 1.571 1.357 21.623 1.426

79 3.165 46.562 2.061 1.828 33.655 2.061 1.828 33.655 1.593 1.370 22.043 1.444

80 3.200 47.514 2.089 1.851 33.809 2.089 1.851 33.809 1.615 1.382 22.463 1.461

81 3.237 47.873 2.111 1.872 34.035 2.111 1.872 34.035 1.623 1.407 22.571 1.475

82 3.275 48.233 2.132 1.894 34.261 2.132 1.894 34.261 1.632 1.431 22.678 1.489

83 3.313 48.592 2.154 1.915 34.488 2.154 1.915 34.488 1.640 1.455 22.786 1.503

84 3.351 48.952 2.175 1.937 34.714 2.175 1.937 34.714 1.648 1.480 22.894 1.517

85 3.389 49.311 2.197 1.958 34.941 2.197 1.958 34.941 1.657 1.504 23.001 1.531

86 3.432 49.503 2.200 1.973 35.115 2.200 1.973 35.115 1.659 1.531 23.112 1.531

87 3.475 49.694 2.203 1.988 35.289 2.203 1.988 35.289 1.661 1.558 23.223 1.532

88 3.518 49.886 2.206 2.002 35.463 2.206 2.002 35.463 1.663 1.586 23.334 1.533

89 3.562 50.077 2.209 2.017 35.637 2.209 2.017 35.637 1.665 1.613 23.445 1.533

90 3.605 50.269 2.212 2.032 35.811 2.212 2.032 35.811 1.667 1.640 23.556 1.534

91 3.645 50.447 2.213 2.044 35.968 2.213 2.044 35.968 1.668 1.654 23.558 1.534

92 3.686 50.626 2.214 2.056 36.125 2.214 2.056 36.125 1.669 1.668 23.560 1.534

93 3.727 50.805 2.215 2.068 36.282 2.215 2.068 36.282 1.671 1.682 23.562 1.535

94 3.767 50.984 2.216 2.081 36.440 2.216 2.081 36.440 1.672 1.696 23.564 1.535

95 3.808 51.162 2.217 2.093 36.597 2.217 2.093 36.597 1.674 1.710 23.567 1.535

96 3.853 51.779 2.227 2.111 36.968 2.227 2.111 36.968 1.680 1.727 23.924 1.547

97 3.898 52.395 2.236 2.129 37.339 2.236 2.129 37.339 1.686 1.744 24.282 1.558

98 3.943 53.012 2.245 2.147 37.710 2.245 2.147 37.710 1.692 1.762 24.639 1.570

99 3.988 53.628 2.254 2.165 38.081 2.254 2.165 38.081 1.698 1.779 24.997 1.581

100 4.033 54.245 2.263 2.183 38.453 2.263 2.183 38.453 1.704 1.796 25.355 1.593

101 4.081 55.131 2.342 2.221 40.429 2.342 2.221 40.429 1.779 1.819 25.871 1.636

102 4.128 56.016 2.420 2.258 42.405 2.420 2.258 42.405 1.854 1.842 26.387 1.678

103 4.175 56.902 2.498 2.295 44.382 2.498 2.295 44.382 1.928 1.865 26.903 1.721

104 4.223 57.788 2.576 2.333 46.358 2.576 2.333 46.358 2.003 1.887 27.419 1.764

105 4.270 58.674 2.654 2.370 48.335 2.654 2.370 48.335 2.078 1.910 27.935 1.807

106 4.300 59.222 2.740 2.404 49.060 2.740 2.404 49.060 2.132 1.936 28.221 1.864

107 4.331 59.771 2.826 2.437 49.785 2.826 2.437 49.785 2.187 1.962 28.506 1.921

108 4.361 60.319 2.912 2.471 50.511 2.912 2.471 50.511 2.241 1.988 28.792 1.978

109 4.391 60.868 2.998 2.504 51.236 2.998 2.504 51.236 2.296 2.014 29.077 2.035

110 4.421 61.416 3.084 2.538 51.962 3.084 2.538 51.962 2.350 2.040 29.363 2.092

111 4.449 61.935 3.101 2.560 52.113 3.101 2.560 52.113 2.365 2.057 29.405 2.107

112 4.476 62.455 3.118 2.582 52.265 3.118 2.582 52.265 2.381 2.074 29.447 2.121

113 4.503 62.974 3.136 2.604 52.417 3.136 2.604 52.417 2.396 2.090 29.489 2.135
64

114 4.531 63.493 3.153 2.625 52.569 3.153 2.625 52.569 2.411 2.107 29.531 2.149

115 4.558 64.013 3.170 2.647 52.721 3.170 2.647 52.721 2.426 2.124 29.573 2.163

116 4.600 64.559 3.173 2.673 52.723 3.173 2.673 52.723 2.430 2.152 29.865 2.166

117 4.642 65.105 3.175 2.698 52.724 3.175 2.698 52.724 2.433 2.179 30.157 2.169

118 4.684 65.651 3.178 2.723 52.726 3.178 2.723 52.726 2.437 2.207 30.449 2.173

119 4.726 66.197 3.181 2.749 52.728 3.181 2.749 52.728 2.441 2.234 30.741 2.176

120 4.768 66.743 3.184 2.774 52.729 3.184 2.774 52.729 2.445 2.262 31.033 2.179

121 4.804 67.600 3.206 2.799 53.168 3.206 2.799 53.168 2.467 2.276 31.230 2.200

122 4.840 68.458 3.229 2.824 53.606 3.229 2.824 53.606 2.489 2.290 31.428 2.222

123 4.876 69.315 3.251 2.850 54.044 3.251 2.850 54.044 2.512 2.304 31.625 2.243

124 4.911 70.173 3.274 2.875 54.483 3.274 2.875 54.483 2.534 2.318 31.823 2.265

125 4.947 71.030 3.296 2.900 54.921 3.296 2.900 54.921 2.557 2.332 32.020 2.286

126 4.983 71.729 3.310 2.920 55.078 3.310 2.920 55.078 2.569 2.355 32.099 2.297

127 5.019 72.427 3.323 2.941 55.236 3.323 2.941 55.236 2.580 2.377 32.178 2.307

128 5.055 73.126 3.337 2.961 55.393 3.337 2.961 55.393 2.592 2.399 32.256 2.318

129 5.091 73.825 3.350 2.981 55.551 3.350 2.981 55.551 2.604 2.422 32.335 2.329

130 5.126 74.523 3.364 3.001 55.708 3.364 3.001 55.708 2.616 2.444 32.413 2.339

131 5.178 75.331 3.370 3.027 55.921 3.370 3.027 55.921 2.619 2.464 32.638 2.343

132 5.230 76.139 3.376 3.052 56.134 3.376 3.052 56.134 2.623 2.485 32.862 2.347

133 5.282 76.947 3.382 3.078 56.346 3.382 3.078 56.346 2.627 2.505 33.086 2.350

134 5.334 77.755 3.388 3.103 56.559 3.388 3.103 56.559 2.630 2.525 33.310 2.354

135 5.386 78.563 3.394 3.129 56.771 3.394 3.129 56.771 2.634 2.545 33.534 2.358

136 5.468 79.372 3.432 3.167 57.854 3.432 3.167 57.854 2.672 2.573 34.147 2.395

137 5.549 80.181 3.469 3.206 58.937 3.469 3.206 58.937 2.711 2.600 34.760 2.431

138 5.630 80.990 3.507 3.244 60.020 3.507 3.244 60.020 2.749 2.628 35.373 2.468

139 5.712 81.798 3.544 3.283 61.102 3.544 3.283 61.102 2.787 2.655 35.985 2.505

140 5.793 82.607 3.582 3.322 62.185 3.582 3.322 62.185 2.826 2.682 36.598 2.542

141 5.825 83.486 3.639 3.342 62.366 3.639 3.342 62.366 2.851 2.702 36.880 2.574

142 5.856 84.365 3.697 3.363 62.548 3.697 3.363 62.548 2.875 2.722 37.162 2.606

143 5.888 85.245 3.754 3.383 62.729 3.754 3.383 62.729 2.900 2.742 37.444 2.638

144 5.920 86.124 3.811 3.404 62.910 3.811 3.404 62.910 2.925 2.762 37.727 2.671

145 5.951 87.003 3.869 3.425 63.091 3.869 3.425 63.091 2.949 2.782 38.009 2.703

146 5.975 87.915 3.892 3.453 63.539 3.892 3.453 63.539 2.959 2.797 38.632 2.715

147 5.998 88.827 3.916 3.482 63.987 3.916 3.482 63.987 2.968 2.811 39.255 2.726

148 6.022 89.739 3.939 3.510 64.435 3.939 3.510 64.435 2.978 2.825 39.878 2.738

149 6.046 90.652 3.963 3.539 64.883 3.963 3.539 64.883 2.987 2.839 40.501 2.750

150 6.069 91.564 3.986 3.568 65.331 3.986 3.568 65.331 2.997 2.853 41.124 2.762

151 6.099 92.475 4.000 3.595 65.704 4.000 3.595 65.704 3.007 2.868 41.450 2.774

152 6.129 93.387 4.014 3.623 66.077 4.014 3.623 66.077 3.017 2.883 41.776 2.786

153 6.159 94.298 4.029 3.650 66.450 4.029 3.650 66.450 3.028 2.898 42.102 2.799

154 6.189 95.209 4.043 3.677 66.823 4.043 3.677 66.823 3.038 2.913 42.428 2.811

155 6.219 96.121 4.057 3.705 67.197 4.057 3.705 67.197 3.049 2.927 42.754 2.823

156 6.313 97.599 4.117 3.767 69.206 4.117 3.767 69.206 3.113 2.969 44.233 2.870

157 6.407 99.077 4.176 3.829 71.215 4.176 3.829 71.215 3.178 3.011 45.712 2.917

158 6.501 100.555 4.236 3.891 73.225 4.236 3.891 73.225 3.242 3.053 47.191 2.964
65

159 6.595 102.033 4.295 3.953 75.234 4.295 3.953 75.234 3.307 3.095 48.670 3.011

160 6.689 103.511 4.355 4.015 77.243 4.355 4.015 77.243 3.371 3.136 50.149 3.057

161 7.010 107.552 4.551 4.078 79.985 4.551 4.078 79.985 3.503 3.182 51.569 3.181

162 7.331 111.593 4.747 4.142 82.727 4.747 4.142 82.727 3.635 3.227 52.988 3.306

163 7.652 115.634 4.943 4.205 85.469 4.943 4.205 85.469 3.767 3.272 54.408 3.430

164 7.972 119.676 5.139 4.268 88.211 5.139 4.268 88.211 3.899 3.318 55.828 3.554

165 8.293 123.717 5.335 4.332 90.953 5.335 4.332 90.953 4.030 3.363 57.247 3.678

166 8.671 125.252 5.516 4.380 93.266 5.516 4.380 93.266 4.145 3.410 58.958 3.796

167 9.050 126.786 5.696 4.428 95.579 5.696 4.428 95.579 4.260 3.458 60.670 3.914

168 9.428 128.321 5.876 4.477 97.892 5.876 4.477 97.892 4.375 3.505 62.381 4.033

169 9.806 129.855 6.056 4.525 100.205 6.056 4.525 100.205 4.490 3.552 64.092 4.151

170 10.184 131.390 6.237 4.573 102.517 6.237 4.573 102.517 4.605 3.600 65.804 4.269

171 10.426 132.095 6.345 4.618 103.813 6.345 4.618 103.813 4.673 3.644 66.939 4.322

172 10.667 132.801 6.452 4.664 105.109 6.452 4.664 105.109 4.741 3.688 68.075 4.374

173 10.909 133.506 6.560 4.709 106.404 6.560 4.709 106.404 4.808 3.732 69.210 4.426

174 11.150 134.211 6.668 4.754 107.700 6.668 4.754 107.700 4.876 3.776 70.345 4.479

175 11.392 134.917 6.776 4.799 108.995 6.776 4.799 108.995 4.944 3.821 71.481 4.531

176 11.439 137.703 6.910 4.858 110.733 6.910 4.858 110.733 5.057 3.856 73.077 4.626

177 11.486 140.490 7.045 4.917 112.471 7.045 4.917 112.471 5.171 3.891 74.674 4.722

178 11.533 143.276 7.179 4.977 114.209 7.179 4.977 114.209 5.284 3.927 76.271 4.817

179 11.581 146.063 7.313 5.036 115.946 7.313 5.036 115.946 5.398 3.962 77.867 4.912

180 11.628 148.849 7.447 5.095 117.684 7.447 5.095 117.684 5.511 3.997 79.464 5.008

181 11.671 154.282 7.621 5.158 119.775 7.621 5.158 119.775 5.641 4.024 81.282 5.111

182 11.715 159.715 7.795 5.221 121.866 7.795 5.221 121.866 5.770 4.050 83.100 5.214

183 11.759 165.147 7.969 5.284 123.956 7.969 5.284 123.956 5.900 4.077 84.919 5.318

184 11.803 170.580 8.143 5.347 126.047 8.143 5.347 126.047 6.029 4.104 86.737 5.421

185 11.846 176.013 8.318 5.411 128.138 8.318 5.411 128.138 6.159 4.131 88.555 5.524

186 11.887 179.970 8.499 5.428 129.673 8.499 5.428 129.673 6.285 4.154 90.333 5.656

187 11.928 183.927 8.681 5.446 131.209 8.681 5.446 131.209 6.411 4.178 92.110 5.787

188 11.969 187.884 8.862 5.463 132.745 8.862 5.463 132.745 6.537 4.202 93.888 5.919

189 12.010 191.841 9.043 5.481 134.281 9.043 5.481 134.281 6.663 4.225 95.665 6.050

190 12.051 195.798 9.225 5.499 135.816 9.225 5.499 135.816 6.789 4.249 97.442 6.182

191 12.090 197.691 9.386 5.561 137.198 9.386 5.561 137.198 6.875 4.285 98.856 6.266

192 12.128 199.584 9.547 5.623 138.580 9.547 5.623 138.580 6.961 4.321 100.271 6.350

193 12.166 201.476 9.708 5.686 139.961 9.708 5.686 139.961 7.047 4.357 101.685 6.435

194 12.205 203.369 9.869 5.748 141.343 9.869 5.748 141.343 7.133 4.393 103.099 6.519

195 12.243 205.262 10.030 5.810 142.724 10.030 5.810 142.724 7.219 4.430 104.513 6.603

