Office of Air and Radiation
Motor Vehicle Tampering Survey -
Field Operations and Support Division
Office of Mobile Sources
Washington, D.C.
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Office of Air and Radiation
Motor Vehicle Tampering Survey - 1989
May 1990
Field Operations and Support Division
Office of Mobile Sources
Washington, D.C.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY. 1
Introduction , I
Conclusions 2
BACKGROUND 5
SURVEY METHODS 6
Site Descriptions 7
RESULTS 12
Vehicle Tampering . , 12
Site and Aggregate Totals . 12
Types of Tampering , . 14
Vehicle Characteristics and Tampering 17
Manufacturer 17
Vehicle Type 18
Vehicle Age 20
Impact of I/M and Antitampering Programs 21
Tampering Trends for Selected Sites 24
Impact of Aftermarket Catalytic Converters . 32
Correlation Between Tampering and Idle Emissions 33
Fuel Switching . 36
Fuel Switching Indicators and Overlap 36
Fuel Switching Trends 39
Fuel Switching by Vehicle Type 41
Fuel Switching and Catalyst Tampering. 41
Gasoline Lead Concentrations 43
APPENDIXES
A. Relevant Portions of Clean Air Act 45
B. Survey and Data Recording Procedures 45
C. Emission Cutpoints for I/M Areas 51
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LIST OF FIGURES
1. Tampering rates for selected components by program type 3
2. (a) Overall tampering by vehicle age for vehicles not covered
by I/M and/or anlitampering programs 4
(b) Comparison of catalyst tampering by vehicle age between
vehicles covered and not covered by a catalyst inspection program 4
3. Breakdown of surveyed vehicles by condition and extent of tampering 12
4. Tampering rates by manufacturer 17
5. Classification of 1989 survey sites by program type (and model year
coverage), with the resulting tampering and fuel switching rates for
each program type 22
6. (a)-(O Comparisons of component-specific tampering rates by model
year between vehicles covered and not covered by ATPs 27 - 29
(a) Catalytic Converter 27
(b) Inlet Restrictor 27
(c) Air Pump System 28
(d) Evaporative System 28
(e) PCV System 29
(0 EGR System 29
7, Comparison of component-specific tampering rates among vehicles
both covered and not covered by ATPs (summary of figures 6(a)-(f)) 30
8. Distribution of unleaded vehicles surveyed among tampering, misfueling,
and idle test categories 34
9. (a) Overlap of fuel switching indicators among misfueled vehicles
for which all three indicators were inspected 38
(b) Breakdown of misfueled vehicles in 9(a) by prevalence of each
indicator combination 38
10. (a) Overlap of indicators used by ATPs to detect missing/damaged catalysts.
Only includes vehicles for which all three indicators were inspected and are
not covered by an ATP with plumbtesmo testing 42
(b) Breakdown of vehicles in ll(a) by prevalence of each indicator combination 42
12. Distribution of lead concentrations in leaded fuel sampled from fuel switched
vehicles: 1984 - 89. Percentages based on all fuel switched vehicles, including
those using unleaded fuel (<0.05 gpg.) 44
-it-
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LIST OF TABLES
1. 1989 Tampering Survey Summary - Light-Duty Vehicles only 13
2. Prevalence of Tampering by Component 14
3. Component-Specific Tampering Rates (%) by Survey Location 15
4. Condition of Gasoline Tank Cap by Survey Site 16
5. Tampering Percentage (and Sample Size) by Model Year
and Vehicle Age at Time of Survey , 19
6. Percentage of Catalyst Removal (and Sample Size) among
Catalyst-Equipped Vehicles by Model Year and Vehicle Age
at Time of Survey , 19
7. Comparison of 1989 Survey Sample to Actual Nationwide
Vehicle Fleet 23
8. Tampering Prevalence among Vehicles and Components
Covered by Antitampering Programs in ATP-only Areas
Surveyed between 1984 -1989 25
9. Tampering Prevalence among Vehicles and Components
Covered by Antitampering Programs in I/M + ATP Areas
Surveyed between 1983 - 1989 26
10. Comparison of 1987 Tampering Rates in Dallas (ATP-only)
to 1989 Rates in Dallas Suburbs (non-I/M). Analysis is Restricted
to the Model Years covered by the Dallas ATP 31
11. Comparison of Tampering and Fuel Switching Rates Surveyed
in Colorado Springs (Fourth Day of Denver Survey) to the Balance
of the Vehicles Surveyed in Denver. Includes Only Vehicles
Covered by the Colorado I/M + ATP 31
12. Comparison of Catalyst Removal Rates to the Prevalence of
Aftermarket Catalysts by Survey Location 32
13. Idle Test Failure Rates (Percent) by Pollutant and
Vehicle Condition 35
14. Mean Idle Emissions for Tampered and Okay Vehicles
Within Each Program Type 36
15. Fuel Switching Rates among Unleaded Vehicles by Site
and Indicator 39
16, Combined Tampering and Fuel Switching Rates _ 40
17. Prevalence of Fuel Switching Indicators by Program Type 41
18. Prevalence of Fuel Switching Indicators by Vehicle Type 41
- ill -
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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 March and August, 1988. The areas surveyed and the total number of vehicles
inspected are listed below.
San Diego, CA 500 Cleveland, OH 368
Bakersfield, CA 520 Springfield, MO 540
Phoenix, AZ 465 Milwaukee, WI 490
Suburbs of Dallas, TX 422 Missoula,MT 500
Baton Rouge, LA 497 Anchorage, AK 503
Jacksonville, FL 580 Fairbanks, AK 436
Detroit, MI 441 Denver, CO 465
Cincinnati, OH 390
TOTAL 7,117 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 effect of vehicle inspection and maintenance (I/M) programs and
antitampering programs (ATPs) on tampering and fuel switching.
b. The relationship between tampering and vehicle idle emissions.
c. The distribution of tampering by vehicle age, type, manufacturer, and
other variables of interest.
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*1 test paper, and checked the integrity
of the fuel filler inlet restrictors. Four categories 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 property
Plumbtesmo* is a registered trademark, and hereafter appears without the ***. It is manufactured by
Machery-Nagel, Durtn, W. Germany, and is marketed by Gallard-Schlesinger Chemical Corp., Carle Place, New
York.
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Motor Vehicle Tampering Survey -1939 page 2
CONCLUSIONS
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.
The site selection in recent tampering surveys has been based more on the need
to evaluate control program effectiveness than the desire to methodically sample the
U.S. vehicle population. In the 1989 survey, for example, vehicles covered by an I/M
and/or antitampering program comprised 62% of the survey, even though only 42% of
the vehicles nationwide are subject to such control programs. The overrepresentation
of control programs within the 1989 survey data base makes it inappropriate to use this
survey as representative of the nationwide vehicle population. Rather, the 1989 survey
sample is an appropriate tool for evaluating tampering prevalence at any particular site,
and for evaluating control program effectiveness where "before" and "after" data exist.
This report will thus refrain from comparing the overall 1989 survey results with prior
surveys.
