United States        Office of Air
Environmenta1 Protection  and Radiation
Agency            Washington. DC 20460
Sentainber ^987
Air   		

Motor  Vehicle Tampering
Survey -  1986


                        OOR87001

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United  States Environmental Protection  Agency

          Office of Air  and Radiation
    MOTOR  VEHICLE TAMPERING SURVEY -  1986

                 September  1987
    FIELD OPERATIONS AND  SUPPORT DIVISION
            OFFICE OF MOBILE  SOURCES
                Washington, D.C.
                   U.S. Environmental Protection IF;
                   Eegion 5, Library (5PL-16)
                   230 S. Dearborn Street, Room 1670
                   Chicago, IL  60604

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                      TABLE OF CONTENTS


EXECUTIVE SUMMARY  	  1

  Introduction	  1
  Conclusions 	  3

BACKGROUND 	  9

SURVEY METHODS 	 11

  Site Descriptions 	 13

RESULTS  	 19

  Vehicle Tampering 	 19
    Site and Aggregate Totals 	 19
    Tampering Trends 1978-1986 	 21
    Types of Tampering 	 26
    Vehicle Characteristics and Tampering 	 26
      Manufacturer	 29
      Vehicle Type  	 29
      Vehicle Age  	 31
    Impact of I/M and Antitampering Programs 	 39
    Tampering Trends for Selected Sites  	,. 40
    Correlation Between Tampering and Idle Emissions . . . . , 44

  Fuel Switching 	 49
    Fuel Switching Indicators and Overlap 	 49
    Fuel Switching Trends	 52
    Fuel Switching by Vehicle Type	 55
    Catalyst Tampering and Fuel Switching 	 55
    Gasoline Lead Concentrations 	 60

APPENDICIES

    A.  Relevant Portions of Clean Air Act 	 62
    B.  Survey and Data Recording Procedures 	 63
    C.  Emission Cutpoint for I/M Areas  	 77


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                       LIST OF FIGURES
 1.  Component specific tampering:
     1982-1986 surveys  	  4

 2.  Overall and catalyst tampering by vehicle model
     year - 1986 survey  	 7

 3.  Breakdown of surveyed vehicles by condition and
     extent of tampering 	 20

 4.  Tampering rates by manufacturer: 1986 survey 	 30

 5.  Comparison of LOT and LDV tampering in the 1982-1986
     surveys 	 32

 6.  Cumulative tampering prevalence as a function of
     vehicle age for the 1982-1986 surveys 	 37

 7.  Cumulative catalyst tampering rates as a function
     of vehicle age for the 1982-1986 surveys 	 38

 8.  Distribution of survey sample among tampering/  fuel
     switching, and idle test categories 	 45

 9.  Overlap of fuel switching indicators among unleaded
     vehicles - 1986 survey	 51

10.  Overlap of catalyst tampering and fuel switching
     among catalyst-equipped vehicles - 1986 survey 	 57

11.  Overlap of indicators used by ATPs to detect missing/
     damaged catalysts-1986 survey	 59

12.  Lead concentrations in leaded fuel sampled from
     misfueled vehicles 	 61
                             -11-

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                        LIST OF TABLES
 1.  Tampering Prevalence by Vehicle Type for
     Critical Control Components 	   7

 2.  1986 Tampering Survey Summary 	  22

 3.  Trends in Vehicle Condition Classification	  23

 4.  Comparison of EGR System Tampering to Overall
     Tampering in the 1982-1986 Surveys 	  25

 5.  Comparison of 1986 Survey Sample to Actual
     Nationwide Vehicle Fleet 	  25

 6.  Prevalence of Tampering by Component and Survey
     Year 	  27

 7.  Component-Specific Tampering Rates (percent) by
     Survey Location - 1986 Survey 	  28

 8.  Tampering Prevalence (and Sample Size) by Model
     Year and Vehicle Age at Time of Survey 	  33

 9.  Percentage of Catalyst Removal (and Sample Size)
     among Catalyst-Equipped Vehicles by Model Year
     and Vehicle Age at Time of Survey 	  34

10.  Tampering Prevalence among Vehicles and Components
     Covered by Three Antitampering Programs for the
     1983-1986 Surveys 	  42

11.  Comparison of Tampering among Missouri Vehicles
     (I/M + ATP) and Illinois Vehicles (non-I/M)
     Surveyed in St. Louis, MO and East St. Louis, IL
     in 1986 	  42

12.  Idle Test Failure Rates (percent) by
     Pollutant and Vehicle Condition 	  47
                            -111-

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13.   Mean Idle Emissions by Vehicle Condition 	 47

14.   Fuel Switching Rates among Unleaded Vehicles by
     Site and Indicator - 1986 Survey 	 53

15.   Fuel Switching Rates among Unleaded Vehicles by
     Indicator and Survey Year 	 54

16.   Combined Tampering and Fuel Switching - 1986 Survey . 56

17.   Percentage of Fuel Switching Indicators by Vehicle
     Type  	 57
                             -iv-

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                      EXECUTIVE SUMMARY


                         INTRODUCTION

     Under the direction of the Field Operations and Support

Division (FOSD) of the Environmental Protection Agency (EPA),

contract personnel from Colorado State University (CSU)

conducted a survey of light-duty motor vehicle tampering in

15 cities between April and September,  1986.  The areas surveyed

and the total number of vehicles inspected are listed below.
St. Louis, MO         413
East St. Louis, IL    551
Jacksonville, FL      477
Orlando, FL           575
Houston, TX           507
Memphis, TN           580
Pittsburgh, PA        504
Richmond, VA          500
Hartford,  CT
Camden,  NJ
Covington, KY
Seattle, WA
Los Angeles, CA
Tucson,  AZ
Baton Rouge, LA
428
498
500
504
505
499
500
                                 TOTAL
          7,541 vehicles
The objectives of this survey were:

     1.  To make local measurements of the types and extent of
        tampering and fuel switching.

     2.  To extend and update the knowledge gained from earlier
        surveys on:

        a. The rates of overall and component-specific
           tampering and fuel switching.

        b. The distribution of tampering by vehicle age,
           type, manufacturer, and other variables of
           interest.

        c. The relationship between tampering and vehicle
           idle emissions.

        d. The effect of vehicle inspection and maintenance
           (I/M) programs and antitampering programs (ATPs)
           on tampering and fuel switching.

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                             -2-


     To achieve these objectives, the inspection teams

visually examined emission control devices and measured the

idle hydrocarbon (HC) and carbon monoxide (CO) emissions of

each vehicle.  To provide information on fuel switching, the

inspectors sampled gasoline from the tanks of vehicles  (for

later laboratory lead analysis), tested for lead deposits in

tailpipes using Plumbtesmo test paper, and checked the

integrity of the fuel filler inlet restrictors.  Four cate-

gories were used to summarize the condition of the inspected

vehicles:

     1. Tampered - at least one control device removed or
        rendered inoperative

     2. Arguably Tampered - possible but not clear-cut
        tampering (i.e., may have resulted from either
        tampering or malmaintenance)

     3. Malfunctioning

     4. Okay - all control devices present and apparently
        operating properly

These brief but thorough inspections were performed with the

consent of the vehicle owners in a variety of settings more

fully detailed elsewhere in this report.

     While the data from a survey such as this seem to invite

inferences regarding program effectiveness,  trends, etc., this

approach can easily lead to incorrect conclusions.  The sample

size is reasonably adequate for evaluating tampering prevalence

in any particular site, but the sampling of sites  is neither

large nor random.  Simple comparisons of tampering by site

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across control program categories,  for example, can overlook



a variety of confounding factors.  These may include geographi-



cal variability, fleet age structure and vehicle mix, variations



in program maturity, coverage, history, and management, and



the interactions among these  factors.  Straightforward



experimental control of these variables, difficult to achieve



under the best of circumstances, becomes impossible in a



situation where site selection is driven by programmatic



considerations unrelated to the experimental questions.






                         CONCLUSIONS



     In this study the vehicles surveyed were classified as



follows:  tampered - 20%; arguably tampered - 25%; malfunc-



tioning - 1%; okay - 54% (overall survey averages).  This



gross classification, while useful for some comparisons, is



less informative concerning the emissions impact of tampering



than an examination of component-specific rates.  The



percentage of tampered vehicles (20%) is the same as was



found in the 1985 survey.



     Component-specific tampering for selected critical



components is shown in Figure 1.  The results shown have not



been weighted to compensate for I/M program representation;



these rates probably underestimate the actual nationwide rates.

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                               -4-
Component or Systgm
Catalytic Converter
 Evaporative  System
    Air Pump  System
   Inlet Restrictor
         PCV  System
         EGR  System
                     ////////////////////A BZ
                                Tampering (%)
              1982


              1983


              1984


              1985


              1986
                                                         J 13*
        Change in classification of evaporative system tampering.
         hava been 4Z using prior classification mothod.
Tampering rate would
         Figure  1.    Compongnt-specific  tamponing:
                       1982 -  1986 surveys.

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Tampering with evaporative and air pump  systems has  increased

since  L985, while the rates for other components have remained

unchanged.  The increase  in evaporative  system tampering,

however, is the result of a change in the classification metho-

dology  in the 1986 survey, as will be discussed later in the

report.  Evaporative system tampering would have been 4% using

the methodology from earlier surveys.

     The catalytic converter removal rate for the 1986 survey

was 5%  overall.  Catalytic converter removal increases HC and

CO emissions by an average of 475% and 425%, respectively.1

For vehicles equipped with three-way converters, substantial

increases in NOX emissions would also be expected to occur.

     The air pump system was the most frequently tampered

system  (8%).  This is the first survey is which air pump

tampering was the most prevalent form of tampering.