196 12.281 208.341 10.188 5.828 144.052 10.188 5.828 144.052 7.346 4.460 106.134 6.706

197 12.319 211.419 10.346 5.845 145.381 10.346 5.845 145.381 7.473 4.490 107.755 6.810

198 12.357 214.498 10.504 5.863 146.709 10.504 5.863 146.709 7.600 4.520 109.376 6.913

199 12.395 217.577 10.662 5.880 148.037 10.662 5.880 148.037 7.727 4.550 110.997 7.017

200 12.433 220.656 10.820 5.898 149.365 10.820 5.898 149.365 7.853 4.580 112.617 7.120

201 12.509 221.810 10.948 5.942 150.214 10.948 5.942 150.214 7.929 4.623 113.207 7.195

202 12.585 222.965 11.075 5.986 151.063 11.075 5.986 151.063 8.005 4.666 113.796 7.270

203 12.661 224.119 11.203 6.029 151.912 11.203 6.029 151.912 8.080 4.709 114.385 7.345
66

204 12.738 225.274 11.330 6.073 152.760 11.330 6.073 152.760 8.156 4.752 114.974 7.419

205 12.814 226.429 11.458 6.117 153.609 11.458 6.117 153.609 8.232 4.795 115.563 7.494

206 12.891 228.364 11.530 6.174 154.888 11.530 6.174 154.888 8.295 4.848 116.847 7.544

207 12.969 230.299 11.601 6.231 156.166 11.601 6.231 156.166 8.357 4.901 118.131 7.594

208 13.046 232.235 11.673 6.288 157.445 11.673 6.288 157.445 8.420 4.955 119.415 7.644

209 13.124 234.170 11.745 6.345 158.724 11.745 6.345 158.724 8.483 5.008 120.699 7.694

210 13.201 236.105 11.817 6.401 160.002 11.817 6.401 160.002 8.545 5.061 121.983 7.744

211 13.233 239.385 11.984 6.451 161.606 11.984 6.451 161.606 8.670 5.090 123.498 7.846

212 13.264 242.664 12.152 6.500 163.210 12.152 6.500 163.210 8.794 5.119 125.012 7.948

213 13.296 245.943 12.319 6.550 164.814 12.319 6.550 164.814 8.919 5.147 126.526 8.051

214 13.328 249.223 12.486 6.599 166.418 12.486 6.599 166.418 9.043 5.176 128.040 8.153

215 13.359 252.502 12.653 6.649 168.022 12.653 6.649 168.022 9.168 5.204 129.554 8.255

216 13.423 253.243 12.780 6.693 168.948 12.780 6.693 168.948 9.251 5.240 130.345 8.328

217 13.487 253.983 12.906 6.737 169.874 12.906 6.737 169.874 9.334 5.275 131.136 8.400

218 13.551 254.724 13.032 6.782 170.800 13.032 6.782 170.800 9.417 5.310 131.928 8.472

219 13.615 255.464 13.159 6.826 171.726 13.159 6.826 171.726 9.500 5.345 132.719 8.545

220 13.679 256.204 13.285 6.870 172.653 13.285 6.870 172.653 9.584 5.380 133.510 8.617

221 13.852 256.417 13.314 6.946 173.200 13.314 6.946 173.200 9.598 5.436 133.899 8.630

222 14.025 256.629 13.343 7.022 173.748 13.343 7.022 173.748 9.612 5.492 134.287 8.642

223 14.198 256.841 13.371 7.098 174.295 13.371 7.098 174.295 9.627 5.548 134.676 8.655

224 14.371 257.053 13.400 7.173 174.843 13.400 7.173 174.843 9.641 5.604 135.064 8.667

225 14.544 257.265 13.429 7.249 175.391 13.429 7.249 175.391 9.655 5.660 135.453 8.680

226 14.737 257.645 13.440 7.334 175.611 13.440 7.334 175.611 9.664 5.699 135.633 8.688

227 14.929 258.025 13.452 7.419 175.831 13.452 7.419 175.831 9.674 5.738 135.814 8.696

228 15.122 258.405 13.464 7.504 176.051 13.464 7.504 176.051 9.683 5.776 135.995 8.704

229 15.315 258.785 13.475 7.589 176.271 13.475 7.589 176.271 9.692 5.815 136.176 8.712

230 15.507 259.165 13.487 7.674 176.491 13.487 7.674 176.491 9.701 5.854 136.356 8.720

231 15.616 259.629 13.498 7.710 176.612 13.498 7.710 176.612 9.710 5.875 136.581 8.727

232 15.725 260.092 13.508 7.746 176.732 13.508 7.746 176.732 9.719 5.897 136.806 8.733

233 15.834 260.556 13.519 7.782 176.853 13.519 7.782 176.853 9.728 5.918 137.031 8.740

234 15.944 261.020 13.530 7.818 176.974 13.530 7.818 176.974 9.737 5.940 137.256 8.746

235 16.053 261.484 13.540 7.853 177.095 13.540 7.853 177.095 9.746 5.961 137.482 8.753

236 16.085 261.890 13.551 7.867 177.463 13.551 7.867 177.463 9.754 5.977 137.680 8.760

237 16.117 262.296 13.561 7.881 177.830 13.561 7.881 177.830 9.761 5.994 137.879 8.767

238 16.149 262.701 13.572 7.894 178.198 13.572 7.894 178.198 9.769 6.010 138.078 8.774

239 16.181 263.107 13.582 7.908 178.566 13.582 7.908 178.566 9.777 6.026 138.277 8.781

240 16.214 263.513 13.592 7.922 178.933 13.592 7.922 178.933 9.785 6.042 138.476 8.788
67

Appendix C

Fast Pass IM240 Standards Developed for Wisconsin
68

Fast Pass IM240 Standards Developed for Wisconsin

Wisconsin requested EPA provide fast-pass cutpoints for final and intermediate standards. A method is outlined below. 

This was applied only to the Appendix. A fast-pass cutpoints but could be used on others also.

1) A scale factor for each pollutant at each second is defined. This was done to calculate the cutpoint at second i

for each pollutant at each standard.

For example: HC Scale Factor for the 0.8 cutpoint

FPHC Scale Factor = [HC(0.8)Fast Pass Cutpoint at t= i ] / [HC(0.8) Fast Pass Cutpoint 

at t=239]

2) The ratio of the Fast Pass cutpoint at t=239 to the distance traveled (1.973 mi) was found. This was done so the

new fast-pass cut points could be scaled to the new full 240 second standard

For HC (0.8g/mi):

FPHC 239 = 1.615 g

Distance = 1.973 mi

FPHC 239 g/mi = 0.81855

% above 0.8 g/mi standard = (0.818-0.8)/0.8*100 = 2.2%

For new HC standard (0.6 g/mi):

(FPHC 239 g/mi - 0.6)/0.6 * 100 = 2.2%

(This provides the same 2.2% overshoot as the phase-in fast-pass standards.)

FPHC 239 g/mi = 0.6132g/mi

FPHC 239 g = 1.2098

3) The new fast pass standards will then be calculated as:

HC(0.6)FP = FP(0.6)239 * HCSF(0.8)i

t HC(0.8) g FPHC SF HC(0.6) g

30 0.124 0.0768 0.0929
69

31 0.126 0.0780 0.0944

.....

238 1.614 0.9994 1.2091

239 1.615 1.0000 1.2098

4) For Phase 2 cut points, where needed:

Take the old standard, for example, FPHC Phase 2 = 0.5 g/mi

The distance traveled from second 108 to second 239 is 1.359 mi

The old FPHC 239 cutpoint is 0.716 g

In terms of g/mi this is 0.716/1.359 = 0.527 g/mi

The delta between this value and the actual standard is: (0.527-0.5) = 0.027 g/mi

The new FPHC 239 g/mi cutpoint is: 0.4 + 0.027 = 0.427 g/mi . In terms of g, this is FPHC 239

g/mi * 1.359 mi = 0.580 g

The Scale Factor is calculated as before for each second of the test, and the Phase 2 cutpoint at

each second is calculated by multiplying this Scale Factor times the new FP cutpoint in g at 239. 

In this case, that new FP cutpoint would be 0.580 * Scale Factor for each second.
70

Hydrocarbon(g) Carbon Monoxide (g) Oxides of Nitrogen (g)

Composite Phase 2 Composite Phase 2 Composite Phase 2 Composite Phase 2 Composite Phase 2 Composite Phase 2 Composit

e

Composite Composite

Sec (0.6) (0.4) (0.8) (0.5) (1.1) (0.7) (10.0) (0.8) (15.0) (12.0) (20.0) (16.0) (1.5) (2.0) (2.5)

30 0.093 n/a 0.124 n/a 0.226 n/a 0.462 n/a 0.693 n/a 1.502 n/a 0.125 0.167 0.262

31 0.095 n/a 0.126 n/a 0.232 n/a 0.515 n/a 0.773 n/a 1.546 n/a 0.133 0.177 0.275

32 0.097 n/a 0.129 n/a 0.237 n/a 0.558 n/a 0.837 n/a 1.568 n/a 0.141 0.188 0.301

33 0.101 n/a 0.135 n/a 0.241 n/a 0.567 n/a 0.851 n/a 1.582 n/a 0.161 0.214 0.317

34 0.105 n/a 0.140 n/a 0.246 n/a 0.569 n/a 0.853 n/a 1.593 n/a 0.174 0.232 0.327

35 0.110 n/a 0.146 n/a 0.254 n/a 0.571 n/a 0.857 n/a 1.602 n/a 0.180 0.240 0.330

36 0.113 n/a 0.150 n/a 0.259 n/a 0.600 n/a 0.900 n/a 1.621 n/a 0.182 0.243 0.332

37 0.115 n/a 0.153 n/a 0.269 n/a 0.640 n/a 0.960 n/a 1.631 n/a 0.184 0.245 0.334

38 0.117 n/a 0.156 n/a 0.272 n/a 0.689 n/a 1.034 n/a 1.702 n/a 0.185 0.246 0.336

39 0.120 n/a 0.160 n/a 0.273 n/a 0.713 n/a 1.070 n/a 1.784 n/a 0.185 0.246 0.337

40 0.124 n/a 0.165 n/a 0.287 n/a 0.717 n/a 1.076 n/a 1.879 n/a 0.188 0.250 0.354

41 0.127 n/a 0.169 n/a 0.293 n/a 0.722 n/a 1.083 n/a 2.162 n/a 0.195 0.260 0.366

42 0.129 n/a 0.172 n/a 0.300 n/a 0.735 n/a 1.102 n/a 2.307 n/a 0.208 0.277 0.410

43 0.130 n/a 0.173 n/a 0.314 n/a 0.741 n/a 1.111 n/a 2.343 n/a 0.233 0.311 0.414

44 0.133 n/a 0.177 n/a 0.330 n/a 0.743 n/a 1.114 n/a 2.376 n/a 0.246 0.328 0.438

45 0.148 n/a 0.197 n/a 0.345 n/a 0.771 n/a 1.157 n/a 2.406 n/a 0.257 0.343 0.477

46 0.150 n/a 0.200 n/a 0.357 n/a 0.896 n/a 1.344 n/a 2.433 n/a 0.269 0.359 0.506

47 0.156 n/a 0.208 n/a 0.374 n/a 0.988 n/a 1.482 n/a 2.458 n/a 0.280 0.373 0.518

48 0.166 n/a 0.221 n/a 0.388 n/a 1.020 n/a 1.530 n/a 2.483 n/a 0.287 0.383 0.522

49 0.174 n/a 0.232 n/a 0.398 n/a 1.028 n/a 1.542 n/a 2.774 n/a 0.289 0.385 0.526

50 0.176 n/a 0.235 n/a 0.407 n/a 1.035 n/a 1.553 n/a 2.844 n/a 0.300 0.400 0.554

51 0.179 n/a 0.238 n/a 0.416 n/a 1.047 n/a 1.571 n/a 2.900 n/a 0.308 0.410 0.574

52 0.180 n/a 0.240 n/a 0.426 n/a 1.063 n/a 1.595 n/a 2.936 n/a 0.326 0.434 0.587

53 0.182 n/a 0.242 n/a 0.433 n/a 1.089 n/a 1.633 n/a 3.133 n/a 0.348 0.464 0.601

54 0.185 n/a 0.246 n/a 0.438 n/a 1.123 n/a 1.685 n/a 3.304 n/a 0.354 0.472 0.615

55 0.187 n/a 0.249 n/a 0.445 n/a 1.126 n/a 1.689 n/a 3.407 n/a 0.360 0.480 0.629

56 0.189 n/a 0.252 n/a 0.452 n/a 1.129 n/a 1.693 n/a 3.456 n/a 0.368 0.491 0.643

57 0.196 n/a 0.261 n/a 0.458 n/a 1.133 n/a 1.700 n/a 3.480 n/a 0.375 0.500 0.667

58 0.203 n/a 0.271 n/a 0.463 n/a 1.149 n/a 1.723 n/a 3.518 n/a 0.380 0.506 0.678

59 0.207 n/a 0.276 n/a 0.471 n/a 1.235 n/a 1.852 n/a 3.560 n/a 0.382 0.509 0.683

60 0.209 n/a 0.278 n/a 0.492 n/a 1.248 n/a 1.872 n/a 3.593 n/a 0.384 0.512 0.686

61 0.210 n/a 0.280 n/a 0.495 n/a 1.248 n/a 1.872 n/a 3.628 n/a 0.387 0.516 0.693

62 0.212 n/a 0.282 n/a 0.498 n/a 1.248 n/a 1.872 n/a 3.641 n/a 0.389 0.519 0.699

63 0.212 n/a 0.283 n/a 0.501 n/a 1.267 n/a 1.900 n/a 3.655 n/a 0.392 0.523 0.703

64 0.213 n/a 0.284 n/a 0.505 n/a 1.278 n/a 1.917 n/a 3.680 n/a 0.397 0.529 0.707

65 0.214 n/a 0.285 n/a 0.512 n/a 1.296 n/a 1.944 n/a 3.700 n/a 0.400 0.533 0.711

66 0.215 n/a 0.286 n/a 0.520 n/a 1.333 n/a 2.000 n/a 3.728 n/a 0.401 0.535 0.716

67 0.216 n/a 0.288 n/a 0.527 n/a 1.373 n/a 2.060 n/a 3.857 n/a 0.405 0.540 0.721

68 0.218 n/a 0.291 n/a 0.539 n/a 1.376 n/a 2.064 n/a 3.894 n/a 0.413 0.551 0.726

69 0.221 n/a 0.294 n/a 0.545 n/a 1.384 n/a 2.076 n/a 3.943 n/a 0.422 0.563 0.742

70 0.222 n/a 0.296 n/a 0.551 n/a 1.403 n/a 2.104 n/a 3.983 n/a 0.431 0.575 0.759

71 0.224 n/a 0.298 n/a 0.556 n/a 1.411 n/a 2.117 n/a 4.009 n/a 0.441 0.588 0.773

72 0.225 n/a 0.300 n/a 0.559 n/a 1.417 n/a 2.125 n/a 4.023 n/a 0.450 0.600 0.784

73 0.227 n/a 0.302 n/a 0.566 n/a 1.420 n/a 2.130 n/a 4.023 n/a 0.452 0.603 0.790

74 0.228 n/a 0.304 n/a 0.578 n/a 1.425 n/a 2.138 n/a 4.053 n/a 0.453 0.604 0.794

75 0.230 n/a 0.307 n/a 0.589 n/a 1.435 n/a 2.152 n/a 4.063 n/a 0.460 0.613 0.799

76 0.231 n/a 0.308 n/a 0.597 n/a 1.447 n/a 2.170 n/a 4.077 n/a 0.468 0.624 0.809

77 0.231 n/a 0.308 n/a 0.604 n/a 1.459 n/a 2.188 n/a 4.225 n/a 0.485 0.646 0.821
71