Tampering among vehicles not covered by I/M and/or anti-tampering programs
was 25%, compared to 15%, 12%, and 10% for those vehicles covered by I/M + ATP,
I/M-only, and ATP-only, respectively. Such comparisons between program categories
should be made carefully, since some of the control programs cover only newer model
years of vehicles, which historically have lower tampering rates than the older vehicles
not covered by the control programs. The I/M-only and ATP-only rates, for example,
are heavily weighted with programs inspecting 1980 and newer vehicles only.
Because of the large variation in program types and coverages, the vehicles are
classified based on the program restrictions within each site. In Cleveland and Cincin-
nati, for example, only the 1980 and newer vehicles are covered by the area's antitamper-
ing program; the 1975-1979 vehicles are thus classified as "non-I/M".
The 1988 tampering survey report noted a disparity in the effectiveness of control
programs to reduce certain kinds of tampering. In particular, tampering with underhood
components was less likely to be corrected by a control program than removal of a
catalytic converter. While this conclusion was generally true in 1989 as well, some control
programs surveyed in 1989 (e.g., Anchorage) were very effective in reducing underhood
tampering. Air pump and PCV tampering rates among vehicles covered by the
Anchorage program were among the lowest ever reported. These rates are particularly
impressive because Alaska's own tampering survey prior to program implementation
found extremely high tampering rates there. Moreover, Anchorage's control program
is decentralized, and such programs have been considered to be less effective for
underhood components than centralized programs. These results will be discussed more
thoroughly later in this report.
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Motor Vehicle Tampering Survey -1989
Page3
Fuel-Related
The prevalence of vehicles with missing or damaged catalytic converters within each
program type is depicted in Figure 1. A vehicle can be considered to have a missing or
inoperative catalyst if the converter has been removed, the inlet restrictor is tampered, or
the plumbtesmo test is positive. (These three criteria are used by many antitampering
programs.) A missing or damaged converter can increase HC and CO emissions by an
average of 475% and 425%, respectively2. For vehicles equipped with three-way con-
verters, substantial increases in NOx emissions would also be expected. In addition,
converter tampering on trucks was found to be slightly greater than on automobiles (5%
vs. 4%).
Fuel switching, defined as the presence of any of three specific indicators3, was found
in 9% of the unleaded vehicles not covered by I/M and/or ATPs in the 1989 survey. Fuel
switching among vehicles in I/M + ATP, ATP-only, and I/M-only areas was 3%, 2% and
4%, respectively. The pattern of overlap among the three misfueUng 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.
Component
Catalytic Converter
Inlet Restrictor
Positive Plumbtesmo
0%
0%
0%
Tampering (%)
Ffgur* 1. Tampering rates for selected components by program type.
The emission! increase* mentioned in thi* report are from a study of three-way catalyst-equipped vehicles
presented in Anti-'T'pm^fipganri Antt-MafueJInff Program^ tn Reduce [n-Uftfl Fjni«imvt tmm Mntor Vehicle.
EPA-AA-TTS-83-10, December 31,1983.
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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Motor Vehicle Tampering Survey -1989
Page 4
Catalyst Tampering and Vehicle Age
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(a), which depicts
vehicles not covered by I/M and/or antitampering programs. Figure 2(b) compares the
impact of vehicle age on catalyst tampering among vehicles covered and not covered by
converter inspection programs. Overall, converter tampering is much lower on vehicles
covered by converter inspection programs than on vehicles not covered by such programs
(1% vs. 7%), and the effectiveness of inspection programs is particularly noticeable
among the oldest vehicles surveyed (vehicles that are most likely to be tampered with).
(%)
80
70
60
50
40
30
20
10
0
Covered
6 7 8 9 10 11 12 13 14 15
Van £»•*«• (years)
CataJyst Tampering (%}
50,
40
30
20
10 r
i vehicles No:
| Covarec
vehicles
CoverM
' 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Vehicle Ag« (years)
(b)
Figure 2(a). Overall tampering by vahlcl* «g« for vehicles not covered
by I/M and/or antftamperlng program*.
2(b). Comparison of catalyst tampering by vehicle age between
vehicle* covered and not covered by a catalyst Inspection
program.
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Motor Vehicle Tampering Survey -1989 Page 5
BACKGROUND
EPA estimates that motor vehicle emissions nationwide account for 56% of the
totaJ carbon monoxide (CO), 32% of the airborne lead, 26% of the hydrocarbons (HQ,
and 31% of the oxides of nitrogen (NOx) emitted into the atmosphere4. 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 introduc-
tion of leaded gasoline into vehicles labeled "unleaded gasoline only". The EPA's Field
Operations and Support Division (FOSD), formerly part of the Mobile Source Enfor-
cement Division (MSED), is responsible for enforcing the tampering and misfueling
provisions of the Act.
Before 1978, the EPA had data suggesting that tampering with emission control
devices and misfueling of "unleaded only" vehicles with leaded gasoline were 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 con-
ducted in 1978. Since 1983, the tampering survey results for some locations have been
used to calculate credits for State Implementation Plans (SlPs), 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 data base for the
Agency's mobile source computer model (MOBILE4) to estimate both the emissions
loading impact and the reductions that may be achieved by various control programs.
Comparing survey results before and after implementation of a control program is an
excellent method for evaluating program effectiveness. 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. , .
National Air Pnllutanr Emission Fjjtjfliates 1940-19SJJ, EPA-450/4-90-001, March, 1990.
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Motor Vehicle Tampering Survey -1 QQQ Page
SURVEY METHODS
The 1989 tampering survey was conducted for FOSD by the National Center for
Vehicle Emissions Control and Safety at Colorado State University (CSU). Ap-
proximately 400 to 600 vehicles were inspected in each of 15 cities between March and
August, 1989. The entire survey included 7,117 vehicles. The mix of vehicles inspected
was assumed to be a self-weighting sample, and no attempt was made to force the sample
into matching the national vehicle mix,
Each inspection team consisted of at least four members: three CSU personnel,
one or two EPA representatives, and frequently a State or local agency representative.
The CSU personnel, assisted by the State or local person, performed the actual inspec-
tions, while the EPA representative(s) monitored 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 HC, CO, CO2, and 02 emissions measured;
4. Fuel sample collected for lead analysis;
5. Tailpipe tested for lead deposits using Plumbtesmo test paper; and
6. Integrity of fuel inlet restrictor checked.
Three minor changes have been made b the survey methodology for 1989. The
survey team utilized a four-gas analyzer to record idle COj and Oa emissions in addition
to the HC and CO emissions. Also, an additional classification code was added for the
air pump. Finally, heavy-duty gasoline-powered vehicles were inspected at selected sites
in addition to the light-duty cars and trucks surveyed. The results from the heavy-duty
trucks will be discussed separately in this report, and, except where noted, were not used
to calculate any tampering or fuel switching rates. The inspections and recording
procedures are fully detailed in Appendix B.
The survey data base 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, as well as gasoline powered heavy-duty trucks at selected sites. 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 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.
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Jlolor Vehicle Tampering Survey -1989 Page 7
site Descriptions
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 analyzing 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 (3%), however, and only one survey site had a refusal rate over 5%. A
brief description of each survey site follows. Unless otherwise noted, the survey locations
within a given city were changed daily.
