United States 

Environmental Protection 

Agency 

Air and Radiation EPA420-P-98-007 

May 1998 

Program User Guide for 

Interim Vehicle Clean Screening 

Credit Utility 

DRAFT REPORT 
May 7, 1998 

Transmittal of the Draft "Description and Documentation for Interim Vehicle Clean 

Screening Credit Utility" 

EPA is today releasing draft guidance on the interim use of clean screening methodologies in 

state Inspection and Maintenance (l/M) programs. The purpose of the guidance is to share 

technical information with states and other interested parties, and to advise them of certain types 

of l/M changes EPA is inclined to approve, should states choose to incorporate them into existing 

or planned l/M programs. The draft guidance is in the form of two documents and a computer 

program. One document addresses concepts and documents the derivation of the credit loss 

estimates. The other document provides detailed steps for use of the FORTRAN utility program 

which is executed before executing MOBILE5b. 

The clean screening concepts described in the draft guidance are potentially of considerable 

importance to those involved in l/M planning and implementation. In general, clean screening is 

aimed at making l/M programs more cost effective by focusing inspections on cars more likely 

than others to be high emitters in need of repair. Clean screening can be used to reduce the 

number of cars required to be inspected each year--with less than a proportional loss of emission 

reduction benefit--which can lead to a more cost-effective l/M program. 

Please note that all credit estimates in this draft guidance are not final, and may change as a result 

of new data or insights brought to EPA's attention during this review and comment process. 

Credit loss estimates for vehicle emitter profiling will change, as EPA continues to make 

refinements to this part its analysis. Even once finalized, EPA may from time to time revise the 

guidance to reflect the best available data and understanding of clean screening options. 

The draft guidance outlines three broad concepts which could be used to excuse likely low 

emitters from traditional l/M testing: remote sensing, vehicle emitter profiling, and model year 

exemptions. The guidance provides brief background and summary information on each of the 

three concepts, comments on the practical application of clean screening in an operating or 

planned l/M program, analyses of the probable credit ramifications associated with each 

approach based on data sets currently available to EPA, instructions on how to calculate rough 

estimates of the credit loss each methodology would likely cause in a specific l/M program, and a 

list of references EPA used to prepare the draft guidance. 

In preparing this draft guidance, EPA considered a variety of sources and data sets currently 

available, which are listed in the "References" section of the guidance. The majority of 

information available comes from analytical studies, pilot programs, and modeling exercises 

aimed at predicting the immediate credit effect states could expect to experience when choosing 

to implement clean screening in an l/M program. While two of the concepts outlined in the 

guidance (RSD and model year exemption) are not new, they have not yet been used as a clean 

screen in any l/M program. Consequently, there is no large body of real-world application data. 

Likewise, utilizing vehicle emitter profiling to identify clean vehicles is fairly new concept as a 
clean screening option, rather than a tried and true approach. In addition, EPA has had to develop 

a modeling approach for using information on immediate credit effects to predict credit effects in 

future years when the mix and condition of cars on the road will be different. For these reasons, 

EPA is particularly interested in receiving comments on the following: 

• additional data sets and analysis not referenced in the draft documents 

the analytical approaches used in determining the modeling protocol for both RSD and 

vehicle emitter profiling, and any alternatives which may be useful 

options on how to keep an a vehicle emitter profile up to date for a given area without 

compromising the technical foundation of the profile 

how EPA and states should approach the ongoing evaluation of clean screening programs in 

operation 

EPA is soliciting comment on the draft guidance for 60 days, until July 11, 1998. Comments can 

be submitted electronically, by mail, or by FAX, at the following locations: 

Electronically, to Joe Somers at: somers.joseph@epa.gov 

By mail: Joe Somers 

U.S. EPA 

Assessment and Modeling Division 

2000 Traverwood Drive 

Ann Arbor, MI 48105 

Phone: 734/214-4321 

By FAX: 734/214-4821 

Additionally, EPA will make every effort to include a discussion of the clean screen guidance at 

any EPA/stakeholder meetings which occur during the comment period. Once EPA has reviewed 

the comments and incorporated them appropriately, we will finalize the guidance for release and 

immediate use. We expect this to take place in the fall of 1998. 
Table of Contents 

1.0 BACKGROUND AND SUMMARY ........... .. .... . .. .. .. . .... . .. . ..... ... .. 1 

2.0 DESCRIPTION OF CLEAN SCREENING .. . ...... . .. . .. . .. .... .. . .... . .. . ..... 1 

3.0 CLEAN SCREENING EFFECTS . . ..... . ... .. . . . .. . ..... ... .... .... . . . ..... . .. 1 

3 .1 Basic Clean-Screening Effect Methodology .... . .. . .... . . .. . .. .. . . . . ... . . ..... 2 

3.2 Options for Fleet Coverage for RSD ........................................ 3 

3 .2.1 Option 1: Commitment to a Level of Effort .. . ......... . .... . .... . .... 4 

3.2.2 Option 2: Commitment to a Specific Fleet Coverage ..................... 5 

3.3 Clean-Screening Effectiveness ............................................. 7 

4.0 CLEAN-SCREENING UTILITY ......... . .. . ..... . ..... . ...... . .... . ... . . .. . . 8 

4.1 Clean-Screening Utility Input Structure . .. . ......... . .. . ..... . ............... 8 

4.1.1 Control Section of Input File ....................................... 9 

4.1.2 Filenames Section .............. . ............ . ................... 10 

4.1.3 RSD Fleet Coverage Option 1: Data Section .......................... 11 

4.1.4 RSD Fleet Coverage Option 2: Data Section .... .. .. ..... . . . . .. . . . .. . . 13 

4.1.5 Program 5: Clean Screening Data Section ............................ 14 

4.1.6 User Supplied RSD Based Clean Screening Effectiveness ............... 16 

4.1.7 User Supplied RSD-Based Clean-Screening Vehicle Fractions ............ 18 

4.1.8 User Supplied Vehicle Emission Profiling Effectiveness ................. 19 

4.1.9 User Supplied Vehicle Emission Profiling Fractions .... . ..... . ......... 21 

4.2 Using Clean-Screening I/M Credits with MOBILES ........................... 23 

APPENDIX A 

List of Records for RSD Utility . .. . .. . ......... . ..... . ... . .. . .. ......... . ..... . . . 26 

APPENDIXB 

Example Clean-screening Input Files . . .............. . ...... . ........ . ...... . . . ... 29 

Example #1: RSD Based Clean-screening with Commitment to Level of Effort 

...... . ... ......................................... . .. . . .......... 30 

Example #2: RSD Based Clean-screening with Commitment to Specific Fleet Coverage 

.................................................................. 32 

Example #3: YEP Based Clean-screening 

........ ... .... ..... . ...................... . ..... .... . . . . .. ....... 35 

Example #4: RSD Based Clean-screening with Commitment to Level of Effort 

and With Alternate Effectiveness and Excused Fractions . .. ............... . . . 38 
1.0 BACKGROUND AND SUMMARY 

"Clean screening" is a generic term for methods used to identify vehicles which are low 

emitting for purposes of exempting these "clean" vehicles from the next scheduled test in the 

periodic vehicle inspection and maintenance (l/M) program required by some state and local 

areas. In September 1996, EPA released a document entitled "User Guide and Description for 

Interim Remote Sensing Program Credit Utility" (EPA 420-R-96-004) providing details on a 

program for States to obtain extra I/M emission credits for using remote-sensing devices (RSD) 

to find high-emitting vehicles and requiring them to obtain early (out of sequence) l/M tests. 

That guidance remains unchanged. The original release of the RSD credit utility did not include 

options for using RSD for clean screening. This program option has now been added to the 

utility along with other clean screening methods, including vehicle emission profiling (VEP). 

This user guide is intended as a companion document to the original user guide. Users should 

refer to that document for information about RSD options to identify high-emitting vehicles. 

2.0 DESCRIPTION OF CLEAN SCREENING 

The original objective of RSD was to identify high emitters in the vehicle fleet. However, 

the measurement of the emissions of vehicles can also be used to identify "clean" vehicles with a 

high probability of passing its periodic inspection test. It is expected that by exempting these 

vehicles from the next periodic inspection, I/M programs can reduce the burden on the inspection 

system, reduce vehicle owner costs, and increase convenience and program acceptance. A more 

detailed description of how remote-sensing is done is contained in the original 1996 user guide. 

Other methods can be used to identify clean vehicles for exemption from the l/M program. 

One method, VEP is included in this utility. This method uses known factors about vehicle 

emissions based on large l/M databases with historic records of failures for different vehicle 

models to choose low-emitting vehicles for exemption without explicit emission measurements. 

Another option for clean screening is to exempt entire model years from inspection. Model years 

can be exempted using parameters within the MOBILES model l/M Program Descriptive Record 

without the use of this utility. 

A separate document, "Description and Documentation for Interim Vehicle Clean Screening 

Credit Utility," (EPA 420-P-98-008) provides a more detailed description of the various 

approaches to clean-screening programs, the emission benefit impacts of clean-screening, and 

how the emission estimates were determined. This document is the basis for the default 

effectiveness values used in this utility. 

3.0 CLEAN SCREENING EFFECTS 

The EPA MOBILES model stores the credits for all l/M programs in separate data files that 

are read during MOBILE runs. EPA can modify or supplement these files to add new data 

and/or options that were not included in the original release of the model, without the need for a 
new version of the MOBILE model itself. The credits in the I/M credit files can thus be adjusted, 

as needed, to reflect the operation of clean-screening scenarios. 

Since clean-screening excuses vehicles from their next scheduled inspection, the primary 

effects clean-screening methods have on the benefits of any specific I/M program is to reduce the 

number of vehicles which receive repairs. The purpose of this utility, then, is to reduce the 

benefit attributed to VM programs in the VM credit file to reflect the effect of clean-screening 

vehicle exemptions. Because excusing vehicles from inspection reduces the number of vehicles 

checked for evaporative emission problems in those I/M programs including evaporative 

emission checks, the evaporative program benefits must also be reduced. 

3.1 Basic Clean-Screening Effect Methodology 

The clean-screening effects are a function of two basic parameters: 1) the fraction of all 

vehicles in each model year that is eligible to be excused from their next scheduled inspection, 

and 2) the effectiveness of the clean-screening method at identifying vehicles which are truly 

clean. The determination of the fraction of eligible vehicles and effectiveness is done for each 

model year (vehicle age) in the fleet. Only vehicles with sufficient information to allow for the 

clean-screening determination are eligible vehicles. 

Mathematically, the process to adjust the I/M credits is as follows: 

New Creditm,p =Old Creditm,p * Fm * Em,p 

Where: 

Old Credit = VM credit from the periodic inspection program; 

F 

E 

m 

p 

Adjusted fraction of the inspected fleet eligible for clean-screening 

(referenced below as fleet coverage); 

Effectiveness of clean-screening at identification of clean vehicles; 

Quantity is a function of vehicle model year; and 

Quantity is a function of pollutant (i.e., HC, CO or NOx). 

(1) 

In the equation, the influence of the underlying I/M program is represented by the variable 

Old Creditm,p which is chosen from the already-released I/M credits used with the MOBILES 

model. The variables Fm and Em,p in the equation represent the clean-screening fleet coverage and 

the remote-sensing effectiveness. The fleet coverage is determined as explained in the original 

user guide (and repeated below). Only coverage options 1 and 2 are allowed for clean-screening 

scenanos. 