78 0.231 n/a 0.308 n/a 0.611 n/a 1.467 n/a 2.200 n/a 4.243 n/a 0.488 0.651 0.833

79 0.236 n/a 0.314 n/a 0.620 n/a 1.475 n/a 2.212 n/a 4.260 n/a 0.494 0.659 0.839

80 0.240 n/a 0.320 n/a 0.624 n/a 1.475 n/a 2.212 n/a 4.282 n/a 0.505 0.673 0.844

81 0.243 n/a 0.324 n/a 0.628 n/a 1.481 n/a 2.221 n/a 4.322 n/a 0.522 0.696 0.857

82 0.245 n/a 0.327 n/a 0.632 n/a 1.481 n/a 2.222 n/a 4.398 n/a 0.530 0.706 0.870

83 0.247 n/a 0.329 n/a 0.636 n/a 1.485 n/a 2.227 n/a 4.482 n/a 0.536 0.715 0.883

84 0.250 n/a 0.333 n/a 0.642 n/a 1.491 n/a 2.236 n/a 4.515 n/a 0.543 0.724 0.894

85 0.252 n/a 0.336 n/a 0.646 n/a 1.495 n/a 2.243 n/a 4.518 n/a 0.553 0.737 0.902

86 0.254 n/a 0.339 n/a 0.650 n/a 1.508 n/a 2.262 n/a 4.520 n/a 0.560 0.747 0.907

87 0.257 n/a 0.343 n/a 0.654 n/a 1.514 n/a 2.271 n/a 4.522 n/a 0.561 0.748 0.910

88 0.260 n/a 0.347 n/a 0.657 n/a 1.523 n/a 2.284 n/a 4.522 n/a 0.561 0.748 0.912

89 0.263 n/a 0.350 n/a 0.661 n/a 1.533 n/a 2.299 n/a 4.523 n/a 0.561 0.748 0.913

90 0.267 n/a 0.356 n/a 0.664 n/a 1.539 n/a 2.308 n/a 4.526 n/a 0.561 0.748 0.914

91 0.269 n/a 0.358 n/a 0.666 n/a 1.551 n/a 2.326 n/a 4.527 n/a 0.561 0.748 0.915

92 0.270 n/a 0.360 n/a 0.668 n/a 1.553 n/a 2.330 n/a 4.527 n/a 0.561 0.748 0.916

93 0.272 n/a 0.363 n/a 0.670 n/a 1.554 n/a 2.331 n/a 4.528 n/a 0.561 0.748 0.917

94 0.275 n/a 0.367 n/a 0.673 n/a 1.563 n/a 2.344 n/a 4.528 n/a 0.561 0.748 0.918

95 0.278 n/a 0.370 n/a 0.678 n/a 1.565 n/a 2.347 n/a 4.528 n/a 0.561 0.748 0.919

96 0.279 n/a 0.372 n/a 0.686 n/a 1.570 n/a 2.355 n/a 4.529 n/a 0.561 0.748 0.920

97 0.282 n/a 0.376 n/a 0.696 n/a 1.597 n/a 2.395 n/a 4.575 n/a 0.561 0.748 0.921

98 0.291 n/a 0.388 n/a 0.707 n/a 1.634 n/a 2.451 n/a 4.703 n/a 0.561 0.748 0.922

99 0.297 n/a 0.396 n/a 0.718 n/a 1.672 n/a 2.508 n/a 4.805 n/a 0.563 0.751 0.924

100 0.304 n/a 0.405 n/a 0.727 n/a 1.727 n/a 2.590 n/a 4.886 n/a 0.573 0.764 0.929

101 0.308 n/a 0.410 n/a 0.743 n/a 1.773 n/a 2.660 n/a 4.957 n/a 0.592 0.789 0.941

102 0.308 n/a 0.411 n/a 0.754 n/a 1.833 n/a 2.749 n/a 5.104 n/a 0.617 0.822 0.970

103 0.309 n/a 0.412 n/a 0.766 n/a 1.942 n/a 2.913 n/a 5.340 n/a 0.650 0.867 1.027

104 0.310 n/a 0.413 n/a 0.782 n/a 2.108 n/a 3.162 n/a 5.496 n/a 0.679 0.905 1.093

105 0.316 n/a 0.421 n/a 0.798 n/a 2.113 n/a 3.170 n/a 5.625 n/a 0.694 0.925 1.155

106 0.321 n/a 0.428 n/a 0.813 n/a 2.131 n/a 3.197 n/a 5.815 n/a 0.716 0.955 1.234

107 0.323 n/a 0.430 n/a 0.824 n/a 2.192 n/a 3.288 n/a 6.473 n/a 0.739 0.985 1.275

108 0.341 n/a 0.455 n/a 0.853 n/a 2.279 n/a 3.419 n/a 7.037 n/a 0.745 0.993 1.305

109 0.344 0.012 0.459 0.015 0.868 0.037 2.391 0.115 3.587 0.168 7.419 0.246 0.746 0.995 1.320

110 0.347 0.014 0.462 0.017 0.877 0.044 2.397 0.119 3.595 0.173 7.643 0.257 0.747 0.996 1.332

111 0.348 0.017 0.464 0.021 0.885 0.049 2.427 0.163 3.640 0.237 7.759 0.286 0.758 1.010 1.346

112 0.350 0.019 0.466 0.024 0.890 0.052 2.493 0.183 3.740 0.266 7.824 0.379 0.771 1.028 1.358

113 0.351 0.019 0.468 0.024 0.896 0.057 2.579 0.192 3.868 0.280 7.889 0.425 0.776 1.034 1.378

114 0.353 0.020 0.471 0.025 0.901 0.060 2.585 0.200 3.877 0.291 7.960 0.457 0.783 1.044 1.406

115 0.366 0.021 0.488 0.026 0.919 0.067 2.623 0.216 3.934 0.314 8.024 0.477 0.794 1.059 1.426

116 0.385 0.023 0.513 0.029 0.944 0.076 2.677 0.227 4.015 0.331 8.076 0.494 0.806 1.075 1.438

117 0.404 0.026 0.538 0.032 0.954 0.077 2.707 0.237 4.061 0.345 8.111 0.504 0.810 1.080 1.448

118 0.421 0.028 0.561 0.035 0.963 0.078 2.709 0.240 4.063 0.350 8.130 0.512 0.810 1.080 1.460

119 0.433 0.028 0.577 0.035 0.964 0.086 2.719 0.245 4.079 0.356 8.148 0.519 0.811 1.081 1.462

120 0.435 0.029 0.580 0.036 0.967 0.088 2.760 0.252 4.140 0.367 8.211 0.529 0.818 1.091 1.467

121 0.440 0.031 0.586 0.038 0.973 0.091 2.790 0.267 4.185 0.388 8.478 0.529 0.822 1.096 1.476

122 0.446 0.032 0.594 0.040 0.982 0.094 2.799 0.280 4.199 0.407 8.548 0.530 0.833 1.111 1.494

123 0.452 0.033 0.603 0.041 0.991 0.096 2.803 0.318 4.205 0.463 8.561 0.531 0.842 1.122 1.505

124 0.458 0.034 0.610 0.042 1.000 0.099 2.808 0.330 4.212 0.480 8.568 0.532 0.851 1.135 1.517

125 0.461 0.034 0.615 0.042 1.010 0.101 2.821 0.348 4.232 0.506 8.572 0.533 0.854 1.138 1.546

126 0.468 0.034 0.624 0.042 1.018 0.103 2.865 0.356 4.298 0.518 8.584 0.548 0.854 1.139 1.569

127 0.471 0.036 0.628 0.045 1.023 0.105 2.896 0.359 4.344 0.522 8.592 0.610 0.854 1.139 1.586

128 0.474 0.037 0.632 0.046 1.028 0.107 2.907 0.361 4.361 0.525 8.596 0.614 0.854 1.139 1.596

129 0.478 0.037 0.637 0.046 1.031 0.109 2.911 0.363 4.366 0.528 8.597 0.622 0.854 1.139 1.603

130 0.481 0.040 0.641 0.049 1.034 0.111 2.913 0.364 4.369 0.530 8.601 0.631 0.854 1.139 1.605
72

131 0.482 0.041 0.643 0.050 1.036 0.112 2.915 0.364 4.372 0.530 8.605 0.640 0.854 1.139 1.606

132 0.483 0.042 0.644 0.052 1.038 0.114 2.957 0.367 4.435 0.534 8.608 0.646 0.854 1.139 1.607

133 0.484 0.044 0.645 0.054 1.040 0.115 3.015 0.378 4.523 0.550 8.626 0.650 0.854 1.139 1.607

134 0.485 0.044 0.647 0.054 1.040 0.116 3.016 0.381 4.524 0.554 8.650 0.652 0.854 1.139 1.608

135 0.488 0.044 0.651 0.054 1.048 0.119 3.017 0.405 4.525 0.590 8.660 0.738 0.854 1.139 1.614

136 0.494 0.045 0.658 0.055 1.051 0.122 3.021 0.423 4.531 0.616 8.767 0.754 0.870 1.160 1.616

137 0.497 0.045 0.663 0.055 1.060 0.126 3.023 0.439 4.534 0.639 9.029 0.780 0.881 1.174 1.631

138 0.500 0.045 0.666 0.056 1.066 0.130 3.028 0.449 4.542 0.653 9.238 0.795 0.887 1.183 1.643

139 0.501 0.048 0.668 0.059 1.087 0.137 3.035 0.455 4.553 0.662 9.389 0.804 0.898 1.197 1.656

140 0.503 0.049 0.670 0.061 1.149 0.140 3.036 0.469 4.554 0.683 9.493 0.810 0.917 1.223 1.673

141 0.504 0.049 0.672 0.061 1.157 0.141 3.036 0.478 4.554 0.696 9.583 0.815 0.941 1.255 1.703

142 0.506 0.049 0.675 0.061 1.165 0.143 3.036 0.486 4.554 0.708 9.626 0.818 0.954 1.272 1.739

143 0.509 0.051 0.678 0.063 1.171 0.145 3.036 0.495 4.554 0.721 9.669 0.821 0.965 1.286 1.767

144 0.511 0.052 0.681 0.064 1.176 0.147 3.036 0.508 4.554 0.739 9.716 0.825 0.978 1.304 1.774

145 0.513 0.053 0.684 0.065 1.183 0.152 3.036 0.510 4.554 0.742 9.763 0.840 0.980 1.307 1.785

146 0.515 0.053 0.686 0.066 1.186 0.154 3.036 0.510 4.554 0.743 9.809 0.847 0.984 1.312 1.806

147 0.516 0.054 0.688 0.067 1.188 0.156 3.036 0.512 4.554 0.745 9.852 0.855 0.988 1.317 1.830

148 0.518 0.055 0.690 0.068 1.190 0.157 3.036 0.514 4.554 0.748 9.885 0.865 0.991 1.321 1.844

149 0.519 0.056 0.692 0.069 1.194 0.158 3.036 0.516 4.554 0.751 9.932 0.874 0.994 1.325 1.845

150 0.521 0.057 0.694 0.070 1.206 0.159 3.036 0.524 4.554 0.762 9.986 0.891 0.996 1.328 1.846

151 0.522 0.058 0.696 0.071 1.219 0.160 3.037 0.542 4.556 0.789 10.039 0.914 0.999 1.332 1.852

152 0.524 0.058 0.698 0.072 1.230 0.161 3.037 0.543 4.556 0.790 10.072 0.929 1.004 1.338 1.868

153 0.525 0.059 0.700 0.073 1.236 0.162 3.043 0.546 4.565 0.794 10.090 0.937 1.008 1.344 1.877

154 0.527 0.059 0.702 0.073 1.240 0.164 3.075 0.549 4.612 0.799 10.105 0.942 1.013 1.350 1.879

155 0.528 0.060 0.704 0.074 1.249 0.167 3.223 0.553 4.834 0.805 10.146 0.949 1.018 1.357 1.886

156 0.530 0.062 0.706 0.077 1.251 0.169 3.801 0.578 5.702 0.842 10.245 1.375 1.024 1.365 1.900

157 0.531 0.064 0.708 0.079 1.252 0.177 3.894 0.680 5.841 0.990 10.397 1.576 1.034 1.379 1.910

158 0.533 0.066 0.710 0.082 1.259 0.185 4.113 0.713 6.170 1.038 10.923 1.943 1.061 1.414 1.936

159 0.534 0.066 0.712 0.082 1.281 0.190 4.447 0.932 6.670 1.357 11.970 2.820 1.100 1.466 1.954

160 0.537 0.070 0.716 0.086 1.304 0.194 4.950 1.000 7.425 1.455 13.421 3.281 1.136 1.514 1.986

161 0.563 0.077 0.750 0.095 1.320 0.200 5.586 1.062 8.379 1.546 15.289 3.483 1.169 1.559 2.050

162 0.588 0.087 0.784 0.107 1.331 0.207 6.432 1.253 9.648 1.824 15.912 3.620 1.193 1.591 2.131

163 0.604 0.093 0.805 0.115 1.343 0.215 7.279 1.887 10.918 2.746 16.530 4.168 1.231 1.641 2.235