Fuel Switching

     Fuel switching,  defined as the presence of any of the

three indicators^, was found in 9% of the unleaded vehicles in

the 1986 survey.   The pattern of overlap among the three misfueling
1  The emissions increases mentioned in this report are from a
study of three-way catalyst vehicles presented in Ant i-Tampering
and Anti-Misfueling Programs to Reduce In-Use Emissions from
Motor Vehicles,  EPA-AA-TTS-83-10,  December 31, 1983.

2  The three fuel switching indicators are: a tampered fuel
filler inlet restrictor,  a positive Plumbtesmo tailpipe test,
or a gasoline lead concentration of more than 0.05 gram per
gallon.

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                              -6-






indicators is discussed in detail later in this report.  While



the emissions impact of fuel switching depends upon its duration



and certain vehicle characteristics, emission increases of 475%



for HC and 425% for CO can easily occur.






Age of Vehicle



     The probability that a vehicle has been tampered with is



clearly related to its age, as has been shown in previous



surveys.  This is evident in Figure 2,  which shows the rates



by model year for both overall tampering and catalyst removal.



These age-specific rates are investigated more thoroughly later



in this report.






Vehicle Types




     The tampering rates for light-duty trucks were equal to



or higher than for automobiles in every tampering category, as



shown in Table 1.   Overall tampering with trucks was the same



as for automobiles (20%), marking the first time overall truck



tampering has not exceeded overall automobile tampering.  This



trend is discussed in greater detail later in this report.



Converter tampering on trucks remained much greater than on



automobiles (9% vs 5%) and fuel switching among trucks was



greater as well (11% vs 8%).

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                        -7-
                                                       Ovvrall Tcnparlng


                                                       Catalyat TcMparlng
 1966  1985  198*  1983  1982 1961  1980  1979  1978  1977 1976  1975
                    Vahlcla Modal Year
    Figure 2.  Overall and  catalyst  tampering by
                vehicle model  year -  1986 survey.
                        TABLE 1

      Tampering  Prevalence by Vehicle Type  for
            Critical  Control Components

                               Tampering Rate (%)
Component /System
Catalytic Converter
Filler Neck Restrictor
Air Pump System
PCV System
Evaporative Control
System
EGR System
OVERALL
Trucks
9
3
10
5
8
7
20
Cars
5
7
8
5
5
7
20
Overall
5
7
8
5
6
1
20
Fuel  Switching
11
8

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I/M Programs and Tampering



     Tampering in non-I/M sites surveyed was 24%, while



tampering in ATP-only, I/M-only, and I/M + ATP sites were



20%, 18%, and 17%, respectively.  Fuel switching was likewise



greater  in non-I/M areas (12%) than in ATP-only, I/M-only,



and I/M + ATP areas (8%,  8%, 6%, respectively).  Such



comparisons across program categories should be made very



carefully, since the number of sites per program category



is small enough that site-specific factors other than program



type may greatly influence tampering prevalence.  In addition,



the classification of sites into program categories is



necessarily somewhat rough.  The antitampering program in



Baton Rouge, for example, only covers 1980 and newer vehicles.



New Jersey's antitampering program,  which was being phased



in over a 16 month period, only covered 1982 and newer vehicles



at the time of the survey.  Because of restricted program



coverage aimed at newer vehicles (those less likely to be



tampered with because of  warranty status and age) the impact



of newly implemented programs may not be observable for



several years.  The effectiveness of control programs in



deterring tampering among components and model years covered



by each specific program will be investigated later in this



report.

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                           BACKGROUND



     Motor vehicle emissions in urban areas account for nearly



90% of the total carbon monoxide  (CO) and airborne lead, over



30% of the hydrocarbons (HC), and nearly 40% of the oxides of



nitrogen  (NOX) emitted into the atmosphere.  As a result, a major




focus of  the nation's efforts to achieve compliance with clean



air standards has been the control of emissions from mobile




sources.  The first pollution control devices were installed on



vehicles  in 1962, and most light-duty vehicles manufactured



since 1968 have been equipped with a variety of emission control



devices to meet required emissions standards.



     The  1977 amendments to the Clean Air Act (sections



203(a)(3)(A) and (B), found in Appendix A) make it illegal for



automobile dealers, repair and service facilities, and fleet




operators to disconnect or render inoperative emission control



devices or elements of design.  Regulations issued under section



211(c) of the Act (40 CFR Part 80) prohibit retailers and



wholesale purchaser-consumers from introducing or allowing the



introduction of leaded gasoline into vehicles labeled "unleaded



gasoline only".   The EPA's Field Operations and Support Division



(FOSD),  formerly the Mobile Source Enforcement Division (MSED),



is responsible for enforcing the tampering and misfueling



provisions of the Act.

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                              -10-



     Before 1978, the EPA had data suggesting that tampering



with emission control devices and misfueling of "unleaded only"



vehicles with leaded gasoline was occurring.  Variability in



the inspection procedures, however, prevented an accurate



assessment of the nature and extent of the tampering.  As a



result, the Agency began conducting nationwide tampering



surveys of light-duty motor vehicles in 1978 to determine the



rates and types of tampering and fuel switching.  These



annual surveys have been conducted either by FOSD directly or



by EPA's National Enforcement Investigations Center (NEIC)



under the direction of FOSD.  Consistent inspection procedures



were used throughout these surveys to permit comparisons and



identification of trends.



     The uses for the tampering surveys have evolved since the



first survey was conducted in 1978.  Since 1983, the tampering




survey results for some locations have been used to calculate



credits for State Implementation Plans (SIPs), the measures



taken by State and local governments to achieve ambient air



quality standards by reducing mobile source emissions.  Data



from the surveys is also used in the default database for the



Agency's mobile source computer model (MOBILES) to estimate




both the emissions loading impact and the reductions that may



be achieved by various control programs.  Sites for the surveys




are chosen in light of the need for data on specific areas



either currently operating or considering programs, as well as



the continuing need to monitor the types and extent of tampering




and fuel switching nationwide.

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                              -11-

                         SURVEY METHODS

     The 1986 tampering  survey was conducted  for FOSD by the

National Center for Vehicle Emissions Control and  Safety at

Colorado State University  (CSU).  Approximately 400 to 600

vehicles were inspected  in each of 15 cities  between April

and September, 1986, and the  entire survey includes 7,541

vehicles.  The mix of vehicles inspected was  assumed to be a

self-weighting sample, and no attempt was made to  approximate

the national vehicle mix.

     Each inspection team  consisted of at least four members:

three CSU personnel, one or two EPA representatives, and fre-

quently a state or local agency representative.  The CSU

personnel, assisted by the state or local person,  performed

the actual inspections, while the EPA representative(s)

supervised the survey.   Each  vehicle inspection included the

following:

     1.  basic vehicle identification data recorded (year,
         make, model)

     2.  all emission control systems checked

     3.  idle EC and CO emissions measured

     4.  fuel sample collected from unleaded-only vehicles for
         lead analysis

     5.  tailpipe tested for lead deposits using Plumbtesmo1
         test paper

     6.  integrity of fuel inlet restrictor checked
1  Plumbtesmo is a registered trademark, and appears hereafter
without the .  It is manufactur- 1 by Machery-Nagel,  Duren, W.
Germany, and marketed by Gallard-Schlesinger Chemical Corp.,
Carle Place, New York.

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                              12-






     The inspection procedures used were consistent with



those of previous surveys,  except for one change made in the



classification methodology for evaporative system tampering.



In prior surveys a vehicle with a unsealed air cleaner was




coded as malfunctioning for the evaporative system.  In 1986



an unsealed air cleaner was receded as tampering to reflect



the deliberate nature of this condition.  As a result,



evaporative system tampering in 1986 was significantly higher



than it would have been if the coding system from earlier



surveys was used.  The inspection and recording procedures



are detailed in Appendix B.



     The survey database has been reviewed by CSU and EPA to



ensure its accuracy, and has been offered to the major



automotive manufacturers to review the classification and



reporting of their respective vehicles.



     The tampering survey included only 1975 and newer



light-duty cars and trucks fueled with gasoline.  For the



purposes of the tampering surveys, a vehicle is considered



to be "unleaded" if a dash label, tank label, or filler inlet



restrictor is observed at the time of the inspection, or if



the emission control label indicates an unleaded fuel



requirement (i.e., catalyst-equipped).  A vehicle's designation



as "unleaded" or "leaded" may be changed upon subsequent

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                              -13-


review of the data.  Fuel switching rates are thus based

only on the population of unleaded vehicles surveyed.

Similarly, tampering rates for specific components are based

only on the vehicles originally equipped with the component.

     The inspections were performed with the consent of the

vehicle owners at either roadside pullovers or inspection

stations.  The survey was designed to minimize the refusal

rate of potential survey participants.  A high refusal rate

increases the uncertainty in the data gathered, since

individuals who have tampered with or misfueled their vehicles

are less likely to allow their vehicles to be surveyed.  The

overall refusal rate was very low (4%),  however,  and no

survey sites had a refusal rate over 10%.  A brief description

of each survey site follows.   Unless otherwise noted, the

survey sites within a given city were changed daily.

St. Louis,  Missouri - I/M + ATP

Dates:               April 14 - 18, 1986
Vehicles Surveyed:       413
Fuel Samples:            338
Refusal Rate:             10%

     The St.  Louis Police Department provided officers to

stop potential survey participants, and the inspectors solicited

permission to conduct the inspections.  The decentralized I/M

program includes a catalytic converter inspection on 1981 and

later vehicles,  and air pump, PCV,  and EGR inspections on all

vehicles.