2 
3.2 Options for Fleet Covera2e for RSD 

Fleet coverage is the fraction "F" in the equation given earlier. The clean-screening utility 

allows a state two options for fleet coverage for RSD-based scenarios. The first option is 

commitment to a level of effort in which a state commits to a specific number of vehicles that 

will have valid RSD tests (i.e., valid readings of HC/CO and NOx (if a NOx cutpoint is used) on 

a specific vehicle, valid recording of license plate, and ability to contact vehicle owners for any 

required VM test) in a given time period. The RSD clean-screening utility will internally convert 

the number of RSD tests to fleet coverage assuming the vehicles to be eligible for cleanscreening must receive two or more valid RSD tests. The second option is to commit to a 

specific RSD fleet coverage in which a certain percentage of the fleet will receive two or more 

valid RSD tests. These options are discussed in detail in Sections 3 .3 .1 and 3 .3 .2 in the original 

user guide for RSD. 

The third vehicle coverage option available in the original 1996 utility (committing to find a 

specific number ofl/M failures using RSD) cannot be applied to RSD clean-screening programs 

and is not discussed here. 

Vehicle Emission Profiling (YEP) programs assume complete (100%) vehicle coverage and 

are unaffected by the user choice of fleet coverage options. 

Option 1: Commitment to a Level ofE[fort 

The user specifies the number of valid remote-sensing measurements done. The utility 

estimates vehicle coverage from this information using coverage information derived from a 

Poisson distribution. The default effectiveness values for RSD-based clean-screening in this 

utility assume that each excused vehicle has had at least two valid RSD readings. The method 

used to make the estimate is described in a later section. 

Option 2: Commitment to a Specific Fleet Coverage 

The user specifies the fraction of the fleet in each model year that is seen using remotesensing. This fraction should be only the fraction of the fleet which has had sufficient valid 

remote-sensing measurements to allow an affirmative decision regarding exemption from the 

next VM inspection. For example, if a state decides (to minimize the chance that a dirty vehicle 

will be excused from its next scheduled inspection) that at least two valid passing RSD readings 

are needed to make a vehicle eligible for exemption from l/M, this fraction should represent the 

portion of the fleet that has received two RSD readings. 

3 
The default effectiveness values for RSD based clean-screening in this utility assume that 

each excused vehicle must have at least two valid RSD readings. If a state decides that some 

other minimum number of valid RSD readings (e.g., one or three) will be used in their RSD 

program, then the default values for the effects of RSD based clean-screening (based on two 

valid readings) cannot be used. Section 4.1 describes how the user may enter the alternate 

effectiveness values if some other minimum number of valid RSD readings are required. 

Since newer vehicles travel more and normally make up a larger fraction of all vehicles in 

an area than older vehicles, newer model years will tend to be more likely to be seen by a 

remote-sensing device than older vehicles. As a result, the fraction of all vehicles in a given 

model year which are eligible for exemption from its next I/M inspection will be larger for newer 

model years than for older model years. Therefore, a program whose intention it is to exempt a 

given fraction of the fleet will exempt mostly the newer model years. 

3.2.1 Option 1: Commitment to a Level of Effort 

This is the simplest of the three options in which a state looks at its resources and commits 

to obtaining a specific number of RSD readings per month. In this option, a modified Poisson 

algorithm is used to estimate the number of vehicles seen by remote-sensing each year in order to 

calculate the fraction of the fleet tested by remote-sensing (factor F). This is necessary, since the 

fraction of all vehicles in the fleet which are measured by remote-sensing is a function of the 

total number of remote-sensing measurements, but is less than obtained by looking at the number 

of RSD readings since some vehicles are seen multiple times by RSD. A Poisson algorithm is a 

standard method to model such a situation. This phenomenon was demonstrated in the 

California Bureau of Automotive Repair Study done in Sacramento where some individual 

vehicles were measured several times over the course of the study. This fraction is a function of 

the annual average vehicle miles traveled (VMT) of a vehicle model year at a given age 

compared to its VMT when new. 

The algorithm used to calculate remote-sensing coverage involves a modification to Lambda 

in the Poisson series using the ratio of the VMT of the youngest model year (age) to the VMT of 

the model year (age) being estimated. This adjustment uses national average VMT information, 

but the VMT information can be modified by the user to reflect local, rather than national 

default, information. The form of the equation is as follows: 

P = 1.0 - exp( k * -Lambda) (2) 

Where k is the ratio of VMTs, 

k = VMT(current age)/VMT(age=l). (3) 

4 
This algorithm is calculated for each model year and gives the probability of measuring 

emissions from vehicles of a given model year. One sums the probabilities for each model year 

to obtain an overall probability for all vehicles. In addition, as mentioned later, this option 

permits the user to specify only vehicles with more than one RSD reading as having sufficient 

information to allow an affirmative decision. Such a specification will lower the overall fraction 

of the fleet seen. 

If an I/M program encourages drivers to visit announced RSD sites in hopes of earning an 

exemption from I/M inspection, or if this practice develops even without encouragement, the 

Poisson-based coverage estimates may not be applicable. Actual experience may be the only 

way to determine coverage accurately. The utility allows the actual observed coverage estimates 

to be inputted using Option 2 (below). 

3.2.2 Option 2: Commitment to a Specific Fleet Covera2e 

In this option, the user inputs related to remote-sensing effort are replaced by a commitment 

to obtain valid remote-sensing readings on a specific fraction of the fleet as determined by the 

state. This commitment is for sufficient RSD readings for each vehicle age category (i.e., by 

model year) separately to meet the commitment of vehicles for RSD targeting. This requires the 

user to supply the number of current vehicles of each age and the number of those vehicles which 

are committed to be seen by remote-sensing in the next year. 

The default effectiveness values for RSD-based clean-screening in this utility assume that 

each excused vehicle must have at least two (2) valid RSD readings. If a state decides that some 

other minimum number of valid RSD readings (e.g., 1or3) will be used in their RSD program, 

then the default values for the effects of RSD-based clean-screening (based on two valid 

readings) cannot be used. Section 4.1 describes how the user may enter the alternate 

effectiveness values if some other minimum number of valid RSD readings are required. 

There are no default values for this fleet coverage option. Some areas may not have 

information available regarding the distribution of number of vehicles by age that will likely be 

seen twice using RSD methods before the clean-screening program actually begins. One 

approach would be to use the level of effort (Option 1) method to define the vehicle coverage for 

clean-screening instead of Option 2, where the distribution information is required. Another 

approach would be to estimate the distribution for different coverage targets using the same 

Poisson methodology as described in Option 1. Table 1 shows the results of using the Poisson 

methodology as described in Option 1 to estimate the number of vehicles by age that will likely 

be seen twice by RSD. This estimate assumes MOBILES default values for mileage 

accumulation and the default passenger car age distribution. 

5 
Table 1 

Distribution of the Number of Vehicles by Age Seen Twice by 

Remote Sensing Versus a Target Fleet Coverage 

Target Fleet Coverage 

V e h. 1c 1 e A _ge 30o/c o o t e f h Fl eet 50o/c o o t e f h Fl eet 70o/c o o t e f h Fl eet 

1 47% 71% 89% 

2 40% 64% 84% 

3 41% 65% 85% 

4 39% 62% 82% 

5 36% 59% 80% 

6 34% 56% 77% 

7 31% 53% 75% 

8 29% 50% 72% 

9 27% 47% 69% 

10 25% 44% 66% 

11 23% 42% 63% 

12 21% 39% 60% 

13 20% 36% 57% 

14 18% 34% 54% 

15 17% 32% 51% 

16 15% 29% 48% 

17 14% 27% 45% 

18 13% 25% 43% 

19 12% 23% 40% 

20 11% 21% 37% 

21 10% 20% 35% 

22 9% 18% 32% 

23 8% 17% 30% 

24 7% 15% 28% 

25 7% 15% 28% 

For example, about 30% had two or more RSD readings in the California Bureau of 

Automotive Repair Study in Sacramento. If this was the target coverage for the proposed RSDbased clean-screening program, the distribution in the above table for the 30% fleet coverage 

could be used as an estimate of the distribution of vehicles seen twice for purposes of calculating 

the effects of RSD based clean-screening. 

3.3 Clean-Screenin2 Effectiveness 

6 
Clean-screening effectiveness (factor E) refers to the ability of the clean-screening tests to 

correctly identify vehicles which would pass an I/M inspection. If assuming that, using remotesensing was possible to identify only those vehicles in that fleet that would pass an VM 

inspection, then the effectiveness of remote-sensing for clean-screening would be 100 percent. 

In practice, not all vehicles identified by remote-sensing for exemption from inspection would 

pass the VM inspection. In general, there will be a non-linear relationship between the percent of 

vehicles excused from their next scheduled inspection and the emissions benefit loss, since the 

least dirty cars will be the first to pass. The shortfall in VM benefit caused by the exemption of 

failing vehicles depends primarily on the remote-sensing emission measurement cutpoints 

chosen by the program. In vehicle emission profiling (VEP) programs, a variety of factors are 

used to identify vehicles for exemption. As in RSD-based clean-screening, the effectiveness of 

these programs will depend on how well they can identify only those vehicles that will pass the 

VM inspection. The full derivation of the default values used for clean-screening effectiveness is 

discussed in a separate document entitled, "Description and Documentation for Interim Vehicle 

Clean Screening Credit Utility," (EPA 420-P-98-008). 

Some programs include a functional check of the evaporative pressure and/or purge system. 

It is assumed that each vehicle excused from its next scheduled inspection in the periodic 

inspection program based on the clean-screening program has an equal probability of having 

excess evaporative emissions as those vehicles which are inspected. (This is in contrast to the 

non-linear relationship for tailpipe emissions.) This means that the reduction in pressure/purge 

effectiveness is directly proportional to the fraction of all vehicles (by age) which are excused 

from their next scheduled inspection by the clean-screening program. However, since most 

vehicles eligible for clean-screening will be newer model years (with fewer evaporative failures), 

the loss in program benefit will be considerably less than the fraction of vehicles excused from 

their next scheduled inspection. 

The default effectiveness values for RSD-based clean-screening in this utility assume that 

each excused vehicle must have at least two (2) valid RSD readings. If a state decides that some 

other minimum number of valid RSD readings (e.g., 1or3) will be used in their RSD program, 

then the default values for the effects of RSD-based clean-screening (based on two valid 

readings) cannot be used. Section 4.1 describes how the user may enter the alternate 

effectiveness values if some other minimum number of valid RSD readings are required. 

The default effectiveness values used by the RSD-based clean-screening utility will assume 

that the effectiveness of the underlying VM program inspections is closer to the effectiveness of 

the IM240 test procedure using the recommended phase-in cutpoints. This is the information 

currently available and described in the document cited above. The utility also contains 

effectiveness values for RSD-based clean-screening which assume that the effectiveness of the 

underlying I/M program inspections is closer to the effectiveness of the IM240 test procedure 

using the recommended final cutpoints. However, the user must specify that the alternate 

effectiveness numbers are to be used by the utility, as described in later sections. The more 

effective the underlying I/M program is, the more likely it is that clean-screening will excuse 

some potentially failing vehicles from their next scheduled inspection, increasing the loss of 

7 
benefit to the I/M program. 

4.0 CLEAN-SCREENING UTILITY 

4.1 Clean-Screenin~ Utility Input Structure 

The updated remote-sensing utility is identical in input structure to the original utility for the 

existing RSD options and programs. Much of the description of sections from the original user 

guide which may be useful for clean-screening options is repeated in this user guide for 

convemence. 

The remote-sensing utility is designed to be used once for a scenario selected by the user. 