164 0.630 0.099 0.840 0.122 1.383 0.231 8.105 2.111 12.157 3.073 17.622 4.338 1.289 1.719 2.320

165 0.640 0.103 0.853 0.127 1.405 0.257 8.487 2.496 12.731 3.633 18.366 4.682 1.333 1.777 2.395

166 0.656 0.129 0.874 0.159 1.425 0.289 8.554 3.095 12.831 4.505 19.869 5.633 1.374 1.832 2.488

167 0.677 0.151 0.903 0.186 1.445 0.298 8.595 3.402 12.892 4.952 20.711 6.137 1.439 1.919 2.563

168 0.683 0.153 0.910 0.189 1.465 0.302 8.621 3.610 12.932 5.254 22.319 6.853 1.479 1.972 2.645

169 0.686 0.162 0.914 0.200 1.483 0.312 9.135 3.937 13.702 5.730 23.751 7.136 1.510 2.013 2.746

170 0.687 0.178 0.916 0.220 1.500 0.321 9.426 4.157 14.139 6.051 24.842 7.320 1.575 2.100 2.778

171 0.689 0.191 0.919 0.236 1.527 0.333 9.976 4.351 14.964 6.333 25.410 7.685 1.650 2.200 2.792

172 0.698 0.200 0.931 0.247 1.545 0.361 10.469 4.459 15.704 6.490 25.798 8.052 1.688 2.251 2.810

173 0.711 0.208 0.948 0.257 1.582 0.383 10.835 4.669 16.253 6.796 26.122 8.344 1.703 2.270 2.847

174 0.737 0.216 0.983 0.267 1.597 0.406 11.271 4.950 16.907 7.205 26.353 8.602 1.726 2.301 2.874

175 0.764 0.229 1.018 0.283 1.610 0.424 11.770 5.600 17.655 8.151 26.638 8.898 1.739 2.318 2.905

176 0.770 0.239 1.027 0.295 1.622 0.434 12.013 5.654 18.020 8.230 27.219 9.251 1.751 2.335 2.950

177 0.776 0.253 1.035 0.312 1.635 0.475 12.233 5.898 18.349 8.584 27.279 10.253 1.762 2.349 3.001

178 0.788 0.258 1.051 0.318 1.652 0.490 12.447 6.046 18.671 8.800 27.320 10.828 1.790 2.387 3.047

179 0.806 0.262 1.074 0.323 1.670 0.495 12.648 6.078 18.972 8.847 27.352 10.933 1.817 2.423 3.104

180 0.813 0.273 1.084 0.337 1.689 0.507 12.819 6.124 19.228 8.913 27.822 11.060 1.847 2.462 3.173

181 0.824 0.280 1.099 0.345 1.709 0.514 13.415 6.267 20.123 9.122 28.763 11.188 1.877 2.503 3.238

182 0.841 0.284 1.121 0.350 1.727 0.524 13.603 6.549 20.405 9.532 29.402 11.345 1.909 2.545 3.302

183 0.849 0.291 1.132 0.359 1.738 0.535 13.836 7.046 20.754 10.256 29.971 11.733 1.940 2.586 3.372
73

184 0.864 0.314 1.152 0.387 1.755 0.547 14.456 7.463 21.684 10.862 30.276 12.598 1.970 2.627 3.452

185 0.871 0.322 1.161 0.398 1.778 0.560 14.637 7.555 21.955 10.996 30.988 12.953 2.005 2.673 3.545

186 0.876 0.324 1.168 0.400 1.795 0.574 15.100 7.699 22.650 11.206 31.095 13.213 2.062 2.749 3.648

187 0.881 0.326 1.175 0.402 1.808 0.585 15.326 7.911 22.989 11.514 31.314 14.131 2.103 2.804 3.701

188 0.886 0.328 1.181 0.405 1.820 0.589 15.690 8.172 23.535 11.894 31.833 14.839 2.138 2.851 3.759

189 0.891 0.339 1.188 0.418 1.825 0.589 15.917 8.258 23.876 12.019 32.239 15.137 2.171 2.894 3.821

190 0.902 0.348 1.203 0.429 1.827 0.598 16.012 8.361 24.018 12.170 32.547 15.138 2.198 2.931 3.870

191 0.914 0.358 1.219 0.442 1.829 0.607 16.309 8.600 24.464 12.517 32.855 15.141 2.228 2.971 3.892

192 0.925 0.370 1.233 0.457 1.834 0.617 16.457 8.655 24.685 12.598 33.153 15.595 2.265 3.020 3.914

193 0.938 0.383 1.251 0.473 1.847 0.621 16.621 8.674 24.931 12.625 33.444 15.658 2.308 3.077 3.955

194 0.941 0.395 1.255 0.487 1.862 0.629 16.792 8.693 25.188 12.653 33.482 15.704 2.349 3.132 3.997

195 0.944 0.406 1.258 0.501 1.876 0.638 16.979 8.778 25.468 12.777 33.516 15.729 2.389 3.185 4.035

196 0.949 0.413 1.265 0.510 1.891 0.649 17.085 8.867 25.627 12.906 33.549 16.058 2.414 3.219 4.089

197 0.960 0.415 1.280 0.512 1.906 0.664 17.164 8.924 25.746 12.989 33.653 16.987 2.451 3.268 4.146

198 0.970 0.416 1.293 0.514 1.920 0.679 17.233 8.973 25.850 13.060 33.973 17.064 2.474 3.299 4.206

199 0.976 0.418 1.301 0.516 1.933 0.693 17.316 9.045 25.974 13.165 34.159 17.073 2.513 3.350 4.243

200 0.985 0.420 1.313 0.518 1.945 0.706 17.427 9.098 26.141 13.242 34.191 17.153 2.555 3.406 4.295

201 0.993 0.427 1.324 0.527 1.953 0.719 17.483 9.215 26.225 13.412 34.250 17.332 2.600 3.466 4.351

202 0.999 0.438 1.332 0.540 1.959 0.726 17.559 9.386 26.338 13.662 34.469 17.406 2.623 3.497 4.398

203 1.006 0.443 1.341 0.547 1.977 0.737 17.698 9.463 26.547 13.773 34.716 17.641 2.636 3.514 4.410

204 1.018 0.448 1.357 0.553 1.991 0.745 17.879 9.579 26.818 13.942 34.969 17.922 2.638 3.517 4.419

205 1.031 0.453 1.375 0.559 2.011 0.752 18.035 9.680 27.052 14.090 35.144 18.484 2.639 3.519 4.426

206 1.044 0.456 1.392 0.563 2.037 0.800 18.262 9.773 27.393 14.224 35.418 18.553 2.642 3.523 4.429

207 1.056 0.459 1.408 0.567 2.058 0.805 18.334 9.911 27.501 14.426 35.766 18.658 2.659 3.545 4.453

208 1.067 0.463 1.422 0.571 2.079 0.817 18.421 9.961 27.632 14.498 35.949 18.953 2.678 3.570 4.486

209 1.075 0.466 1.433 0.575 2.089 0.836 18.535 10.152 27.803 14.776 36.010 19.266 2.700 3.600 4.542

210 1.082 0.469 1.443 0.579 2.097 0.839 18.635 10.242 27.953 14.907 36.548 19.309 2.714 3.619 4.598

211 1.090 0.482 1.453 0.595 2.109 0.846 18.803 10.248 28.205 14.916 37.179 19.731 2.729 3.639 4.638

212 1.097 0.490 1.463 0.605 2.123 0.866 19.029 10.315 28.543 15.014 37.651 19.902 2.765 3.686 4.715

213 1.101 0.497 1.468 0.614 2.138 0.879 19.331 10.458 28.997 15.221 38.041 20.012 2.799 3.732 4.774

214 1.103 0.504 1.470 0.622 2.150 0.882 19.333 10.630 29.000 15.472 38.591 20.260 2.843 3.791 4.829

215 1.106 0.508 1.474 0.627 2.158 0.891 19.337 10.687 29.005 15.555 38.852 20.739 2.875 3.833 4.872

216 1.109 0.517 1.478 0.638 2.165 0.905 19.387 10.754 29.081 15.652 38.861 21.346 2.918 3.890 4.931

217 1.111 0.521 1.481 0.643 2.171 0.917 19.521 10.971 29.281 15.969 38.926 21.810 2.949 3.932 4.960

218 1.113 0.521 1.484 0.643 2.178 0.918 19.655 11.012 29.483 16.028 39.194 22.001 2.970 3.960 4.963

219 1.115 0.523 1.487 0.645 2.185 0.919 19.823 11.250 29.734 16.375 39.474 22.290 2.998 3.997 4.965

220 1.118 0.527 1.490 0.651 2.192 0.941 19.869 11.327 29.803 16.487 39.668 22.324 3.010 4.013 4.968

221 1.120 0.531 1.493 0.655 2.195 0.952 19.881 11.353 29.821 16.524 39.781 22.343 3.026 4.035 4.971

222 1.128 0.537 1.504 0.663 2.200 0.957 19.898 11.390 29.847 16.578 39.890 22.522 3.029 4.038 4.974

223 1.142 0.544 1.522 0.671 2.205 0.963 19.908 11.463 29.862 16.684 39.954 22.661 3.038 4.050 4.977

224 1.160 0.547 1.547 0.675 2.208 0.970 19.915 11.511 29.873 16.755 39.984 22.666 3.050 4.066 4.979

225 1.162 0.554 1.549 0.684 2.212 0.975 20.005 11.522 30.008 16.770 39.989 22.667 3.053 4.070 4.980

226 1.172 0.562 1.562 0.694 2.214 0.979 20.084 11.546 30.126 16.805 39.990 22.668 3.054 4.072 4.981

227 1.181 0.568 1.574 0.701 2.216 0.985 20.085 11.587 30.127 16.865 39.990 22.669 3.054 4.072 4.982

228 1.184 0.569 1.579 0.702 2.217 0.988 20.085 11.652 30.127 16.960 39.990 22.670 3.055 4.073 4.983

229 1.188 0.574 1.584 0.708 2.218 0.992 20.139 11.652 30.208 16.960 39.991 22.671 3.055 4.073 4.984

230 1.192 0.574 1.589 0.708 2.219 0.995 20.209 11.654 30.314 16.962 40.012 22.671 3.055 4.073 4.985

231 1.193 0.574 1.590 0.709 2.221 0.996 20.215 11.672 30.323 16.988 40.061 22.672 3.055 4.073 4.986

232 1.197 0.575 1.596 0.710 2.223 0.996 20.217 11.729 30.325 17.072 40.116 22.673 3.056 4.074 4.987

233 1.199 0.575 1.598 0.710 2.225 0.996 20.245 11.744 30.368 17.094 40.249 22.673 3.056 4.074 4.988

234 1.203 0.576 1.604 0.711 2.227 0.997 20.274 11.806 30.411 17.184 40.253 22.673 3.056 4.075 4.989

235 1.208 0.577 1.610 0.712 2.228 0.997 20.277 11.808 30.416 17.187 40.290 22.674 3.056 4.075 4.990

236 1.209 0.577 1.612 0.712 2.228 0.999 20.285 11.809 30.428 17.188 40.385 22.675 3.057 4.076 4.991
74

237 1.210 0.577 1.613 0.712 2.229 1.001 20.287 11.810 30.430 17.189 40.488 22.675 3.057 4.076 4.992

238 1.211 0.578 1.614 0.713 2.230 1.004 20.301 11.845 30.452 17.241 40.720 22.675 3.057 4.076 4.993

239 1.211 0.580 1.615 0.716 2.231 1.007 20.325 11.934 30.488 17.370 40.763 22.677 3.057 4.076 4.994
75

Appendix D

Fast Pass IM240 Standards: Modal Regression Technique

Developed by Sierra Research

Contract 68-C4-0056 Work Assignment 2-04
76

Fast Pass IM240 Standards: Modal Regression Technique

Sierra Research

Contract 68-C4-0056 Work Assignment 2-04

Development of Fast-Pass Standards

This method differs from those presented in Appendices A, B, and C in that second-by-second standards are not used,

rather the second-by-second emissions are used to project a final IM240 score which is then compared to the appropriate IM240

standard as listed on pages 1-4 of this document. A sample of the regression coefficients used to project the full IM240 scores

are presented in this appendix. The complete set of coefficients, including an example calculation, can be downloaded from the

EPA web site.

Full-duration, second-by-second IM240 data collected in the Arizona I/M program were used for this analysis. Nearly

110,000 individual tests were in the database used in the analysis, which is comprised of all full-duration IM240 tests conducted

in Arizona from April 1995 through April 1997. Regression coefficients were generated separately for light-duty gasoline

vehicles (i.e., passenger cars) and light-duty trucks for the following model year groups listed below.

 1981 to 1984,

 1985 to 1989, and

 1990 and later.

Regression coefficients were developed for HC, CO, and NOx and for both the composite IM240 and for Phase 2 of

the IM240 after dividing the IM240 drive trace into 24 separate modes. The Phase 2 regressions used mode 11 as the first mode

and continued through mode 23. The composite IM240 regressions used modes 1 through 23. (Although the trace was divided

into 24 modes, if a fast-pass decision is not made by mode 23, then the vehicle would run the full IM240. At that point, a

pass/fail decision should be made on the actual IM240 score, not the predicted score.) Finally, it is recommended that the first

mode at which a pass/fail decision should be made is mode 4 (which ends at second 32 of the IM240) for a composite IM240

prediction, or mode 13 (which ends at second 113 of the IM240) for a Phase 2 prediction.

The regression coefficients for a 0.8 g/mi HC composite IM240 cutpoint are given in this appendix, along with the

coefficients for a 0.5 g/mi HC Phase 2 IM240 cutpoint. The full series of regression coefficients developed in this effort were

provided to EPA electronically, and are available on the OMS web page.

Using the 2% Random Sample from the Arizona program (which consists of 26,000 records), pass/fail rates were

calculated with the modal regression procedures outlined above as well as the current fast-pass cutpoint tables. This analysis

was performed using the final IM240 HC, CO, and NOx standards, and the results are presented in Table D1.