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                             -J4-

East St. Louisf  Illinois - non-I/M

Dates:               April 21 - 25, 1986
Vehicles Surveyed:       551
Fuel Samples:            392
Refusal Rate:              5%

     Roadside pullovers were conducted with the help of the

Illinois State Police.  Inspection locations included East

St. Louis (two days), Washington Park (2 days), arid Alorton.


Jacksonville, Florida - non-I/M

Dates:               May 5-9, 1986
Vehicles Surveyed:       477
Fuel Samples:            426
Refusal Rate:              3%


Or1ando, Florida - non-1/M

Dates:               May 12 - 16, 1986
Vehicles Surveyed:       575
Fuel Samples:            475
Refusal Rate:              4%

     Roadside pullovers were conducted with the assistance

of the Florida State Police in both Jacksonville and Orlando.


Houston, Texas _- ATP-Only

Dates:               May 19 - 23, 1986
Vehicles Surveyed:       507
Fuel Samples:            422
Refusal Rate:              7%

     The Texas Department of Public Safety provided officers

to assist with the roadside pullovers.  Inspection locations

included Houston (three days), La Porte, and South Houston.

The decentralized antitamper ing program includes Plumbtesmo

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                             -15-

testing and inspection of the catalytic converters and inlet

restrictors on 1980 and newer vehicles, and inspection of the

PCV, air pump, EGR, and evaporative systems on 1968 and later

vehicles.


Memphis, Tennessee - I/M-only

Dates:               June 2-6, 1986
Vehicles Surveyed:       580
Fuel Samples:            464
Refusal Rate:              1%

     The survey was conducted each day at the downtown centralized

inspection station in Memphis.  The inspection team set up

and conducted the survey while vehicles were undergoing the

emissions and safety inspection.  The I/M program in Memphis

covers all model years of light duty vehicles.


Pittsburgh, Pennsylvania - I/M-only

Dates:               June 16 - 20, 1986
Vehicles Surveyed:       504
Fuel Samples:            401
Refusal Rate:              4%

     The Pittsburgh survey was conducted using roadside

pullovers in the townships of Penn Hills, Moon, Ross, Shaler,

and Robinson with the help of the local law enforcement

officers in these municipalities.  Pittsburgh's decentralized

I/M program covers 1968 and newer vehicles.


Richmond, Virginia - ATP-only

Dates:               June 23 - 27, 1986
Vehicles Surveyed:       500
Fuel Samples:            395
Refusal Rate:              4%

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                             -16-

     The Richmond survey was conducted usinc^ roadside pullovers

with the assistance of the Virginia State Police.  Richmond

has an untitampering inspection incorporated into its annual

safety inspection program.


Hartford, Connecticut - I/M-only

Dates:               July 7-11, 1986
Vehicles Surveyed:        428
Fuel Samples:            341
Refusal Rate:              7%

     The Hartford Police Department assisted with the roadside

pullovers.  Hartford's centralized I/M program covers 1968

and newer vehicles.


Carnden, New Jersey - I/M + ATP

Dates:               July 14 - 18,  1986
Vehicles Surveyed:        498
Fuel Samples:            394
Refusal Rate:              8%

     The New Jersey Police Department assisted with the

roadside pullovers.  New Jersey's I/M program dates back to

1974,  and the antitampering inspection is being phased in to

cover 1975 and newer vehicles by May 1987.  At the time of

the survey the ATP included a catalytic converter and inlet

restrictor check on 1982 and newer vehicles.


Cov i ng ton, Kentucky - non-1/M

Dates:               July 21 - 25,  1986
Vehicles Surveyed:        500
Fuel Samples:            403
Refusal Rate:              4%

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                             -17-

     Th e Covington  survey was conducted  in Boone County  (two

clays), Campbell County, and Kenton County (two days).  The

respective County Police Departments assisted with the road-

side pullovers.  Covington was a non-I/M area at the time of

the survey, but implemented a decentralized ATP-only in

September 1986.


Seattle, Washington - I/M-only

Dates:               August 12 -16, 1986
Vehicles Surveyed:       504
Fuel Samples:            311
Refusal Rate:              3%

     The survey was conducted at five centralized I/M stations

in the metropolitan Seattle area.  Seattle's I/M program

covers all vehicles in the most recent 13 model years.


Los Angeles, California - I/M + ATP

Dates:               August 25 - 29,  1986
Vehicles Surveyed:       505
Fuel Samples:            373
Refusal Rate:              3%

     The California Highway Patrol provided officers to assist

*dth the roadside pullovers.  The decentralized I/M + ATP

includes inspection of the catalytic converter, air pump,

PCV, EGR, and evaporative systems on all vehicles.


Tucson, Arizona - I/M-only

Dates:               September 8-12, 1986
Vehicles Surveyed:       499
Fuel Samples:            382
Refusal Rate:              1%

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                             -18-

     Th e Tucson survey was Conducted at three centralized I/M

stations.  Tucson was an I/M-only area at the time of the

survey, but added an ATP covering 1975 and newer vehicles in

January 1987.


Baton Rouge, Louisiana - ATP-only

Dates:               September 15 - 19, 1986
Vehicles Surveyed:       500
Fuel Samples:            451
Refusal Rate:              4%

     The Baton Rouge survey was conducted using roadside

pullovers with the assistance of the Louisiana State Police.

Survey locations were the same as in the 1985 survey.  The

decentralized ATP was implemented in September 1985, and

includes a check of the converter,  inlet restrictor, and

Plumbtesmo test on 1980 and newer model year vehicles.

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                             -19-

                            RESULTS

A. VEHICLE TAMPERING

1. Site and Aggregate Totals

     The vehicles surveyed have been classified into four

categories established by previous surveys: tampered,

arguably tampered, malfunctioning, and okay.  Each vehicle

was classified by the worst state of any component in the

vehicle.  For example, a vehicle would be classified as

"tampered" if any one component had been tampered, even if

all other components were functioning properly.  A vehicle

classified as "okay" must have all observed components

functioning properly!.  The criteria used for component

classification are presented in Appendix B.  This overall

tampering rate is useful only as a rough indicator of the

emissions impact of a tampering problem, since the different

components making up the rate may have widely varying emissions

implications.

     The proportion of inspected vehicles with at least one

tampered component was 20%.  Nearly half of the vehicles

surveyed (46%) displayed some form of malfunction, arguable

tampering, or clear tampering of emission control components.

The specific distribution of surveyed vehicles among these

categories is depicted in Figure 3.
1  An "okay" vehicle,  however, may still be classified as
fuel switched (see sectioa 8.1., ^uel Switching Indicators
and Overlap of this report).

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                            -21-



     The frequency distribution of tampering instances for




those vehicles classified as "tampered" is also shown in



Figure 3.  Forty-six percent of the tampered vehicles had



multiple components tampered, and 15% had four or more



instances of tampering.



     Table 2 summarizes the 1986 survey data by site.  As



in previous surveys, the overall tampering in 1986 varies



considerably from site to site.  This can be attributed



to the variety of program configurations among the cities



surveyed and to geographic differences.



     Table 2 also contains the refusal rate at each survey



site.  The overall refusal rate for the survey was very



low (4%), and only one survey site (St. Louis) had a refusal



rate equal to or exceeding 10%.  The actual tampering rate



in St. Louis may thus be higher than is reported here,



since individuals who tamper with or misfuel their vehicles



are less likely to allow their vehicles to be surveyed.






2.  Tampering Trends 1978-1986



     Table 3 shows the overall rates found in each of the



eight tampering surveys.  Overall tampering and arguable



tampering generally appear to be decreasing,  and the percent



of properly maintained vehicles has been steadily increasing.



The decrease in overall tampering can be examined more



carefully by separating NOx-related tampering (EGR system

-------
                                -22-
Survey
Location
St. Louis, MO

East St. Louis, ^

Jacksonville, FL

Orlando, FL

Houston, TX

Memphis, TN

Pittsburgh, PA

Ri chmond,  VA

Hartford,  CT

Camden, NJ

Covington, KY

Seattle, WA

Los Angeles, CA

Tucson, AZ

Baton Rouge, LA
             TABLE 2

  1986 Tampering Survey Summary

Number of  Tampering  Misfueling  Survey  Refusal
Vehicles   Rate (%)   Rate (%)    Type*   Rate  (%
413
0 551
477
575
507
580
504
500
428
498
500
504
505
499
500
15
23
21
26
24
21
12
14
13
19
24
18
15
25
23
4
8
9
15
9
14
4
5
5
6
15
4
6
10
10
R
R
R
R
R
C
R
R
R
R
R
C
R
C
R
10
5
3
4
7
1
4
4
7
8
4
3
3
1
4
OVERALL
 7,541
20
4
  *R = roadside pullovers, C = centralized I/M stations

-------
                          TABLE 3

         Trends in Vehicle Condition Classification
Survey
Year
1978
1979
1981*
1982
1983
1984
1985
1986
Tampered
19
18
14
17
25
22
20
20
Arguably
Tamper ed(%)
48
47
45
38
30
29
27
25
Malfunctioning
2
2
3
1
3
4
1
1
Oka
31
33
38
44
42
46
52
54
^Because the 1981 survey involved only two sites and a very
 limited sample size,  these results may exhibit more variance
 than the other larger surveys.