The scenario is for one evaluation calendar year, and each model year is indexed by its age in 

that calendar year, not by the model year itself. It is assumed that the number of scenarios that a 

user might consider is small enough so that batch run options are not necessary. Each run 

requires a single input file which contains all of the information required by the utility and 

supplied by the user. The user is prompted for the name (including the path, if not in the local 

directory) of the input file. 

If the user selects the Vehicle Emission Profiling (YEP) based clean-screening option, the 

user must enter both the effectiveness and fraction of vehicles excused from their next scheduled 

inspection. There are no default values stored in this utility for those choices and without the 

user supplied data, the resulting I/M credits will not reflect the effect of the YEP program. 

Guidance on how to determine the effectiveness and fraction of vehicles excused from their next 

scheduled inspection for YEP programs can be found in a separate document entitled, 

"Description and Documentation for Interim Vehicle Clean Screening Credit Utility," (EPA 420-

P-98-008). 

The remote-sensing utility is run by simply invoking its name (RSDNEW.EXE) at the DOS 

prompt. The utility will prompt the user on the screen for the name of the input file. 

Enter the name of the remote-sensing input file: (default RSD.D) 

All inputs have default values. Here, if the user does not enter a name, the utility will look 

for a file labeled "RSD.D" in the local directory. Enter the name of the file containing the 

control information that has been constructed for the desired scenario. This is the only 

interactive user input necessary to run the utility. 

The following sections describe how to construct the input file. The input file contains all of 

the remaining information needed to calculate the remote-sensing effects, including the location 

of the original I/M credit data files and the names and location of the output remote-sensing 

credit files. 

The input file is structured so that each line (record) begins with an identification number. 

8 
This number indicates what information is contained on that record and allows the records to be 

entered in any order. Although some records are mandatory, any records missing from the input 

file revert to default values stored in the utility. In this way, only the information that the user 

wishes to supply is included in the input file. Any records with a record number of 000 are 

considered comment records and are not processed. In addition, text may be added to records 

beyond the last formatted data entry on any card to clarify the contents of that record. This 

additional text is not read or processed by the utility. 

A summary of all of the input records and their contents is shown in Appendix A. Many of 

these records do not apply to clean-screening options and are not described in this user guide. A 

description of these records and their contents can be found in the original RSD user guide. 

4.1.1 Control Section of Input File 

Records 001 and 002 are mandatory records. 

Record 001 contains the user selection of the fleet coverage option. The format of this record 

is (13,l lX,Il), meaning the first three characters contain the record number, followed by 11 

blank characters, followed by the user selection of Option. Any characters following the user 

selection are ignored by the utility, but can be used to annotate the input file. The available 

option levels for RSD-based clean-screening are: 

1: Commitment to a Level of Effort; and 

2: Commitment to a Specific Fleet Coverage 

An additional option is available in.the RSD utility (Commitment to a Number of Failures), 

but this option is not available for use with clean-screening programs. A more complete 

description of the third user option is located in the original RSD user guide. Although fleet 

coverage is assumed to be 100% for vehicle emission profiling (YEP) options, Record 001 must 

be entered. Since Option 2 requires more user input, users who intend to select a YEP cleanscreening scenario should choose Option 1. 

Record 002 contains the user selection of I/M program design. The format of this 

record is identical to Record 001. For clean-screening, this record must be set to: 

5: Clean-Screening Remote-Sensing Program 

A more complete description of the other four user options is located in the original 1996 

RSD user guide. The user must always enter both Record 001 and 002 in order to use the 

remote- sensing utility. The following is an example input of the control section, including some 

added comments to add clarity. 

9 
000 Control Section 

000 ---------------

001 2 Option (may be 1, 2, or 3, but may not be 3 if Program Type is 5) 

002 5 Program Type (may be 1, 2, 3, 4, or 5) 

4.1.2 Filenames Section 

In this section, Records 005 through 008 indicate the name and location of the standard VM 

credit data files and Records 015 through 018 determine the location and name of the resulting 

remote-sensing adjusted VM credit data files. Normally, the resulting VM credit data will be 

written to the filenames in Records 015-018. The indicated VM credit input files are not altered 

by the utility. Instead, new replacement credit files are created with the appropriate adjustment 

of the I/M credits to reflect the effects of the user specified remote-sensing program. 

The format of each record is (13, 1X,A40), meaning the first three characters contain the 

record number, the next character is blank, followed by up to 40 characters which indicate the 

file name, including any necessary path information. If no path is specified, the data files must 

reside in the same (local) directory from which the utility is run. The record numbers for each 

file are as follows. 

Input Files 

Record Description 

005: 1981 and newer model year credits 

006: 1981 and newer model year Retest-Hybrid credits 

007: Pre-1981 model year credits 

008: Pre-1981 model year Retest-Hybrid credits 

009: Standard pressure/purge credits 

010: Retest-Hybrid pressure/purge credits 

Output Files 

Record Description 

011 : Adjusted standard pressure/purge credits 

012: Adjusted Retest-Hybrid pressure/purge credits 

015: Adjusted 1981 and newer model year credits 

016: Adjusted 1981 and newer model year Retest-Hybrid 

017: Adjusted Pre-1981 model year credits 

018: Adjusted Pre-1981 model year Retest-Hybrid credits 

Since there are default filenames for the standard VM credit files and the output files, the user 

may skip all of these input records and the default names are used. All of the files, however, 

10 
must be in the local directory. The following is an example input of the filename section, using 

files other than the default filenames, including some added comments to add clarity. 

000 User Input and Output Filenames 

000 ----------------------------------------

005 C:\DATA\IMl.D 

006 C:\DATA\IMH.D 

007 TCl.D 

008 TCH.D 

009 PP.D 

010 PPH.D 

011 PPRSD.D 

012 PPHRSD.D 

015RSDDATl1.D 

016 RSDDATA.H 

017 TECDATll.D 

018 TECDATA.H 

Default Filename 

IMDATA.D 

HYBRID.IMC 

TECH12.D 

TECH12.D 

PPEFFM5.D 

PPEFF.D 

PPM5RSD.D 

PPHYRSD.D 

RSDDATA.D 

RSDDATA.H 

TECDATA.D 

TECDATA.H 

For maximum flexibility, separate input has been allowed for Retest-Hybrid l/M credits for 

the pre-1981 model year vehicles, even though EPA has not calculated separate credits for that 

case. For this reason, the default input for that case is identical to the standard input file. 

4.1.3 RSD Fleet Covera2e Option 1: Data Section 

The first vehicle coverage input option requires that the user supply information on the level 

of effort which is applied to make a given number of valid vehicle measurements using remotesensing. This information includes: 

Record Description 

021: The number of vehicles in the fleet 

022: The number of valid measurements per month that are made using remote-sensing devices 

023: The number of times that a vehicle must be seen by RSD before it can be targeted for RSD 

based clean-screening. (This value must be "2" for RSD based clean-screening options.) 

In addition, the user may supply the average vehicle miles traveled per year by vehicle age to 

override the MOBILES default values normally used in the calculations. 

The number of vehicles in the fleet represents the population of vehicles which are subject to 

the inspection program in the area. This number excludes out-of-area vehicles and vehicles 

excused from the inspection. The number of vehicles in the fleet is entered on Record 021. The 

format for this record is (13,IX,111). 

The number of valid measurements per month that are made using remote-sensing devices is 

11 
the primary measure of the level of effort related to vehicle coverage. The number of valid 

measurements that can be made with remote-sensing devices depends on a great variety of 

factors including the number of practical remote-sensing locations, the number of devices 

provided, the amount of staff required and available to operate the remote-sensing devices, the 

density of vehicles subject to the inspection program at the remote-sensing sites, the number of 

hours and days that the remote-sensing devices are operated, the staff allocated to remote-sensing 

data processing and the quality of the remote-sensing readings. The number entered by the user 

represents the commitment by the program to expend sufficient effort to make that numper of 

valid measurements in each month. This number is entered on Record 022. The format for this 

record is (13 ,lX,111). 

The number of times that a state determines a vehicle must be seen using remote-sensing 

before it can be excused from I/M inspection is entered on Record 023. The default value for this 

record is two, and although the utility allows the user to specify up to 11 measurements; the 

present EPA effects of RSD-based clean-screening are based on two measurements and give no 

additional credit for multiple measurements beyond two. User entry of less than or greater than 

two measurements is ignored. The format for this record is (13,lX,111). 

The following is an example input of the Option 1 data section, using values other than the 

default values, including some added comments to add clarity. 

000 

000 

021 

022 

023 

Option 1 Data Section 

810498 

110808 

2 

No. of vehicles in inspection area default 1000000 

Valid veh. measurements per month default 50000 

No. times a veh. must be measured default 2 (1-11 ) 

In addition, the user may supply the average vehicle miles traveled per year by vehicle age to 

override the MOBILES default values normally used in the calculations. This requires the entry 

of 25 separate records (Records 101 through 125). Record 101 contains the mileage 

accumulation of vehicles from 0 to 1 year of age. Record 102 contains the mileage accumulation 

of vehicles from 1 to 2 years of age, and so forth. Since vehicles are more likely to be measured 

if they are driven more, a higher mileage accumulation in proportion to other vehicles increases 

the expected number of vehicles of that age that are measured. The default values assume that all 

vehicles travel the roadways which are monitored using remote-sensing. If remote-sensing is to 

be restricted to only some roadways (such as limited access freeways), the distribution of 

mileages should be adjusted to reflect the actual distribution of ages expected on those roadways. 

The format for these records is (13,lX,111). 

4.1.4 RSD Fleet Coverai:e Option 2: Data Section 

The second vehicle coverage input option requires that the user supply information on the 

fraction of the fleet in each model year which have sufficient valid vehicle measurements using 

remote-sensing to allow an affirmative decision on exemption. For example, if it takes, at 

minimum, two RSD tests excuse a vehicle from it's next I/M inspection, this is the fraction of the 

fleet which will be measured two or more times by RSD. This is a commitment on the part of the 

program to apply sufficient resources to find and measure a fraction of each model year using 

remote-sensing. The fraction of the fleet measured can vary from model year to model year, 

12 
reflecting the difficulty in finding and measuring older model years, which drive less and tend to 

avoid some roadway types, such as limited access freeways. 

A separate record must be entered for each of 25 vehicle ages (Records 201through225). 

There are no default values for these inputs. Each record contains the record number, the number 

of vehicles of that age which are eligible for targeting each year (i.e., the total number of 

vehicles subject to state regulation), and the total number of vehicles of that age in the vehicle 

fleet which have sufficient information to allow an affirmative decision on whether to excuse 

those vehicles from their next l/M inspection (i.e., the total number of vehicles in the eligible 

fleet on which a state commits to obtain valid remote-sensing readings). The entry of both the 

number of vehicles subject to the program and the number expected to be eligible for cleanscreening in each vehicle age (instead of a fractional estimate) provides an explicit goal of the 

number of vehicles which must obtain valid remote-sensing readings in each vehicle age (model 

year) in order to achieve the effect estimated by the utility. 

The format for the record is (13,lX,2111). This means that the first 3 characters contain the 

record number, the next character is a blank followed by an integer number in the next 11 spaces, 

indicating the total number of vehicles of that age subject to state regulation, followed by another 

integer number in the next 11 spaces, indicating the number of vehicles in that age which have 

sufficient valid vehicle measurements using remote-sensing to allow an affirmative decision on 

whether to excuse those vehicles from their next VM inspection. 

