United States

Environmental Protection

Agency

Air and Radiation EPA420-P-99-030

October 1999

M6.HDE.003

Development and Use of

Heavy-Duty NOx Defeat

Device Emission Effects for

MOBILE5 and MOBILE 6

 Printed on Recycled Paper
EPA420-P-99-030

October 1999

Development and Use of Heavy-Duty Defeat Device

Emission Effects for MOBILE5 AND MOBILE6

Report Number M6.HDE.003

 October, 1999

Edward L. Glover

Assessment and Modeling Division

Office of Mobile Sources

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.
M6.HDE.003--Defeat Device Page 1

Introduction

This document describes the methodology used to estimate excess NOx emissions produced

by heavy-duty diesel vehicles (HDDV) as the result of built-in defeat devices. Also, presented in the

document are emission estimates based on two programs designed to mitigate the effect of the defeat

device on fleet NOx emission levels. These include the incorporation of more stringent HDDV

standards earlier than originally required (pull ahead), and accelerated engine rebuild programs

(rebuild) to get in-use engines into better compliance. The document describes two basic models.

The first model is an Excel spreadsheet model (Spreadsheet Model) used to calculate excess HDDV

NOx emission effects in units of tons per year. Both a MOBILE6 and a MOBILE5 version of the

spreadsheet model were developed. The excess NOx emission results in tons from this spreadsheet

model are compared with the official EPA heavy-duty defeat device inventory emission results

prepared by EPA’s Office of Compliance and Enforcement (OECA). The second model is the

heavy-duty defeat device module that is built into the MOBILE6 emission factor model. It was

developed and programmed into MOBILE6 using parameters from the spreadsheet model. The

specific methodologies, parameters, procedures and their incorporation in the MOBILE6 model (the

second model) are also discussed in this document. 

The defeat device parameters were also incorporated in the MOBILE5 version of the

Spreadsheet Model and into the MOBILE5 model because of the need to create a baseline

comparison with MOBILE5 that included the emission effects of the defeat device . For example,

the effects of the defeat device were incorporated in the MOBILE5 Spreadsheet Model to create

Calendar Year (CY) 1990 or CY1995 baseline NOx inventories that included defeat device

operation. A modified version of MOBILE5 that included the defeat device effects was also created

so that consistency could be maintained between past baseline inventories made with MOBILE5 and

future projections. 

The MOBILE5 version of the defeat device spreadsheet model and the defeat device module

that is built-in the MOBILE5 code is completely analogous to the MOBILE6 based spreadsheet

model and code module. The only differences are in the data parameters. These parameters include

the heavy-duty vehicle conversion factors, the basic heavy-duty vehicle NOx emission factors

without the defeat device present, the VMT distribution by vehicle class, and the VMT distribution

by model year. The only difference between the MOBILE6 and MOBILE5 values is that the

MOBILE6 values are updated to account for more recent data collection by EPA.

For purposes of this modeling, a defeat device is a vehicle component or software which

allows excess emissions to be produced during operating modes which are not explicitly covered by

a certification test while still controlling emissions during the certification test. In the case of the

heavy-duty NOx defeat device, the device was active (shut off emission control systems) during

steady-state operating modes such as cruising down the freeway, but was mostly inactive during

transient operation. It was built into heavy-duty diesel vehicles beginning in the 1988 model year,

and completely removed by the 2000 model year. In the late 1980's and early 1990's the defeat

device was being phased into the fleet and was mostly confined to the heavy end of the heavy-duty
M6.HDE.003--Defeat Device Page 2

diesels (8a and 8b vehicles). However, by the mid to late 1990's it was widespread on virtually all

of the heavy end engines and most of the medium and light end heavy-duty diesels. 

This document is NOT a legal document, or an official emission inventory document. These

official documents can be found in the official EPA Consent Decree documents and supporting

material. This current document is merely an attempt to compile estimates of the impact of the

defeat device, the proposed solutions from official sources, and fit it to the framework of the

MOBILE6 model. These results may differ from the official EPA emission estimates in tons per

year. A reader interested in the fleet impact of the defeat device based on official sources should

refer to the official consent decree document.

This document is structured into three principal parts. The first part describes the structure,

parameters, and use of the spreadsheet model. This part is composed of several sub-sections. These

include a description of the model’s overall structure, the data parameters of the model, the control

parameters and a brief look at the results. The second part describes the implementation of the

Spreadsheet Model outputs and parameters into the existing MOBILE6 model structure. An

appendix at the end of the paper presents the FORTRAN code used to implement the algorithm.

Currently, the code has not been fully integrated into the MOBILE6 model; thus, results are not

available. The third section briefly describes (in a very limited way) the use of the MOBILE5 and

MOBILE6 defeat device spreadsheet models to provide heavy-duty vehicle defeat device emission

effects for subsequent inventory modeling. 
M6.HDE.003--Defeat Device Page 3

1. Heavy-Duty Diesel Vehicle Defeat Device Spreadsheet Model

This section describes the overall structure, data parameters, and input / output structure of

the HDDV defeat device spreadsheet model (spreadsheet model). The actual models are available

at the EPA OMS website as an Excel spreadsheet entitled “DefeatM6.xls” - MOBILE6, and

“DefeatM5.xls” - MOBILE5. Excel spreadsheets entitled “DDM6_Data.xls” and “DDM5_Data.xls”

are also available that contains a summary of the important data parameters. Both of the data

spreadsheets are in exactly the same format, and should be viewed as a companion to this text

document.

1.1 Overview of the Basic Structure

The spreadsheet model is a calculator that weights the individual model year and vehicle

class emission factors with vehicle miles traveled (VMT) inputs and sums these results into overall

yearly excess NOx emission levels in tons. The following data parameters are used in the

spreadsheet, and are defined in the subsequent sections. The term “MOBILE6/5" means MOBILE6

and MOBILE5.

MOBILE6/5 Heavy-Duty Vehicle Conversion Factors

MOBILE6/5 Basic Emission Factors WITHOUT Defeat Device Effects

Basic Emission Factors WITH Defeat Device Effects

Defeat Device Operating Parameter and Fleet Penetration Rates

Total HDDV Vehicle Miles Traveled (VMT)

MOBILE6/5 Distribution of VMT by Roadway Type, Vehicle Class and Model Year

MOBILE6/5 HDDV Speed Correction Factors

Several equations are used to weight together these parameters and sum the results. These

equations are shown in the section labeled “Calculations”.