San Diego, CA
I/M + ATP
Dates: March 13-17,1989
Vehicles Surveyed: 500
Fuel Samples: 399
Refusal Rate: 1%
Bakersfield, CA
I/M + ATP
Dates: March 20-24, 1989
Vehicles Surveyed: 520
Fuel Samples: 426
Refusal Rate: 1%
Roadside pullovers in San Diego and Bakersfield were conducted with the assis-
tance of the California Highway Patrol, California Air Resources Board, and the Bureau
of Automotive Repair. California's decentralized, biennial inspection program covers
all components on all vehicles, but does not require converter replacement if the inlet
restrictor fails.
Phoenix, AZ
I/M + ATP
Dates: March 27-31,1989
Vehicles Surveyed: 465
Fuel Samples: 401
Refusal Rate: 0%
The Phoenix survey was conducted at five of the city's centralized inspection
stations with the assistance of the Arizona Vehicle Emissions staff. The antitampering
program in Phoenix includes a Plumbtesmo test and inspection of the catalytic converte r,
air injection system, and inlet restrictor on all 1975 and newer vehicles.
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Motor Vehicle Tampering Survey -1989 Page 8
Suburbs of Dallas, TX
Non-I/M
Dates: April 10-14,1989
Vehicles Surveyed: 422
Fuel Samples: 268
Refusal Rate: 3%
The Dallas survey was conducted in four of the outlying counties which surround
Dallas-Fort Worth (Ellis, Kaufman, Collins, and Denton counties). As of April 1,1990,
these four counties, as well as three others, will adopt the antitampering inspection
program currently in place in Dallas and Tarrant counties. At that time Dallas and
Tarrant counties will add an I/M tailpipe test to their control program. The Texas
Department of Public Safety provided assistance with the roadside pullovers.
Baton Rouge, LA
ATP-only
Dates: April 17-21, 1989
Vehicles Surveyed: 497
Fuel Samples: 398
Refusal Rate: 3%
Roadside pullovers were conducted with the assistance of the Louisiana State
Police, Louisiana Motor Vehicle Police, and the Louisiana Department of Environmen-
tal Quality. Survey locations were nearly the same as in the 1985,1986, and 1988 surveys.
The decentralized antitampering program in Baton Rouge includes a Plumbtesmo test
and inspection of all emission control devices on 1980 and newer vehicles.
Jacksonville, FL
Non-I/M
Dates: April 24-28, 1989
Vehicles Surveyed: 580
Fuel Samples: 461
Refusal Rate: 1%
The Florida State Police and the Jacksonville Department of Health, Welfare, and
Bioenvironmental Services assisted with the roadside pullovers.
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Motor Vehicle Tampering Survey -1989 Page 9
Detroit, MI
I/M-only
Dates: May 8-12, 1989
Vehicles Surveyed: 441
Fuel Samples: 297
Refusal Rate: 5%
The Michigan State Police and Michigan Department of Natural Resources
assisted with the roadside pullovers. Detroit's decentralized, annual I/M program covers
1980 and newer vehicles.
Cincinnati, OH
ATP-only
Dates: May 15-19, 1989
Vehicles Surveyed: 390
Fuel Samples: 310
Refusal Rate: 5%
Cleveland, OH
ATP-only
Dates: May 22-26, 1989
Vehicles Surveyed: 368
Fuel Samples: 321
Refusal Rate: 5%
Roadside pullovers were conducted with the help of local law enforcement officers
in the municipalities in the Cleveland and Cincinnati areas, as well as State and local
pollution control personnel. The annual, decentralized antitampering program in
Cleveland and Cincinnati includes a Plumbtesmo test and an inspection of all emission
control devices on 1980 and newer vehicles.
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Motor Vehicle Tampering Survey -1989 Page 10
Springfield, MO
Non-I/M
Dates: June 5-9, 1989
Vehicles Surveyed: 540
Fuel Samples: 483
Refusal Rate: 5%
Roadside pullovers were conducted with the assistance of the Springfield Police
Department and the Greene County Air Pollution Control Agency. Seventeen of the
540 vehicles surveyed were heavy-duty trucks.
Milwaukee, WI
I/M-only
Dates: June 12-16, 1989
Vehicles Surveyed: 490
Fuel Samples: 336
Refusal Rate: 0%
The Milwaukee survey was conducted at five centralized I/M stations in Mil-
waukee (three stations), Racine, and Waukesha. The Wisconsin Department of
Transportation assisted with the survey. In April 1989, Milwaukee added an antitamper-
ing inspection to the existing I/M program, but the area will still be considered I/M-only
for this survey because the entire vehicle fleet had not been subjected to the ATP at the
time of the survey. Two of the 490 vehicles surveyed were heavy-duty trucks.
Missoula, MT
Non-I/M
Dates: June 19-23,1989
Vehicles Surveyed: 500
Fuel Samples: 404
Refusal Rate: 2%
Roadside pullovers were conducted with the assistance of the Missoula Police
Department and the Missoula Health Department. Forty-two of the 500 vehicles
surveyed were heavy-duty trucks.
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>tor Vehicle Tampering Survey -1989 Page 11
Anchorage, AK
l/M + ATP
Dates: July 10-14, 1989
Vehicles Surveyed: 503
Fuel Samples: 372
Refusal Rate: 2%
The roadside pullovers in Anchorage were conducted with the assistance of the
Anchorage Municipal Police and the Alaska Department of Environmental Conserva-
tion. The decentralized program includes an annual Flumbtesmo test and inspection of
the catalyst, inlet restrictor, air injection system, and PCV system on the last 15 model
years. Twenty-six of the 503 vehicles surveyed were heavy-duty trucks.
Fairbanks, AK
I/M + ATP
Dates: July 17-21, 1989
Vehicles Surveyed: 436
Fuel Samples: 350
Refusal Rate: 9%
The Fairbanks survey was conducted with the assistance of the Alaska State Police,
the Alaska DEC, and the Fairbanks North Star Borough, The survey was conducted at
a privately-owned inspection facility on one day, and roadside pullovers were used the
other four days. The decentralized program includes an annual Plumbtesmo test and
inspection of the catalyst, air injection system, and PCV system on the last 15 model
years. Twenty-three of the 436 vehicles surveyed were heavy-duty trucks. The higher
refusal rate in Fairbanks is believed to be more indicative of the independent nature of
its citizens than of any desire to avoid the survey and conceal instances of tampering.
Denver, CO
I/M + ATP
Dates: August 7-11, 1989
Vehicles Surveyed: 465
Fuel Samples: 330
Refusal Rate: 1%
The roadside pullovers were conducted in Denver, Littleton, Aurora, Colorado
-Springs, and Thornton with the assistance of the Colorado Department of Health and
the local municipal law enforcement agencies. Colorado's decentralized program en-
compasses nine counties and includes an annual inspection of the catalyst, inlet restric-
tor, air injection system, and oxygen sensor on 1975 and newer vehicles. Sixteen of the
465 vehicles surveyed were heavy-duty trucks.
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Motor Vehicle Tampering Survey -1989
Page 12
RESULTS
A. VEHICLE TAMPERING
L. Site and Acereffate 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 properly5. The criteria used for component clas-
sification 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
18%. One-third of the surveyed vehicles 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.