The following is an example input of the Option 2 data section. The example assumes a 

MOBILES default distribution of 1 million vehicles and assumes, using remote-sensing, that 

50% (500,000) of the vehicles will get two or more valid RSD tests. The distribution of the 

500,000 vehicles among the ages of vehicles is taken from the examples in Section 3.3.2 of this 

document. The records include some added comments after the numbers to add clarity. 

000 OQtion 2 Data Section 

000 Total Eligible 

000 -------------------- -- 201 49000 34761 Option 2 Age 0 - 1 

202 79000 50544 Option 2 Age 1 - 2 

203 83000 54025 Option 2 Age 2 - 3 

204 82000 50922 Option 2 Age 3 - 4 

205 84000 49644 Option 2 Age 4 - 5 

206 81000 45433 Option 2 Age 5 - 6 

207 77000 40895 Opt i on 2 Age 6 - 7 

208 56000 28084 Option 2 Age 7 - 8 

209 50000 24103 Option 2 Age 8 - 9 

210 51000 22659 Option 2 Age 9 - 10 

211 50000 20835 Option 2 Age 10 - 11 

212 54000 21060 Option 2 Age 11 - 12 

213 47000 17122 Option 2 Age 12 - 13 

214 37000 12565 Option 2 Age 13 - 14 

215 24000 7579 Option 2 Age 14 - 15 

216 19000 5573 Option 2 Age 15 - 16 

13 
217 14000 3807 Option 2 Age 16 - 17 

218 15000 3774 Option 2 Age 17 - 18 

219 11000 2556 Option 2 Age 18 - 19 

220 8000 1715 Option 2 Age 19 - 20 

221 6000 1185 Option 2 Age 20 - 21 

222 5000 908 Option 2 Age 21 - 22 

223 4000 667 Option 2 Age 22 - 23 

224 3000 459 Option 2 Age 23 - 24 

225 10000 1529 Option 2 Age 24 - 25 

4.1.5 Pro2ram 5: Clean Screenin2 Data Section 

There are six records that describe the extent and variety of the clean-screening program. 

The first five (Records 034 through 038) determine which l/M credits are adjusted to reflect the 

effects of clean-screening. Each record contains an integer value which indicates whether the 

vehicles represented in that record are subject to clean-screening. If not, no adjustment will be 

made to the I/M credits represented by the record. If the integer value is set to 11 l11 , the vehicles 

will not be included in the clean screening program and full I/M credits will be retained. If the 

integer value is set to 11 2, 

11 the vehicles are assumed to be eligible for clean-screening and the VM 

credits for that vehicle group will be adjusted to reflect the effects of clean-screening on the I/M 

benefits. The default value for each of these four records is 11 2," indicating that all vehicles are 

included in the clean-screening program. If the user wishes to exclude vehicle model year 

groupings from the clean-screening program, then the appropriate record for those model years 

must be entered. The five records cover the following vehicle model year groupings: 

034: Clean Screening for Pre-1975 model year vehicles (default value=2) 

035: Clean Screening for 1975-80 model year vehicles (default value=2) 

036: Clean Screening for 1981-85 model year vehicles (default value=2) 

037: Clean Screening for 1986-89 model year vehicles (default value=2) 

038: Clean Screening for 1990 and newer model year vehicles (default value=2) 

Record 039 indicates the choice of clean-screening options the user wishes to apply to the 

vehicles in the fleet. This record must be entered if the program choice is "5", indicating a cleanscreening option. Both remote-sensing device (RSD) and vehicle emission profiling (YEP) 

program options are available in the utility. These choices are selected by entry of an integer into 

Record 039 indicating the choice. The allowed values are: 

1: RSD using 0.5/200/1000 (%/ppm/ppm) CO/HC/NOx cutpoints 

2: RSD using 0.5/20011500 (%/ppm/ppm) CO/HC/NOx cutpoints 

3: RSD using 0.5/200/2000 (%/ppm/ppm) CO/HC/NOx cutpoints 

4: RSD using 0.5/200 (%/ppm) CO/HC cutpoints (no NOx cutpoint) 

5: Vehicle Emission Profile with overall 30% excused 

6: Vehicle Emission Profile with overall 40% excused 

7: Vehicle Emission Profile with overall 50% excused 

14 
8: Alternate clean-screening scenario (user supplied effectiveness and fractions) 

Choice #8 is intended as a placeholder for additional options not included in this version of 

the utility. There are default values for the effectiveness and fraction of vehicles excused from 

their next scheduled inspection for each of the choices (except #8). The following sections 

describe in more detail how the user can override these default values. 

Record 044 indicates the choice of one of two cases for the effectiveness of the underlying 

periodic VM test. This information has no effect on any vehicle emission profiling (YEP) 

program options available in the utility and does not need to be entered for YEP options. If an 

RSD-based- clean-screening option is chosen, the default effectiveness values used by the RSDbased clean-screening utility will assume that the effectiveness of the underlying I/M program 

inspections is closer to the effectiveness of the IM240 test procedure using the recommended 

phase-in cutpoints. The utility also contains effectiveness values for RSD-based clean-screening 

which assume that the effectiveness of the underlying VM program inspections is closer to the 

effectiveness of the IM240 test procedure using the recommended final cutpoints. The user can 

specify that the alternate effectiveness numbers are to be used by the utility by entering Record 

044. If the user replaces the existing default values for RSD-based clean-screening, entering 

Record 044 will have no effect, since the user supplied RSD-based clean-screening effectiveness 

values will be used. The allowed values for Record 044 are: 

1: RSD clean-screening with IM240 phase in cutpoint effectiveness; and 

2: RSD clean-screening with IM240 final cutpoint effectiveness. 

The format for each clean-screening control record is (I3,1X,Il 1). This means that the first 

3 characters contain the record number. The next character is a blank followed by an integer 

number within the next 11 spaces, indicating the user choice for that record. Only Record 039 is 

required. 

The following is an example input of the clean-screening control data. The example 

assumes the user wishes to have a clean-screening program that only allows exemptions for 

vehicle that are 1981 and newer model years (Records 034 and 035 = 1). The example assumes 

that the user wishes to have a RSD based clean-screening program that uses the 0.5/200/2000 

CO/HC/NOx cutpoint set for determination of vehicles to be excused from inspection (Record 

039 = 3). The records include some added comments (in comment records and also outside the 

format and not read by the utility) to provide clarity. 

000 ----------- 034 1 Clean-screening for Pre-1975 model year vehicles (default=2) 

035 1 Clean-screening for 1975-80 model year vehicles (default=2) 

036 2 Clean-screening for 1981-85 model year vehicles (default=2) 

037 2 Clean-screening for 1986-89 model year vehicles (default=2) 

038 2 Clean-screening for 1990 and newer vehicles (default=2) 

039 3 Clean-screening choice (default=8) 

044 2 Clean-screening IM240 final cutpoint effectiveness (default=l) 

15 
4.1.6 User Supplied RSD Based Clean Screening Effectiveness 

RSD based clean-screening effectiveness is the fraction of all l/M tailpipe benefits that is 

retained by the program, even though vehicles are excused from the inspection. An effectiveness 

of 90%, for example, means that 10% of the emissions benefit from all vehicles which would 

have failed an I/M inspection are associated with vehicles which are instead excused from the 

inspection by RSD based clean-screening. The utility assumes that the loss of tailpipe I/M 

benefits is proportional to the fraction of emissions represented by vehicles excused from the 

inspection in each model year, not the fraction of vehicles themselves. For example, 50% of the 

vehicles might be excused from their next scheduled inspection, but they may represent a much 

smaller fraction of overall potential emissions benefit. The fraction of vehicles excused from 

their next scheduled inspection (by age) is used directly to calculate evaporative HC benefit 

losses. An effectiveness of 100% for RSD based clean-screening would have no effect on the 

benefits of I/M programs. 

The default effectiveness values for each of these cutpoint combinations assume that a 

vehicle must have at least two valid measurements before the vehicle is eligible for cleanscreening. In addition to the data describing the vehicle coverage options, users may enter the 

effectiveness of RSD- or YEP-based clean-screening and the fraction of vehicles excused from 

their next scheduled inspection by the chosen cutpoints by age. This entry is not required. User 

entry will override the default values provided by the utility. 

The effectiveness array used for the RSD based clean-screening choices have values for 

three model year groupings, four cutpoint combinations and three pollutants (HC, CO and NOx). 

The model year groupings are: 

• 1981-1985 model years 

• 1986-1989 model years 

• 1990 and newer model years 

The effectiveness for 1981-1985 model years is also applied to pre-1981 model years. The 

same effectiveness is used for both passenger car and light duty truck benefits for each model 

years grouping. The available default RSD cutpoint combinations are: 

1: 0.5/200/1000 (%/ppm/ppm) CO/HC/NOx cutpoints 

2: 0.5/200/1500 (%/ppm/ppm) CO/HC/NOx cutpoints 

3: 0.5/200/2000 (%/ppm/ppm) CO/HC/NOx cutpoints 

4: 0.5/200 (%/ppm) CO/HC cutpoints (no NOx cutpoint) 

Since the user input of RSD effectiveness overrides the default values, the user input does 

not need to conform to these combinations. However, if the RSD effectiveness values entered by 

the user do not match the cutpoint combinations described above, the user must also enter the 

16 
fraction of vehicles excused from their next scheduled inspection, which ought to be consistent 

with the user supplied effectiveness values (see the next section). The RSD effectiveness data 

entry is optional. It is only required if the user wishes to override one or more of the default 

effectiveness values used by the utility with user supplied RSD effectiveness estimates. 

A separate record containing user supplied RSD effectiveness may be entered for each of 

12 (Records 951 through 962) combinations of cutpoint combinations and model year groupings. 

The format for each effectiveness record is (13,lX,Fl0.3,Fl0.3,Fl0.3). This means that the first 

3 characters contain the record number, the next character is a blank followed by a number 

(including a decimal) within the next 10 spaces, indicating the effectiveness value that will be 

used for HC, followed by another number (including a decimal) within the next 10 spaces, 

indicating the effectiveness value that will be used for CO, followed by another number 

(including a decimal) within the next 10 spaces, indicating the effectiveness value that will be 

used for NOx. Records 951, 952 and 953 override the effectiveness values for Choice #1 for Pre1986, 1986-1989 and 1990 and newer model years respectively. Records 954, 955 and 956 

override the effectiveness values for Choice #2. Records 957, 958 and 959 override the 

effectiveness values for Choice #3. Records 960, 961and962 override the effectiveness values 

for Choice #4. The user supplied set of RSD-based clean-screening effectiveness values will be 

used regardless of the entry of Record 044, described in Section 4.1.5. 

The following is an example input of the RSD clean-screening effectiveness data. The 

example assumes an effectiveness of 100% (no improperly excused vehicles) for all pollutants, 

cutpoint combinations and model year groupings. The records include some added comments (in 

comment records and also outside the format and not read by the utility) to provide clarity. 