-------
                             -24-
tampering) from HC- and CO-related tampering.   Table 4
shows that HC- and CO-related tampering have in fact regained
relatively constant since 1983.  EGR tampering, however,
has declined markedly since 1983.
     Direct comparisons between survey years should be made
carefully, since they do not take into account differences
among surveys in site selection, vehicle age,  and car/truck
distributions.  More importantly, because of the 1986
survey's specific goals, it greatly over represents the portion
of the national vehicle fleet under local control programs
(see Table 5).  Areas with control programs comprised 72% of
the survey sample, while only approximately 41% of the national
vehicle fleet were under such programs.
     This discrepancy can be corrected to some degree by
applying a weighting factor to the tampering rates found
under each program type.  The 1986 tampering rate weighted
for program representation is 21%.  The 1986 weighted tampering
rate can be compared to the weighted rates from the 1985,, 1984,
1983, and 1982 surveys  (21%, 26%, 28% and 19%, respectively.)
Applying weighting factors to the 1981 and earlier surveys
would be difficult, since some surveys contained no I/M
areas.  The use of weighting factors here also does not account
for differences in program coverage between sites.  For the
sake of clarity, only the actual, unweighted rates found
during the surveys will be reported.

-------
                            -25-
                           TABLE 4

   Comparison of EGR System Tampering to Overall Tampering
                   in the 1982-1986 Surveys

                            Tampering (%) by Survey Year

Tampering Category          1982  1983   1984  1985  1986

Overall Tampering            17%   25%    22%   20%   20%

Overall Tampering (excluding
  EGR System Tampering)       10*   19*    16*   17    17

EGR System Tampering         10    13     10     7     7

EGR System-only Tampering**   76      433

 * Tampering with idle stop solenoid and vacuum spark retard
   were also excluded since these components were not inspected
   in 1985 and later surveys.

** Vehicles with EGR system tampering and no other tampering.
                           TABLE 5

   Comparison of 1986 Survey Sample to Actual Nationwide
                       Vehicle Fleet

   Program      Percentage within    Approx. Percentage of
    Type        Survey Sample _(_%)_    Nationwide Fleet (%)*

   non-I/M             28                    59

   I/M-only            33                    14

   I/M + ATP           19                    21

   ATP-only            20                     6
   *Based on 1986 population J^ta gathered from EPA Regional
    and State contacts.

-------
3   Types of Tamperj. ng



     The tampering rates 'ror specific emission control



components and systems for the surveys conducted since 1982



are presented in Table 6.   The component-specific tampering



rates for the 1986 survey are presented by survey site in




Table 7.  Only those vehicles originally equipped with a



particular component are considered when computing the



tampering rate for that component.



     Table 6 shows that tampering with the major emission



control components has generally remained unchanged from the



1985 survey.  Air pump system tampering has been gradually



increasing since 1982,  and EGR system and catalytic converter




tampering have been decreasing since 1983.



     Table 7 shows the wide variation in tampering from site




to site for any given component.  Catalytic converter removal,



for example, ranged from 1% in Los Angeles and Hartford to



11% in Covington and Orlando.  This range is partly due to



the effectiveness of I/M and antitampering programs (as



will be discussed later in this report), geographic location,



and socioeconomic background.






4.  Vehicle Characteristics and Tampering



     The next section of tliio report investigates the impact



on tampering of three vehicle characteristics: manufacturer,



vehicle type (car or truck), aad age.

-------
                             -27-


                           TABLE 6

     Prevalence of Tampering by Component and Survey Year
  Component/System     1982

  Catalytic Converter

  Filler Neck
  Restrictor

  Air P imp System
   Air Pump Belt
   Air Pump/Valve

  Aspirator*

  PCV System

  Evaporative
  Control System

  EGR System
   EGR Control Valve
   EGR Sensor

  Heated Air Intake

  Vacuum Spark
  Retard

  Idle Stop
  Solenoid

  Oxygen Sensor
  Survey Year

1983    1984   1985
1986
4%
6
5
5
4
1
3
2
10
7
7
1
0
0
**
7%
7
7
7
3
1
5
5
13
9
12
1
1
1
0
7%
10
7
7
4
1
2
3
10
7
6
1
5
1
0
5%
7
7
4
6
2
5
4
7
6
4
1
**
**
0
5%

8
7
5
2
5
5***
7
6
5
2
**
**
1
  *Vehicles with aspirated air systems are not equipped with
   other listed air-injection components,  nor do conventional
   systems include aspirators.

 **Component not checked during survey.

***Change in tampering classification system in 1986.
   Evaporative system tampering would have been 4% using the
   prior classification method.

-------
                                -28-
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-------
                            -29-

     Manufacturer.  Figure 4 presents the L986 tampering

rates for each major manufacturer.  Separate tampering rates

are listed for each manufacturer with more than 100 vehicles

in the survey.  The remaining foreign manufacturers have been
                                                         5
combined into two groups, Other European and Other Asian.

With the exception of Volkswagen, vehicle tampering was

higher among vehicles of domestic manufacture than among

fiose of foreign manufacture.  Overall, tampering with domes-

tically manufactured vehicles was twice that found for the

foreign manufactured vehicles (22% vs. 11%).

     A number of factors might explain the discrepancy in

tampering among manufacturers.   Differences in design may

make some vehicles more tamper-prone  than others.  Changing

market share history results in different age distributions

for vehicles of different makes, and  vehicle age is clearly

related to tampering prevalence.  Tampering rates probably

vary with geographic location and socioeconomic background,

so the owner demographics for different makes may affect the

likelihood of tampering.

     Vehicle Type.   The overall tampering prevalence for

light-duty trucks (LDTs) was the same as for automobiles

(L'Ws), as was mentioned previously (Table 1).   While the

tampering rate for each emissions component on trucks was

equal to or greater than on passenger cars (as in previous

surveys) the 1986 survey is the first in which overall

-------
  I
  1
                         -30-
                               33%
  t
  1
  1
  1
  Ford
        -\  American Motors I-
                 Motors r
               21%
Chrysler    r
              20%
 Mcrzdo
            13%
        ^  Other Eurnpenn I
                        10%
        I   Llther Asjnn   I
                        8%
                        6%
   Tampering (%)
                      26%
                     25%
Figure  4.    TampQring by Manufacturer:
              1986  Survey.

-------
                            -31-

tampering with trucks and cars was the same.  Figure 5 shows
that the discrepancy between car and truck tampering has
been decreasing for the past five years.
     One factor that may be contributing to the convergence
in car and truck tampering is the increasing sales of imported
trucks.  Between 1982 and 1986 the proportion of imported
trucks within the total truck population surveyed has increased
from 10% to 15%.   Since imported vehicles are tampered with
much less frequently than domestic vehicles, the increase in
imported trucks within the truck population surveyed may be
contributing to the lower truck tampering prevalence.  Another
contributing factor may be the delayed impact of closed loop
technology on truck tampering relative to car tampering.
Closed loop technology first became widespread on trucks in
1983, while it had been widely used on cars since 1981.  Any
tampering deterrence from closed loop technology should thus
be evident on cars first/ and then later on trucks.
     Vehicle Age.   Table 8 relates vehicle age and model
year with tampering prevalence for the 1978-1986 surveys.
Catalytic converter removal rates are similarly related to
vehicle age and model year in Table 9.  The results from
any given survey  are entered diagonally in each table.
     The results in Tables 8 and 9 indicate that vehicle
tampering increases directly with vehicle age.   Examining
Table 8 diagonally (by survey) shows that tampering increases

-------
                          -32-
TampQring  (%)
     35
     30
     25
     20
     15
     10
      0
                                                  LDV

                                                  LOT
          1982     1983    1984     1985    1986
                      Survey Year
Figure 5.   Comparison  of LDV  and LOT  tampering
            in  the  1982 - 1986 surveys.

-------
                             -33-
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                               -34-
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-------
                             -35-

con.-jistently with vehicle age in each survey conducted.  In
the 1986 survey, for example, 'the tampering rate increases
i!rom 1% foe first year (1986) vehicles to 60% among the 1975
model year vehicles surveyed.  Table 9 shows a similar,
though less pronounced, increase in catalyst removal.  Examin-
ing these tables in this manner has the advantage of comparing
data collected during one survey in one set of locations, but
ignores the possible effects of model year differences (i.e.,
technology) on tampering.
     Two additional ways of analyzing Tables 8 and 9 address
the impact of model year on tampering rates.  Analyzing the
tables horizontally (holding the model year constant) provides
a look at the tampering rates over time for the vehicles of
a particular model year.   This approach shows the same distinct
irv:-ease in tampering with vehicle age for all model years
since 1975.  (The 1974 and 1973 data sets are too small to
permit any conclusions.)  For example, the tampering incidence
for 1973 vehicles increased from 7% in their first year to
50% by the ninth year of use.  The degree of overall tampering
among very old vehicles (ninth through twelfth years of usage)
appears to remain fairly constant at approximately 50% of the
vehicles surveyed.  A similar examination of Table 9 suggests
that converter removal continues to increase among these very
old vehicles.   More data from future surveys may be necessary
to discern any trend in tampering among these older vehicles.

-------
                             -56-



Analyziag Tables 8 and 9 horizontally combines observations



made from different survey sites -3,t different tim-.o and



should be undertaken cautiously.



     The influence of vehicle age on tampering can be more



clearly seen when the data in Tables 8 and 9 is presented



graphically.  Figures 6 and 7 plot overall and catalyst



tampering, respectively, as a function of vehicle age for



the 1982-1986 surveys.  This is equivalent to the diagonal



method of analysis used for Tables 8 and 9 that was outlined



previously.   Figure 6 demonstrates that the relationship



between tampering rate and vehicle age is not only linear,



but has remained nearly constant over the five most recent



surveys.  The strong correlation is obvious despite the



different sizes, vehicle compositions, and locations of the



>~rveys.  In Figure 7 the catalyst tampering rate remains



 agligible for the first two to three years of a vehicle's



 ice, and then increases thereafter.  This delay in catalyst



 :~pering is understandable, since the emission control



omponents on all new vehicles are warranted for 5 years/50,000



.>, les by the manufacturer, providing an incentive to maintain



the catalysts on vehicles still under warranty.  A similar



delay in overall tampering would also be expected, but is



not readily apparent  in Figure 6.