1.2 Heavy-Duty Vehicle Conversion Factors

The HDDV conversion factors (CF) used in this model are shown in Excel Spreadsheet

DDM6_Data.xls (or DDM5_Data.xls) in worksheet CF. These conversion factors were taken from

MOBILE6 (or MOBILE5) and are referenced in EPA report “Update Heavy-Duty Engine Emission

Conversion Factors for MOBILE6: Analysis of BSFCs and Calculation of Heavy-Duty Engine

Emission Conversion Factors” - EPA420-P-98-015. The conversion factors are used to convert

the basic heavy-duty diesel emission factors from g/bhp-hr into g/mi units. This is necessary so that

the four individual heavy-duty diesel vehicle class emission factors and the individual roadway

factors can be properly weighted together by VMT. Emission factors in units of g/bhp-hr cannot be

VMT weighted because the basis units are in bhp-hr rather than in miles. The analogous conversion
M6.HDE.003--Defeat Device Page 4

factors for the MOBILE5 model were taken from the MOBILE5 source code.

The conversion factors are shown as a function of model year and vehicle class. The model

years range from 1964 through 2030. Each column in the worksheet CF contains a conversion factor

for one of the four heavy-duty vehicle classes: Light, Medium, Class 8a and Class8b. In all cases,

the Light class conversion factors are composite values obtained by weighting the individual subclasses (light-heavy duty standard classes of 2b, 3, 4 and 5) together with the Bus conversion factors

based on VMT. This was done because neither the Light or Bus class contain defeat device effects

in any appreciable quantity.

1.3 MOBILE6 Basic Emission Factors WITHOUT Defeat Device Effects

The basic emission factors without defeat device effects used in the spreadsheet model are

shown in Excel Spreadsheet DDM6_Data.xls (or DDM5_Data.xls) in worksheet BEFs. These are

the base emission levels for a particular model year and vehicle class if the defeat device is not

present or not working. The first five columns show the Without Defeat Device Emission factors.

These are shown as a function of vehicle class (Light, Medium, 8a and 8b), and as a function of

model year. Basic emission factors are shown for model years 1964 through 2030, and are in units

of grams per brake-horsepower-hr (g/bhp-hr or g/hp-hr). These values are the default emission levels

for HDDVs in MOBILE6, and are very heavily based on certification test results. The analogous

MOBILE5 values are also default emission levels and are based on certification test results. The

reference for the MOBILE6 values is EPA report EPA420-R-99-010 - “Update of Heavy-Duty

Emission Levels (Model Years 1988 - 2004+) for Use in MOBILE6." The MOBILE5 values were

taken from the MOBILE5 model code.

1.4 MOBILE6 Basic Emission Factors WITH Defeat Device Effects

The last four columns in worksheet BEFs of the Excel Spreadsheet DDM6_Data.xls (or

DDM5_Data.xls) show the basic NOx emission factors in g/bhp-hr units when the defeat device is

active and operating. Like the WITHOUT defeat device emission levels, the WITH defeat emission

levels are shown as a function of vehicle class and model year. The same WITH defeat device

emission levels are used in both the MOBILE5 and MOBILE6 spreadsheet model version. The

“Light-Duty” class is unaffected by the defeat device so it shows the same NOx emission factors for

both “WITH” and “WITHOUT” defeat devices. NOx emission factors are shown for the model year

range of 1964 through 2030. One exception is the WITH defeat device NOx emission factors for

model years 2002 and 2003. These are lower than the WITHOUT defeat device emission levels as

the result of “Pull Ahead” requirements for lower certification standards. For model years 2004 and

later, and model years 1987 and earlier, the WITH and WITHOUT defeat device emission levels are

equivalent, since there would be no defeat device effects on emissions for these model year engines.

The defeat device emission effects were determined on an engine by engine basis using

available data and engineering judgement by experts familiar with engine control software. These

individual estimates were weighted together by engine family using diesel vehicle sales information
M6.HDE.003--Defeat Device Page 5

to produce model year average emission levels (this document uses a summary of the individual

manufacturer results). The individual engine family or manufacturer specific engine control logic,

emission results and sales projections are proprietary in nature and were made available to the EPA

on a confidential basis as part of the Heavy-Duty Diesel Defeat Device Consent Decree. Thus, they

are not provided in this document nor are they publically available in any other source.

1.5 Defeat Device Operating Parameter and Fleet Penetration Rates

The defeat device operating parameters and fleet penetration rates used in the spreadsheet

model are shown in worksheet “Fleet Fractions” of Excel Spreadsheet DDM6_Data.xls (or

DDM5_Data.xls). These are shown as a function of vehicle class (light, medium, 8a and 8b), model

year, and roadway type. The three roadway types are Urban, Arterial, and Interstate. There are four

sub-types within each of these three broad classes, and they are also listed in spreadsheet

DD_Data.xls worksheet “Fleet Fractions.” The Urban type represents city driving which includes

considerable stop-and-go transient operation. The Arterial type represents driving on primary roads

in which there is both transient operation and steady-state operation. The Interstate type represents

the operation which includes mostly steady state type driving at higher speeds. A zero (0.00) means

that the defeat device does not operate during that mode, and a one (1.00) would mean that it

operates all of the time in that mode. This information is on a fleet summary basis. It was calculated

from individual engine family defeat device response data that was determined from proprietary and

confidential data submitted by the engine manufacturers, limited testing of affected engines, and

engineering judgment by experts in engine control and emission control software. As a general rule,

the Urban type contains relatively little defeat device operation, and the Interstate type contains

considerable defeat device operation, as can be seen in the low fractions for Urban and the high

fractions for Interstate. The defeat device operating fractions are also a function of model year. 

The columns entitled “Fleet Fraction” show the percent of a particular model year and vehicle

class that is equipped with the defeat device or affected by the legal settlement. A value of zero

means for that particular combination of vehicle class and model there are no defeat devices, and a

value of unity (1.0) means that in that model year, all vehicles of that class were equipped with

defeat devices. In general, the data suggests that the defeat device penetration began slowly in the

1988 model year on the heavier class diesels, and slowly progressed to encompass most of the fleet.

Virtually full penetration seems to have occurred by the mid 1990's on the heavier engines.

Penetration drops off abruptly around calendar year 2000, presumably due to the settlement. The

only exception to this rule is for the case of the 2002 and 2003 model years. These model year

groups contain a coded factor to calculate the impact of “Pull Ahead.” No defeat devices will be

produced in those model years. The MOBILE6 With Defeat Device operating parameters and fleet

penetration rates were used in the MOBILE5 version directly.