000 

000 HC co NOx 

000 --------- --------- --------- Format 

951 1. 00 1. 00 1. 00 Choice #1, Pre-1986 model years 

952 1. 00 1. 00 1. 00 Choice #1, 1986-1989 model years 

953 1. 00 1. 00 1. 00 Choice #1, 1990 and newer vehicles 

954 1. 00 1. 00 1. 00 Choice #2, Pre-1986 model years 

955 1. 00 1. 00 1. 00 Choice #2, 1986-1989 model years 

956 1. 00 1. 00 1. 00 Choice #2, 1990 and newer vehicles 

957 1. 00 1. 00 1. 00 Choice #3, Pre-1986 model years 

958 1. 00 1. 00 1. 00 Choice #3, 1986-1989 model years 

959 1. 00 1. 00 1. 00 Choice #3, 1990 and newer vehicles 

960 1. 00 1. 00 1. 00 Choice #4, Pre-1986 model years 

961 1. 00 1. 00 1. 00 Choice #4, 1986-1989 model years 

962 1. 00 1. 00 1. 00 Choice #4, 1990 and newer vehicles 

4.1.7 User Supplied RSD-Based Clean-Screenin2 Vehicle Fractions 

Exhaust emission measurements using RSD are assumed not to detect problems with the 

evaporative emission control systems. If an l/M program includes a functional inspection of the 

evaporative emission control systems (either a gas cap or fuel tank pressure check or an 

evaporative system purge check), then excusing those vehicles from the I/M inspection by RSD 

17 
based clean-screening will reduce the I/M benefits from these evaporative system checks. The 

utility does this by reducing the benefits of evaporative emission control system checks by the 

fraction of vehicles in that vehicle age that are excused from the inspection by RSD based cleanscreening. For example, if 40% of vehicles of a given age are excused from their next scheduled 

inspection by clean-screening, then the benefits of the evaporative system checks for that age are 

reduced by 40%. 

There is a separate default fraction of vehicles excused from their next scheduled inspection 

by age for each default RSD cutpoint combination in the utility. The combinations are described 

in the above section regarding RSD-based clean-screening effectiveness. Since the user input of 

excused fractions overrides the default values, the user input does not need to conform to these 

cutpoint combinations. However, the user must also enter the corresponding effectiveness values 

in order to be consistent. This data entry is optional. It is only required if the user wishes to 

override one or more of the default excused fraction values used by the utility. 

A separate record may be entered for each of 25 (Records 971 through 995) ages. The 

format for each excused fraction record is (13,lX,Fl0.3,Fl0.3,Fl0.3,Fl0.3). This means that the 

first 3 characters contain the record number, the next character is a blank followed by a number 

(including a decimal) within the next 10 spaces, indicating the excused fraction that are used for 

the choice #1 cutpoint combination, followed by another number (including a decimal) within the 

next 10 spaces, indicating the excused fraction that are used for the choice #2 cutpoint 

combination, followed by another number (including a decimal) within the next 10 spaces, 

indicating the excused fraction that are used for the choice #3 cutpoint combination, followed by 

another number (including a decimal) within the next l 0 spaces, indicating the excused fraction 

that are used for the choice #4 cutpoint combination. Record 971 overrides the excused fractions 

for vehicles of age 1. Record 972 overrides the excused fractions for vehicles of age 2, etc. 

Record 995 overrides the excused fractions for vehicles of age 25. 

The following is an example input of the RSD clean-screening excused fraction data. The 

example assumes that 40% of vehicles are excused from their next scheduled inspection for all 

cutpoint combinations and ages. The records include some added comments (in comment 

records and also outside the format and not read by the utility) to provide clarity. 

000 

000 Choice #1 Choice #2 Choice #3 Choice #4 

000 --------- --------- --------- --------- Format 

971 0.40 0.40 0.40 0.40 Age 1 

972 0.40 0.40 0.40 0.40 Age 2 

973 0.40 0.40 0.40 0.40 Age 3 

974 0.40 0.40 0.40 0.40 Age 4 

975 0.40 0.40 0.40 0.40 Age 5 

976 0.40 0.40 0.40 0.40 Age 6 

977 0.40 0.40 0.40 0.40 Age 7 

978 0.40 0.40 0.40 0.40 Age 8 

979 0.40 0.40 0.40 0.40 Age 9 

18 
980 0.40 0.40 0.40 0.40 Age 10 

981 0.40 0.40 0.40 0.40 Age 11 

982 0.40 0.40 0.40 0.40 Age 12 

983 0.40 0.40 0.40 0.40 Age 13 

984 0.40 0.40 0.40 0.40 Age 14 

985 0.40 0.40 0.40 0.40 Age 15 

986 0.40 0.40 0.40 0.40 Age 16 

987 0.40 0.40 0.40 0.40 Age 17 

988 0.40 0.40 0.40 0.40 Age 18 

989 0.40 0.40 0.40 0.40 Age 19 

990 0.40 0.40 0.40 0.40 Age 20 

991 0.40 0.40 0.40 0.40 Age 21 

992 0.40 0.40 0.40 0.40 Age 22 

993 0.40 0.40 0.40 0.40 Age 23 

994 0.40 0.40 0.40 0.40 Age 24 

995 0.40 0.40 0.40 0.40 Age 25 

4.1.8 User Su1rnlied Vehicle Emission Profilin2 Effectiveness 

Vehicle emission profiling (YEP) can be used as a method to exempt vehicles from 

inspection in l/M programs. Like RSD based clean-screening, YEP clean-screening will affect 

l/M benefits because some vehicles which would have failed the l/M inspection will be excused 

from their next scheduled inspection by clean-screening. As with RSD based clean-screening, 

the utility assumes that a 90% effectiveness will result in a 10% loss of l/M benefit for the 

fraction of the fleet subject to the VEP program. Unlike RSD based clean-screening, YEP based 

clean-screening is assumed by the utility to apply to all vehicles subject to state regulation 

included in the program and is unaffected by the user choice of vehicle coverage options. This is 

reflected in the calculations by assuming 100% vehicle coverage. Also, VEP effectiveness varies 

by age, instead of by model year grouping as for RSD based clean-screening. 

The existing flags described in the Clean-screening Data Section 4.1.5 allow the user to 

restrict YEP clean-screening only to selected model year ranges. Users may wish to apply YEP 

based clean-screening to only vehicles within a certain range of vehicle ages within these model 

year ranges, even though a larger range of ages will be subject to the l/M program. This case can 

be modeled by entering 100% effectiveness for the ages in a given evaluation calendar year 

which will not be subject to YEP based clean-screening. A separate set of l/M credits must be 

generated for each evaluation calendar year where YEP based clean-screening is applied. 

There are four default choices for YEP clean-screening programs: 

5: Vehicle Emission Profile with overall 30% excused (100% coverage) 

6: Vehicle Emission Profile with overall 40% excused (100% coverage) 

7: Vehicle Emission Profile with overall 50% excused (100% coverage) 

8: Alternate clean-screening scenario (user supplied effectiveness and fractions) 

Although these choices are available, there are no default effectiveness values available in 

19 
this version of the utility. Users must enter the effectiveness values for the users choice of a YEP 

program. The set of effectiveness values includes values by age for the three pollutants (HC, CO 

and NOx). The user must assure that the user supplied effectiveness values will be consistent 

with the user supplied fractions of vehicles excused from their next scheduled inspection 

(described below). Only the set of effectiveness values corresponding to the YEP program 

choice made by the user will be overridden. This should present no difficulties, since that will be 

the scenario used by the utility to calculate the effect of the YEP program on the I/M credits. 

EPA's current guidance regarding effectiveness values for YEP is given in a separate document, 

"Description and Documentation for Interim Vehicle Clean-Screening Credit Utility," (EPA 420-

P-98-008). 

A separate record may be entered for each of 25 (Records 651 through 67 5) ages. The 

format for each effectiveness record is (13,lX,Fl0.3,Fl0.3,Fl0.3). This means that the first 3 

characters contain the record number, the next character is a blank followed by a number 

(including a decimal) within the next 10 spaces, indicating the effectiveness value that will be 

used for HC, followed by another number (including a decimal) within the next 10 spaces, 

indicating the effectiveness value that will be used for CO, followed by another number 

(including a decimal) within the next 10 spaces, indicating the effectiveness value that will be 

used for NOx. Record 651 overrides the effectiveness for vehicles of age 1. Record 652 

overrides the effectiveness for vehicles of age 2, etc. Record 675 overrides the effectiveness for 

vehicles of age 25. 

The following is an example input of the YEP clean-screening effectiveness data. The 

example assumes an effectiveness of 100% (no improperly excused vehicles) for all pollutants 

and ages. The records include some added comments (in comment records and also outside the 

format and not read by the utility) to provide clarity. 

000 

000 HC co NOx 

000 --------- --------- --------- Format 

651 1. 00 1. 00 1. 00 Age 1 

652 1. 00 1. 00 1. 00 Age 2 

653 1. 00 1. 00 1. 00 Age 3 

654 1. 00 1. 00 1. 00 Age 4 

655 1. 00 1. 00 1. 00 Age 5 

656 1. 00 1. 00 1. 00 Age 6 

657 1. 00 1. 00 1. 00 Age 7 

658 1. 00 1. 00 1. 00 Age 8 

659 1. 00 1. 00 1. 00 Age 9 

660 1. 00 1. 00 1. 00 Age 10 

661 1. 00 1. 00 1. 00 Age 11 

662 1. 00 1. 00 1. 00 Age 12 

663 1. 00 1. 00 1. 00 Age 13 

664 1. 00 1. 00 1. 00 Age 14 

665 1. 00 1. 00 1. 00 Age 15 

666 1. 00 1. 00 1. 00 Age 16 

667 1. 00 1. 00 1. 00 Age 17 

20 
668 1. 00 1. 00 1. 00 Age 18 

669 1. 00 1. 00 1. 00 Age 19 

670 1. 00 1. 00 1. 00 Age 20 

671 1. 00 1. 00 1. 00 Age 21 

672 1. 00 1. 00 1. 00 Age 22 

673 1. 00 1. 00 1. 00 Age 23 

674 1. 00 1. 00 1. 00 Age 24 

675 1. 00 1. 00 1. 00 Age 25 

4.1.9 User Supplied Vehicle Emission Profilin2 Fractions 

Vehicle emission profiling (YEP) can affect evaporative emission system check benefits in 

the same way as RSD based clean-screening options. The utility assumes that, as for RSD based 

clean-screening, YEP clean-screening will reduce the benefits of evaporative emission control 

system checks by the fraction of vehicles of that vehicle age that are excused from the inspection 

by YEP based clean-screening. For example, if 40% of vehicles of a given age are excused from 

their next scheduled inspection by clean-screening, then the benefits of the evaporative system 

checks for that age are reduced by 40%. 

Although these choices are available, there is no default fraction of excused values 

available in this version of the utility. Users must enter the fraction of vehicles excused from 

their next scheduled inspection for each age for the users choice of a YEP program. The user 

must assure that the user supplied fractions of vehicles excused from their next scheduled 

inspection will be consistent with the user supplied effectiveness values (described above). Only 

the set of fractions of vehicles excused from their next scheduled inspection corresponding to the 

YEP program choice made by the user will be overridden. This should present no difficulties, 

since that will be the scenario used by the utility to calculate the effect of the YEP program on 

the l/M credits. EPA's current guidance regarding effectiveness values for YEP is given in a 

separate document, "Description and Documentation for Interim Vehicle Clean-screening Credit 

Utility," (EPA 420-P-98-008). 

A separate record is entered for each of 25 (Records 621 through 645) ages. The format for 

each excused fraction record is (13,lX,Fl0.3). This means that the first 3 characters contain the 

record number, the next character is a blank followed by a number (including a decimal) within 

the next 10 spaces, indicating the excused fractions that are to be used for the YEP program 

selected. Record 621 overrides the excused fraction for vehicles of age 1. Record 622 overrides 

the excused fraction for vehicles of age 2, etc. Record 645 overrides the excused fraction for 

vehicles of age 25. 