-------
-37-

-------
                        -38-
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-------
                            -39-



     Tables 8 and 9 can also be -analyzed vfi.-rt ically (holding



vehicle age constant), which provides a look at the tampering



rates for different model year vehicles of the same age.



This approach suggests that improvements in automotive



technology, such as closed loop emission control systems,



may affect overall tampering rates.  For example, vehicle



tampering among 1977 model year vehicles surveyed in



their third year of usage was at 18%.  By contrast, only 5%



of the 1984 model year vehicles in their third year of



usage were tampered.  A similar vertical analysis of Table



8, however, fails to show a clear pattern or trend in



age-specific catalyst tampering.  Vertical analysis of



Tables 8 and 9 introduces the same variability as the



horizontal analysis.





5.  Impact of I/M and Antitamperinq Programs



     Inspection and maintenance (I/M) programs require vehicles



to meet specific idle emission standards.   Vehicles registered



in areas with these programs are required to be periodically



tested to assure that they comply with the specific idle



emission cutpoints established by these jurisdictions.  In



addition to reducing emission levels by stimulating better



owner maintenance, I/M programs may deter some tampering with



emission control components.  Data from previous surveys has



tended to support this proposition, since tampering in I/M



areas has historically been lower than in non-I/M areas.

-------
                             -40-
     Some I/M areas have also instituted aatitampering
programs (ATPs),  which involve periodic vehicle inspections
to check the integrity of specific emission control components.
Antitanpering programs vary greatly in the components inspected
and the vehicle model years covered, so that a vehicle or
component which would be inspected in one program area might
not be inspected in a different program area.  Successful
antihampering programs should reduce existing tampering and
deter future tampering with the components and model years
covered by the program.
     The sites surveyed in 1986 can be classified very
generally as four non-I/M areas, five I/M-only areas, three
I/M + ATP areas,  and three ATP-only areas.  Such classification
is based solely on the presence or absence of a control
program at the time the area was surveyed, and does not take
into consideration variations in program coverage or
effectiveness.  Any comparisons between program types (i.e.,
I/M-only vs. non-I/M) should thus be made carefully.

5.   Tampering Trends for Selected Sites
     The impact of I/M and antitampering programs in specific
locations can be examined by comparing the 1986 survey data
with that from earlier surveys.  Comparisons made between
surveys widely spaced in time, however, must take into con-
sideration the differences in average vehicle age in each

-------
                             -41-
survey.  The average miles traveled per vehicle surveyed in
1986, for example, is one third greater than it was in
1983.  Since vehicle age is directly related to tampering
prevalence, a significant increase in tampering might be
expected to have occurred between 1983 and 1986, if all
other factors remained constant (car/truck distribution,
owner demographics, etc.).  Inferences regarding program
effects should thus be made with this in mind.
     Table 10 presents tampering data for three sites -
Camden, Houston, and Baton Rouge.  The comparisons made in
this table have been limited to the specific components and
vehicle model years covered by each antitampering program as
of the 1986 survey.  The tampering data listed in Table 10
were compiled only for surveyed vehicles included within the
local program jurisdiction.  The Houston tampering data,
for example,  are for Harris County vehicles only.  Any non-
Harris County vehicles surveyed were excluded from this
analysis.
     It is difficult to determine from Table 10 whether or
not New Jersey's recently implemented antitampering program
has had any impact on converter and inlet restrictor tampering
found on 1982 and newer vehicles, since the incidence of
tampering on these vehicles was already negligible.  As of
May 1, 1987,  New Jersey's antitampering program expanded to
1975 and newer vehicles,  and future surveys will examine the
program's effectiveness against older vehicles having a higher
tampering prevalence.

-------
                                    -42-

                                  TABLE 10

         Tampering Prevalence among Vehicles and Components Covered
              by Three Antitampering Programs for the 1983-1986
                             Tampering Surveys
Survey Location

Camden, NJ


Houston, TX
     Component and
  Model_ Years__ Covered

Catalytic Converter 82+
Inlet Restrictor    82+

Catalytic Converter 80+
Inlet Restrictor    80+
Positive Plumbtesmo 80+
PCV System          75+
Evaporative System  75+**
Air Pump System     75+

Catalytic Converter 80+
Inlet Restrictor    80+
PCV System          80+
Evaporative System  80+**
EGR System          80+
Air Pump System     80+
  survey was conducted after ATP had been implemented.
 Tampering Prevalence (%)
      by Survey Year
1983    1984    1985    1986
         1%
         1
 6
 1
 7
 9
 8
 9
Baton Rouge, LA
1*
0*
2*
4*
4*
6*

4
3
2
3
4
6
0%*
0*

3*
2*
2*
7*
7*
8*

3*
1*
3*
3*
4*
4*
 ^classification of evaporative system tampering changed in 1986 survey.
  Evaporative system tampering in Houston and Baton Rouge would have been
  5% and 2%, respectively, using the prior coding method.
                                  TABLE 11

               Comparison of Tampering among Missouri Vehicles
            (I/M + ATP) and Illinois Vehicles (non-I/M)  Surveyed
              in St. Louis, MO and East St. Louis, IL in 1986
                  Component and
                Model Years Covered
                                         Tampering (%) by State of
                                            Vehicle Registration
                        Missouri
         Illinois
             Catalytic Converter  81+

             Air Pump System      75+

             EGR System           75+

             PCV System           75+
                           0%

                           4

                           4

                           4
            2%

           10

            9

            6

-------
                             -43-
     The tampering data for vehicles cohered by Houston's
ATP-only suggest that this program was less effective in
its second year of operation than in its first.  Catalyst
and fuel-related tampering decreased sharply in 1985, after
one year of program operation, and underhood components
covered by the program had moderately reduced rates.  Tampering
seemed to have rebounded in 1986, however, particularly for
the underhood components.   Baton Rouge's ATP-only has been
partially effective in its first year of operation, since
tampering with 3 of the 6 components covered showed weak
declines between the 1985 survey (before program implemen-
tation) and the 1986 survey (one year after program imple-
mentation).  The other three components either did not
change or actually showed higher tampering.
     Table 11 examines the difference in tampering found in
St. Louis,  MO and East St.  Louis, IL.  In Table 11 the
vehicles surveyed at these two sites have been classified by
state of registration rather than location surveyed, since a
number of Missouri vehicles were surveyed in Illinois and
vice versa.   Also the tampering rates were determined for
the model year and components covered by Missouri's I/M + ATP
to examine  the Missouri program's effectiveness.   Table 11
shows a dramatic difference in tampering among vehicles in
close geographic proximity but under different control programs.
Part of this difference is probably due to the different

-------
                             _44-
socioeconomic makeup of the two cities -jarveyed, but the
presence of an I/M + ATP in Missouri is no doubt a contributing
factor to the lower tampering rates.

7.   Correlation between Tampering and Idle Emissions
     As was mentioned previously, vehicles which are subject
to an I/M program must meet specific idle emissions cutpoints.
To assess the relationship between tampering and fuel switch-
ing and idle failure rates, the idle emissions from vehicles
have been tested against the cutpoints established by the
I/M program where they were sampled.  Vehicles in non-I/M
areas were tested against the cutpoints specified by the New
Jersey I/M program.  The cutpoints for each I/M area are
listed in Appendix C.
     The results of the idle tests are presented in Figure 8
for vehicles in the various tampering and fuel switching
categories.  Only 17% of the surveyed vehicles that were free
of tampering and fuel switching failed an idle test, while
62% of the tampered and fuel switched vehicles failed that
test.  These results indicate that a substantially larger
proportion of tampered and fuel switched vehicles than of
okay vehicles fail an idle test at typical I/M cutpoints.
This is partly due to the tendency for tampered vehicles to
have misadjusted carburetors, since 77% of the tampered
vehicles with conventional carburetors also had missing

-------
                               -45-
 *
 en
 c

 L
 Q)
 Q.
        10


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a
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    CO
                                T3
                         cu  ;
                         i-!
                         D
OJ
(
Xw /j 1
D i 	 , ^j
4J
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LU





Arguably
tampored
25%






Fuel
switched
2%

 fl "Q
o; at
3 -C N*
**" " 
^_) TH
0 *
z: w








if 

|

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                                                                        a
                                                                        -P
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                                                                        >>



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Fuel
switched
1%

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grn

* i . #

W Kt
05 en
os malfunctioning vehicle

-------
                            -46-






sealed plugs or limiter caps.  It should be noted fro." Figure



'J,  however,  that 38% of the tampered and fuel  switched vehicles



were still able to pass the idle test.



     Table 12 shows the percentage of vehicles that failed



the idle emissions test for each vehicle condition.  The



failure rates are listed for the entire survey,  as well as




in two model year groupings representing "old" technology



(1975-1980)  and "new" technology (19814) vehicles.  "New"



technology signifies closed loop emissions control, which



came into widespread usage in 1981 model year  vehicles.



     The overall percentage of tampered vehicles exceeding I/M



cutpoints for HC emissions was nearly three times greater



than for okay vehicles (41% vs 14%).  Over five times as



many tampered vehicles exceeded CO cutpoints as did okay



vehicles (44% vs 9%).  The majority (60%) of the vehicles



that either  had been fuel switched or had their catalysts



removed also exceeded HC or CO limits.  Conversely, 40% of



the vehicles with missing catalysts or classified as fuel



switched were still able to pass an idle emissions test.  As



in previous  surveys, a significant number of arguably tampered



vehicles also produced excess idle emissions.   Since the



majority of  arguable tampering involves idle speed limiter



caps and sealed plugs, the high failure rate demonstrates



the adverse  idle emissions impact of improperly adjusted



carburetors.