As observed in Table D1, the revised fast-pass methodology results in a lower fraction of false passes than the current

method, particularly for older cars. However, this improvement in failing vehicle identification is offset by a longer average test

time for passing vehicles in the older model year groups. For newer vehicles (i.e., 1990 and later), the revised methodology

results in significant improvements in average test time, without a significant increase in the fraction of false passes. 
77

Table D1

Comparison of Current and Revised Fast-Pass Methodologies Under the Final IM240 Standards

(26,000 Vehicle Sample)

Vehicle

Class

Model

Year

Group

"True"

Failure

Ratea

Current Fast-Pass Revised Fast-Pass

Failure

Rate

Pass Time

(seconds)

Failure

Rate

Pass Time

(seconds)

LDV 81 - 84 79% 76% 125 78% 157

85 - 89 45% 41% 130 43% 121

1990+ 8% 7% 88 7% 57

LDT 81 - 84 62% 51% 71 60% 113

85 - 89 42% 35% 70 40% 93

1990+ 9% 7% 60 7% 57

a The "true" failure rate is based on full-duration IM240 test scores.
78

Composite IM240 HC Regression Coefficients Developed from Modal IM240 Data Analysis

1981-1984 Model Year Light-Duty Gasoline Vehicles

0.8 g/mi Cutpoint

Regression Coefficients

Mode

RMSError

Const C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18 

M1 0.301 0.566 5.043 . . . ...... . .......

M2 0.253 0.378 0.187 2.802 . . ...... . .......M3 0.247 0.371 -0.383 2.022 2.586 . ...... . .......M4 0.232 0.337 -0.363 0.828 0.771 3.854 ...... . .......M5 0.228 0.325 -0.454 1.046 -0.497 2.884 3.156 ..... . .......M6 0.214 0.286 0.371 0.566 0.327 -0.040 1.592 4.850 .... . .......M7 0.202 0.274 0.697 0.468 0.136 -0.077 1.315 2.032 2.632 . . . . .......M8 0.194 0.260 0.489 0.715 -0.044 -0.411 1.211 2.268 0.853 2.410 . . . .......M9 0.189 0.247 0.452 0.747 0.049 -0.370 1.228 2.028 0.757 0.664 2.993 . . .......

M10 0.185 0.242 0.163 0.947 -0.410 -0.223 0.801 1.855 0.909 0.463 2.017 2.189 . .......M11 0.182 0.236 -0.613 1.036 -0.076 -0.458 0.652 1.882 0.997 0.312 1.900 1.397 4.130 .......M12 0.160 0.179 0.127 0.496 0.458 -0.049 0.861 0.657 0.532 0.742 0.756 1.363 1.119 2.786 ......M13 0.151 0.160 0.257 0.519 0.463 -0.050 0.494 0.783 0.574 0.498 0.793 1.013 1.266 2.081 2.388 .....M14 0.149 0.156 0.285 0.535 0.377 0.080 0.324 0.741 0.578 0.480 0.878 0.729 1.310 2.069 1.748 1.228 ....M15 0.146 0.152 0.397 0.612 0.326 -0.091 0.754 0.525 0.543 0.420 0.631 0.591 0.768 1.894 1.505 0.562 2.644 ...M16 0.144 0.150 0.428 0.652 0.276 -0.140 0.404 0.656 0.668 0.406 0.658 0.454 -0.393 1.833 1.390 0.498 1.810 1.915 ..M17 0.140 0.142 0.463 0.579 0.511 -0.148 0.619 0.189 0.756 0.455 0.462 0.632 -0.086 1.551 1.247 0.516 0.846 1.432 2.815 .M18 0.138 0.140 0.505 0.566 0.462 -0.015 0.443 0.386 0.676 0.317 0.386 0.622 -0.033 1.600 1.086 0.435 0.399 1.133 1.908 1.738 M19 0.134 0.128 0.506 0.528 0.820 -0.205 0.294 0.539 0.735 0.259 0.147 1.098 -0.693 1.478 0.929 0.550 0.693 0.252 1.463 1.566 M20 0.102 0.058 0.441 0.520 0.567 0.283 0.334 0.275 0.678 0.396 0.600 1.082 0.232 0.525 0.815 0.244 0.831 1.083 0.721 1.244 M21 0.068 0.032 0.507 0.551 0.501 0.508 0.307 0.466 0.393 0.487 0.542 1.195 0.446 0.329 0.563 0.546 0.500 0.690 0.700 0.763 M22 0.041 0.013 0.518 0.516 0.564 0.503 0.329 0.622 0.398 0.508 0.395 1.055 0.557 0.394 0.483 0.526 0.715 0.469 0.615 0.618 M23 0.030 0.007 0.517 0.526 0.512 0.515 0.448 0.487 0.455 0.519 0.429 0.938 0.682 0.389 0.577 0.509 0.500 0.654 0.403 0.575 

NOTE: Results for only 23 modes are shown here because if the 24th mode is completed the actual IM240 score would then be used rather than th
79

Phase 2 IM240 HC Regression Coefficients Developed from Modal IM240 Data Analysis

1981-1984 Model Year Light-Duty Gasoline Vehicles

0.5 g/mi Cutpoint

Regression Coefficients

Mode

Number

RMS

Error

Reg. 

Const. C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 

P11 0.179 0.346 8.141 . . ........P12 0.145 0.219 2.349 3.104 . ........P13 0.136 0.198 1.727 2.209 2.823 ........P14 0.134 0.192 1.330 2.210 2.034 1.470 .......P15 0.131 0.188 0.571 1.862 1.732 0.807 2.665 ......P16 0.129 0.184 -0.983 1.887 1.610 0.588 1.883 2.208 .....

P17 0.125 0.171 -0.505 1.456 1.415 0.728 0.712 1.820 3.193 ....P18 0.122 0.168 -0.516 1.481 1.215 0.533 0.276 1.426 2.227 1.985 ...P19 0.118 0.154 -0.904 1.381 1.041 0.803 0.703 0.602 1.573 1.758 1.711 ..P20 0.086 0.076 0.344 0.701 0.965 0.539 1.035 1.357 0.881 1.678 0.988 1.091 . P21 0.061 0.041 0.994 0.508 0.691 0.796 0.735 1.173 0.792 1.146 0.925 0.640 1.372 P22 0.039 0.016 1.142 0.562 0.700 0.745 1.010 0.779 0.752 0.874 0.560 0.732 0.647 P23 0.029 0.007 1.198 0.561 0.777 0.755 0.770 1.005 0.484 0.833 0.607 0.715 0.560 

NOTE: Results for only modes are presented only for modes 11 through 23. Mode 11 is the first mode of Phase 2 and if the 24th mode is complet

composite score would be used rather than the predicted score.
80

Composite IM240 HC Regression Coefficients Developed from Modal IM240 Data Analysis

1985-1989 Model Year Light-Duty Gasoline Vehicles

0.8 g/mi Cutpoint

Regression Coefficients

Mode

RMSError

Const C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18 

M1 0.301 0.430 5.602 . . . . . . . . . . .......M2 0.248 0.259 0.159 3.044 . . . . . . . . . .......M3 0.242 0.255 -0.183 2.108 2.824 . . . . . . . . .......M4 0.224 0.223 0.012 1.015 0.555 3.864 . . . . . . . .......M5 0.219 0.212 -0.084 1.168 -0.763 2.919 3.395 . . . . . . .......M6 0.207 0.189 0.424 0.758 -0.026 0.591 1.742 4.092 . . . . . .......M7 0.194 0.181 0.649 0.668 -0.372 0.443 1.314 1.053 3.066 . . . . .......M8 0.184 0.169 0.369 0.880 -0.438 0.037 1.302 1.440 0.797 2.830 . . . .......M9 0.174 0.157 0.342 0.927 -0.266 -0.055 1.335 1.391 0.656 0.035 4.534 . . .......

M10 0.171 0.154 0.180 1.101 -0.631 0.068 0.949 1.233 0.822 -0.082 3.332 2.217 . .......M11 0.167 0.150 -0.536 1.168 -0.318 -0.082 0.705 1.264 0.846 -0.127 3.103 1.373 4.334 .......M12 0.144 0.106 0.170 0.593 0.221 0.266 0.883 0.515 0.448 0.428 1.462 1.314 1.001 2.829 ......M13 0.137 0.095 0.153 0.601 0.146 0.360 0.542 0.548 0.519 0.277 1.402 1.109 1.248 2.159 2.122 . . . . . M14 0.135 0.091 0.169 0.583 0.126 0.499 0.226 0.547 0.530 0.265 1.482 0.760 1.225 2.183 1.358 1.490 . . . . M15 0.131 0.089 0.272 0.609 0.139 0.358 0.572 0.388 0.544 0.195 1.174 0.605 0.985 1.914 1.217 0.696 2.684 . . . M16 0.129 0.087 0.278 0.683 0.092 0.322 0.166 0.487 0.671 0.212 1.115 0.457 -0.039 1.831 1.143 0.626 1.714 2.124 . . M17 0.125 0.081 0.348 0.641 0.274 0.241 0.418 0.209 0.775 0.207 0.887 0.657 0.145 1.602 0.944 0.500 0.969 1.584 2.648 . M18 0.122 0.080 0.348 0.651 0.147 0.387 0.291 0.439 0.622 0.115 0.812 0.631 0.217 1.651 0.809 0.246 0.548 1.358 1.605 1.837 M19 0.116 0.070 0.355 0.591 0.583 0.180 0.199 0.559 0.697 0.082 0.426 1.018 -0.368 1.511 0.738 0.346 0.826 0.523 1.293 1.374 M20 0.085 0.029 0.432 0.465 0.545 0.443 0.311 0.226 0.677 0.359 0.604 1.148 0.387 0.555 0.731 0.187 1.034 0.908 0.755 1.211 M21 0.055 0.018 0.542 0.524 0.385 0.537 0.398 0.546 0.373 0.556 0.462 1.214 0.466 0.368 0.484 0.520 0.679 0.708 0.564 0.703 M22 0.035 0.009 0.575 0.503 0.544 0.511 0.339 0.596 0.434 0.512 0.371 1.085 0.490 0.400 0.498 0.500 0.819 0.484 0.555 0.610 M23 0.024 0.004 0.574 0.499 0.516 0.525 0.455 0.493 0.482 0.528 0.353 0.981 0.668 0.420 0.558 0.534 0.542 0.577 0.422 0.576 

NOTE: Results for only 23 modes are shown here because if the 24th mode is completed the actual IM240 score would then be used rather than th
81

Phase 2 IM240 HC Regression Coefficients Developed from Modal IM240 Data Analysis

1985-1989 Model Year Light-Duty Gasoline Vehicles

0.5 g/mi Cutpoint

Regression Coefficients

Mode

Number

RMS

Error

Reg.

Const. C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 

P11 0.177 0.259 9.328 ..........P12 0.140 0.150 2.179 3.452 .........P13 0.132 0.131 1.779 2.527 2.741 ........P14 0.129 0.125 1.374 2.545 1.628 1.888 .......P15 0.125 0.121 0.861 2.070 1.387 1.001 2.991 ......P16 0.123 0.119 -0.368 2.053 1.269 0.818 2.160 2.195 .....

P17 0.118 0.109 0.059 1.736 1.014 0.823 1.032 1.762 3.119 ....P18 0.115 0.107 -0.009 1.760 0.833 0.559 0.556 1.401 2.128 2.030 ...P19 0.109 0.094 -0.526 1.622 0.698 0.823 0.762 0.636 1.569 1.573 2.175 ..P20 0.077 0.041 0.637 0.716 0.900 0.635 1.081 1.205 1.005 1.455 1.267 1.123 . P21 0.057 0.025 0.945 0.562 0.700 0.868 0.834 1.063 0.867 0.971 1.063 0.658 1.363 P22 0.037 0.013 0.917 0.590 0.738 0.748 1.105 0.785 0.740 0.839 0.583 0.740 0.631 P23 0.027 0.006 1.052 0.609 0.774 0.810 0.757 0.906 0.536 0.802 0.675 0.711 0.575 

NOTE: Results for only modes are presented only for modes 11 through 23. Mode 11 is the first mode of Phase 2 and if the 24th mode is complet

composite score would be used rather than the predicted score.
82

Composite IM240 HC Regression Coefficients Developed from Modal IM240 Data Analysis

1990+ Model Year Light-Duty Gasoline Vehicles

0.8 g/mi Cutpoint

Regression Coefficients

Mode

RMSError

Const. C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18 

M1 0.368 0.162 10.855 . . . . . . . . .........

M2 0.271 0.028 0.252 4.621 . . . . . . . .........M3 0.253 0.036 0.096 2.693 4.788 . . . . . . .........M4 0.230 0.031 0.720 0.868 1.740 4.997 . . . . . .........M5 0.221 0.026 0.391 1.110 0.060 3.325 5.174 . . . . .........M6 0.207 0.021 0.862 0.623 1.005 0.397 2.743 5.132 . . . .........M7 0.192 0.025 1.279 0.372 0.699 0.393 2.028 1.127 3.732 . . .........M8 0.175 0.030 1.076 0.515 0.477 0.150 1.178 1.750 0.608 3.725 . .........M9 0.162 0.032 1.111 0.490 0.510 0.142 1.351 1.370 0.587 0.494 5.180 .........

M10 0.155 0.034 0.742 0.835 -0.133 0.470 0.754 0.829 0.980 0.287 3.033 3.511 ........M11 0.149 0.037 -0.292 0.916 0.270 0.141 0.342 0.923 1.049 0.326 2.661 2.172 5.629 .......M12 0.123 0.028 0.433 0.321 0.650 0.528 0.818 -0.003 0.245 1.037 0.672 2.127 1.234 3.583 ......M13 0.115 0.025 0.578 0.296 0.562 0.394 0.374 0.234 0.492 0.715 0.629 1.553 1.271 2.743 2.839 .....M14 0.113 0.025 0.618 0.262 0.555 0.503 -0.034 0.227 0.569 0.714 0.776 1.121 1.069 2.758 1.607 2.069 ....M15 0.107 0.027 0.747 0.284 0.574 0.244 0.529 0.033 0.676 0.571 0.487 1.011 0.912 2.369 1.258 0.591 3.362 ...M16 0.102 0.027 0.719 0.462 0.356 0.136 0.065 0.303 0.778 0.668 0.345 0.659 -0.008 2.189 1.033 0.401 2.153 2.766 ..M17 0.098 0.026 0.794 0.426 0.518 0.062 0.242 0.168 0.786 0.737 0.079 0.882 0.127 1.928 0.726 0.488 1.245 1.994 2.960 .M18 0.095 0.026 0.769 0.455 0.367 0.197 0.174 0.420 0.710 0.561 0.016 0.870 0.128 2.015 0.442 0.256 0.759 1.521 1.733 2.083 M19 0.090 0.023 0.816 0.385 0.654 0.080 0.083 0.642 0.717 0.557 -0.358 1.269 -0.488 1.916 0.340 0.282 0.819 0.888 1.357 1.477 M20 0.068 0.009 0.575 0.360 0.539 0.382 0.257 0.458 0.639 0.556 0.034 1.205 0.514 0.804 0.472 0.255 0.693 1.266 0.881 1.203 M21 0.041 0.007 0.544 0.483 0.489 0.528 0.539 0.520 0.388 0.588 0.284 1.157 0.523 0.367 0.461 0.575 0.548 0.853 0.677 0.674 M22 0.027 0.003 0.559 0.500 0.535 0.538 0.444 0.602 0.406 0.514 0.284 0.992 0.497 0.407 0.518 0.526 0.656 0.637 0.661 0.573 M23 0.019 0.002 0.553 0.496 0.515 0.537 0.525 0.518 0.438 0.535 0.349 0.870 0.650 0.429 0.549 0.567 0.521 0.624 0.554 0.536 

NOTE: Results for only 23 modes are shown here because if the 24th mode is completed the actual IM240 score would then be used rather than th
83

Phase 2 IM240 HC Regression Coefficients Developed from Modal IM240 Data Analysis

1990+ Model Year Light-Duty Gasoline Vehicles

0.5 g/mi Cutpoint

Regression Coefficients

Mode

Number

RMS

Error

Reg. 