The frequency distribution of tampering instances for those vehicles classified as
"tampered" is also shown in Figure 3. Forty-three percent of the tampered vehicles had
multiple components tampered, and 12% had four or more instances of tampering.
Okay (67%)
Malfunctioning (4%)
Arguably Tampered
(11%) .,.-••••"
Tampered (18%)
Four or more (12%)
j- Three (10%)
-Two (21%)
One (57%)
Condition of
Surveyed Vehicles
Number of Tampered
Components
Figure 3. Breakdown of surveyed vehicles by condition and extent of tampering.
5 An 'okay* vehicle, however, may ctill be classified ax fuel switched (see section B.I., Fuel Switrhinf Indir
and Overlap of this report).
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Motor Vehicle Tampering Survey -1989
Page 13
TABLE 1
1989 Tampering Survey Summary - Light-Duty Vehicles only
Number of Tampering Misfueling
Survey Location
San Diego, CA
Bakersfield, CA
Phoenix, AZ
Dallas (Suburbs), TX
Baton Rouge, LA
Jacksonville, PL
Detroit, MI
Cincinnati, OH
Cleveland, OH
Springfield, MO
Milwaukee, WI
Missoula, MT
Anchorage, AK
Fairbanks, AK
Denver, CO
OVERALL
Vehicles
500
520
465
422
497
580
441
390
368
523
488
458
477
413
449
6,991
Rate (%) Rate (%)
11
16
25
30
19
17
14
16
21
25
15
21
9
14
14
18
*R = roadside pullovers, C = centralized
D = decentralized stations
4
8
5
11
7
4
2
5
5
9
2
8
2
7
3
6
Survey
Type*
R
R
C
R
R
R
R
R
R
R
C
R
R
R,D
R
-
Refusal
Rate (%)
1
1
0
3
3
1
5
5
5
5
0
2
2
9
1
3
inspection stations,
Table 1 summarizes the 1989 survey data by site for the light-duty vehicles surveyed.
As in previous surveys, the overall tampering in 1989 varied considerably from site to
site. This can be attributed to the variety of program configurations among the cities
surveyed and to geographic differences.
Table 1 also contains the refusal rate at each survey site. The overall refusal rate
for the survey was very low (3%), and only one survey site had a refusal rate exceeding
5%. The higher refusal rate in Fairbanks (9%) is believed to be more indicative of the
independent nature of its citizenry than of any desire by these citizens to avoid the survey
and conceal instances of tampering.
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Motor Vehicle Tampering Survey -1989
Page u
2. TVivt nf Tampering
The tampering rates for all emission control components and systems surveyed in
1989 are presented in Table 2. The component-specific tampering rates for the 1989
survey are presented by survey site in Table 3. Only those vehicles originally equipped
with a particular component are considered when computing the tampering rate for that
component. The site-specific tampering rates listed in Tables 1 and 3 are for all light-duty
vehicles surveyed at each location, including out-of-state vehicles and other vehicles
possibly not covered by any local inspection program. The tampering rates for only
vehicles covered by local control programs will be examined later in this report.
TABLE 2
Prevalence of Tampering by Component
Component/System Tampering Rate (%)
Catalytic Converter
Inlet Restrictor
Air Pump System
Air Pump Belt
Air Pump/Valve
Aspirator*
PCV System
Evaporative System
EGR System
Heated Air Intake
Oxygen Sensor and
Computer System
4
5
10
6
7
1
5
6
6
3
1
* Vehicles with aspirated air systems are not equipped with
other listed air-injection components, nor do conventional
systems include aspirators.
Table 2 shows that air pump system tampering remains the single most tampered
component (10% of equipped vehicles). Tampering with evaporative systems also shows
no evidence of subsiding. Also of interest is the slight but measurable tampering found
with the oxygen sensor and computer control system. Because of the difficulty in
inspecting the oxygen sensors (no determination could be made on 61 vehicles), the one
percent rate reported is a conservative estimate. Oxygen sensor tampering is of consid-
erable interest because of the dramatic emissions increases which result from its disable-
ment -- an average increase of 445% for HC and 1,242% for CO.
id Antt.Mkfugling Pf
itn Rrrtiirr ln-TV Frni"'""*fmm Mntnr Vehicles.
EPA-AA-TTS-83-10, December 31,1983,
-------
Motor Vehicle Tampering Survey -1989
Page 15
Table 3 shows the wide variation in tampering from site to site for any given
component. Air pump system tampering, for example, ranged from 4% in Anchorage
to 19% in Missoula. This range U partly due to the effectiveness of I/M and antitamper-
ing programs (as will be discussed later in this report), geographic location, and
socioeconomic background.
TABLE 3
Component-Specific Tampering Rates (%) by Survey Location*
Survey Catalytic
Location Converter
San Diego, CA
Bakersfield, CA
Phoenix, AZ
Dallas (Subs.), TX
Baton Rouge, LA
Jacksonville, TN
Detroit, MI
Cincinnati, OH
Cleveland, OH
Springfield, MO
Milwaukee, WI
Missoula, MT
Anchorage, AK
Fairbanks, AK
Denver, CO
OVERALL
1
1
1
13
5
6
3
4
5
11
0
8
2
1
2
4
Inlet
Restricter
4
8
4
10
6
4
2
5
4
9
2
9
2
5
3
5
Air Pump
System
6
6
10
18
15
9
7
12
8
15
5
19
4
7
6
10
PCV
System
2
5
11
11
6
4
5
4
6
5
4
4
3
2
7
5
* Indudes any out-of-state vehicles or non-covered light-duty vehicles
applicable).
EGR
System
2
3
6
11
8
4
3
8
8
11
7
10
5
5
5
6
Evap.
System
2
4
10
11
7
6
5
6
7
7
3
6
3
3
5
6
surveyed within the
Any
Component
11
16
25
30
19
17
14
16
21
25
15
21
9
14
14
18
program area (if
-------
Motor Vehicle Tampering Survey -1989
Page 16
Table 4 shows the condition of the gas tank cap among surveyed light-duty vehicles
by survey location. Although a missing or malfunctioning tank cap is not classified as
tampering, the emissions impact of a missing cap nonetheless is substantial. A missing
or malfunctioning gas cap can completely negate an otherwise properly functioning
evaporative system, causing large increases in evaporative HC emissions. The mal-
functioning rate among non-stock gas tank caps was considerably higher than among
stock gas tank caps (5% vs. < 1%).
Condition
Survey Location
San Diego, CA
Bakersfield, CA
Phoenix, AZ
Dallas (Suburbs), TX
Baton Rouge, LA
Jacksonville, FL
Detroit, MI
Cincinnati, OH
Cleveland, OH
Springfield, MO
Milwaukee, WI
Missoula, MT
Anchorage, AK
Fairbanks, AK
Denver, CO
OVERALL
TABLE
4
of Gasoline Tank Cap by Survey
Malfunctioning
Tank Cap (%)
0
0
1
1
2
1
1
0
1
1
1
1
0
1
1
1
Site
Missing Tank Missing or
Cap (%) Malfunctioning (%)
1
0
3
2
1
2
3
3
1
1
0
1
1
1
1
2
2
1.