-------
                             -47-
                           TABLE 12

        Idle Test Failure Rates (Percent) by Pollutant
                    and Vehicle Condition
Cat.  Removed
or Misfueled
                   Failure Rate (%) by Pollutant
                      for Model Years listed
Veh i c 1 e
Condition
Okay
Arguably
Tampered
Tampered
1975-80
HC
22
34
44
CO
14
37
49
1981+
HC
13
20
29
CO
8
21
27
HC
14
29
41
Overall
CO
9
31
44
HC or
17
42
57
CO



44   48
38   40
43   47
  60
                           TABLE 13

           Mean Idle Emissions by Vehicle Condition
    Prgram
    Type


    non-I/M

    I/M*

    ATP-only
   HC emissions(ppm)
   Tampered    Okay
    402.6      51.4

    280.2      51.5

    328.9      45.2
            CO emissions(%)
            Tampered  Okay
              3.5

              2.4

              2.8
           0.4

           0.3

           0.4
    OVERALL
    346.1
   50.6
  2.9
0.3
    *  category includes any program where idle emissions are
       checked, including 1/M + ATP areas.

-------
                              -48-



     The effectiveness of xnle emissions testing on "new"



technology vehicles can also be seen in Table 12.  The data in



Table 12 actually minimizes the impact of "new" technology



because "old" technology trucks manufactured after 1980 have



been included in the "new" technology category due to the



model year split.  As was found in the 1985 survey, idle emissions



testing is more effective in identifying tampering on 1980



and older vehicles than on 1981 and newer vehicles.  For example,



49% of the tampered "old" technology vehicles exceeded CO



cutpoints compared to 27% of the tampered "new" technology



vehicles.  This suggests that idle emissions testing may not



be an effective strategy for identifying tampering and fuel



switching among "new" technology vehicles, since many vehicles



with closed loop systems are able to produce low idle emissions



even with tampered emission control devices.



     The mean idle emissions for tampered and okay vehicles are



presented in Table 13 by program type.  Vehicles from Baton



Kouge are considered to be ATP-only for model years 1980 and



newer, while vehicles from model years 1975-1979 are classified



as non-I/M (following the program coverage in the area).  The



vehicles surveyed in Memphis are classified as I/M for CO



emissions but as non-l/M for HC emissions because the I/M



program effectively has no cutpoints for HC (see Appendix C).



Also areas with I/M or I/M + ATP have been combined in Table 13.

-------
                             -49-




     Th e mean  idle emissions from  tampered vehicles were


considerably greater than from properly maintained vehicles


(Table 13).  Overall, HC emissions from tampered vehicles were
                                                   <

nearly seven times greater on average than from okay vehicles,


while CO emissions were nearly 10  times greater.  Tampered


vehicles from  areas with I/M programs had the lowest average


HC and CO emissions, while tampered vehicles from areas with


ATP-only had slightly higher average emissions.  The slightly


higher idle emissions from vehicles in ATP-only areas is not


surprising, since these vehicles have not been tuned to pass


I/M cutpoints.




B. FUEL SWITCHING


1.  Fuel Switching Indicators and Overlap




     Fuel switching is more easily defined than measured,


since no single indicator can accurately determine its preva-


lence.  Since  1981 the surveys have used a combination of


three indicators to measure fuel switching more accurately:


a tampered fuel filler inlet restrictor, a positive Plumbtesmo


test for lead deposits in the tailpipe, and a gasoline lead


concentration of more than 0.05 gram per gallon (gpg)  Of


these three indicators,  only a tampered inlet restrictor is


also considered tampering, and as such is used to calculate


both tampering and fuel  switching rates.  Since false positive


indications should be extremely rare for these measures, the


percentage of vehicles with at least one positive indicator


is a reasonable minimum estimate of fuel switching.

-------
                             -50-






     Th e presence of any of these three indicators suggests



that a given vehicle has been misfueled;  their absence,  how-



ever, does not rule it out.  For example,  fuel samples could



only be obtained from 81% of the unleaded  vehicles surveyed,



limiting the scope of this variable.  A vehicle misfueled



repeatedly with leaded gasoline may also have little detect-



able lead in its fuel tank due to subsequent proper fueling.



Similarly, a vehicle with an untampered fuel filler inlet



restrictor may have been fueled at a leaded pump equipped



with a smaller nozzle, or by using a funnel or similar device.



The tailpipe lead test, due to the difficulties of field



administration, may also fail to identify  misfueling,  and



older vehicles may have had their tailpipes replaced since



last operated on leaded fuel.  As the lead phasedown program



is lowering lead levels in leaded gasoline, the incidence of



false negative Plumbtesmo results may be increasing.  The



uncertainty in these measures, then, is always toward under-



estimating the number of vehicles misfueled.



     The limitations of the fuel switching indicators can be



seen in their incomplete overlap.  The results from these



indicators would be expected to overlap significantly, since



they are three indicators of the same phenomenon.   This has



not held true, however, in the 1986 survey or in previous




surveys.  The Venn diagram (Figure 9) illustrates  the degree



of overlap in the misfueling indicators for all unleaded

-------
      Positiv Plumfatamo
         (278 Total)
         Landed fual in Took
            (255 Total)
                                                         Tonparad Inlat
                                                           Rastrictor
                                                           (441 Total)
               Tamparad Inlet Only,
                   C37Z)
           Plumbtosmo < Gas
                (32)
              Plumbtosmo  Inlat
                  (11Z)
                         Gas + Inlat
                           C2X)
   Laadad Gas Only
      OU)
                                                         Plurabtasmo Only
                                                            (6Z)
Ml Threo Indicators
      (30X)
Figure  9.    Overlap  of fuel  switching  indicators  among
                unleaded  vehicles  -  1986  survey.

-------
                             -52-






vehicles surveyed in 1986 in which data for all three indicators



were recorded.  For example,  only 72% of the vehicles having



leaded fuel in their tank also registered a positive Plumbtesmo



test.  Additionally, only 41% of the vehicles with tampered



inlet restrictors actually had leaded gasoline in their



tanks at the time of the survey.  The incomplete overlap



reflects the limitations of each indicator as well as the



different aspects of fuel switching each indicator identifies.



     Figure 9 also shows that 80% of the fuel switched vehicles



had a tampered inlet restrictor, making it the most frequently



observed indicator of fuel switching.  A positive Plumbtesmo



result was observed on 50% of the fuel switched vehicles,




while leaded fuel was found in the tanks of 46% of the fuel



switched vehicles sampled.  An antitampering program consisting



of an inlet restrictor inspection and a Plumbtesmo test



would have detected fuel switching in 89% of the fuel switched



vehicles surveyed in 1986.






2.  Fuel Switching Trends






     Of the vehicles requiring unleaded fuel, 9% were



identified as misfueled by at least one of the indicators



discussed above.  The fuel switching incidence by survey site



is listed in Table 14.  Table 15 compares the prevalence of



each fuel switching indicator in the 1986 survey with previous



surveys.  The data in Table 15 suggest a general pattern of

-------
Survey
Locat; "
East St. Louis, IL

Jacksonville, FL

Orlando, FL

Covington, KY



Memphis, TN

Pittsburgh, PA

Hartlord, CT

Seattle, WA

1\ K son,  AZ



St. Louis, MO

CaiTiden,  NJ

LC'S Angeles, GA



Houston, TX

Kichmond, VA

baton Rouge, LA

03-
1A6LE 14


Switching Rates Among Unleaded Vehicles By
Site and Indicator - 1986 Survey
Leaded
Fuel in
Tank (%)
5
5
H
9
7
3
3
2
3
2
2
1
6
2
6
Tampered
Inlet
kestrictor (%)
Kon-l/M Areas
7
7
14
12
I/M-only Areas
12
2
4
4
6
I/M + ATP Areas
3
6
5
ATP-Only Areas
7
4
9
Positive
Plumbtesino
C%)
4
5
8
10
7
2
1
2
6
1
2
1
5
3
7
Overall Fuel
Switching (%)
8
9
15
15
14
4
5
4
10
4
6
b
9
5
10
ALL SITES

-------
                                -54-
                           TABLE 15

         Fuel Switching Rates ^rnong Unleaded Vehicles
                 by Indicator and Survey Year

Survey  Leaded Fuel  Tampered Inlet  Positive       Overall Fuel
Yejar	  in Tank(%)   Restrictor (%)   Plumbtesmo(%)  Switch ing  (%)
1978
1979
1931
1982
1983
1984
1985
1986
4
10
7
6
7
8
5
5
3
4
6
6
7
10
7
7
*
*
8
7
10
9
5
4
4
10
16
11
14
14
9
9
*?lumbtesmo test not used.

-------
                             -55-



decline in fuel switching.  Since such a pattern could result



from the selection of sites surveyed this year, strong con-



clusions must await the data from subsequent surveys.



     Table 16 presents the combined tampering and fuel switching



rates for the 1986 survey.  The percentage of unleaded vehicles



that were tampered or fuel switched was 20%, and the percentage



of unleaded vehicles with missing or damaged converters was 10%.



Table 16 thus suggests that half of all tampering and fuel



switching is composed of vehicles in the catalyst removed or



fuel switched category.  Since these conditions have the



largest emissions impact, this indicates the very serious



nature of most tampering.






3.   Fuel Switching by Vehicle Type






     The prevalence of each fuel switching indicator by



vehicle type is presented in Table 17.  Overall fuel switching



among trucks was higher than for passenger cars (11% vs. 8%)



and the prevalence of each indicator was also greater among



trucks .