The following is an example input of the YEP clean-screening excused fraction data. The 

example assumes that 40% of vehicles are excused from their next scheduled inspection for all 

ages. The records include some added comments (in comment records and also outside the 

format and not read by the utility) to provide clarity. 

000 --------- Format 

21 
621 0.40 Age 1 

622 0.40 Age 2 

623 0.40 Age 3 

624 0.40 Age 4 

625 0.40 Age 5 

626 0.40 Age 6 

627 0.40 Age 7 

628 0.40 Age 8 

629 0.40 Age 9 

630 0.40 Age 10 

631 0.40 Age 11 

632 0.40 Age 12 

633 0.40 Age 13 

634 0.40 Age 14 

635 0.40 Age 15 

636 0.40 Age 16 

637 0.40 Age 17 

638 0.40 Age 18 

639 0.40 Age 19 

640 0.40 Age 20 

641 0.40 Age 21 

642 0.40 Age 22 

643 0.40 Age 23 

644 0.40 Age 24 

645 0.40 Age 25 

4.2 Usin2 Clean-Screenin2 l/M Credits with MOBILES 

MOBILES uses two external data files which contain the l/M tailpipe credits whenever an 

l/M program is specified in the user input. The benefit ofl/M program options can be adjusted 

by altering the numbers contained in those data files. The remote-sensing I/M credit utility takes 

advantage of that fact by adjusting the default l/M credit files to reflect the user supplied 

information about the use of clean-screening in the inspection programs. Therefore, any current 

version of MOBILES (MOBILE5a, March 1993, MOBILE5a_H, February 1995, or 

MOBILE5b, September 1996) can be used to evaluate clean-screening options. 

The first step is to describe the clean-screening program to be modeled in sufficient detail 

to create an input file for the remote-sensing I/M credit utility. For some proposed programs, it 

may be necessary to estimate or assume some of the necessary input data. However, the inputs 

should reflect, as near as possible, the actual expected performance of the clean-screening 

program element. 

Once the clean-screening program design has been determined, the necessary input data 

must be collected together in the input data file. An example input data file is provided with the 

clean-screening l/M credit utility which shows the format for all of the necessary input 

parameters. The user should carefully read this User Guide to identify the necessary data and to 

22 
properly locate the data in the input file. The input data file is a simple ASCII text file that can 

be changed using any standard editor or word processor. However, the user must save any 

changes in a text format. The Remote-Sensing I/M Credit Utility cannot read input files that are 

saved in a word processing format. 

The next step is to use the remote-sensing l/M credit utility to create an alternative set of 

l/M credit data files. The input file designates the names of the default l/M credit files to be used 

and the names of the altered (clean-screening) I/M credit files output by the remote-sensing 

utility. These filenames can include "path" information if the default l/M credit files are not 

located in the local directory. If a path is not specified, the default l/M credit files must be in the 

local directory when the remote-sensing utility is run. The new l/M credit files created by the 

utility which have been adjusted to reflect the effects of clean-screening will be in the same 

directory as the remote-sensing utility is run. These files can be written to a different directory if 

a path is specified in the input file. 

The remote-sensing utility is run by simply invoking its name (RSDNEW.EXE) at the DOS 

prompt. The utility will prompt the user on the screen for the name of the input file. No further 

user input is required. The processing is quite lengthy, and some time will pass. There will be 

some diagnostic information on the screen during processing. When completed without errors, 

the remote-sensing utility will display a completion message on the screen. 

Once the processing has been completed, the new I/M credits, adjusted for clean-screening, 

will be in the filenames indicated by the user in the input file. Although these files can be 

renamed to the MOBILES default l/M credit filenames, there will be no output in MOBILES 

which indicates that alternate I/M credits were used. It may be less confusing to access these 

alternate l/M credits using the alternate credit option in MOBILES described in the MOBILES 

User Guide Section 2.2.S.4. In this case, each input file for MOBILES would indicate which set 

of alternate credits was used in the two input records following the l/M Descriptive Record(s ). 

Since the effect of clean-screening is contained in the alternate I/M credit files, there should 

be no need to change any of the normal MOBILES input parameters (other than those to access 

the use of alternate l/M credits) to reflect the use of clean-screening. It is very important, 

therefore, to carefully choose the right combination of factors in the remote-sensing l/M credit 

utility that properly reflect the features of the clean-screening program elements. 

If either a functional check of the evaporative pressure or purge system is included as part 

of the l/M program, the benefits of these programs must also be replaced with adjusted values. 

These are contained in an external data file created by this utility and can be used in 

MOBILESa H or MOBILESb. MOBILESa does not allow the use of alternate benefits for the 

pressure/purge checks. 

In MOBILESa_H, the alternate pressure/purge credits are read automatically from a file 

named PPEFF.D located in the same directory as the model is run. These credits are read when 

the Program Type in the I/M Descriptive Record is set to four (4), indicating a retest-base hybrid 

23 
program. As long as the I/M credit file supplied to the model contains the appropriate cleanscreening adjusted I/M credits, the model will properly calculate both the exhaust and 

evaporative benefits for the program. The appropriate clean-screening adjusted pressure/purge 

credit file should be renamed to PPEFF .D and made available in the local directory when 

modeling. The user will need to be careful about which files are being used, because 

MOBILE5a_H will not be able to detect and warn the user about inappropriate combinations of 

credits. The credits generated by the utility will have an extra record at the beginning of the 

PPEFF .D data file. This record contains a brief description of the credits included in the file. 

MOBILE5b will read and echo this information in the descriptive output of the model (see 

below). However, MOBILE5a_H is not designed to read this descriptive record and an error will 

occur. If you intend to use MOBILE5a_H, then you must edit this data file to remove the first 

(description) record from the data file before using it with MOBILE5a_H. 

In MOBILE5b, the exhaust emission credits are provided as described for RSD programs 

above. However, the credits for the evaporative emissions pressure and purge system check must 

be made available in a file named PPEFF.D located in the same directory as the model is run. 

These credits are read when the Program Type in the Pressure or Purge Check Descriptive 

Record is set to four (3), indicating a Retest-base Hybrid program. The appropriate cleanscreening adjusted pressure/purge credit file must be renamed to PPEFF.D and made available in 

the local directory when modeling. You will need to be careful about which files are being used, 

because MOBILE5b will not be able to detect and warn the user about inappropriate credits. 

However, the record describing the altered PPEFF .D file, located in the first record of the file, 

will be echoed in the descriptive output of MOBILE5b. It will be located just below the 

description of the ATP or just below the I/M program if no ATP is included. 

24 
APPENDIX A 

List of Records for RSD Utility 

000 comments 

001 fleet coverage 

1 commitment to level of effort RSD program 

2 commitment to specific fleet coverage RSD program 

3 commitment to a number of failures RSD program (cannot be used with Program #5) 

002 l/M program design 

1 basic remote-sensing program 

2 test-and-repair remote-sensing program 

3 retest hybrid remote-sensing 

4 remote sensing only program 

5 clean-screening remote-sensing program 

005-008 - no user input; indicates name & location of standard VM credit data input files 

015-018 - no user input; indicates location and name of the resulting remote-sensing adjusted 

VM credit data output files 

Input Files 

005 1981 & newer model year credits 

006 1981 & newer model year retest-hybrid credits 

007 pre-1981 model year credits 

008 pre-1981 model year retest-hybrid credits 

009 Standard pressure/purge credits 

010 Retest-hybrid pressure/purge credits 

Output Files 

011 adjusted standard pressure/purge credits 

012 adjusted retest-hybrid pressure/purge credits 

015 adjusted 1981 & newer model year credits 

016 adjusted 1981 and newer model year only for retest-hybrid credits 

017 adjusted pre-1981 model year credits 

018 adjusted pre-1981 model year only for retest-hybrid credits 

25 
024 the age at which vehicles first become eligible for targeting 

by remote-sensing, 1 to 24 (default= 1 year) 

031 the CO cutpoints to be applied to remote-sensing measurements 

for 1974 and older model year vehicles, default= 3% 

032 the CO cutpoints to be applied to remote-sensing measurements 

for 1975 through 1980 model year vehicles, default = 3% 

033 the CO cutpoints to be applied to remote-sensing measurements 

for 1981 and newer model year vehicles, default= 3% 

041 the test and repair effectiveness for HC emissions, default= 0.5 

042 the test and repair effectiveness for CO emissions, default= 0.5 

043 the test and repair effectiveness for NOx emissions, default = 0.5 

Option 1: Data Section (level of effort) 

021 the# of vehicles in the fleet (in inspection area) 

022 the # of valid measurements per month that are made using RSD 

023 the# of times a vehicle must be failed by RSD before it can be targeted for I/M 

inspection; default 1, range 1-11 

Option 2: Data Section (specific fleet coverage) 

201-225 

the # of vehicles for each of last 25 model years that are eligible for RSD targeting and the 

# of vehicles of that age that actually receive RSD; the ratio of the two #sis the fleet coverage by 

model year 

Option 3: Data Section (#of failures) 

301-325 The # of vehicles which normally fail I/M annually for each of the past 25 model years 

and the # of additional vehicles which are targeted by RSD and also fail the confirmatory I/M 

test 

The program contains default benefits for RSD. However, the user also has the option of 

specifying benefits for option 3 based on a measure of the average excess emission levels of 

vehicles failing the remote-sensing cutpoint chosen. Such values would presumably come from 

an operating I/M program using RSD. This measure is the ratio of the average excess emissions 

of vehicles found at that remote-sensing cutpoint divided by the average emissions of all vehicles 

with excess emissions. There are 15 records for each of the three pollutants (HC, CO, and NOx) 

corresponding to RSD cutpoints from 0.5% to 7.5%. These records are the ratio of the average 

IM240 excess emissions identified per vehicle to the average excess emissions per vehicle in the 

fleet as a whole for a particular CO RSD cutpoint. Each of the 15 records has three model year 

groupings (1974 and older, 1975-80, and 1981 and newer). 