4
3
3
3
4
3
3
2
1
2
1
2
2
2
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Motor Vehicle Tampering Survey -1989
Page 17
3. VphiHit Oiarartpfi
-------
Motor Vehicle Tampering Survey -1989 Page 18
A number of factors might explain the difference in tampering prevalence 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 seem to vary with geographic location and socioeconomic background, so the
owner demographics for different makes may affect the likelihood of tampering.
Vehicle Typ<>- The overall tampering prevalence for light-duty trucks (LDTs)
was 18%, compared to 17% for automobiles (LDVs). Since the 1986 tampering survey,
the tampering rates for cars and trucks have basically been the same, and the discrepancy
between car and truck tampering decreased steadily in surveys prior to 1986. While the
overall tampering rate is less meaningful than the rates for individual components, even
the component-specific truck rates tend to converge upon the usually lower automobile
rates. Catalytic converter tampering, for example, was only slightly higher for trucks
than for cars (5% vs. 4%).
Many factors may be contributing to the convergence in car and truck tampering.
Since most of the vehicles surveyed in 1989 were subject to control programs, the relative
car and truck tampering rates may reflect increased emphasis on truck tampering
detection by the inspection programs. Also, the proportion of imported trucks within
the total truck population surveyed has increased from 15% to 26% between 1982 and
1989, with many of the smaller trucks being ntiKreA as cars. 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.
Heavy-duty gasoline-powered tracks (HDTs) were also surveyed at selected sites
in the 1989 survey. Of the 126 HDTs surveyed, nearly one-third (32%) had one or more
components tampered. This high tampering rate is largely attributable to the skewed
model year distribution of the HDTs surveyed, since 60% of the HDTs surveyed were
manufactured in 1979 or earlier. By comparison, the overall tampering rate for 1979 and
older light-duty trucks was even higher (68%). This suggests that vehicle age has a much
greater effect on tampering prevalence than vehicle type. Heavy-duty tampering may
increase in significance as the prevalence of catalyst-equipped HDTs increases.
-------
Motor Vehicle Tampering Survey -1989 Page 19
Table 5
Tampering Percentage (and Sample Size) by Model Year and Vehicle Age at Time of Survey
Year of Vehicle LJJe
Model
Year 1& 2nd 2ld M 5lh 6th 2th, Slh 2th 10th llth 12th Ufrh 14th 15th
1989 0(444)
1988 1(524) 1(794)
1987 1(627) 1(832) 3(741)
1986 1(757) 2(1058) 3(915) 4(758)
1985 2(816) 3(1130) 3(972) 6(855) 7(779)
1984 1(462) 2(1001) 5(1018) 7(908) 8(765) 13(681)
1983 7(182) 4(471) 6(710) 7(706) 10(633) 15(532) 12(414)
1982 1(250) 4(226) 7(466) 9(621) 11(574) 19(525) 21(506) 25(414)
1981 2(57) 7(448) 13(206) 15(458) 11(607) 19(560) 26(501) 34(479) 28(384)
1980 5(63) 9(454) 15(211) 18(516) 25(564) 25(556) 28(472) 32(419) 37(351)
1979 6(371) 9(59) 18(477) 31(288) 28(503) 37(673) 36(699) 42(555) 44(464) 46(416)
1978 7(298) 14(502) 15(79) 21(430) 39(238) 34(559) 37(562) 50(548) 49(443) 55(404) 54(318)
1977 10(457) 15(476) 21(66) 26(316) 44(190) 41(408) 48(452) 48(465) 49(356) 54(265) 57(250)
1976 18(395) 19(374) 29(52) 26(317) 40(171) 39(385) 49(369) 53(318) 60(219) 61(179) 56(162)
1975 22(274) 22(271) 32(22) 37(183) 55(89) 46(197) 54(194) 60(198) 65(103) 62(113) 66(83)
1974 33(276) 27(242)
1973 32(253) 36(251)
Table 6
Percentage of Catalyst Removal (and Sample Size) among Catalyst-Equipped Vehicles by Model Year
and Vehicle Age at Time of Survey
Year of Vehicle Life
Model
l5l2nsi2ld4jh.5jh6jh.2thaUl2tli IQth llth 12th 13th 14th 15jh
1989 0(444)
1988 0(521) 0(794)
1987 0(627) 0(810) 0(741)
1986 0(757) 0(1058) 0(887) 0(758)
1985 0(808) 1(1128) 0(972) 1(818) 1(779)
1984 0(462) 0(978) 1(1018) 1(908) 1(726) 1(680)
1983 1(179) 2(471) 0(686) 1(706) 1(633) 2(505) 2(414)
1982 0(250) 1(225) 2(465) 2(597) 1(574) 3(525) 3(466) 5(414)
1981 0(57) -2(441) 5(204) 6(457) 3(567) 5(552) 7(499) -9(421) 7(378) .
1980 2(61) 2(428) 3(200) 6(487) 6(522) 7(528) 8(440) 9(346) 9(332)
1979 0(326) 4(55) 6(4») 12(252) 10(455) 12(572) 12(638) 13(505) 13(376) 13(383)
1978 0(291) 0(445) 0(71) 4(362) 8(213) 8(486) 10(472) 10(466) 15(394) 13(312) 17(277)
1977 1(417) 1(417) 2(59) 2(271) 11(166) 14(357) 17(379) 19(409) 11(320) 19(212) 17(221)
1976 2(377) 2(305) 10(48) 6(257) 12(139) 12(314) 15(291) 20(276) 19(184) 15(137) 24(135)
1975 2(242) 2(204) 26(19) 12(139) 23(75) 16(174) 21(130) 23(167) 25(77) 14(72) 30(63)
-------
Motor Vehicle Tampering Survey -1989 Page 20
Vehicle. Am>. Table 5 relates vehicle age and model year with tampering
prevalence for the 1978-1989 surveys. Catalytic converter removal rates are similarly
related to vehicle age and model year in Table 6. The results from any given survey are
entered diagonally in each table.
The results in Tables 5 and 6 indicate that vehicle tampering increases directly with
vehicle age. Examining Table 5 diagonally (by survey) shows that tampering increases
consistently with vehicle age in each survey conducted. In the 1989 survey, for example,
the tampering rate increases from 0% for first year (1989) vehicles to 66% among the
1975 model year vehicles surveyed.
Table 6 shows a similar, though less pronounced, increase in catalyst removal. The
catalyst tampering rate remains negligible for the first six years of a vehicle's life, and
then increases thereafter. This delay in catalyst tampering is understandable, since the
emission control components on all new vehicles are warranted for 5 years/50,000 miles
by the manufacturer, providing an incentive to maintain the catalysts on vehicles still
under warranty. A simitar delay in overall tampering is less apparent in Table 5, but
becomes more evident when only non-I/M vehicles are examined (Figure 2 (a)), 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), geography, or program coverage on tampering.