4.   Fuel Switching and Catalyst Tampering






     Consumers and mechanics remove catalytic converters for



a number of reasons,  but much of their motivation is related



to fuel switching.  The vehicle owner may remove the catalytic



converter either prior to misfueling,  or after some misfueling

-------
                                    -56-



                                  TABLE 16



            Combined Tampering and Fuel Switching - 1986 Survey
                       Catalyst-equipped vehicles
                           Unleaded Vehicles
Survey
Location
East St. Louis, IL
Jacksonville, FL
Orlando, FL
Covington, KY
with catalysts removed or
that were fuel switched (%)
Non-I/M Areas
10
12
19
18
either tampered o
fuel switched (%)
23
22
27
25
Memphis, TN



Pittsburgh, PA



Hartford, CT



Seattle, WA



Tucson, AZ









 it. Louis, MO



Camdem, NJ



Los Angeles, CA








Houston, TX



Richmond, VA



Baton Rouge, LA
                                      I/M-only Areas
16
6
6
6
11
I/M -f ATP Areas
5
9
7
ATP-only Areas
11
6
13
22
13
14
16
26

16
19
16

25
15
25
TOTAL
10%
21%

-------
                                     -57-

                                   Table 17

          Prevalence of Fuel Switching Indicators  by Vehicle Type
    Fue1 Swi tch i nq Indi cator

    Tampered Inlet Restrictor

    Positive Plumbtesmo

    Leaded Fuel in Tank

    Overall Fuel Switching
Percent Fuel Switching by Vehicle Type
     LDV                 LOT
      7

      4

      4

      8
 8

 8

 7

11
 ,otolyt Tampering

    (336 Total)
                      Ful Switching
                        (543 Total)
Figure  10.   Overlap of  catalyst tamponing  and fuel switching
              among catalyst-equipped vehicles  - 1986 survey.

-------
                             -53-




if the vehicle's driveability has been adversely affecteJ cy a




cat^yst -""d'nage-d from the repeated misfueling.  The data from




this survey cannot be used to distinguish between these two




situations, but can be used to examine the extent to which




thesj tyi-,-.-d of abuse occur in conjunction.




     Figure 10 depicts the degree of overlap between catalyst




removal and fuel switching.  Vehicles with catalyst tampering




exclusive of fuel switching were relatively uncommon -- only




38% of the catalyst tampered vehicles were not fuel switched.




Fuel switching, however,  is not always accompanied by catalyst




removal, since 62% of the fuel switched vehicles still had




their catalysts.




     Figure 11 examines the relationship between converter




tampering and two of the three misfueling indicators (positive




Plumbtes-no and tampered inlet restrictor) .  Only vehicles in




which all three of these parameters were inspected are included




in Figure 11.   These three criteria have been incorporated




into a number of antitampering programs, such as in Houston




and Baton Rouge, to determine if a converter is missing or




damaged.  A vehicle failing the Plumbtesmo test or inlet




restrictor inspection in these programs would have to have




its converter replaced.

-------
                                        -59-
      Poeitiva PlumbtasM
         (303 totol)
         Mllng Catalytic
            Convwtv
            (367 Total)
                                                         ToMparad Inlvt
                                                          RMttrlctar
                                                          (471 total)
                                                Convortor Only
                                                   (20
             Tamporod Inlt Only
                 (262)
            Plumbtosmo + Cat.
                (22)

                 Cat. * lnlt
                    (92)
                                                                Only
ThrM Indicator*
  (242)
                      Inlat * Plimi>tcmo
                           (122)
Figure  11.    Overlap  of  indicators  used  by ATPs to detect
                 missing/damaged  catalysts -  1986 survey.

-------
                             -60-



     Figure 11 shows the value of these programmatic criteria



in detecting missing or damaged converters.  A simple inspection



of the converter for example, would only catch 55% of the



vehicles with missing or damaged converters.  Inspecting



both the converter and inlet restrictor, however, woulJ



detect 93% of these vehicles.  The usefulness of Plumbtesmo




as an indicator may be declining with the advent of lead



phasedown, since only 7% of the vehicles in Figure 11 failed



for Plumbtesmo only.  In 1984, prior to lead phasedown, 17%



of the vehicles failing one of these programmatic criteria



failed for Plumbtesmo only.






5.   Gasoline Lead Concentrations






     Of the vehicles identified as misfueled by any of the



three misfueling indicators, 52% had only trace amounts of



lead (less than 0.05 gpg) in their gasoline when inspected.



These vehicles, then, were identified as fuel switched by a



tampered filler restrictor and/or a positive Plumbtesmo



test.  Figure 12 presents the distribution of lead concen-



trations of 0.05 gpg or more in misfueled vehicles.  The



impact of lead phasedown can be dramatically seen when




Figure 12 is compared to similar data from the 1984 and 1985



surveys.  In the 1984 survey 39% of the misfueled vehicles




had a gasoline lead concentration in excess of 1.0 gpg,



compared to 1% in 1985 and 1986.  The distribution of lead



concentrations in 1986 is centered on the 0.2-0.4 gpg range,




compared to 0.4-0.6 gpg in 1985 and 1.0+ gpg in 1984.

-------
                          -61-
Psrcontaga of Misfuoled Vehicles
       J5
       10
                   10*   102
                   r// 7
                   I
I
 1Z    1Z
77A VTA
                  GosoJina Lead Concantration (grams/gallon)
                   IX
   Figure  12.   Lead concentrations in  leaded fuel
                 sampled  from  misfueled  vehicles.

-------
                             -62-

                          APPGNDIX A


            RELEVANT PORTIONS OF THE CLEAN AIR ACT

Section 203{a){3):   The following acts and the causing thereof
                    are prohibited 

(A)  for any person to remove or render inoperative any device

or element of design installed on or in a motor vehicle or

motor vehicle engine in compliance with regulations under this

title prior to its  sale and delivery to the ultimate purchaser,

or for any manufacturer or dealer knowingly to remove or

render inoperative  any such device or element of design after

such sale and delivery to the ultimate purchaser; or

                                                       &
(B)  for any person engaged in the business of repairing,

servicing, selling, leasing, or trading motor vehicles or

motor vehicle engines, or who operates a fleet of motor

vehicles, knowingly to remove or render inoperative any

device or element of design installed on or in a motor

vehicle or motor vehicle engine in compliance with regulations

under this title following its sale and delivery to the

ultimate purchaser.

-------
                             -63-



                          APPENDIX B





             SURVEY AND DATA RECORDING PROCEDURES



1.   Explanation of Survey Forms



     Tne forms on the following pages were used for recording



the survey data in the field.  The forms were forced choice to



ensure coding consistency, and were designed to facilitate



direct data entry.  The following codes were used to record



data for the major system components on the data sheets:



 0 - Not originally equipped      8 - Misadjusted item



 1 - Functioning properly         9 - Malfunctioning



 2 - Electrical disconnect        A - Stock equipment



 3 - Vacuum disconnect            B - Non-stock



 4 - Mechanical disconnect        D - Add on equipment



 5 - Incorrectly routed hose      Y - Yes



 6 - Disconnect/Modification      Z - No



 7  - Missing item





     Additional codes were used for those components which



could not be classified into the above categories.  If a



determination could not be made about a given component's



condition,  the variable was left blank.  A brief description



of;  each data entry follows.

-------
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-------
                               -65-
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-------
                             -66-



Form A - Underhood





  1-4  ID Number - Vehicles are numbered sequentially as



       they are inspected.  This number is preceded by a



       site identifying letter.





  5-8  Month and year of last I/M inspection (left blank



       if vehicle is licensed in non-I/M area).





 9-12  Displacement - as recorded on the underhood emission



       label.





13-14  Vehicle Model year





15-25  Engine Family - as recorded on the underhood emission



       label.





26-36  Non-serial number portion of VIN - as recorded on the



       driver's side of the dash under the windshield or the



       driver's door post.  The VIN is recorded  only if the



       engine family can not be determined.





   37  Originally Catalyst Equipped - as recorded on the



       underhood emission label or the driver's  door post.





   38  Air Cleaner - is coded 'A1, 'B', or '?'.

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                          -67-




39  leaded Air Intake - provides warm air to the cc



    luring coJid engine operation.  The heated air intake




    is coded  '0', 'I1, '3', '4', '!' (stovepipe hose),



    '9' (vacuum override), or 'B' (custom air clearer).






40  Positive Crankcase Ventilation  (PCV) system - prevents



    crankcase emissions by purging the crankcase of blow-



    by gases which leak between the piston rings and the



    cylinder wall in the combustion chamber under high



    pressures.  The PCV system is coded  'I1, '3', '4'



    (fresh air hose),  '7', '9',  or 'B'  (includes fuel




    economy devices).






41  Turbocharger - coded '0',  'A',  'B1,  or 'D'.






42  Evaporative Control System (ECS) - controls vapors



    from the fuel tank and carburetor.   Some systems have



    two lines: from the fuel tank to the canister, and



    from the canister  to the carburetor  or air cleaner



    (for purging the canister).   Other systems have a



    third line connected to the  carburetor.   The ECS is



    coded 'I1, '31 (carburetor line), '4' (tank line),



    '5', '6'  (air cleaner unsealed), '?', or '9' (cracked



    hose or canister).






    Air Injection System - extends the combustion process



    into the engine's  exhaust system by injecting fresh



    air into the exhaust ports,  lowering exhaust emissions



    while still maintaining proper vehicle performance.

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                          -68-






    Two types of air injection systems are currently ised.



    One type uses a belt-driven air pump to direct aic



    through a control valve and into the exhaust manifold.



    The other type is a Pulse Air Injection Reaction



    (PAIR) system, which uses an aspirator commonly



    located in the air cleaner to supply air to the exhaust



    manifold.






43  PAIR - coded '0' (if air pump system or none), 'I'.,



    '4',   '?', or  '9'.