1.6 Total VMT Estimates

The Total VMT Estimates are shown in worksheet Total_VMT of Spreadsheet
M6.HDE.003--Defeat Device Page 6

DDM6_Data.xls (or DDM5_Data.xls). Separate values are shown for calendar years 1988 through

2010. The VMT values were obtained from the EPA Trends model, and are typical HDDV VMT

levels used in Air Quality modeling. Linear equations are used to project future VMT levels. The

Total VMT estimate is an important factor in determining the total tons of NOx produced by the

defeat devices. However, it is not explicitly used in the MOBILE6 model inputs because MOBILE6

does not produce NOx emissions in units of tons (only in grams per mile). The same Total VMT

estimates were used for both the MOBILE6 and MOBILE5 models.

1.7 Distribution of VMT by Roadway Type, Vehicle Class and Model Year

1.7.1 Distribution of VMT by Roadway Type

The VMT distribution by Roadway Type used in the spreadsheet model is shown in

worksheet “Road_VMTDist” of Excel Spreadsheet DDM6_Data.xls (or DDM5_Data.xls). In

general, there are three basic facility types - Urban, Arterial and Interstate. Within each of these

three basic types, there are four individual roadway types (a total of 12 roadway types). The VMT

weighted distribution for each roadway type by vehicle class is shown at the top of worksheet

Road_VMTDist. These values were obtained from the report “Documentation of Mobile Source

Inventories Used in OAQPS Trends Report” by EH Pechan under EPA Contract 68-D3-0035. They

are used to properly weight the impact of the defeat device by vehicle class for each of the 12

roadway types. The values for the VMT distribution by roadway type were used in both the

MOBILE6 and MOBILE5 versions.

1.7.2 Distribution of VMT by Vehicle Class

The next small table in the worksheet Road_VMTDist of DDM6_Data.xls (or

DDM5_Data.xls) contains the vehicle class distribution, which distributes VMT by vehicle class.

It is combined with the defeat device roadway distribution, to create a VMT distribution by roadway

type and vehicle class. Different values were used for the MOBILE5 spreadsheet model. The

MOBILE5 values contained a somewhat higher fraction of VMT allocated to the 8a class of heavyduty diesel vehicle, and thus accounted for one of the biggest differences between the MOBILE6 and

MOBILE5 NOx defeat device inventories.

1.7.3 Distribution of VMT by Vehicle Class and Roadway

The table at the bottom of Road_VMTDist is a combined VMT distribution by Vehicle Class

and Roadway type. It is the product of the previous two tables and is used directly in the calculation

of defeat device effects. Mathematically, each row in the table sums to unity for a given roadway

type. Different values are computed for the MOBILE6 and MOBILE5 models due to the different
M6.HDE.003--Defeat Device Page 7

VMT distribution by vehicle class.

1.7.4 Distribution of VMT by Model Year

The VMT distribution by age and vehicle class used in the spreadsheet model is shown in

worksheet “TF” of Excel Spreadsheets DDM6_Data.xls and DDM5_Data.xls. The TF represents

Travel Fraction, and is used to distribute the defeat device emission effects by model year / age. The

values are the standard MOBILE6 travel fractions calculated from MOBILE6 parameters such as

diesel fleet penetration, annual mileage accumulation rates by vehicle class, and registration

distributions by vehicle class. The primary reference for these parameters is EPA report “Update

of Heavy-Duty Emission Levels (Model Years 1988 - 2004+) for Use in MOBILE6" - EPA report

EPA420-R-99-010. The MOBILE5 distribution was taken from the MOBILE5 computer code. It

differs from the MOBILE6 distribution because it is a single distribution that represents all four of

the vehicle classes; whereas, for MOBILE6, separate age distributions are used for each of the four

vehicle classes.

1.8 MOBILE6/5 HDDV Speed Correction Factors

An average speed is associated with each of the twelve roadway types. The average speed

information was obtained from the report “Documentation of Mobile Source Inventories Used in

OAQPS Trends Report” by EH Pechan under EPA Contract 68-D3-0035. The twelve roadway

types and the average speeds are listed below in Table 1. The letters I, A and U in parentheses stand

for Interstate, Arterial and Urban, respectively. These average speeds are based on an analysis EH

Pechan did in 1991 on DOT data. 

In this analysis, speed correction factors are used only to model the effect of speed on the

heavy-duty emissions which are associated with “without defeat device operation.” The “with defeat

device heavy-duty emission factors” implicitly contain speed correction factors, and need no

additional speed correction. This implicit relationship is an assumption that the defeat device

emission effects inherently contain all of the remaining speed related NOx emission effects that

occur as the result of vehicle operation outside of the certification test cycle, and the certification

cycle’s average speed of 20 MPH. The basis for this assumption is that the defeat device effects are

a strong function of speed and typically only occur during the steady-state higher speed activity of

the trucks. Also, based on the limited test and engineering data, it is not feasible to separate defeat

device NOx emission effects from normal speed correction NOx emission effects.

The average speed for each roadway type is used to calculate the NOx speed correction

factors. The speed correction factor equation used in this analysis is the standard MOBILE5/6

equation for heavy-duty diesels (the same value is used in both MOBILE6 and MOBILE5. It is not

a function of roadway type. The speed correction factors are calculated for each of the roadway types

by inserting the appropriate average speed into Equation 1 below:
M6.HDE.003--Defeat Device Page 8

NOx Speed CF = 0.676 - 0.0480*speed + 0.00071*speed**2 Eqn 1

‘**2' means squared.
M6.HDE.003--Defeat Device Page 9

Table 1

Roadway Types and Average Speeds

Roadway Number and Name Average Speed (MPH)

1. Rural Interstate (I) 40

2. Rural Other Principal Arterial (I) 35

3. Urban Interstate (I) 35

4. Urban Freeway & Expressway (I) 35

5. Rural Minor Arterial (A) 30

6. Rural Major Collector (A) 25

7. Rural Minor Collector (A) 25

8. Rural Local (A) 25

9. Urban Other Principal Arterial (U) 15

10. Urban Minor Arterial (U) 15

11. Urban Collector (U) 15

12. Urban Local (U) 15

1.9 Calculations

1.9.1 With Defeat Device Emission Calculation

The calculations in the spreadsheet model DefeatM6.xls (or DefeatM5.xls) are fairly simple

and straightforward in concept, although quite voluminous due to the need to duplicate them twice

for each of the twelve roadway types (24 times). The following general method and equations were

used:

1. The Without Defeat Device emission factors are speed corrected, but the With Defeat Device

are not speed corrected because the defeat device inherently contains NOx speed effects.

2. The speed correction factor was calculated using Equation 1 and the appropriate speed from

Table 1.

3. For each model year, roadway type, and vehicle class, Equation 2 is used to calculate a basic
M6.HDE.003--Defeat Device Page 10

fleet emission factor that is a weighted average of the With and Without defeat device rates.