Const. C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 

P11 0.153 0.098 13.195 ..........P12 0.114 0.048 3.112 4.074 .........P13 0.102 0.041 1.873 2.680 3.765 ........P14 0.099 0.039 1.406 2.668 2.167 2.454 .......P15 0.095 0.040 1.107 2.141 1.738 1.122 3.342 ......P16 0.091 0.040 -0.030 2.065 1.365 0.858 2.119 3.157 .....P17 0.088 0.038 0.165 1.791 1.043 0.931 1.028 2.401 3.357 ....P18 0.085 0.038 0.093 1.843 0.719 0.663 0.610 1.854 2.189 2.206 ...P19 0.081 0.035 -0.272 1.779 0.514 0.829 0.678 1.356 1.669 1.515 1.952 ..

P20 0.057 0.016 0.581 0.846 0.727 0.616 0.627 1.840 1.313 1.345 0.856 1.195 . P21 0.040 0.010 0.817 0.585 0.723 0.936 0.588 1.434 1.014 0.886 0.731 0.623 1.512 P22 0.028 0.005 0.823 0.606 0.751 0.837 0.740 1.015 0.843 0.855 0.581 0.717 0.749 P23 0.020 0.003 0.909 0.612 0.790 0.837 0.609 0.957 0.714 0.775 0.632 0.719 0.591 

NOTE: Results for only modes are presented only for modes 11 through 23. Mode 11 is the first mode of Phase 2 and if the 24th mode is comple

composite score would be used rather than the predicted score.
84

Appendix E

Calculation of Raw Emission Scores from Dilute Measurements
85

Calculation of Raw Emission Scores from Dilute Measurements

The constant volume sampling technique, which has been part of the FTP for the exhaust emissions testing of

passenger cars and light-duty trucks since the 1972 model year, involves the collection of a sample of exhaust gas after

it has been diluted to a known, constant volume. Using this procedure, a device called a "constant volume sampler"

dilutes the vehicle exhaust and then samples a constant volume fraction of the dilute mixture. In a typical test facility,

the dilution is achieved by drawing "background" air from the room where the vehicle is being driven on a chassis

dynamometer. A slipstream from the diluted exhaust is pumped into a series of sample bags during the test. Three

sample bags are used for dilute exhaust samples: the first represents the "cold start" phase of the test, the second

represents "stabilized" operation, and the third represents the "hot start" phase of the test. Samples of background air are

simultaneously collected in three additional bags. At the end of the test, measurement of the concentration of pollutants

in the sample bags and calculation of the total flow of the dilute mixture during each phase allows the mass of emissions

emitted during each phase of the test to be calculated. Division of the calculated mass by the associated driving distance

provides the mass emissions rate (normally expressed in grams per mile). 

A variation of the FTP test procedure is used in CVS-based I/M testing. Instead of filling sample bags with

dilute mixture during separate phases of the test, the concentrations of pollutants in the dilute exhaust stream are

continuously monitored. Mass emissions per mile of travel are calculated from integration of the continuous

measurements divided by the distance driven during the test. (This technique facilitates the use of "fast pass" and "fast

fail" algorithms for shortening the test in cases where a vehicle is extremely clean or extremely dirty during the early

portion of the test.)

In CVS-based testing, the volume of background (dilution) air in the sample substantially exceeds the volume

of exhaust gas, usually by a factor of ten or more. As a result, the extent to which the dilution air is contaminated with

pollutants can significantly affect the calculated mass emissions. To eliminate this interference, the extent to which the

vehicle exhaust has been diluted must be known. The FTP specifies that the ratio of total volume to exhaust volume

("dilution factor") be calculated using the following equation:

[1] D F 13.4

CO CO HC

EPA

2e e e

= + +

where: CO2e, COe, and HCe are the concentrations measured in the dilute sample expressed as percent volume.

In the above equation, the DF calculated in accordance with the FTP is specified as "DFEPA" to distinguish it

from an improved formulation of the DF discussed below. As noted above, DFEPA is used in the FTP to correct the

emissions concentration in the sample bag for pollutants in the dilution (background) air. Although not required by the

FTP, the average DF can also be used to calculate the average concentration of the undiluted tailpipe emissions emitted

while the sample bag was being filled. If there were no pollutants in the dilution air, the tailpipe concentrations could be

calculated simply by multiplying the dilute measurement by the DF:
86

[2] Ctp = Cconc * DF

where: Ctp is the actual raw tailpipe concentration, and Cconc is the concentration of a pollutant in the dilute sample

defined as:

[3] Cconc = Ce - Cd (1 - )

1

D F

where Ce is the pollutant dilute concentration and Cd is the pollutant background concentration.

 Substituting [3] into [2] yields:

[4] Ctp Ce Cd 1 1

D F =− − D F 



 



 



 





As noted above, the CVS technique used to measure emissions in I/M programs involves calculating mass

emissions by integrating the continuously monitored dilute sample. An average dilution factor can still be calculated

from the integrated average of the dilute emissions. The DF can also be calculated continuously and used to calculate

the undiluted tailpipe concentration at any point in time. This capability makes it possible to use the CVS emissions

measurement system to determine whether a vehicle meets emissions standards that are based on tailpipe concentrations. 

If, for example, a CO concentration of 0.1% is measured in the dilute exhaust stream, and if the calculated DF is 10,

then the tailpipe emission concentration would be calculated to be 1.0% CO (assuming background concentrations were

zero).

Although there are several advantages associated with the use of the reverse dilution calculation method, some

error is introduced in the calculation of the tailpipe concentration due to the discrepancies that can exist between actual

test conditions and the assumptions on which the standard DF calculation is based. As described in detail in a

previously referenced technical paper (SAE paper 980678), the DF equation contained in the FTP is based on three

assumptions:

1. Exhaust emissions of vehicles are the product of a chemically balanced (i.e., stoichiometric) ratio of air and

fuel;

2.The concentrations of pollutants in the background air have an insignificant effect on the calculation of the

DF; and

3. No water vapor has been removed from the sample.

Each of these assumptions is problematic when the reverse dilution technique is used to calculate the

concentration of pollutants in a vehicle tailpipe that would otherwise be measured directly in an I/M program. First,

although most vehicles run very close to a stoichiometric air-fuel ratio, this is not always the case. Second, in the
3

So-called "BAR90" analyzers actually use a condensate removal system to dispose of the water that condenses

when raw exhaust is drawn through the sample probe; however, the efficiency of water removal depends on the

temperature of the exhaust sample because no temperature control is provided by the analyzer.

4

The DF equation in the previously referenced SAE paper is based on the simplifying assumption that there is no

residual oxygen in the exhaust of stoichiometric or richer air-fuel mixtures. This assumption holds unless there is

substantial misfire. In the case of misfire, the exhaust may contain oxygen that dilutes the concentration of other

constituents. Equation 4 is a refinement of the equation contained in the SAE paper that accounts for misfire.

5

Air injection can reduce mass emissions by facilitating more complete combustion in either the exhaust manifold or

the catalytic converter. However, the dilution associated with air injection causes the measured concentration to be

87

environment of an I/M test lane, pollution in the background air can be significant. Third, analyzers routinely used for

raw exhaust measurement remove a substantial amount of water from the sample.3

A more complicated expression of the DF is required to address the limitations of the DF equation contained in

the FTP. The recommended equation is as follows:4

( )()

( ) ( ) D F 100 K CO K CO K (HC )

K CO CO K CO CO K (HC HC )

1 2 d 2 d 3 d

1 2e 2d 2 e d 3 e d

= − −−

− + −+ −

where: K1, K2, and K3 are constants that depend on the fuel type (see below);

CO2d is the concentration of CO2 in the background air;

COd is the concentration of CO in the background air;

HCd is the concentration of HC in the background air;

CO2e is the concentration of CO2 in the dilute sample;

COe is the concentration of CO in the dilute sample; and 

HCe is the concentration of HC in the dilute sample.

All of the concentrations in the above equation are expressed in volume percent. The HC values are expressed

in hexane equivalent. The values of K1, K2, and K3 depend on the type of fuel and whether the calculated pollutant

concentrations are on a wet or dry basis. When attempting to match measurements that would be made by typical

systems for raw exhaust measurement, the values for dry exhaust should be used. For gasoline fuel with pollutant

concentrations measured on a wet basis, such as in IM240 set-ups, the value of K1 is 6.5431, the value for K2 is 4.6561,

and the value of K3 is 57.0945.

Dilution Correction of Tailpipe Measurements

As noted earlier, one of the problems associated with I/M standards based on maximum allowable tailpipe

concentrations is that certain causes of dilution (e.g., air injection,5

 exhaust leaks, or inadequate sample probe insertion
reduced by more than the true reduction in mass emissions.

6

With measurement systems that remove water, and for an engine running a stoichiometric, a 6% sum of CO and

CO2 represents each part exhaust being diluted with 1.5 parts air.

88

depth) may cause measured concentrations to be substantially lower than for another vehicle with identical mass

emissions. Because of this problem, EPA guidance for concentration measurement during simple I/M tests specifies

that the sum of CO plus CO2 emissions should be at least 6% in order for the test to be considered valid. Although the

basis for the recommendation is not documented, it appears to represent the maximum level of exhaust dilution that

might be expected with a relatively high output air injection system installed on a relatively small engine. As a result, it

allows the exhaust concentration to be reduced by more than 50% due to various sources of dilution.6

 It is therefore a

relatively ineffective means of preventing exhaust dilution from affecting the results of an I/M test.

Recently, the California Bureau of Automotive Repair (BAR) devised an improved procedure for eliminating

the effects of exhaust dilution. BAR’s procedure uses equations developed from basic combustion chemistry to

determine the extent to which an exhaust sample must have been diluted before a concentration measurement was made. 

The measured concentrations are adjusted to what they would be under stoichiometric conditions with no dilution air

from any source (including leaner than stoichiometric operation). BAR’s exhaust dilution correction essentially

involves the application of a dilution factor to the concentrations measured at the tailpipe. As described in Sierra’s SAE

paper, BAR’s method is more sophisticated than the DF calculation incorporated into the FTP because it accounts for

variations in air-fuel ratio. However, the BAR procedure ignores the effects of background air, which is not a factor

during tailpipe measurements. As the SAE paper illustrates, Sierra’s recommended DF equation incorporates the same

basic dilution correction used by BAR in combination with a correction for pollutants in the background air. When

correcting tailpipe concentrations for dilution, where no background air is involved, Sierra’s DF calculation and BAR’s

dilution adjustment produce the same result.

Recognizing the advantages of BAR’s new dilution correction procedure, EPA has incorporated it in Guidance

to states on Acceleration Simulation Mode (ASM) testing. Although BAR’s procedure is equally applicable to other

tests that rely on concentration measurement, it has not yet been incorporated into revised guidance for idle, 2500 rpm,

and other steady-state tests. However, when CVS testing is used in combination with Sierra’s recommended reverse

dilution calculation procedure, the effect is similar to using BAR’s dilution correction.
89

Appendix F

Modal Analysis of Second-by-Second Data Preconditioning Guidelines 

Developed by Sierra Research

Contract 68-C4-0056 Work Assignment 2-04
90

Modal Analysis of Second-by-Second Data Preconditioning Guidelines 

Developed by Sierra Research

Contract 68-C4-0056 Work Assignment 2-04

 Using the replicate IM240 data collected by Gordon-Darby, it was possible, through trial and error, to identify criteria

to determine whether a vehicle failing an initial IM240 is inadequately preconditioned and should be tested again. This

analysis was performed for each pollutant individually, and then for all pollutants combined. The analysis included 283

LDVs and 83 LDTs. The evaluation followed a step-wise progression in which the aim was to maximize the identification

of vehicles that could benefit from a second test, while minimizing testing of vehicles likely to fail a second test. 

Recommendations for passenger cars are summarized below. A similar set of conditions was also developed for light-duty

trucks, which are subject to different IM240 standards than passenger cars.

IM240 Retest Criteria for Passenger Cars

HC Failures - If PPmHC209-214 is less than 1,500, a retest is recommended if any of the following occur:

1. Phase 2 HC < 0. 8 g/mi; or

2. massHC175-199 < 0.2 g; or

3. (ppmHC75-80/ppmHC214) > 4.0

For vehicles failing only HC, the following additional constraints are required for a vehicle to be retested:

1. Mass HC175-199<0.3g and (ppmHC75-80/ppmHC209-214)>1.5;or

2. Mass HC175-199 < 0.3g and Phase 2 HC < 1.0 g/mi

CO Failures - For CO failures, the above criteria for HC are recommended. In addition, the following constraints are

recommended:

1. do not retest if Phase 2 CO > 20 g/mi and (Phase 1 CO/Phase 2 CO) <2; and

2. if the vehicle fails both HC and CO, retest if Mass HC175-199 <0.3 g and mass 

CO175-199 < 5.0 g.