Two additional ways of analyzing Tables 5 and 6 address the impact of model year
on tampering rates. Analyzing these Tables horizontally (holding the model year con-
stant) provides a look at the tampering rates over time for the vehicles of a particular
model year. This approach shows the same distinct increase in tampering with vehicle
age for all model years since 1975. (The 1974 and 1973 data sets are too small to permit
any conclusions.)
Tables 5 and 6 can also be examined vertically (holding vehicle age constant),
which provides a look at the tampering rates for different model year vehicles of the same
age. This approach permits a crude examination of trends in tampering adjusted for
vehicle age. Examining Table 5 vertically, for example, shows a decrease in overall
tampering from the 1978 survey to the 1989 survey for vehicles in each of their first seven
years of use. This decrease in overall tampering appears to lessen in the later years of a
vehicle's life. A similar, though less pronounced, trend is apparent in the age-specific
catalyst tampering data (Table 6).
-------
Motor Vehicle Tampering Survey -1989 Page 21
The comparisons made in the two preceding paragraphs involve observations
made in different survey locations during different years, and are affected by the site
selection in each survey. An increasing percentage of the 1981 and newer vehicles in
recent surveys have been covered by antitampering programs, which could contribute to
the lower tampering found among newer vehicles. The impact of improved technology
on tampering can be more accurately assessed by examining only vehicles from non-I/M
areas (Figure 2(a)). The data in Figure 2(a) suggest that tampering with new technology
vehicles that are no longer covered by new car or emissions warranties (i.e., post-1980
vehicles that are six to nine years old) is consistent with tampering among older
technology vehicles (pre-1981 - over nine years old).
4. Tpinart1 rtf T/\^ and Anfifaningriiiiy
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 outpoints
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.
Many local areas have also instituted antitampering programs (ATPs), which
involve periodic vehicle inspections to check the integrity of specific emission control
components. Antitampering programs vary greatly in the components inspected and the
vehicle model years covered, so that a vehicle or component which would be inspected
b one program area might not be inspected in a different program area. Successful
antitampering programs should reduce existing tampering and deter future tampering
with the components and model years covered by the program.
Classifying the survey areas into program types is made difficult by the consider-
able variation in control programs. For example, three antitampering programs sur-
veyed (Cleveland, Cincinnati, and Baton Rouge) include inspection of all emission
control devices, but only on 1980 and newer vehicles. In contrast, California's inspection
program covers all components on all vehicles.
In order to minimizr. the impact of these variations in program types and model
year coverages, the vehicles in the 1989 survey can be classified by the model year
restrictions applicable in the program areas surveyed. These classifications, and the
resulting tampering rates for each program type, are shown in Figure 5. Since
Cleveland's antitampering program only covers 1980 and newer vehicles, for example,
only those model year vehicles are classified as "ATP-only"; the 1975-1979 vehicles
surveyed in Cleveland are classified as "non-I/M", Additionally, 86 of the vehicles
surveyed in the Dallas suburbs were covered by the Dallas inspection program. Those
vehicles have been classified as "ATP-only", while the balance of the vehicles have been
classified as "non-I/M*. This method of classification does not take into consideration
the components inspected by each program, a program's effectiveness, or the frequency
of inspection. Any comparisons between program types (e^, I/M + ATP vs. non-I/M)
should thus be made carefully.
-------
Motor Vehicle Tampering Survey -1989
Page 22
I/M + ATP
Dallaa (Suburb*), TX*
Jackaonvait, FL
SprtngflaW.MO
Mluoula,MT
Datrott, Ml (1975-79)
davatand, OH (1975-79)
Baton Houga. LA (1875-79)
andnrad. OH (1975-79)
ATP-onfy
Bttonflaug*.LA(19M-*>)
OtMtand.OH(1«W4)
Cincinnati. OH (1980+)
d CA
2
Anchong*,AK
Dan*. Ml (1980+)
M!hnukM,WI
Noto: Pregrameov«na«inocWyMntufv«y«dunl*iaaD^anriMlndlcitad.
•86 wahlclM wowy*! In tna DaJlac submba wv* ooMrad by tf» OaUu ATP,
and haw bMn daatfflad'ATP-ony.
29%
10%
Futf SwttoWng (%)
Rgura S CI«Mlf IcatJon of 1989 survey site* by program lyp« (and model
year coverage), wtth the reeuttlng tempering end fuel ewttchlng
ratee for eech program type. (The fuel ewttohlng ratee era derived
from e slightly different clasarficetlon scheme - eee the text of
this report for details.)
-------
Motor Vehicle Tampering Survey -1989
Page 23
Two alterations were made in this classification system for calculating the fuel
switching rates. The vehicles covered by the I/M + ATP in Fairbanks have been
excluded because the program includes a Plumbtesmo test but does not inspect inlet
rcstrictors. Additionally, the- vehicles surveyed in San Diego and Bakersfield were
classified as "I/M-only" instead of T/M + ATP" because convener replacement is not
required by the programs in the event of an inlet restrictor failure (hence, EPA does not
grant credit for the inlet inspection).
Another factor affecting comparisons in Figure 5 is the overreprcsentation in the
survey sample of areas with some kind of control program. This is a deliberate feature
of the survey's design, as was discussed earlier, and focuses attention on evaluating the
effectiveness of specific individual programs. Table 7 compares the proportion of the
1989 survey sample and the national vehicle fleet under control programs. Because of
the need to evaluate control program effectiveness, the survey overrepresents the portion
of the national vehicle fleet under control programs. Vehicles covered by an I/M + ATP
or an ATP-only comprised 50% of the survey sample, while only approximately 30% of
the national vehicle fleet were under such programs.
TABLE?
Comparison of 1989 Survey Sample
to Actual Nationwide Vehicle Fleet
Program Type
Percentage within
Survey Sample (%)
Approximate Percentage
of Nationwide Fleet (%)*
non-I/M
I/M-only
ATP-only
I/M -l- ATP
38
12
12
38
1 From County Poulation Estimates: Jur 1,
58
12
10
20
1987. and 1986. U.S.
Department of Commerce - Bureau of the Census, August, 1989.
-------
Motor Vehicle Tampering Survey -1989 Paqe 24
5. Tampering Trends for Selected
The impact of I/M and antitampering programs in specific locations can be
examined by comparing the 1989 survey data with that from earlier surveys. Com-
parisons made between surveys widely spaced in time, however, must take into con-
sideration the differences in average vehicle age in each survey. The average odometer
reading per vehicle surveyed in 1989, for example, is over 20% greater than it was in 1984.
Since vehicle mileage correlates with vehicle age, which is directly related to tampering
prevalence, a significant increase in tampering might be expected to have occurred
between 1984 and 1989, even if all other factors remained constant (car/truck distribu-
tion, owner demographics, etc.). Inferences regarding program effects should thus be
made with this in mind.
Tables 8 and 9 present tampering data for the three ATP-only and six I/M + ATP
sites surveyed, respectively. Because of the large number of programs represented in
Tables 8 and 9, only a few representative comparisons will be discussed in this report.