Fleet = [ NO_DD*(1-DD_equip)*SpeedCF + NO_DD*DD_equip*(1-DDmode)*SpeedCF

 + DD*DD_equip*DDmode] * CF Eqn 2

Where:

NO_DD is the basic emission factor if no defeat device is present (from worksheet BEFs of

DD_Data.xls).

DD is the basic emission factor if a defeat device is present and operating (from worksheet BEFs of

DD_Data.xls).

DD_equip is the fraction of the fleet which has a defeat device installed on it (from worksheet Fleet

Fractions of DD_Data.xls).

DD_mode is the VMT fraction in a given roadway type mode that the defeat device is in operation

(from worksheet Fleet Fractions of DD_Data.xls).

SpeedCF is the appropriate speed correction factor for the given roadway number (calculated from

Equation 1).

CF is the appropriate heavy-duty conversion factor to convert the emission rate in grams/bhp-hr into

grams/mile. It is a function of vehicle class (from worksheet CF of DD_Data.xls).

Fleet is the fleet average NOx emission level with defeat devices for a given roadway type mode and

model year in units of g/mile

1.9.2 Without Defeat Device Emission Calculation

The Without Defeat Device emission calculation is analogous to the With Defeat Device

calculation. Equation 3 is used to calculate the NOx emission level for a particular permutation of

roadway, model year, vehicle class and speed.

The Without Defeat Device emission factor is speed corrected using the appropriate speed

correction factor for a given roadway number. Equation 1 is multiplied by the Without Defeat Device

basic emission factors found in DD_Data.xls sheet BEFs.
M6.HDE.003--Defeat Device Page 11

Fleet2 = [ NO_DD* SpeedCF * CF] Eqn 3

NO_DD is the emission factor if no defeat device is present.

SpeedCF is the appropriate speed correction factor.

CF is the appropriate heavy-duty conversion factor to convert the emission rate into grams/mile. It

is a function of vehicle class.

Fleet2 is the fleet average NOx emission level without defeat devices for a given mode and model

year in units of g/mile

1.9.3 Overall NOx Defeat Device Tons

The defeat device spreadsheet model found in DefeatM6.xls and DefeatM5.xls calculates

total excess NOx tons for a given calendar year and other inputs. The model only calculates the

excess NOx tons for a speed of 20 mph. The calculation procedure is described below using

Equations 4, 5 and 6. The values in brackets are parameters for the value. For example, Fleet is a

function of vehicle class (icls), roadway type (iroad), and model year (imy).

DD(icls,iroad,imy) = Fleet(icls,iroad,imy) - Fleet2(icls,iroad,imy) Eqn 4

Where:

DD(icls,iroad,imy) is the net defeat device NOx emission effect for each combination of vehicle

class(light, medium, 8a and 8b), roadway type(12 types), and model year.

Fleet(icls,iroad,imy) is the With Defeat Device NOx emission level for each vehicle class, roadway

type, and model year calculated using Equation 2.

Fleet2(icls,iroad,imy) is the Without Defeat Device NOx emission level for each vehicle class,

roadway type, and model year calculated using Equation 3.

The total HDDV excess NOx emissions in tons for a given calendar year are calculated using

Equation 5.

DD_Tons =  [DD(icls,iroad,imy)*TF(icls,imy)*TotalVMT(iroad,icls)*Constant] Eqn 5
M6.HDE.003--Defeat Device Page 12

Where:

The summation is over the four vehicle classes (light, medium, 8a and 8b).

DD(icls,iroad,imy) the net defeat device effect calculated from Equation 4.

TF(icls,imy) is the model year VMT distribution for each vehicle class.

TotalVMT(iroad,icls) is the total VMT in millions of miles for a given combination of roadway

type and vehicle class.

Constant contains the conversion factors from grams to tons per calendar year.

1.10 Rebuild Program Inputs to the Excess NOx Emission Spreadsheet Model

Most heavy-duty diesel engines are rebuilt after their initial useful life has elapsed.

Typically, this occurs around the 350,000 mile point, and often includes replacing engine parts that

affect NOx emissions. The practice of rebuilding is considerably more cost-effective to the truck

owner than scrapping the engine. Because the rebuild practice is so widespread, the engine

manufacturing industry agreed as part of the Consent Decree to rebuild a portion of the fleet in such

a way as to reduce the effect of the defeat device on rebuilt engines. This NOx excess spreadsheet

model will reflect the effects of the rebuild program.

The following parameters are defined and used in the MOBILE6 and MOBILE5 spreadsheet

models to account for rebuilds.

Rebuild Fraction - This is the fraction of the eligible fleet that will be rebuilt. Currently this

fraction is assumed to be 0.90.

Model Year Range - Two options were available in the consent decree. The one which is modeled

in the spreadsheet model includes only the 1994 through 1998 model years. The other rebuild option

(not modeled) includes the 1993 model year.

After Rebuild Emission Level - This is the NOx emission level that the rebuilt engines will emit

in units of g/bhp-hr, and is set equal to 7.00 g/bhp-hr. The other rebuild option (not modeled) in the

consent decree set this level at 7.50 g/bhp-hr. These were conservative values because the consent

decree set these standards as “not-to-exceed” levels.

Years of Use Before Rebuild - This is the number of years prior to the first rebuild. 

12 years for a medium duty

 5 years for a 8a truck
M6.HDE.003--Defeat Device Page 13

 3 years for a 8b truck

Also, no rebuild credit is given before calendar year 2000. Thus, a 1994 model year 8b engine will

not be lowered to the 7.00 g/bhp-hr standard upon its first rebuild in 1997.

The effects of rebuild are implemented in the model by replacing the With Defeat Device

Emission levels with the rebuild emission level of 7.00 g/bhp-hr on the fraction of the fleet that is

rebuilt. The default value for the fraction of the fleet that is rebuilt is 90% of the 1994 through 1998

model years.

1.11 MOBILE6 Model Results

This section presents the overall NOx excess emission results in tons per calendar year from

the MOBILE6 based Spreadsheet model. Figure 1 shows the excess NOx emissions for a range of

calendar years with and without the effects of rebuilding the 1994 through 1998 model year engines.

The effect of “Pull Ahead” is present in both the With and Without rebuild curves.

Figure 2 shows a comparison of the MOBILE6 Spreadsheet model excess NOx emission

results with the original EPA Office of Enforcement Model (OECA Model). The differences

between the two models in terms total excess NOx tons stems from a difference in approach and the

use of different basic parameters. This difference is sizable for some calendar years between 1995

and 2000.