701-715 values for HC 

26 
801-815 values for CO 

901-915 values for NOx 

Program #5: Clean-screening Programs 

034 Coverage for pre-1975 model year vehicles (default=2) Yes:l, No:2 

035 Coverage for 1975-1980 model year vehicles (default=2) Yes: 1, No:2 

036 Coverage for 1981-1985 model year vehicles ( default=2) Yes: 1, No:2 

037 Coverage for 1986-1989 model year vehicles ( default=2) Yes: 1, No:2 

038 Coverage for 1990 and newer model year vehicles ( default=2) Yes: 1, No:2 

039 Selection of Clean-screening Program choice (default= 1) range 1-8 where: 

Choice 1: RSD using 0.5/200/1000 CO/HC/NOx cutpoints and scanning 2 times 

2: RSD using 0.5/200/1500 CO/HC/NOx cutpoints and scanning 2 times 

3: RSD using 0.5120012000 CO/HC/NOx cutpoints and scanning 2 times 

4: RSD using 0.5/200 CO/HC cutpoints (no NOx) and scanning 2 times 

5: Vehicle Emission Profile with overall 30% excused (100% coverage) 

6: Vehicle Emission Profile with overall 40% excused (100% coverage) 

7: Vehicle Emission Profile with overall 50% excused (100% coverage) 

8: Alternate clean-screening scenario (user supplied effectiveness and fractions) 

044 Indicates the RSD clean-screening IM240 cutpoint effectiveness to be used. 

621-645 contain the user supplied clean-screening fraction of vehicles excused from inspection 

by age for the current choice of vehicle emission profiling program. (choices 5-8) 

651-675 contains the user supplied clean-screening effectiveness by age and pollutant for the 

current choice of vehicle emission profiling program. (choices 5-8) 

951-962 contains the user supplied clean-screening effectiveness by model year grouping, RSD 

cutpoint and pollutant for RSD clean-screening program options. (choices 1-4) 

971-995 contains the user supplied clean-screening fraction of vehicles excused from inspection 

by age and RSD cutpoint. (choice 1-4) 

27 
APPENDIXB 

Example Clean-screenin2 Input Files 

28 
000 

000 

000 

000 

000 

000 

001 

002 

000 

000 

000 

000 

005 

006 

007 

008 

009 

010 

011 

012 

015 

016 

017 

018 

000 

000 

000 

000 

021 

022 

023 

000 

000 

000 

000 

000 

000 

000 

000 

000 

000 

Example #1: RSD Based Clean-screening with Commitment to Level of Effort 

Example #1: RSD Based Clean-screening with Commitment to Level of Effort 

assuming IM240 phase in level effectiveness 

CONTROL SECTION 

1 Option (may be 1, 2, or 3) Commitment to Level of Effort 

5 Program Type (may be 1, 2, 3, 4, or 5 if Option is not 3) Clean-screening 

INPUT AND OUTPUT FILENAMES 

5<-40 characters total, same as MOB5->44 

IMDATAT.D 1981 & newer model year vehicles credits 

'81 & newer mod. yr veh . Retest-Hybrid er. pre-1974 & 1975-1980 mod. yr veh. er. IMDATAT.D 

TECH12.D 

TECH12.D 

PPEFFM5.D 

PPEFF .D 

PP.D 

PPH.D 

IM.D 

IMH.D 

TEC.D 

TECH.D 

pre-'74 & '75-'80 mod. yr veh. Retest-Hyb. er. standard pressure/purge effectiveness array 

retest-based hybrid pressure/purge effectiveness 

CHANGED standard pressure/purge effectiveness 

CHANGED retest-based hybrid press/purge effect 

CHANGED 1981 & newer model year vehicles credits 

CHANGED '81 & newer mod. yr veh. Retest-Hybrid er. CHANGED pre-1974 & 1975-1980 mod. yr veh. er. CHANGED pre-'74 & '75-'80 mod. yr veh. Retest-Hyb. 

GENERAL DATA SECTION 

5<-llch->15 

2400000 No. of veh. in RSD program default 1000000 

12000 Valid veh . measurements per month default 50000 

2 No. of times a veh. must be scanned (1-11) default 2 for clean-screening 

Clean-screening Choices (may be 1-8) 

Choice 1: RSD using 0.5/200/1000 CO/HC/NOx cut points and scanning 2 times 

2: RSD using 0.5/200/1500 CO/HC/NOx cut points and scanning 2 times 

3: RSD using 0.5/200/2000 CO/HC/NOx cutpoints and scanning 2 times 

4: RSD using 0.5/200 CO/HC cutpoints (no NOx) and scanning 2 times 

5: Vehicle Emission Profile with overall 30% excused (100% coverage) 6: Vehicle Emission Profile with overall 40% excused (100% coverage) 

7: Vehicle Emission Profile with overall 50% excused (100% coverage) 

8: Alternate clean-screening scenario (user supplied effectiveness and fractions) 

29 

er. 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

IMDATA.D 

HYBRID. IMC 

TECH12.D 

TECH12.D 

PPEFFM5 .D 

PPEFF.D 

PPM5RSD.D 

PPHYRSD.D 

RSDDATA.D 

RSDDATA .H 

TECDATA.D 

TECDATA.H 
000 ----------- 034 2 Clean-screening for Pre-1975 model year vehicles (default=2) 

035 2 Clean-screening for 1975-80 model year vehicles (default=2) 

036 2 Clean-screening for 1981-85 model year vehicles (default=2) 

037 2 Clean-screening for 1986-89 model year vehicles (default=2) 

038 2 Clean-screening for 1990 and newer model year vehicles (default=2) 

039 3 Clean-screening choice (default=8, user supplied effectiveness and fractions) 

044 1 Clean-screening IM240 phase in cutpoint effectiveness (default=l) 

000 

30 
000 

000 

000 

000 

000 

000 

001 

002 

000 

000 

000 

000 

005 

006 

007 

008 

009 

010 

011 

012 

015 

016 

017 

018 

000 

000 

000 

000 

000 

201 

202 

203 

204 

205 

206 

207 

208 

209 

210 

211 

212 

Example #2: RSD Based Clean-screening with Commitment to Specific Fleet Coverage 

Example #2: RSD Based Clean-screening with Commitment to Specific Fleet Coverage 

assuming IM240 final cutpoint level effectiveness 

CONTROL SECTION 

2 Option (may be 1, 2, or 3) Commitment to Specific Fleet Coverage 

5 Program Type (may be 1, 2, 3, 4, or 5 if Option is not 3) Clean-screening 

INPUT AND OUTPUT FILENAMES 

5<-40 characters total, same as MOB5->44 

IMDATAT.D 

IMDATAT.D 

TECH12.D 

TECH12.D 

PPEFFM5.D 

PPEFF.D 

PP.D 

PPH.D 

IM.D 

IMH .D 

TEC.D 

TECH.D 

OPTION #2 DATA SECTION 

1981 & newer model year vehicles credits 

'81 & newer mod. yr veh. Retest-Hybrid er. pre-1974 & 1975-1980 mod. yr veh. er. pre-'74 & '75-'80 mod. yr veh. Retest-Hyb. er. standard pressure /purge effectiveness array 

retest-based hybrid pressure/purge effectiveness 

CHANGED standard pressure/purge effectiveness 

CHANGED retest-based hybrid press/purge effect 

CHANGED 1981 & newer model year vehicles credits 

CHANGED '81 & newer mod. yr veh. Retest-Hybrid er. CHANGED pre-1974 & 1975-1980 mod. yr veh. er. CHANGED pre-'74 & '75-'80 mod. yr veh. Retest-Hyb. 

Number of vehicles eligible for clean-screening (two valid readings) 

Total------Sent-------

5<-llch->1516<-llc->26 

10000 1500 Total veh., veh. sent to IM via RSD, age 0- 1 

10000 1500 Total veh., veh. sent to IM via RSD, age 1- 2 

10000 1500 Total veh., veh. sent to IM via RSD, age 2- 3 

10000 1500 Total veh., veh. sent to IM via RSD, age 3- 4 

10000 1500 Total veh., veh. sent to IM via RSD, age 4- 5 

10000 1500 Total veh., veh. sent to IM via RSD, age 5- 6 

10000 1500 Total veh., veh. sent to IM via RSD, age 6- 7 

10000 1500 Total veh., veh. sent to IM via RSD, age 7- 8 

10000 1500 Total veh., veh. sent to IM via RSD, age 8- 9 

10000 1500 Total veh., veh. sent to IM via RSD, age 9-10 

10000 1500 Total veh., veh. sent to IM via RSD, age 10-11 

10000 1500 Total veh., veh. sent to IM via RSD, age 11-12 

31 

er. 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

IMDATA.D 

HYBRID. IMC 

TECH12.D 

TECH12.D 

PPEFFM5.D 

PPEFF.D 

PPM5RSD.D 

PPHYRSD.D 

RSDDATA.D 

RSDDATA .H 

TECDATA.D 

TECDATA.H 
213 10000 1500 Total veh., veh. sent to IM via RSD , age 12-13 

214 10000 1500 Total veh., veh. sent to IM via RSD, age 13-14 

215 10000 1500 Total veh . , veh. sent to IM via RSD, age 14-15 

216 10000 1500 Total veh., veh. sent to IM via RSD, age 15-16 

217 10000 1500 Total veh., veh . sent to IM via RSD, age 16-17 

218 10000 1500 Total veh . , veh . sent to IM via RSD, age 17-18 

219 10000 1500 Total veh., veh . sent to IM via RSD, age 18-19 

220 10000 1500 Total veh., veh . sent to IM via RSD, age 19-20 

221 10000 1500 Total veh., veh . sent to IM via RSD, age 20-21 

222 10000 1500 Total veh., veh . sent to IM via RSD, age 21-22 

223 10000 1500 Total veh., veh . sent to IM via RSD, age 22-23 

224 10000 1500 Total veh., veh . sent to IM via RSD, age 23-24 

225 10000 1500 Total veh ., veh. sent to IM via RSD, age 24-25 

000 

000 Clean- screening Choices (may be 1-8) 

000 Choice 1 : RSD using 0 . 5 / 200/1000 CO/ HC/NOx cutpoints and scanning 2 times 

000 2 : RSD using 0 . 5/200/1500 CO/ HC/NOx cutpoints and scanning 2 times 

000 3 : RSD using 0.5/200/2000 CO/HC/ NOx cutpoints and scanning 2 times 

000 4: RSD using 0.5/200 CO/HC cutpoints (no NOx) and scanning 2 times 

000 5: Vehicle Emission Profile with overall 30% excused (100% coverage) 

000 6: Vehicle Emission Profile with overall 40% excused (100% coverage) 

000 7: Vehicle Emission Profile with overall 50% excused (100% coverage) 

000 8: Alternate clean-screening scenario (user supplied effectiveness and fractions) 

000 ----------- 034 2 Clean- screening for Pre-1975 model year vehicles (default=2) 

035 2 Clean- screening for 1975-80 model year v ehicles (default=2) 

036 2 Clean-screening for 1981-85 model year vehicles (default=2) 

037 2 Clean-screening for 1986-89 model year vehicles (default=2) 

038 2 Clean-screening for 1990 and newer model year vehicles (default=2) 

039 3 Clean-screening choice (default=8, user supplied effectiveness and fractions) 

044 2 Clean- screening IM240 final cutpoint effectiveness (default=l) 

000 

32 
000 

000 

000 

000 

000 

001 

002 

000 

000 

000 

000 

005 

006 

007 

008 

009 

010 

011 

012 

015 

016 

017 

018 

000 

000 

000 

000 

000 

000 

000 

000 

000 

000 

000 

034 

035 

036 

037 

038 

039 

000 

Example #3: YEP Based Clean-screening 

Example #3: VEP Based Clean-screening 

CONTROL SECTION 

1 Option (must choose 1 but has no effect) 

5 Program Type (may be 1, 2, 3, 4, or 5 if Option is not 3) Clean-screening 

INPUT AND OUTPUT FILENAMES 

5<-40 characters total, same as MOB5->44 

IMDATAT.D 1981 & newer model year vehicles credits 

'81 & newer mod. yr veh. Retest-Hybrid er. pre-1974 & 1975-1980 mod. yr veh. er. IMDATAT.D 

TECH12.D 

TECH12.D 

PPEFFM5.D 

PPEFF.D 

PP.D 

PPH.D 

IM.D 

IMH.D 

TEC.D 

TECH.D 

pre-'74 & '75-'80 mod. yr veh. Retest-Hyb. er. standard pressure/purge effectiveness array 

retest-based hybrid pressure/purge effectiveness 

CHANGED standard pressure/purge effectiveness 

CHANGED retest-based hybrid press/purge effect 

CHANGED 1981 & newer model year vehicles credits 

CHANGED '81 & newer mod. yr veh. Retest-Hybrid er. CHANGED pre-1974 & 1975-1980 mod. yr veh. er. CHANGED pre-'74 & '75-'80 mod . yr veh . Retest-Hyb. 