If the vehicle is a CO-only failure, then a vehicle would benefit from a retest if:

1. Mass CO175-199 < 6.0 g; or

2. (ppmCO75-80/ppmCO209-214) > 4.0; or

3. Mass CO175.199 < 10 g and (Phase I CO > 0.75 x Phase 2 CO).

NOx Failures - For vehicles failing HC or CO and NOx, a retest is recommended if the following condition occurs:

1. Mass NOx175-199 = 1.0g
91

For NOx Only failures, retest is recommended if the following criteria are met:

1. Mass NOx175199<9; or 

2. Mass NOx175-199<1.l and(ppmNOx40-45/ppmNOx209-215)>1.5;or

3. IM240 NOx<2.2 and (ppmNOx40-45/ppmNOx209-215)> 1.0

Multiple Pollutants - For multiple pollutant failures, a retest is eliminated under the following conditions:

1. the vehicle fails for all pollutants; or

2. the vehicle fails HC and CO and (Phase 2 CO > 20 g/mi and mass CO175-199 >6.0 g); or

3. the vehicle fails HC and NOx and (ppmHC209-214 >1,200) or (ppmNOx209-214 > 1,200

 IM240 Retest Criteria for Light-Duty Trucks

 Because they are subject to different numerical IM240 emission standards, a different set of retest criteria were

developed for light-duty trucks. These criteria are similar to those established for passenger cars, with adjustments to

account for standards differences.

HC Failures - For 1981 to 1983 model year vehicles, if ppmHC209-214 < 2,000 and any of the following conditions

exist, then a retest is recommended:

1. Phase 2 HC < 3.0 g/mi; or

2. Mass HC175-199 < 0.8 g; or

3. (ppmHC75-80/ppmHC209-214)>4.0

In addition, if the full IM240 is less than 3.5 g/mi HC (regardless of the value of ppmHC209-214), then a retest is

recommended.

For 1984 and later model year vehicles, if ppmHC209-214<1,500 and any of the following conditions exist a retest

is recommended:

1. Phase 2 HC< 2.0 g/mi; or

2. MassHC175-199 < 0.4 g; or

3. (ppmHC75-80/ppmHC209-214)>4.0

In addition, if 0.4<Mass HC175-199<0.8 and (ppmHC75-80/ppmHC209-214)>2.0 (regardless of the value of

ppmHC209-214) then a retest is recommended.

 A retest is not recommended if Phase 2 HC > 3.2 g/mi.

CO Failures - For CO failures, the above criteria outlined for HC were also used. In addition, the following

conditions were also imposed to cut down on the number of vehicles incorrectly identified as needing a retest:
92

1. If 1981 to 1983 model year and Mass CO175-199>36g then do not retest.

2. If 1984 or later model year and Mass CO175-199>18g then do not retest.

3. If Phase 2 CO>40 and Phase 2 CO > Phase I CO then do not retest.

NOx Failures - If the vehicle failed NOx and either HC or CO, the above criteria were used to determine the need

for a retest. For LDT1&2s, if the vehicle failed only NOx. then a retest is recommended if Mass NOxl75-199 < 1.4

g. For 1988 and later LDT3&4s, a retest is recommended only if Mass NOx175-199 < 2.5 g.
93

Appendix G

Full and Fast-Pass IM240 Positive Kinetic Energy Speed Variation Limits

Developed by Sierra Research

Contract 68-C4-0056
7

W. J. Webster and C. Shih, "A Statistically Derived Metric to Monitor Time-Speed Variability in Practical Emissions

Testing," New York State Department of Environmental Conservation, presented at the 6th CRC On-Road Vehicle

Emissions Workshop, March 18-20, 1996.

94

D P V2 P P t t t1 t VV 2

t -1

2

t-2

2 =− = − + −

S p ecific Power p ower

mass

work

m ass tim e

kinetic energ y

m ass tim e

mass V

m ass tim e

1

2 = = × = × = × ×

∆ ×

∆

∆

∆

∆

2

Pt Vt 2 Vt 12 = −−

Full and Fast-Pass IM240 Positive Kinetic Energy Speed Variation Limits

Developed by Sierra Research

Contract 68-C4-0056

Evaluation of Alternative Statistical Measures

Based upon similar work conducted by the New York Automotive Emissions Laboratory (AEL,)7 two easily

determined, alternative statistical metrics were evaluated for their ability to identify and quantify IM240 speed variations that

significantly affect emissions:

(1). DPWRSUM - the sum of absolute changes in specific power; and

(2). Positive Kinetic Energy (PKE) - the sum of positive differences in kinetic energy per unit distance.

Each of these metrics are explained in more detail below.

DPWRSUM - Specific power is defined as power per unit mass, which can be restated as follows:

Over a transient driving cycle of second-by-second speeds, EPA defines the specific power P at any time t (and dropping the

factor of 1⁄2) as:

The absolute difference in specific power at time t can then be written as:

The DPWRSUM statistic then is defined over a cycle of N seconds as:
95

DPWRSUM DP V 2 V V t

t 0

N

t

2

t -1

2

t-2

2

t 0

N

= = −+

= =

∑ ∑

PKE

P P

d x

t

t 0

N

0

x = =

∑

∫

PP V V t t

2

t -1

2 = −

PKE - Positive Kinetic Energy has been defined mathematically as:

over a traveled driving cycle of distance x where PP is the positive specific power and is given by the following expression

when Vt > Vt-1, and is zero when Vt  Vt-1.

Each of these metrics can be easily computed from the second-by-second speed measurements collected in IM240

testing. In comparing their relative ability to identify speed variations that produce high emissions, it is helpful to consider

which speed variations contribute to the value of each metric (similar to the earlier examination of the SE statistic) over an

IM240 test. 

Note that although both DPWRSUM and PKE are affected by differences in specific power or squared speeds over

"adjacent" seconds of an IM240 trace, the value of DPWRSUM is increased during decelerations as well as accelerations. 

PKE on the other hand, is only increased during acceleration periods. 
96

IM240 REFERENCE

DATA PKE VARIATION CUTPOINTS (miles/hr2)

CUM

PKE

"BASE

" MULT. VARYING CUMULATIVEPKE

TIME SPEED (miles/hr2

)

DELTA FACTO

R

DELTA LOW HIGH

0 0.0 0.0 . . . . .

1 0.0 0.0 . . . . .

2 0.0 0.0 . . . . .

3 0.0 0.0 . . . . .

4 0.0 0.0 . . . . .

5 3.0 10,800.0 . . . . .

6 5.9 14,080.4 . . . . .

7 8.6 15,214.6 . . . . .

8 11.5 16,417.2 . . . . .

9 14.3 17,001.5 . . . . .

10 16.9 17,079.7 . . . . .

11 17.3 13,902.5 . . . . .

12 18.1 12,336.8 . . . . .

13 20.7 13,263.7 . . . . .

14 21.7 12,284.1 . . . . .

15 22.4 11,261.4 . . . . .

16 22.5 9,964.5 . . . . .

17 22.1 8,890.2 . . . . .

18 21.5 8,046.4 . . . . .

19 20.9 7,366.6 . . . . .

20 20.4 6,805.5 . . . . .

21 19.8 6,336.9 . . . . .

22 17.0 5,983.3 . . . . .

23 14.9 5,704.2 . . . . .

24 14.9 5,450.1 . . . . .

25 15.2 5,306.1 . . . . .

26 15.5 5,171.6 . . . . .

27 16.0 5,103.3 . . . . .

28 17.1 5,213.3 . . . . .

29 19.1 5,599.3 . . . . .