The approach taken for the two models is somewhat different. The OECA model starts with

basic NOx emission and market share information on each engine family, and weights these together

by market share, defeat device penetration within a given engine family, vehicle scrappage rates, and

VMT information. These weighted NOx emission values for each engine family are then summed

together on a calendar year basis to produce the fleet NOx excess emission totals in tons. Because

of the proprietary nature of many of these inputs such as projected market share for individual engine

manufacturer and individual engine families, neither this model or its data parameters can be

released. The OECA model also reports only the increase in fleet NOx emissions due to the defeat

device by calendar year. No model year specific results are possible. It also does not include a

heavy-duty vehicle fleet estimate of NOx emissions if no defeat device were present (base level), nor

does it provide a combined base and defeat device fleet emission level in tons by calendar year.

The approach taken for the Spreadsheet models (MOBILE6 and MOBILE5) is different from

the OECA model. Instead of summing the individual engine family contributions to the total excess

NOx emission level, these individual engine family parameters (emission level, operation in defeat

device by roadway type, and penetration of defeat device) were combined into fleet average values

by model year and vehicle class using fleet average sales and projected sales information. The actual

and projected sales numbers were generally consistent between the OECA and M6/M5 Spreadsheet

models; however, discrepancies arose when aggregating specific engine information into fleet

average vehicle information segregated into the four heavy-duty diesel vehicle classes. Recent

model year sales and future projected sales were the most problematic. The Spreadsheet model also
M6.HDE.003--Defeat Device Page 14

Figure 1

Heavy-duty Diesel Vehicle Excess NOx by Calendar Year

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1985 1990 1995 2000 2005 2010 2015 2020

Calendar Year

HDDV Excess NOx (tons/year)

W/O Rebuild With Rebuild

contains Without defeat device (base) emission levels by model year. These are from the

MOBILE6/5 heavy-duty vehicle data parameters. For the MOBILE6 Spreadsheet model, the NOx

emission effect of the defeat device is essentially the difference between the With and Without

Defeat Device emission factors. The final With defeat device emission levels and the Without defeat

device emission levels are shown in worksheet BEFs of DDM6_Data.xls. The process used to

develop the “With Defeat Device” fleet average emission levels by model year is not shown due

restrictions on publishing proprietary data. 

The MOBILE6 Spreadsheet model and the OECA model also differ in the data parameters

that were used to build the models. The Spreadsheet model uses MOBILE6 emission and VMT

parameters, while the OECA model uses some MOBILE5 based parameters. These include different

conversion factors (CF), different VMT distribution by vehicle class, and different total VMT levels.
M6.HDE.003--Defeat Device Page 15

Figure 2

Heavy-duty Diesel Vehicle Excess NOx Projections

Comparison of MOBILE6 and OECA Model Approaches

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

2,000,000

1985 1990 1995 2000 2005 2010 2015 2020

Calendar Year

HDDV Excess NOx (tons/year)

M6 Model OECA

Projections Include Rebuild and 

Pull-Ahead Effects
M6.HDE.003--Defeat Device Page 16

2.0 Defeat Device Model Implementation in FORTRAN

This brief section and the following Appendix discuss the integration of the HDDV defeat

device NOx emission spreadsheet model into the MOBILE6 code. It is presented in this document

for readers who are interested in seeing the exact code. This may be important since the Spreadsheet

model will not produce results in the same units as the MOBILE6 defeat device implementation.

During this integration, every attempt was made to preserve as much continuity between the two

models as possible. However, this was not always possible since MOBILE6 reports emissions as

emission factors in units of grams per mile while the spreadsheet model produced an emission result

in terms of tons. Because of this basic difference, perfect agreement will never be attained between

the two models.

The primary difference between the two models is the use of VMT to weight different vehicle

classes, roadway types, and model years together. MOBILE6 generally will not use these

parameters since the output is in terms of grams per mile for specific vehicle classes, roadway types,

and model years. When the MOBILE6 model is called to produce average gram per mile emission

factors that include a number of model years, vehicle classes or roadway types, the same VMT

parameters will be used as presented earlier in this document in Section 1.0. The list of parameters

which overlap between the two models are the Conversion Factors and the speed correction factors.

The basic HDDV NOx excess emission factors which are used in MOBILE6 are the

difference between the With and Without defeat device emission levels. These delta emission values

(difference between With and Without Defeat Device) are analogous to the values calculated in

Equation 4, and are in units of g/mi. They can be found in the MOBILE6 BLOCK DATA in Module

DDNOBD in array NEFFCT. Also, found in Module DDNOBD are the defeat device operating

parameters and the fleet penetration rates. 

The basic defeat device data and other parameters are utilized in subroutine “Defeat” This

subroutine takes the basic emission and defeat device operating parameters and calculates a new

average fleet NOx emission level for MOBILE6 that includes the effect of the defeat device for the

various roadway types, affected model years, calendar years, and vehicle classes.
M6.HDE.003--Defeat Device Page 17

3.0 Use of the MOBILE6 and MOBILE5 Spreadsheet Models

The MOBILE6 and MOBILE5 Heavy-duty Diesel Vehicle NOx Defeat Device Spreadsheet

models (Spreadsheet Model) were used in four emission inventory and air quality applications to

model the NOx emissions associated with the heavy-duty defeat device. These applications are:

1. Regional Ozone Transport Rule (ROTR) 

2. Revised Regional Ozone Transport Rule (RROTR)

3. Tier2 Rulemaking (Tier2)

4. Southern Appalachian Ozone Modeling (SAOM)

In all four of these cases, the output of the Spreadsheet model that was used in subsequent

modeling were ratios of “With Defeat Device” NOx emissions and “Without Defeat Device” NOx

emissions for various calendar years, roadway types, and speeds. For all cases, separate ratios were

computed for each of the twelve roadway types, and for thirteen different speeds (in five mile per

hour increments) ranging from 5 MPH to 65 MPH. A set of these ratios was generated for a series

of calendar years that included CY1995 and CY1996 as a baseline, and CY2004, CY2007 and

CY2010. For both the MOBILE6 and MOBILE5 Spreadsheet models, the ratios can be found in the

sub-worksheet DD_Summary.

The four individual applications also differed in their requirements for the ratios. The ratios

that were computed for the ROTR were MOBILE5 With Defeat Device NOx (numerator) over

MOBILE5 Without Defeat Device NOx (denominator). These ratios include the effects of “Pull

Ahead,” but did not include “Engine Rebuild Effects” in the With Defeat Device NOx levels. The

ratios that were computed for the RROTR were MOBILE5 With Defeat Device NOx over MOBILE5

Without Defeat Device NOx , including the effects of “Pull Ahead,” and the “Engine Rebuild

Effects” in the numerator. The ratios that were computed for the Tier2 rulemaking were MOBILE6

With Defeat Device NOx over MOBILE5 Without Defeat Device NOx. These ratios include both

the effects of “Pull Ahead,” and the “Engine Rebuild Effects” in the numerator. Finally, the ratios

that were computed for the SAOM work were MOBILE6 With Defeat Device NOx over MOBILE5

Without Defeat Device NOx. However, these ratios did not include the effects of “Pull Ahead,” or

the “Engine Rebuild Effects.”