Detailed analysis of each program's effectiveness is beyond the scope of this report. The
comparisons made in these Tables have been limited to the specific components and
vehicle model years covered by each antitampering program actually in operation during
the 1989 survey. In some instances this reduces the sample size substantially. The
tampering data listed in Tables 8 and 9 were compiled only for surveyed vehicles included
within the local program jurisdiction. The Fairbanks tampering rates listed, for example,
are for vehicles registered b the Fairbanks North Star Borough only. Any vehicles
surveyed from outside of the Borough were excluded from this analysis.
The data in Table g suggest that the ATPs in Baton Rouge, Cleveland, and
Cincinnati have helped lower catalyst tampering and misrueling rates (i.e., plumbtesmo,
inlet restrictor). Tampering with underhood components, however, has not declined
appreciably. In fact, evaporative and air pump system tampering in each city increased
from earlier surveys. A similar pattern is apparent in Table 9, where I/M + ATP
programs have been generally effective in reducing catalyst tampering and misfueling,
but much less so in reducing underhood tampering.
Anchorage is the notable exception in Table 9. Air pump system tampering among
covered vehicles in Anchorage is one of the lowest rates ever observed. The low rates
in Anchorage are particularly impressive because that program is decentralized, and
such programs are historically less effective than centralized programs.
The difference in programmatic impact on catalyst and fuel-related tampering
versus the underhood components is illustrated by Figures 6(a)-(Q, where tampering
rates by model year for the major components covered by inspection programs (either
ATP-only or I/M + ATP) are compared to tampering rates for the same components on
vehicles that were not covered by inspection programs. Catalyst and inlet restrictor
tampering (Figs. 6 (a) and (b), respectively) were much lower on vehicles covered by
converter and inlet inspection programs than on vehicles not covered by such inspec-
tions. Air pump system tampering (Fig. 6(c)) was also lower in areas with inspections
than in areas without inspections, although it remained relatively high even in areas
inspecting that component. Areas inspecting evaporative, PCV, and EGR systems (Figs.
6(d), (e), and (0, respectively) had only slightly lower tampering rates. The PCV and
evaporative system rates are noteworthy because these two systems control crankcase
and evaporative HC emissions, respectively — emissions which the catalytic converter
does not control The overall rates for the data presented in Figs. 6(a)-(f) are shown in
Figure 7.
-------
Motor Vehicle Tampering Survey -1989
Page 25
Table8
Tampering Prevalence among Vehicles and Components
Covered by An ti tampering Programs in ATP-only Areas
Surveyed between 1984 - 1989
Tfrmnerintt Prevalence ( °7a\ bv Survey Year
Survey Location Component and
(Prop-am Start Date^ Model Years Covered
Baton Rouge, LA
(1/86)
Cincinnati, OH
(2/88)
Cleveland, OH
(2/88)
Catalyst
Inlet Restrictor
Pos. Plumbtesmo
PCV System
Evap. System
Air Pump System
EGR System
Catalyst
Inlet Restrictor
Pos. Plumbtesmo
PCV System
Evap. System
Air Pump System
EGR System
Catalyst
Inlet Restrictor
Pos. Plumbtesmo
PCV System
Evap. System
Air Pump System
EGR System
80 +
80 +
80 +
80 +
80 +
80 +
80+
80 +
80 +
80 +
80 +
80 +
80 +
80 +
80+
80 +
80+
80 +
80+
80 +
80 +
* Rates from surveys conducted after the
1984
-
-
-
-
-
-
-
2
3
2
1
1
3
7
-
-
-
-
-
-
start
1985 1286 1987 1988
4 3* - 1
31-2
52-0
23-6
33-3
64-7
44-5
,
.
.
,
.
. -
1 ...
2
1
3
1
2
2 ...
date of an inspection program are given in italics.
12S2
2
2
0
4
4
10
4
1
1
0
2
3
6
5
1
I
0
3
4
3
2
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Motor Vehicle Tampering Survey -1989
Page 26
Table 9
Tampering among Vehicles and Components
Covered by An ti tampering Programs in I/M + ATP Areas
Surveyed between 1983 - 1989
Tamnerino Prevalence (%1 bv Survev Year
Survey Location Component and
rPrngram Start Hatel y ndel Years Covered J2S3 19S4 1285 1286 1282 1288
Bakersfield, CA
(1/86)
San Diego, CA
(3/84)
Phoenix, A2
(I/M-1/77,
ATP - 1/87)
Anchorage, AK
(7/85)
Fairbanks, AK
(7/85)
Denver, CO
(1/83)
Catalyst 75+ - 8
Inlet Restrictor 75+ 11
PCV System 75-*- - 3
Evap. System 75+ 4
Air Pump System 75+ 9
EGR System 75+ - 18
Catalyst 75+ -
Inlet Restrictor 75+ -
PCVSystem 75+ ----- -
Evap. System 75+ -
Air Pump System 75+ ------
EGR System 75+ -
Catalyst 75+ 7 . - - - 2
Inlet Restrictor 75+13 - - - - 5
Pos. Plumbtesmo 75+12 - - - - l
Air Pump System 75+ 13 - - -12
Catalyst 75+ -
Inlet Restrictor 75+ -
Pos. Plumbtesmo 75+ -
PCVSystem 75+ ------
Air Pump System 75+ -
Catalyst 75+ ------
Pos. Plumbtesmo 75+ ------
Air Pump System 75+ ------
EGR System 75+ ------
Catalyst 75+ 4
Inlet Restrictor 75+4
Air Pump System 75+6
* Rates from surveys conducted after the start date of an inspection program are given in italics.
,
0282
/*
8
5
4
6
3
1
4
2
2
6
3
1
4
2
10
1
I
0
2
2
1
2
7
2
2
3
4
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Motor Vehicle Tampering Survey -1989
Page 27
Tampering (%)
30
20
10
Tampering (%)
40
30
20
10
0 ' <-
Mode) Year
(a) Catalytic Converter
Covered by Program
Not Covered by
Program
Covered by Program
Not Covered by
Prog ram
Model Year
(b) Inlet Restrictor
Figure 6. Comparisons of component-specific tampering rates by model
(a-0 year among vehicles both covered and not covered by ATPs.
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Motor Vehicle Tampering Survey -1989
Page 28
Tampering (%)
so
so
40
30
89 58 87 M S3 M S3 02 81 «0 79 78 77 70 75
Model Year
(c) Air Pump System
Tampering (%)
10 -
Covered by Program
Not Covered by
Program
Covered by Program
Not Covered by
Program
9868B7WS3S48382S1 SO 7» 7S 77 76 75
Model Year
(d) Evaporative System
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Motor Vehicle Tampering Survey -1989
Page 29
Tampering (%)
20
10
Covered by Program
Not Covered by
Program
88 M 87
86 M « 82 «1 80 79 7« 77 76 75
Modal Year
(e) PCV System
Tampering (%)
40
30
20
10
Covered by Program
Not Covered by
Program
Model Year
(f) EGR System
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Motor Vehicle Tampering Survey -1989
Page30
Component/System
Catalytic Converter
Inlet Restrtetor
Air Pump System
Evaporative System
PCV System
EGR System
7%
Component not cvrd.
by ATP Inspection
Component covered
by ATP Inspection
13%
Tampering (%)
Figure 7. Comparison of componant-apsclflc tampering rates among
vahlclM both covarsd and not eovarad by ATPa.