30 21.1 5,990.0 342.3 4.000 1,369.3 4,621 7,359

31 22.7 6,242.3 356.7 3.986 1,421.8 4,820 7,664

32 22.9 6,014.8 343.7 3.971 1,365.1 4,650 7,380

33 22.7 5,745.3 328.3 3.957 1,299.3 4,446 7,045

34 22.6 5,500.0 314.3 3.943 1,239.3 4,261 6,739

35 21.3 5,287.2 302.2 3.929 1,187.0 4,100 6,474

36 19.0 5,110.8 292.1 3.914 1,143.3 3,968 6,254

37 17.1 4,961.9 283.6 3.900 1,105.9 3,856 6,068
97

38 15.8 4,831.8 276.1 3.886 1,072.9 3,759 5,905

39 15.8 4,708.3 269.1 3.871 1,041.7 3,667 5,750

40 17.7 4,937.5 282.2 3.857 1,088.4 3,849 6,026

41 19.8 5,220.8 298.4 3.843 1,146.5 4,074 6,367

42 21.6 5,450.3 311.5 3.829 1,192.5 4,258 6,643

43 23.2 5,638.2 322.2 3.814 1,229.0 4,409 6,867

44 24.2 5,685.3 324.9 3.800 1,234.6 4,451 6,920

45 24.6 5,592.5 319.6 3.786 1,209.9 4,383 6,802

46 24.9 5,481.7 313.3 3.771 1,181.5 4,300 6,663

47 25.0 5,332.7 304.8 3.757 1,145.0 4,188 6,478

48 25.7 5,321.5 304.1 3.743 1,138.2 4,183 6,460

49 26.1 5,245.9 299.8 3.729 1,117.8 4,128 6,364

50 26.7 5,216.3 298.1 3.714 1,107.2 4,109 6,323

51 27.5 5,230.2 298.9 3.700 1,105.9 4,124 6,336

52 28.6 5,307.9 303.3 3.686 1,118.0 4,190 6,426

53 29.3 5,298.0 302.8 3.671 1,111.6 4,186 6,410

54 29.8 5,246.1 299.8 3.657 1,096.4 4,150 6,343

55 30.1 5,155.0 294.6 3.643 1,073.2 4,082 6,228

56 30.4 5,068.3 289.6 3.629 1,051.0 4,017 6,119

57 30.7 4,985.6 284.9 3.614 1,029.8 3,956 6,015

58 30.7 4,848.3 277.1 3.600 997.5 3,851 5,846

59 30.5 4,719.2 269.7 3.586 967.0 3,752 5,686

60 30.4 4,597.2 262.7 3.571 938.3 3,659 5,535

61 30.3 4,481.7 256.1 3.557 911.1 3,571 5,393

62 30.4 4,389.2 250.8 3.543 888.7 3,501 5,278

63 30.8 4,352.1 248.7 3.529 877.6 3,474 5,230

64 30.4 4,250.1 242.9 3.514 853.6 3,397 5,104

65 29.9 4,154.4 237.4 3.500 831.0 3,323 4,985

66 29.5 4,064.1 232.3 3.486 809.6 3,255 4,874

67 29.8 4,022.9 229.9 3.471 798.1 3,225 4,821

68 30.3 4,013.3 229.3 3.457 792.9 3,220 4,806

69 30.7 3,988.8 228.0 3.443 784.8 3,204 4,774

70 30.9 3,935.5 224.9 3.429 771.1 3,164 4,707

71 31.0 3,869.4 221.1 3.414 755.0 3,114 4,624

72 30.9 3,791.8 216.7 3.400 736.8 3,055 4,529

73 30.4 3,718.5 212.5 3.386 719.5 2,999 4,438

74 29.8 3,649.2 208.5 3.371 703.1 2,946 4,352

75 29.9 3,595.5 205.5 3.357 689.8 2,906 4,285

76 30.2 3,569.2 204.0 3.343 681.9 2,887 4,251

77 30.7 3,569.2 204.0 3.329 678.9 2,890 4,248

78 31.2 3,569.3 204.0 3.314 676.0 2,893 4,245

79 31.8 3,582.2 204.7 3.300 675.6 2,907 4,258

80 32.2 3,569.2 204.0 3.286 670.2 2,899 4,239
98

81 32.4 3,531.2 201.8 3.271 660.2 2,871 4,191

82 32.2 3,469.8 198.3 3.257 645.9 2,824 4,116

83 31.7 3,411.4 195.0 3.243 632.2 2,779 4,044

84 28.6 3,360.3 192.0 3.229 620.0 2,740 3,980

85 25.1 3,316.8 189.5 3.214 609.3 2,708 3,926

86 21.6 3,280.2 187.5 3.200 599.9 2,680 3,880

87 18.1 3,250.2 185.7 3.186 591.7 2,658 3,842

88 14.6 3,226.3 184.4 3.171 584.7 2,642 3,811

89 11.1 3,208.4 183.4 3.157 578.9 2,630 3,787

90 7.6 3,196.3 182.7 3.143 574.1 2,622 3,770

91 4.1 3,189.8 182.3 3.129 570.3 2,619 3,760

92 0.6 3,188.9 182.2 3.114 567.5 2,621 3,756

93 0.0 3,188.9 182.2 3.100 564.9 2,624 3,754

94 0.0 3,188.9 182.2 3.086 562.3 2,627 3,751

95 0.0 3,188.9 182.2 3.071 559.7 2,629 3,749

96 0.0 3,188.9 182.2 3.057 557.1 2,632 3,746

97 0.0 3,188.9 182.2 3.043 554.5 2,634 3,743

98 3.3 3,203.1 183.0 3.029 554.4 2,649 3,757

99 6.6 3,250.7 185.8 3.014 560.0 2,691 3,811

100 9.9 3,331.3 190.4 3.000 571.1 2,760 3,902

101 13.2 3,443.8 196.8 2.986 587.6 2,856 4,031

102 16.5 3,587.2 205.0 2.971 609.1 2,978 4,196

103 19.8 3,760.1 214.9 2.957 635.4 3,125 4,396

104 22.2 3,892.7 222.5 2.943 654.7 3,238 4,547

105 24.3 4,013.3 229.4 2.929 671.7 3,342 4,685

106 25.8 4,090.8 233.8 2.914 681.3 3,409 4,772

107 26.4 4,093.0 233.9 2.900 678.3 3,415 4,771

108 25.7 4,045.3 231.2 2.886 667.1 3,378 4,712

109 25.1 3,999.9 228.6 2.871 656.4 3,344 4,656

110 24.7 3,956.1 226.1 2.857 646.0 3,310 4,602

111 25.2 3,951.8 225.8 2.843 642.0 3,310 4,594

112 25.4 3,924.1 224.3 2.829 634.3 3,290 4,558

113 27.2 4,024.3 230.0 2.814 647.2 3,377 4,672

114 26.5 3,979.2 227.4 2.800 636.7 3,342 4,616

115 24.0 3,939.2 225.1 2.786 627.1 3,312 4,566

116 22.7 3,902.0 223.0 2.771 618.0 3,284 4,520

117 19.4 3,870.9 221.2 2.757 609.9 3,261 4,481

118 17.7 3,842.9 219.6 2.743 602.4 3,241 4,445

119 17.2 3,816.0 218.1 2.729 595.0 3,221 4,411

120 18.1 3,834.3 219.1 2.714 594.8 3,240 4,429

121 18.6 3,832.2 219.0 2.700 591.3 3,241 4,423

122 20.0 3,879.0 221.7 2.686 595.4 3,284 4,474

123 20.7 3,887.7 222.2 2.671 593.5 3,294 4,481
99

124 21.7 3,914.4 223.7 2.657 594.4 3,320 4,509

125 22.4 3,923.5 224.2 2.643 592.6 3,331 4,516

126 22.5 3,895.8 222.6 2.629 585.2 3,311 4,481

127 22.1 3,863.1 220.8 2.614 577.1 3,286 4,440

128 21.5 3,831.7 219.0 2.600 569.3 3,262 4,401

129 20.9 3,801.8 217.3 2.586 561.8 3,240 4,364

130 20.4 3,772.9 215.6 2.571 554.4 3,219 4,327

131 19.8 3,745.4 214.0 2.557 547.3 3,198 4,293

132 17.0 3,722.1 212.7 2.543 540.9 3,181 4,263

133 17.1 3,703.4 211.6 2.529 535.1 3,168 4,239

134 15.8 3,682.2 210.4 2.514 529.1 3,153 4,211

135 15.8 3,661.2 209.2 2.500 523.1 3,138 4,184

136 17.7 3,720.0 212.6 2.486 528.4 3,192 4,248

137 19.8 3,794.6 216.9 2.471 535.9 3,259 4,330

138 21.6 3,860.2 220.6 2.457 542.1 3,318 4,402

139 22.2 3,863.3 220.8 2.443 539.3 3,324 4,403

140 24.5 3,964.6 226.6 2.429 550.2 3,414 4,515

141 24.7 3,943.1 225.3 2.414 544.0 3,399 4,487

142 24.8 3,915.9 223.8 2.400 537.1 3,379 4,453

143 24.7 3,883.2 221.9 2.386 529.4 3,354 4,413

144 24.6 3,851.1 220.1 2.371 521.9 3,329 4,373

145 24.6 3,819.6 218.3 2.357 514.5 3,305 4,334

146 25.1 3,817.5 218.2 2.343 511.1 3,306 4,329

147 25.6 3,815.4 218.0 2.329 507.7 3,308 4,323

148 25.7 3,789.6 216.6 2.314 501.2 3,288 4,291

149 25.4 3,758.6 214.8 2.300 494.0 3,265 4,253

150 24.9 3,728.8 213.1 2.286 487.1 3,242 4,216

151 25.0 3,704.9 211.7 2.271 480.9 3,224 4,186

152 25.4 3,698.2 211.3 2.257 477.0 3,221 4,175

153 26.0 3,702.8 211.6 2.243 474.6 3,228 4,177

154 26.0 3,673.1 209.9 2.229 467.8 3,205 4,141

155 25.7 3,644.1 208.3 2.214 461.1 3,183 4,105

156 26.1 3,637.9 207.9 2.200 457.4 3,181 4,095

157 26.7 3,643.0 208.2 2.186 455.0 3,188 4,098

158 27.3 3,648.1 208.5 2.171 452.7 3,195 4,101

159 30.5 3,812.6 217.9 2.157 470.0 3,343 4,283

160 33.5 3,978.0 227.3 2.143 487.1 3,491 4,465

161 36.2 4,133.0 236.2 2.129 502.8 3,630 4,636

162 37.3 4,172.3 238.4 2.114 504.1 3,668 4,676

163 39.3 4,282.5 244.7 2.100 513.9 3,769 4,796

164 40.5 4,330.6 247.5 2.086 516.2 3,814 4,847

165 42.1 4,412.1 252.1 2.071 522.3 3,890 4,934

166 43.5 4,477.8 255.9 2.057 526.4 3,951 5,004
100

167 45.1 4,561.4 260.7 2.043 532.5 4,029 5,094

168 46.0 4,584.2 262.0 2.029 531.4 4,053 5,116

169 46.8 4,598.2 262.8 2.014 529.3 4,069 5,127

170 47.5 4,603.2 263.1 2.000 526.1 4,077 5,129

171 47.5 4,546.8 259.8 1.986 516.0 4,031 5,063

172 47.3 4,492.0 256.7 1.971 506.1 3,986 4,998

173 47.2 4,438.6 253.7 1.957 496.4 3,942 4,935

174 47.2 4,386.5 250.7 1.943 487.0 3,899 4,874

175 47.4 4,352.1 248.7 1.929 479.7 3,872 4,832

176 47.9 4,343.2 248.2 1.914 475.1 3,868 4,818

177 48.5 4,342.6 248.2 1.900 471.5 3,871 4,814

178 49.1 4,342.0 248.1 1.886 467.9 3,874 4,810

179 49.5 4,324.9 247.2 1.871 462.5 3,862 4,787

180 50.0 4,316.3 246.7 1.857 458.1 3,858 4,774

181 50.6 4,316.0 246.7 1.843 454.5 3,861 4,771

182 51.0 4,299.3 245.7 1.829 449.3 3,850 4,749

183 51.5 4,291.0 245.2 1.814 444.9 3,846 4,736

184 52.2 4,299.3 245.7 1.800 442.3 3,857 4,742

185 53.2 4,332.3 247.6 1.786 442.1 3,890 4,774

186 54.1 4,356.8 249.0 1.771 441.0 3,916 4,798

187 54.6 4,347.7 248.5 1.757 436.6 3,911 4,784

188 54.9 4,322.3 247.0 1.743 430.5 3,892 4,753

189 55.0 4,280.9 244.6 1.729 422.9 3,858 4,704

190 54.9 4,232.4 241.9 1.714 414.6 3,818 4,647

191 54.6 4,185.2 239.2 1.700 406.6 3,779 4,592

192 54.6 4,139.1 236.5 1.686 398.7 3,740 4,538

193 54.8 4,109.5 234.9 1.671 392.5 3,717 4,502

194 55.1 4,088.2 233.6 1.657 387.2 3,701 4,475

195 55.5 4,075.0 232.9 1.643 382.6 3,692 4,458

196 55.7 4,046.6 231.3 1.629 376.6 3,670 4,423

197 56.1 4,034.0 230.5 1.614 372.1 3,662 4,406

198 56.3 4,006.4 229.0 1.600 366.3 3,640 4,373

199 56.6 3,986.7 227.8 1.586 361.3 3,625 4,348

200 56.7 3,952.4 225.9 1.571 354.9 3,597 4,307

201 56.7 3,911.4 223.5 1.557 348.1 3,563 4,259

202 56.3 3,871.4 221.2 1.543 341.3 3,530 4,213

203 56.0 3,832.5 219.0 1.529 334.8 3,498 4,167

204 55.0 3,795.0 216.9 1.514 328.4 3,467 4,123

205 53.4 3,759.3 214.8 1.500 322.3 3,437 4,082

206 51.6 3,725.4 212.9 1.486 316.3 3,409 4,042

207 51.8 3,704.9 211.7 1.471 311.5 3,393 4,016

208 52.1 3,691.1 210.9 1.457 307.4 3,384 3,998

209 52.5 3,683.7 210.5 1.443 303.7 3,380 3,987
101

210 53.0 3,682.8 210.5 1.429 300.7 3,382 3,984

211 53.5 3,682.0 210.4 1.414 297.6 3,384 3,980

212 54.0 3,681.1 210.4 1.400 294.5 3,387 3,976

213 54.9 3,705.8 211.8 1.386 293.5 3,412 3,999

214 55.4 3,704.7 211.7 1.371 290.4 3,414 3,995

215 55.6 3,684.4 210.6 1.357 285.8 3,399 3,970

216 56.0 3,677.1 210.1 1.343 282.2 3,395 3,959

217 56.0 3,644.6 208.3 1.329 276.7 3,368 3,921

218 55.8 3,612.7 206.5 1.314 271.3 3,341 3,884

219 55.2 3,581.7 204.7 1.300 266.1 3,316 3,848

220 54.5 3,551.6 203.0 1.286 261.0 3,291 3,813

221 53.6 3,522.5 201.3 1.271 255.9 3,267 3,778

222 52.5 3,494.5 199.7 1.257 251.1 3,243 3,746

223 51.5 3,467.4 198.2 1.243 246.3 3,221 3,714

224 50.5 3,441.2 196.7 1.229 241.6 3,200 3,683

225 48.0 3,416.8 195.3 1.214 237.1 3,180 3,654

226 44.5 3,394.4 194.0 1.200 232.8 3,162 3,627

227 41.0 3,374.0 192.8 1.186 228.6 3,145 3,603

228 37.5 3,355.6 191.8 1.171 224.6 3,131 3,580

229 34.0 3,339.0 190.8 1.157 220.8 3,118 3,560

230 30.5 3,324.3 190.0 1.143 217.1 3,107 3,541

231 27.0 3,311.4 189.2 1.129 213.6 3,098 3,525

232 23.5 3,300.3 188.6 1.114 210.2 3,090 3,510

233 20.0 3,290.9 188.1 1.100 206.9 3,084 3,498

234 16.5 3,283.1 187.6 1.086 203.7 3,079 3,487

235 13.0 3,277.1 187.3 1.071 200.7 3,076 3,478

236 9.5 3,272.7 187.0 1.057 197.7 3,075 3,470

237 6.0 3,269.9 186.9 1.043 194.9 3,075 3,465

238 2.5 3,268.7 186.8 1.029 192.1 3,077 3,461

239 0.0 3,268.7 186.8 1.014 189.5 3,079 3,458

Cycle Sums 3,268.7 3,079 3,458
102

Appendix H

Derivation of TRLHP Coefficients
103

Derivation of TRLHP Coefficients

(a) Road Load Equation

(1) Vehicle Loading. Road load is defined by the following equation relating track road load

horsepower and vehicle velocity.

TRLHP@ Obmph = (Av * Obmph) + (Bv * Obmph2) + ( Cv * Obmph3 )

Where: TRLHP = Track Road Load Horsepower.

Av, Bv, Cv = Coefficients relating TRLHP and velocity.

Obmph = Observed velocity in mph.

 (2) Coefficients. Av, Bv, and Cv are horsepower coefficients from EPA vehicle certification data

or EPA default values. Coefficients shall be calculated to a minimum of five significant digits

by the following equations. Power fractions determined from track coast-down data shall be

calculated to a minimum of two significant digits. In the absence of new car certification

coefficients, the default power fractions shall be used.

(A) A

A PF

5 0 * (TRLHP ) hp / mph v

v = @50mph

(B) B

B PF

2500 * (TRLHP ) hp / m ph v v

@50mph

2 =

(C) C

C PF

125,000 * (TRLH P ) h p / m p h v

v

@50m ph

3 =

Where: Av, Bv, Cv = Coefficients relating TRLHP and velocity.

AvPF, BvPF, and CvPF are power fractions, and indicate the fraction of the

total power at 50 mph contributed by each of the Av*50, Bv*2500, and

Cv*125,000 terms.

TRLHP@50mph = Track Road Load Horsepower at 50mph.

(D) AvPF + BvPF + CvPF = 1

Derivation of AvPF, BvPF, and CvPF from known track coastdown curves shall be computed as

follows:

(E) ( )( )( ) A PF

A

A B* C* v

v

vv v

= + +

*

* ,

5 0

50 2500 125 000
104

(F) ( )( )( ) B PF

B *

A* B* C* v

v

vv v

= + +

2500

50 2500 125 000 ,

(G) ( )( )( ) C PF

C *

A* B* C* v

v

vv v

= + +

125 000

50 2500 125 000

,

,

Default values:

AvPF = 0.35

BvPF = 0.10

CvPF = 0.55

(3) TRLHP@50mph. In absence of new vehicle certification data, the 50 mph TRLHP shall be

selected from the EPA I/M Look-up Table. It is based on the following equation:

( ) TRLHP

0.5 * ETW

32.2 * (V V

550* ET

1

2

2

2

= − )

Where: ET = Elapsed time for the vehicle on the road to coast down from 55 to 45

mph

ETW = Equivalent Test Weight in pounds

V1 = Initial velocity in feet/second

V2 = Final velocity in feet/second
105

Appendix I

Derivation of GTRL Coefficients
106

Derivation of Dynamometer Tire/Roll Interface Losses

(a) Generic Tire Roll Loss

(1) Tire/Roll Interface Losses. Tire/roll losses include vehicle drive train losses and may be

determined on a vehicle and dynamometer roll size specific basis, or using the default values

presented below.

Tire losses may be characterized on a vehicle and roll size specific basis by the following

equation:

GTRL@ Obmph = (At * Obmph) + (Bt * Obmph2) + ©t * Obmph3)

Where: GTRL = Generic tire/roll interface losses, in horsepower.

At, Bt, Ct are coefficients derived by fitting a third order curve of tire losses,

in horsepower, and velocity.

Obmph is the observed velocity in mph.

(A) A

0.76

5 0 * (GTRL ) hp / m ph t8 = @ 50m ph-8

(B) B

0.33

2500 * (G TRL ) hp / m ph t8 @ 50m ph-8

2 =

(C) C

-0.09

125,000 * (GTRL ) hp / m p h t8 @50m p h -8

3 =

Where: At8, Bt8, Ct8 are coefficients relating tire losses, in horsepower, and velocity

on an 8.65 inch twin roll dynamometer.

0.76, 0.33, -0.09 are default 50 mph power fraction values derived from

experimental data.

GTRL@50mph-8 = -0.378193 + 0.0033207*DAXWT

DAXWT = (VAXF + VAXE)/2

VAXF = Drive axle weight for a vehicle with a full fuel tank from EPA

Certification database.

VAXE = Drive axle weight for a vehicle with an empty fuel tank from EPA

Certification database.
107

(D) A

0.65

5 0 * (GTRL ) hp / mph t20 = @ 50mph-20

(E) B

0.48

2500 * (GTRL ) hp / mph t20 @ 50mph -20

2 =

(F) C

-0.13

125,000 * (G TRL ) h p / m p h t20 @50m p h-20

3 =

Where: At20, Bt,

20, Ct20 are coefficients relating tire losses, in horsepower, and

velocity on a 20 inch twin roll dynamometer.

0.65, 0.48, -0.13 are default 50 mph power fraction values derived from

experimental data.

GTRL@50mph-20 = 0.241645 + 0.0020844*DAXWT

DAXWT = (VAXF + VAXE)/2

VAXF = Drive axle weight for a vehicle with a full fuel tank from EPA

Certification database.

VAXE = Drive axle weight for a vehicle with an empty fuel tank from EPA

Certification database.

(2) Look-up Table. The vehicle specific values for GTRL@50mph-8 and GTRL@50mph-20 using 

default values for 50 mph power fractions are published in the latest version of the EPA I/M

Look-up Table.