Figure 3 shows a set of With and Without Defeat Device Ratios for Calendar Year 2010. It

includes both Rebuild and Pull Ahead provisions. The ratios are the MOBILE6 With Defeat Device

Emission Factors over the MOBILE5 Without Defeat Device Emission Factors. In general, the ratios

are typically 1.0 or less. The small numbers reflect relatively little defeat device activity in CY2010,

and the relative difference between MOBILE6 parameters and MOBILE5 parameters such as CF,

TF, Basic Emission Rates, and VMT distributions. Ratios less than 1.0 can occur due to differences

between MOBILE6 and MOBILE5 and as the result of “Pull Ahead.” They occur when MOBILE6

parameters produce lower excess NOx emission levels than analogous MOBILE5 parameters. 
M6.HDE.003--Defeat Device Page 18

Figure 4 shows a similar set of With and Without Defeat Device Ratios for Calendar Year

2007. It also includes both Rebuild and Pull Ahead provisions. However, in Figure 4 both the

numerator and the denominator are both based on MOBILE6. These ratios clearly isolate the effect

of the defeat device, and suggest that it can be as high as 20 to 30 percent of the CY 2007 fleet for

some roadways. 
M6.HDE.003--Defeat Device 

2010 2010 2010 2010 2010 2010 2010 2010 2010 2010 

Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD 

Speed Speed Speed Speed Speed Speed Speed Speed Speed Speed 

Facility Description Roadway # 5 10 15 20 25 30 35 40 45 50 Interstate Rural Interstate 1 0.8803 0.9253 0.9685 1.0062 1.0350 1.0521 1.0557 1.0455 1.0225 0.9890 Interstate Rural Other Prin Arterial 2 0.8803 0.9253 0.9685 1.0062 1.0350 1.0522 1.0558 1.0456 1.0225 0.9891 Interstate Urban Interstate 3 0.8805 0.9257 0.9691 1.0070 1.0360 1.0532 1.0568 1.0466 1.0234 0.9898 Interstate Urban Other Freeways 4 0.8804 0.9255 0.9687 1.0065 1.0353 1.0525 1.0561 1.0459 1.0228 0.9893 Arterial Rural Minor Arterial 5 0.8591 0.8724 0.8851 0.8963 0.9048 0.9099 0.9110 0.9079 0.9011 0.8912 Arterial Rural Major Collector 6 0.8592 0.8725 0.8853 0.8964 0.9050 0.9100 0.9111 0.9081 0.9013 0.8914 Arterial Rural Minor Collector 7 0.8599 0.8730 0.8856 0.8967 0.9051 0.9101 0.9111 0.9082 0.9014 0.8916 Arterial Rural Local 8 0.8585 0.8718 0.8846 0.8958 0.9043 0.9094 0.9105 0.9074 0.9006 0.8907 Urban Urban Other Prin Arterial 9 0.8319 0.8325 0.8332 0.8338 0.8342 0.8344 0.8345 0.8343 0.8340 0.8335 Urban Urban Minor Arterial 10 0.8325 0.8332 0.8338 0.8344 0.8348 0.8351 0.8351 0.8350 0.8346 0.8341 Urban Urban Collector 11 0.8297 0.8304 0.8311 0.8316 0.8321 0.8323 0.8324 0.8322 0.8319 0.8314 Urban Urban Local 12 0.8321 0.8328 0.8335 0.8340 0.8345 0.8347 0.8348 0.8346 0.8343 0.8338 

2007 2007 2007 2007 2007 2007 2007 2007 2007 2007 

Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD Fleet w DD 

Speed Speed Speed Speed Speed Speed Speed Speed Speed Speed 

Facility Description Roadway # 5 10 15 20 25 30 35 40 45 50 Interstate Rural Interstate 1 0.8623 0.9233 0.9818 1.0329 1.0720 1.0952 1.1001 1.0863 1.0550 1.0097 

Interstate Rural Other Prin Arterial 2 0.8623 0.9233 0.9818 1.0330 1.0721 1.0953 1.1002 1.0863 1.0551 1.0097 Interstate Urban Interstate 3 0.8626 0.9239 0.9827 1.0341 1.0733 1.0967 1.1016 1.0877 1.0563 1.0107 Interstate Urban Other Freeways 4 0.8624 0.9235 0.9821 1.0333 1.0724 1.0957 1.1006 1.0867 1.0555 1.0100 Arterial Rural Minor Arterial 5 0.8398 0.8583 0.8760 0.8915 0.9034 0.9104 0.9119 0.9077 0.8982 0.8845 Arterial Rural Major Collector 6 0.8399 0.8584 0.8761 0.8916 0.9035 0.9105 0.9120 0.9078 0.8983 0.8846 Arterial Rural Minor Collector 7 0.8406 0.8589 0.8764 0.8917 0.9034 0.9104 0.9118 0.9077 0.8983 0.8847 Arterial Rural Local 8 0.8394 0.8579 0.8757 0.8912 0.9031 0.9102 0.9117 0.9074 0.8980 0.8842 Urban Urban Other Prin Arterial 9 0.8189 0.8199 0.8208 0.8216 0.8222 0.8226 0.8227 0.8225 0.8220 0.8212 Urban Urban Minor Arterial 10 0.8194 0.8204 0.8213 0.8221 0.8227 0.8231 0.8232 0.8230 0.8225 0.8218 

Urban Urban Collector 11 0.8170 0.8179 0.8189 0.8197 0.8203 0.8207 0.8208 0.8205 0.8200 0.8193 Urban Urban Local 12 0.8190 0.8199 0.8209 0.8217 0.8223 0.8227 0.8228 0.8225 0.8220 0.8213 

TABLE 3TABLE 4
M6.HDE.003--Defeat Device Page 20

Appendix

FORTRAN Code Used to Implement the Defeat Device Emission Effects in MOBILE6

 SUBROUTINE DEFEAT(MY,ICY,IV,IROAD,IPULL,IBUILD,VVHDDV,RBLEV,DDNOX)

C

C

C..Rebuild modeling options using variable IBUILD.

C IBUILD = 0 - Default option - Rebuild effects are included at a

C 90% penetration for MY 1993-98

C IBUILD = 1 - No Rebuild effects are included.