Clean-screening Choices (may be 1-8) 

Choice 1: RSD using 0.5/200/1000 CO/HC/ NOx cutpoints and scanning 2 times 

2 : RSD using 0.5/200/1500 CO/HC/NOx cutpoints and scanning 2 times 

3: RSD using 0.5/200/2000 CO/HC/NOx cutpoints and scann~ng 2 times 

4 : RSD using 0.5/200 CO/HC cutpoints (no NOx) and scanning 2 times 

5: Vehicle Emission Profile with overall 30% excused (100% coverage) 

6: Vehicle Emission Profile with overall 40% excused (100% coverage) 

7: Vehicle Emission Profile with overall 50% excused (100% coverage) 

8: Alternate clean-screening scenario (user supplied effectiveness and fractions) 

2 Clean-screening for Pre-1975 model year vehicles (default=2) 

2 Clean-screening for 1975-80 model year vehicles (default=2) 

2 Clean-screening for 1981-85 model year vehicles (default=2) 

2 Clean-screening for 1986-89 model year vehicles (default=2) 

2 Clean-screening for 1990 and newer model year vehicles (default=2) 

8 Clean-screening choice (default=8, user supplied effectiveness and fractions) 

33 

er. 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

default 

IMDATA .D 

HYBRID . IMC 

TECH12.D 

TECH12.D 

PPEFFM5.D 

PPEFF.D 

PPM5RSD .D 

PPHYRSD.D 

RSDDATA.D 

RSDDATA.H 

TECDATA.D 

TECDATA.H 
000 

000 

000 

000 

000 

651 

652 

653 

654 

655 

656 

657 

658 

659 

660 

661 

662 

663 

664 

665 

666 

667 

668 

669 

670 

671 

672 

673 

674 

675 

000 

Variable VEPX containing the alternate 

by age and age for the clean-screening 

HC co NOx 

--------- --------- --------- Format 

0.50 0.50 0.50 Age 1 

0 . 50 0 . 50 0.50 Age 2 

0.50 0 . 50 0.50 Age 3 

0.50 0 . 50 0.50 Age 4 

0 . 50 0.50 0.50 Age 5 

0 . 50 0 . 50 0.50 Age 6 

0 . 50 0.50 0.50 Age 7 

0.50 0 . 50 0.50 Age 8 

0.50 0.50 0.50 Age 9 

0.50 0.50 0.50 Age 10 

0.50 0.50 0.50 Age 11 

0.50 0 . 50 0 . 50 Age 12 

0.50 0.50 0.50 Age 13 

0.50 0.50 0.50 Age 14 

0.50 0.50 0.50 Age 15 

0.50 0.50 0.50 Age 16 

0.50 0.50 0 . 50 Age 17 

0.50 0.50 0.50 Age 18 

0 . 50 0.50 0.50 Age 19 

0.50 0 . 50 0.50 Age 20 

0.50 0.50 0.50 Age 21 

0.50 0.50 0.50 Age 22 

0.50 0.50 0 . 50 Age 23 

0.50 0.50 0.50 Age 24 

0.50 0.50 0 . 50 Age 25 

clean-screening effectiveness 

choice (5-8). Required Input 

000 Variable ACSCRN containing the alternate clean-screening fraction excused 

000 by age for clean-screening choice (5-8). Required Input 

000 --------- Format 

621 0.50 Age 1 

622 0.50 Age 2 

623 0.50 Age 3 

624 0.50 Age 4 

625 0 . 50 Age 5 

626 0.50 Age 6 

627 0.50 Age 7 

628 0.50 Age 8 

629 0 . 50 Age 9 

34 
630 

0. 50 Age 10 

631 0. 50 Age 11 

632 0.50 Age 12 

633 0. 50 Age 13 

634 0.50 Age 14 

635 0. 50 Age 15 

636 0.50 Age 16 

637 0.50 Age 17 

638 0. 50 Age 18 

639 0. 50 Age 19 

640 0.5 0 Age 20 

641 

0. 50 Age 21 

642 0.50 Age 22 

643 0.50 Age 23 

644 0.50 Age 24 

645 0.50 Age 25 

000 

35 
000 

000 

000 

000 

000 

000 

001 

002 

000 

000 

000 

000 

00 5 

006 

007 

00 8 

009 

010 

011 

012 

015 

016 

017 

018 

000 

000 

000 

000 

021 

022 

023 

000 

000 

000 

000 

000 

000 

000 

000 

Example #4: RSD Based Clean-screening with Commitment to Level of Effort 

and With Alternate Effectiveness and Excused Fractions 

Example #4: RSD Based Clean-screening with Commitment to Level of Effort 

with user input of RSD effectiveness and excused fractions. 

CONTROL SECTION 

1 Option (may be 1, 2, or 3) Commitment to Level of Effort 

5 Program Type (may be 1, 2, 3, 4, or 5 if Option is not 3) Clean-screening 

INPUT AND OUTPUT FILENAMES 

5<-40 characters 

IMDATAT.D 

IMDATAT.D 

TECH12.D 

TECH12.D 

PPEFFM5.D 

PPEFF.D 

PP.D 

PPH.D 

IM.D 

IMH.D 

TEC.D 

TECH.D 

total, same as MOB5->44 

GENERAL DATA SECTION 

5< -llch ->15 

1981 & newer model year vehicles credits ' 81 & newer mod. yr veh. Retest-Hybrid er. pre-1974 & 1975- 1980 mod. yr veh. er. p r e -' 74 & '75 - '80 mod. yr veh. Retest-Hyb. er. standard pressure/purge effectiveness array 

retest-based hybrid pressure/purge effectiveness 

CHANGED standard pressure/purge effectiveness 

CHANGED retest-based hybrid press/purge effect 

CHANGED 1981 & newer model year vehicles credits 

CHANGED ' 81 & newer mod. yr veh . Retest- Hybrid er. CHANGED pre-1974 & 1975-1980 mod. yr veh. er. CHANGED pre - '74 & '75-'80 mod. yr veh. Retest-Hyb. 

2400000 No. of veh. in RSD program default 1000000 

2400000 Valid veh. measurements per month default 50000 

2 No. of times a veh. must be scanned (1 - 11 ) default 2 for clean-screening 

Clean-screening Choices (may be 1- 8) 

Choice 1: RSD using 0.5/200/1000 CO/HC/NOx cutpoints and scanning 2 times 

2: RSD using 0.5/200/1500 CO/HC/NOx cutpoints and scanning 2 times 

3 : RSD using 0.5/200/2000 CO/HC/NOx cutpoints and scanning 2 times 

4: RSD using 0.5/200 CO/HC cutpoints (no NOx) and scanning 2 times 

5: Vehicle Emission Profile with over all 30% excused (100% coverage) 

6: Vehicle Emission Profile with overall 40% excused (100% coverage) 

36 

er. 

de f ault 

de f ault 

de f ault 

de f ault 

de f ault 

de f ault 

de f ault 

de f ault 

de f ault 

de f ault 

de f ault 

de f ault 

IMDATA.D 

HYBRID. IMC 

TECH12.D 

TECH12.D 

PPEFFM5 .D 

PPEFF . D 

PPM5RSD.D 

PPHYRSD.D 

RSDDATA.D 

RSDDATA .H 

TECDATA.D 

TECDATA.H 
000 

000 

000 

034 

035 

036 

037 

038 

039 

000 

000 

000 

000 

000 

000 

000 

000 

000 

000 

000 

951 

952 

953 

954 

955 

956 

957 

958 

959 

960 

961 

962 

000 

000 

000 

000 

000 

000 

000 

000 

000 

000 

000 

7: Vehicle Emission Profile with overall 50% excused (100% coverage) 

8: Alternate clean-screening scenario (user supplied effectiveness and fractions) 

2 Clean-screening for Pre-1975 model year vehicles (default=2) 

2 Clean-screening for 1975-80 model year vehicles (default=2) 

2 Clean-screening for 1981-85 model year vehicles (default=2) 

2 Clean-screening for 1986-89 model year vehicles (default=2) 

2 Clean-screening for 1990 and newer model year vehicles (default=2) 

3 Clean-screening choice (default=8, user supplied effectiveness and fractions) 

Variable CLEANX containing the clean-screening effectiveness 

by pollutant, model year group and choice for Choices #1-4. 

Choice 1: 0.5/200/1000 HC/CO/NOx cutpoints 

2 : 0.5/200/1500 HC/CO/NOx cutpoints 

3: 0.5/200/2000 HC/CO/NOx cutpoints 

4: 0.5/200 HC/CO cutpoints (no NOx cutpoint) 

HC co NOx 

--------- --------- --------- Format 

0.98 1. 00 0.85 Choice #1, Pre-1986 model years 

1. 00 1. 00 0.88 Choice #1, 1986-1989 model years 

1. 00 1. 00 1. 00 Choice #1, 1990 and newer model 

0.98 1. 00 0.85 Choice #2, Pre-1986 model years 

1. 00 1. 00 0.88 Choice #2, 1986-1989 model years 

1. 00 1. 00 0.92 Choice #2, 1990 and newer model 

0.98 1. 00 0.85 Choice #3, Pre-1986 model years 

1. 00 1. 00 0.85 Choice #3, 1986-1989 model years 

0.82 0. 71 0.92 Choice #3, 1990 and newer model 

0.98 1. 00 0.85 Choice #4, Pre-1986 model years 

1. 00 1. 00 0.83 Choice #4, 1986-1989 model years 

0.82 0. 71 0.69 Choice #4, 1990 and newer model 

years 

years 

years 

years 

Variable CSCRN containing the clean-screening fraction exampted 

by age for Choices #1-4. 

Choice 1: 0.5/200/1000 HC/CO/NOx cutpoints 

2: 0.5/200/1500 HC/CO/NOx cutpoints 

3: 0 .5/200/2000 HC/CO/NOx cutpoints 

4: 0.5/200 HC/CO cutpoints (no NOx cutpoint) 

Choice #1 Choice #2 Choice #3 Choice #4 

--------- --------- --------- --------- Format 

37 
971 0.614 0.694 0.724 0.834 Age 1 

972 0.553 0.633 0.663 0.773 Age 2 

973 0.492 0.572 0.602 0. 712 Age 3 

974 0.431 0. 511 0.541 0.651 Age 4 

975 0.370 0.450 0.480 0 . 590 Age 5 

976 0.309 0.389 0.419 0.529 Age 6 

977 0.248 0.328 0.358 0.468 Age 7 

978 0 . 187 0.267 0 . 297 0 . 407 Age 8 

979 0.157 0.237 0 . 267 0 . 377 Age 9 

980 0.128 0.208 0 . 238 0.348 Age 10 

981 0.099 0.179 0 . 209 0 . 318 Age 11 

982 0 . 069 0.149 0.179 0.289 Age 12 

983 0.040 0 . 120 0.150 0.260 Age 13 

984 0.025 0 . 105 0 . 135 0.245 Age 14 

985 0 . 010 0 . 090 0 . 120 0.230 Age 15 

986 0 . 010 0.075 0 . 105 0.215 Age 16 

987 0.010 0.075 0.105 0.215 Age 17 

988 0 . 010 0.075 0.105 0.215 Age 18 

989 0 . 010 0.075 0.105 0.215 Age 19 

990 0 . 010 0 . 075 0.105 0.215 Age 20 

991 0.010 0 . 075 0.105 0 . 215 Age 21 

992 0 . 010 0.075 0.105 0 . 215 Age 22 

993 0 . 010 0 . 075 0.105 0 . 215 Age 23 

994 0.010 0 . 075 0.105 0.215 Age 24 

995 0.010 0.075 0 . 105 0.215 Age 25 

000 

38