44  Air Pump Belt - is coded '0' (if PAIR or none), 'I1,



    '7',  or '8' (loose belt).






45  Air Pump System - for the purposes of this variable,



    consists of the air pump and control valve and is



    coded '0' (if a PAIR or none),  'I1, '4' (other than



    belt removal),  '?', or  '9'(frozen pump).






46  Exhaust Manifold - coded 'A1 or 'B1.






47  Oxygen Sensor - Controls the air-fuel mixture going



    into the engine of vehicles equipped with three-way



    catalytic converters.  The sensor is coded  '0', '!',



    '2',   '4' (unscrewed), or '7'.

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48  Carburetor Type - is coded 'S' (sc-al^l ,-Iugs covering




    /nixtare adjustment), "F"  (fuel injection),  'A',



    or '3' .






49  Limiter Caps - plastic caps on the idle mixture screws



    to limit carburetor adjustments.   The limiter caps



    are coded '0', 'I1,  '4*  (tabs broken or bent), '7',



    or '3'  (sealed plugs removed).






    Exhaust Gas Recirculation (EGR) System - directs a



    portion of the exhaust gases back into the cylinders



    to reduce NOX emissions  in the exhaust gas.  The




    standard EGR configuration consists of a vacuum line



    from the carburetor to a sensor (used to detect



    engine  operating temperature to activate the EGR




    valve), and another vacuum line from the sensor to



    the EGR valve.






50  EGR Control Valve -  coded '0', 'I1, '3', '4', '7',



    or '9'.






51  EGR Sensor - coded '0',  '!',  '3',  '5', '7'.






52  Computer Systems and Related Sensors - computerized



    engine  and emissions control system which receives



    input from various sensors for engine condition



    information, and constantly adjusts the air/fuel



    ratio,  distributor,  and  emissions devices for optimum



    economy,  driveability, and emissions.   The system

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                             -70-





       is coded '9',  'I1,  or '6'.  This variable includ-:.-; the



       entire computer system except for the oxygen sensor,



       which is coded separately (see variable *47, Form A).





Form B - Rear





  1-4  ID Number - Same as on Form A.





  5-3  Make





 9-12  Model





   13  Vehicle Type - coded as follows: C = car, T = truck





14-15  License Plate - State abbreviation





16-19  Exhaust gas HC concentration (in ppm) at curb idle.





20-22  Exhaust gas CO concentration  (in percent) at curb idle.





23-25  Odometer - mileage  in thousands





   26  Dash Label - displays the fuel required and is coded



       'O'(for leaded vehicles), 'I1, or '7'.





   27  Catalytic Converter - oxidizes the HC and CO to water



       and C0 in the exhaust gas.   Later model catalysts



       also reduce oxides  of nitrogen.  The converter is



       coded '0', "I1, or  '7' (entire catalyst canister



       removed) .

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                          -7L-






28  Exhaust System - if as originally equipped an 'A'  is co



    If non-stock a "B1 is coded.






29  Exhaust System Integrity - the condition of the exhaust-




    system is coded 'I1 (no obvious leaks) or  '9' (leaks



    evident).






30  Tank Cap - seals the fuel tank during normal operating



    conditions and is coded 'I1,  '7', or  '9' (loose cap).






31  Tank Label - displays required fuel and is coded '0'



    (for leaded vehicles), '!', or '7'.






32  Filler Neck Inlet Restrictor - The restrictor is




    designed to prevent the introduction of leaded fuel



    into a vehicle requiring unleaded fuel.  It is coded



    '0' (for leaded vehicles),  'I1, '4' (widened), or '7'.






33  Plumbtesmo - Plumbtesmo paper is  used to check for the



    presence of lead in vehicle exhaust pipes.  A positive



    indication is coded as 'P1 and a  negative as 'N'.






34  Fuel Sample - indicates if inspector was able to obtain



    fuel sample for later lead analysis ('Y1 or 'Z').

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                                "V "i
                                I .


2.   Clussification Of Component Conditions

     The  table below was  used to classify the various  system

components  as tampered  (T),  arguably  tampered (A),  or

malfunctioning (M).  Only those codes  which are applicable

to a given  component are  listed.   Codes for  'not originally

equipped1 and 'functioning properly1  are not included  in

this table.  Refer to Appendix B,  Part 1 for an explanation

of the  codes.



                    	 Codes from forms A and B

   Component/systern
2 3|4|5|6|7|8|9
A
A M
A
or T T
T
T T T
T T T M
T A AM
T T T T T M
B






T
T

   Dash Label

   Tank Cap

   Tank Label

   Filler Neck Restrictor

   Catalytic Converter

   Oxygen Sensor

   PCV System

   Heated Air Intake

   Evaporative Control
    System

   Aspirated Air                     T               T          M
    Injection System

   Air Pump Belt                                     T    M
   T = tampered
   A = arguably tampered
   M = malfunctioning

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                                -73-
                                        Codes  from forms A and B
Component/system     |2|3|4|5|6|7|8|9|B











Air Punp System                     T                 T          M




EGR Control Valve             T     T                 T          M




EGR Sensor                    T           T           T

-------
                              -74-






3.   Fuel Sample Collection and Labeling Procedures






     A fuel sample was taken from each vehicle requiring



unleaded fuel.  These samples were collected in two-our.ce



bottles with a hand-operated fuel pump.  Once the sample w".s



drawn, the fuel was replaced with an equivalent amount of



unleaded fuel if the driver requested, and the pump was flushed



with unleaded fuel.



     Each bottle was identified with an adhesive label that



had the vehicle identifying survey number on it.  The vehicle



identifying number was the first entry on the data forms



described in Part 1 of Appendix B.  The bottles were packed,



labeled, and shipped to EPA's Motor Vehicle Emissions Laboratory




in Ann Arbor according to the shipper's requirements.

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4.   Plumbtesmo Application

1)    Clean a portion of the inside of the tailpipe large enough

     for the test paper by wiping it out with a paper towel or

     cloth.  This may be necessary to remove soot deposits

     which might mask the color change.

2)    Moisten the Plumbtesmo paper with distilled water and

     immediately* press firmly against the surface to be tested

     for approximately thirty seconds.  If the tailpipe is hot

     you may wish to clamp the test paper in the tailpipe

     using a clean clamp.

     *Not_e:  The Plumbtesmo paper must be applied during the
     time that the paper is yellow for the reaction to take
     place.  After approximately 15 seconds the yellow color
     disappears and the paper is no longer effective.  Excess
     water also interferes with the reaction.

     Care must be taken to avoid contamination of the test paper

     If a person has recently handled a test paper with a

     positive reaction, some lead or reactive chemical may

     have been transferred to their fingers.  Subsequently

     handling a clean test paper may cause contamination.

3)    Aiter removing the test paper, determine whether a color

     change has occurred.   Red or pink coloration indicates

     the presence of lead.

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                              -76-






5-  Field Quality Control/Assurance






     Reference and calibration gases were used to ensure the




accuracy of the emissions analyzer.  Horiba gases certified by




RTF were used as reference gases.   Two cylinders of reference




gas were used to validate the accuracy of the calibration gases




before they were taken to the field on each survey.




     Three calibration gases (Horiba) were used.  These gases




were a mixture of CO and HC in nitrogen and were used to check




the instrument at least three times daily.  These calibration




gases were certified by the manufacturer and the RTF reference




gases.  Their approximate compositions were:




     8% CO




     1560 ppm HC (Hexane equivalent)








     4% CO




     827 ppm HC (Hexane equivalent)








     1.6% CO




     320 ppm HC (Hexane equivalent)

-------
                           APPENDIX C

               EMISSION OUTPOINTS FOR I/M AREAS


The table below lists the emission cutpoints used in 1986 by

the I/M areas covered in the 1986 tampering survey.  The cut-

points for pre-1975 vehicles are not included, since these

vehicles were not surveyed.
Survey Site

St. Louis, MO



Memphis, TN



Pittsburgh, PA



Hartford, CT



Camden,  NJ


Seattle, WA
Model Year

1975-79
  1980
  1981 +

1975-79
  1980+
  1981 +

1975-79
  1980
  1981+

1976-79
  1980
  1981+

1975-80
  1981+
1975-78
1979+(no CC)
1979+(CC, 4 cyl.)
1979+(CC, 6-8 cyl.) 1.5
Emissions Cutpoints
 CO (%)    HC (ppm)
6.0
3.0
1.2
8.5
6.5
3.0
4.0
3.0
1.2
3.0
2.5
1.2
3.0
1.2
3.0
3.0
2.0
1.5
600
300
220
1990
1990
1990
400
300
220
300
275
220
300
220
800
600
300
300
KEY:  CC = catalytic converter (all types), CYL. = cylinder,
      OC = oxidation catalytic converter, AI = air injection,
      TWC = three way catalytic converter.

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             DATE DUE
                              -78-
Survey Site

Los Angeles, CA
Tucson, AZ
Model Year

1975-79(no CC)       3.
1975-79(00, no AI)  4,
1975-79(00, Al)     1.
1975-79(TWC)        1.
1980+(no CO)        2.
1980+(00, no AI)    2
1980+(OC, AI)       1.
1980+(TWO)          1.0

1975-78(4 cyl.)     2.2
1975-78(6-8 cyl.)   2.0
1979 (4 cyl.)       2.2
1979 (6-8 cyl.)     2.0
1980+               1.2
Emissions Outpoints
 CO (%)    HO (ppm)
    5
    5
    5
    5
    5
    5
    2
200
250
150
100
150
150
150
100

250
250
220
220
220
KEY:  00 = catalytic converter (all types), CYL. = cylinder,
      OC = oxidation catalytic converter,  AI = air injection,
      TWO = three way catalytic converter.

-------