C IBUILD = 2 - Rebuild effects are included for MY 1993-98 at a

C user specified level (RBLEV).

C

C IPULL = 0 - Default option - Pull ahead effects are included for

C MY 2002 and 2003. Negative emission increases.

C IPULL = 1 - Pull ahead effects are not included for MY 2002 and

C 2003. Defeat Device Effects are 0.0.

C

 USE DDDATA

C

 IMPLICIT NONE

C

 INTEGER, INTENT(IN) :: MY

 INTEGER, INTENT(IN) :: ICY

 INTEGER, INTENT(IN) :: IV

 INTEGER, INTENT(IN) :: IROAD

 INTEGER, INTENT(IN) :: IPULL

 INTEGER, INTENT(IN) :: IBUILD

 INTEGER, INTENT(IN) :: VVHDDV

 INTEGER :: IMY, IVV ! Local variables

C

 REAL, INTENT(IN) :: RBLEV

 REAL, INTENT(OUT) :: DDNOX

C

 REAL :: DDNOXX ! Local variables

C

C

 IF(MY.LT.1988.OR.MY.GT.2003.OR.ICY.LT.1988.OR.

 * IROAD.EQ.4.OR.VVHDDV.EQ.0) THEN

 DDNOX = 0.0 ! Out of Range: No defeat device

effects

 RETURN

 ELSEIF((MY.EQ.2002.OR.MY.EQ.2003).AND.IPULL.EQ.1) THEN

 DDNOX = 0.0 ! Out of Range if no pull ahead

effects

 RETURN

 ENDIF

C

 IF(MY.GE.2004) THEN

 IMY = 1

 ELSEIF(MY.LE.1987) THEN

 IMY = 18

 ELSE

 IMY = 2004 - MY + 1

 ENDIF

C

C

 IF(IV.GE.16.OR.IV.LE.19) THEN
M6.HDE.003--Defeat Device Page 21

 IVV = 1

 ELSEIF(IV.EQ.26.OR.IV.EQ.27) THEN

 IVV = 1

 ELSEIF(IV.EQ.20.OR.IV.EQ.21) THEN

 IVV = 2

 ELSEIF(IV.EQ.22) THEN

 IVV = 3

 ELSEIF(IV.EQ.23) THEN

 IVV = 4

 ENDIF

C

 IF(IBUILD.EQ.2 .AND. (RBLEV.GT.0.AND.RBLEV.LE.0.90) ) THEN

 DDNOXX = RBLEV*((RBLD(IMY,IVV)-0.10*NEFFCT(IMY,IVV))/0.90)

 * + (1-RBLEV)*NEFFCT(IMY,IVV)

 ELSEIF(IBUILD.EQ.2 .AND. RBLEV.GT.0.90) THEN

 DDNOXX = RBLD(IMY,IVV)

 ELSEIF(IBUILD.EQ.1 .OR. (RBLEV.LE.0.AND.IBUILD.EQ.2) ) THEN

 DDNOXX = NEFFCT(IMY,IVV)

 ELSE

 DDNOXX = RBLD(IMY,IVV)

 ENDIF

C

 IF(IROAD.EQ.1) THEN

 DDNOX = DDNOXX * FLEET(IMY,IVV) * URBAN(IMY,IVV)

 ELSEIF(IROAD.EQ.2) THEN

 DDNOX = DDNOXX * FLEET(IMY,IVV) * ARTERL(IMY,IVV)

 ELSEIF(IROAD.EQ.3) THEN

 DDNOX = DDNOXX * FLEET(IMY,IVV) * EXPRES(IMY,IVV)

 ENDIF

C

 RETURN

 END
M6.HDE.003--Defeat Device Page 22

 MODULE DDDATA

C

 IMPLICIT NONE

 SAVE

C

 INTEGER, PARAMETER :: NCY = 18

 INTEGER, PARAMETER :: NVCLS = 4

C

 REAL, DIMENSION(NCY,NVCLS) :: NEFFCT

 REAL, DIMENSION(NCY,NVCLS) :: URBAN

 REAL, DIMENSION(NCY,NVCLS) :: ARTERL

 REAL, DIMENSION(NCY,NVCLS) :: EXPRES

 REAL, DIMENSION(NCY,NVCLS) :: FLEET

 REAL, DIMENSION(NCY,NVCLS) :: RBLD

C

 INTEGER, DIMENSION(NVCLS) :: IRBLD

C

C Dimension 18 reflects the MY's and 4 reflects the vehicle classes.

C In RBLD - 7 reflects the MY's and 4 reflects the vehicle classes.

C

C Values for NEFFCT are the increase in NOx emission levels

C as the result of the heavy-duty NOx defeat device.

C

C Light duty includes all diesel except classes 6,7,8a and 8b.

C

C..First entry is for model year 2004. Last entry is

C model year 1987 and earlier. Negatives reflect Pull ahead effects.

C Value of Zero is assigned if no Pull Ahead or effect. There are no

C effects for model years 2004+ or 1987 and earlier.

C

C..URBAN is the fraction of the time that the defeat device operates

C when an equipped vehicle is operating in Urban type driving.

C

C..ARTERL is the fraction of the time that the defeat device operates

C when an equipped vehicle is operating in Arterial type driving.

C

C..EXPRES is the fraction of the time that the defeat device operates

C when an equipped vehicle is operating in Expressway type driving.

C

C..FLEET is the fraction of the fleet that is equipped with a defeat

C device.

C

C..First year is 1999+ and last is 1993 and earlier.

C Rebuilds only in 1994 through 1998 MYs for Plan A.

C..7.00 g/bhp-hr is the rebuild emission target.

C Rebuild effect is the difference between the value and 7.00.

C

C..IRBLD is the age of a vehicle when the first rebuild is done.

C parameters are available for the four vehicle classes.

C These parameters are currently implicit in the results; thus,

C the array IRBLD is not currently used in Defeat.

C

 DATA IRBLD / 99, 12, 5, 3 /

C

C

 DATA NEFFCT/

C LIGHT DIESELS & BUSES

 *0.0000, -1.6300, -0.4075, 15*0.0000,

C MEDIUM DIESELS (CLS 6 & 7)

 * 0.0000, -1.8500,-0.4625, 0.0000, 0.2420,

 * 0.3295, 3.3623, 2.7163, 2.7408,
M6.HDE.003--Defeat Device Page 23

 * 2.9136, 2.4900, 2.5700, 0.0680,

 * 0.0680, 0.7890, 1.5000, 1.5000, 0.0000,

C 8A HEAVY-DUTIES

 * 0.0000,-1.8400, -0.4600, 0.0000, 1.1031,

 * 1.4863, 8.2377, 7.1143, 6.9407,

 * 7.1260, 6.9118, 7.4985, 7.9025,

 * 8.8713, 8.3125, 8.9200, 8.9200, 0.0000,

C 8B HEAVY-DUTIES

 * 0.0000, -1.8400,-0.4600, 0.0000, 1.4488,

 * 1.9520, 8.2617, 7.2067, 6.9501,

 * 7.1022, 6.8980, 7.3978, 7.7489,

 * 8.8179, 7.8961, 8.9200, 8.9200, 0.0000/

C

 DATA RBLD/

C LIGHT DIESELS & BUSES

 *0.0000, -1.6300, -0.4075, 15*0.0000,

C MEDIUM DIESELS (CLS 6 & 7)

 * 0.0000, -1.8500,-0.4625, 0.0000, 0.2420,

 * 0.3295, 3.3152, 2.4226, 2.4251,

 * 2.4424, 2.4000, 2.5700, 0.0680,

 * 0.0680, 0.7890, 1.5000, 1.5000, 0.0000,

C 8A HEAVY-DUTIES

 * 0.0000,-1.8400, -0.4600, 0.0000, 1.1031,

 * 1.4863, 3.8118, 2.8624, 2.8451,

 * 2.8636, 2.8422, 7.4985, 7.9025,

 * 8.8713, 8.3125, 8.9200, 8.9200, 0.0000,

C 8B HEAVY-DUTIES

 * 0.0000, -1.8400,-0.4600, 0.0000, 1.4488,

 * 1.9520, 3.8142, 2.8717, 2.8460,

 * 2.8612, 2.8408, 7.3978, 7.7489,

 * 8.8179, 7.8961, 8.9200, 8.9200, 0.0000/

C

 DATA URBAN/

C LIGHT DIESELS & BUSES

 * 0.0000, 1.0000, 1.0000, 15*0.0000,

C MEDIUM DIESELS (CLS 6 & 7)

 * 0.0000, 1.0000, 1.0000, 0.0009, 0.0009,

 * 0.0009, 0.0009, 0.0042, 0.0049,

 * 0.0692, 0.1200, 0.1200, 0.0000,

 * 0.0000, 0.0000, 0.0000, 0.0000, 0.0000,

C 8A HEAVY-DUTIES

 * 0.0000, 1.0000, 1.0000, 0.0210, 0.0210,

 * 0.0210, 0.0210, 0.0083, 0.0107,

 * 0.0468, 0.0341, 0.0271, 0.0188,

 * 0.0295, 0.0612, 0.0000, 0.0000, 0.0000,

C 8B HEAVY-DUTIES

 * 0.0000, 1.0000, 1.0000, 0.0267, 0.0267,

 * 0.0267, 0.0267, 0.0116, 0.0115,

 * 0.0487, 0.0362, 0.0299, 0.0216,

 * 0.0363, 0.0753, 0.0000, 0.0000, 0.0000/

C

C

 DATA ARTERL/

C LIGHT DIESELS & BUSES

 * 0.0000, 1.0000, 1.0000, 15*0.0000,

C MEDIUM DIESELS (CLS 6 & 7)

 * 0.0000, 1.0000, 1.0000, 0.2000, 0.2000,

 * 0.2000, 0.2000, 0.0385, 0.0247,

 * 0.3516, 0.6100, 0.6100, 0.0000,

 * 0.0000, 0.0000, 0.0000, 0.0000, 0.0000,

C 8A HEAVY-DUTIES
M6.HDE.003--Defeat Device Page 24

 * 0.0000, 1.0000, 1.0000, 0.3651, 0.3651,

 * 0.3651, 0.3651, 0.3592, 0.3399,

 * 0.4022, 0.3704, 0.4080, 0.4392,

 * 0.5095, 0.5093, 0.6600, 0.6600, 0.0000,

C 8B HEAVY-DUTIES

 * 0.0000, 1.0000, 1.0000, 0.3949, 0.3949,

 * 0.3949, 0.3949, 0.3881, 0.3511,

 * 0.4130, 0.3825, 0.4103, 0.4384,

 * 0.5188, 0.4810, 0.6600, 0.6600, 0.0000/

 DATA EXPRES/

C LIGHT DIESELS & BUSES

 * 0.0000, 1.0000, 1.0000, 15*0.0000,

C MEDIUM DIESELS (CLS 6 & 7)

 * 0.0000, 1.0000, 1.0000, 0.8220, 0.8220,

 * 0.8220, 0.8220, 0.5026, 0.5396,

 * 0.9249, 0.9800, 0.9800, 0.0000,

 * 0.0000, 0.0000, 0.0000, 0.0000, 0.0000,

C 8A HEAVY-DUTIES

 * 0.0000, 1.0000, 1.0000, 0.9225, 0.9225,

 * 0.9225, 0.9225, 0.9154, 0.9153,

 * 0.9439, 0.9357, 0.9510, 0.9568,

 * 0.9023, 0.8925, 0.9800, 0.9800, 0.0000,

C 8B HEAVY-DUTIES

 * 0.0000, 1.0000, 1.0000, 0.9377, 0.9377,

 * 0.9377, 0.9377, 0.9373, 0.9285,

 * 0.9533, 0.9478, 0.9625, 0.9697,

 * 0.9064, 0.8756, 0.9800, 0.9800, 0.0000/

 DATA FLEET/

C LIGHT DIESELS & BUSES

 * 0.0000, 1.0000, 1.0000, 15*0.0000,

C MEDIUM DIESELS (CLS 6 & 7)

 * 0.0000, 1.0000, 1.0000, 0.0000, 1.0000,

 * 1.0000, 1.0000, 0.4950, 0.2470,

 * 0.0592, 0.0120, 0.0060, 0.0000,

 * 0.0000, 0.0000, 0.0000, 0.0000, 0.0000,

C 8A HEAVY-DUTIES

 * 0.0000, 1.0000, 1.0000, 0.0000, 0.9225,

 * 0.9225, 0.9225, 0.9154, 0.9153,

 * 0.9439, 0.9357, 0.9510, 0.9568,

 * 0.9023, 0.8925, 0.9800, 0.9800, 0.0000,

C 8B HEAVY-DUTIES

 * 0.0000, 1.0000, 1.0000, 0.0000, 1.0000,

 * 1.0000, 1.0000, 1.0000, 1.0000,

 * 1.0000, 1.0000, 1.0000, 0.9940,

 * 0.4680, 0.3400, 0.1510, 0.0880, 0.0000/

C

 END MODULE DDDATA