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Motor Vehicle Tampering Survey -1989
Page 31
Table 10 compares the 1989 tampering rates found in the Dallas suburbs to those
found within the Dallas program area in 1987. This analysis is restricted to the same
model year limitations for each component used by the Dallas ATP. The data in Table
10 suggest that tampering rates outside of the Dallas program area are considerably
higher than those found within the program area.
TABLE 10
Comparison of 1987 Tampering Rates in Dallas (ATP-onLy) to 1989 Rates
In Dallas Suburbs (noo-I/M). Analysis Is Restricted to the Model Years covered
by the Dallas ATP.
Component/System Dallas Dallas Suburbs
and Model Years Covered (1987 Survey) (1989 Survey)
Catalytic Converter
Inlet Restrictor
Pos. Plumbtesmo
PCV System
Evap. System
Air Pump System
EGR System
80 +
80 +
80 +
75 +
75+
75+
75+
2
2
2
6
7
6
4
6
3
2
11
11
18
11
The Denver survey was somewhat unique in that four days of that survey were spent
in the Denver metropolitan area, while one day was spent surveying vehicles in Colorado
Springs (approximately 50 miles south of Denver). Table 11 presents the tampering rates
found in Colorado Springs (101 vehicles) vs. those found in the Denver area, and includes
only those vehicles covered by the Colorado I/M + ATP. (Both Colorado Springs and
Denver are within the program area.) Table 11 suggests that the Colorado inspection
program is being more effectively implemented in Denver than in Colorado Springs.
Those components not covered by Colorado's inspection program show no difference
in tampering between Denver and Colorado Springs.
TABLE 11
Comparison of Tampering and Fuel Switching Rates Surveyed in Colorado
Springs(Fourtn Day of Denver Survey) to the Balance of the \ihfcles Surveyed In
Denver. Includes Only Vehicles Covered by the Colorado I/M + ATP
Component/Indicator
Tampering Rate (%)
Colorado Springs Greater Denver
Catalytic Converter
Inlet Restrictor
Air Pump System
Components Inspected by Program
3
7
9
Components Not Inspected by Program
PCV System 5
Evap. System 5
EGR System 11
Leaded Fuel in Tank 4
Positive Plumbtesmo 1
1
2
2
7
5
2
0
1
Overall Tampering
Overall Fuel Switching
19
7
12
2
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Motor Vehicle Tampering Survey -1989
Page 32
fi. Imnact of Aftermarket P-atalvtic Cnnvertmx
The impact of catalytic converter inspection programs can be studied by examining
the prevalence of aftennarket converters among the survey vehicles. Aftermarket
converters, by virtue of their low cost and high availability relative to original equipment
converters, can often be used to replace missing or damaged converters, particularly in
program areas that require converter replacement in those instances. Table 12 compares
the prevalence of aftennarket converters vs. mi^ii^g converters among converter-
equipped vehicles at each survey location. In the nine cities with converter inspection
programs, only the converter-equipped vehicles subject to the local inspection program
were analyzed; in the six cities without converter inspections, all catalyst-equipped
vehicles surveyed were analyzed.
TABLE 12
Comparison of Catalyst Removal Rates to the Prevalence
of Aftermarket Catalysts by Survey Location
Survey Location
% of Catalyst- % of Catalyst-
Equipped Vehicles Equipped Vehicles Vehicles Covered
with Aftermarket with Missing by Local Catalyst
Converters Converters* Inspection Program
San Diego, CA
Bakersfield, CA
Phoenix, AZ
Anchorage, AK
Fairbanks, AK
Denver, CO
Baton Rouge, LA
Cincinnati, OH
Cleveland, OH
Jacksonville, FL
Detroit, MI
Dallas (Suburbs), TX
Springfield, MO
Milwaukee, WI
Missoula,MT
OVERALL
Sites with Converter Inspection Programs
2 1 1975+
3 1 1975 +
6 '1 1975 +
2 1 1975 +
3 1 1975 +
3 2 1975 +
1 2 1980 +
1 1 1980+
2 1 . 1980 +
Sites without Converter Inspection Programs
1 6 None
1 3 None
1 13 None
1 11 None
3 0 None**
0 8 None
2 4
•Percentages listed are for catalyst-equipped vehicles subject to the local inspection program.
In areas without converter inspections, the percentage* listed are for all catalyst-equipped
vehicles surveyed.
"Milwaukee's program does Inspect converters on 1975 and newer vehicles, but this program
was added to tfie existing t/M program only two months prior to the survey, so the entire vehicle
fleet had not been exposed to the inspection at the time of the survey.
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Motor Vehicle Tampering Survey -1989 Page 33
The data in Table 12 indicate that areas with converter inspection programs
generally have a higher percentage of aftermarket converters than missing converters
among the covered vehicle fleet. Phoenix in particular has a large percentage of its
vehicle fleet equipped with aftermarket converters (6%). The environmental benefits
of retrofitting such a large percentage of the vehicle fleet is considerable. In contrast,
the cities with the highest percentages of missing conveners (Dallas suburbs, Springfield,
and Missoula) are all non-I/M areas, and also had the lowest percentage of aftermarket
converters. The only city where this trend does not hold is Milwaukee, where the
converter inspection program had only been added to the existing I/M program two
months prior to the survey. The high percentage of aftermarket converters may be
attributed to the State's efforts to educate the public prior to implementation of the
anti-tampering inspection program or the fact that the survey was conducted at the
centralized lanes, where the vehicle owners may have anticipated the inspection and
made corrective repairs to their vehicles.
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 switching and idle failure rates, the idle emissions from unleaded vehicles have
been tested against the cutpoints established by the I/M program where they were
sampled Vehicles in non-I/M and ATP-only 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. The failure rates for fuel switched vehicles that
were arguably tampered with or otherwise okay are based upon very small samples and
may be unreliable. The results in Figure 8 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. For example, only 19% of the unleaded vehicles surveyed that were free
of tampering and fuel switching failed an idle test, while 66% of the tampered and fuel
switched vehicles failed that test It should be noted from Figure 8, however, that 34%
of the tampered and fuel switched vehicles were still able to pass an idle test.
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Motor Vehicle Tampering Survey -1989
Page 34
Entire Survey
Sample
100%
Figure 8. Distribution of unleaded vehicle* eurveyed among
tampering*, mlefuellng, and Idle teet categories.
*^udM malfunctioning vthldM (4% of total)
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Motor Vehicle Tampering Survey -1989 Page 35
Idle Test Failure Rates
Vehicle Condition
Okay
Arguably Tampered
Tampered
Catalyst Removed
or Misfueled
Table 13
(Percent) by Pollutant and Vehicle Condition
Failure Rate(%) by Pollutant for Model Years Listed
1975 - 80 1981 + Entire Survey ( 1975 + )
HC CO HC CO HC CO HCorCO
32 23 15 6 16 8 19
27 9 26 15 26 20 36
43 40 35 27 40 35 53
49 43 44 36 48 41 63
Table 13 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
(1981 + } vehicles. "New" technology includes 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 over twice that for okay vehicles (40% vs. 16%). Over four times as many
tampered vehicles exceeded CO cutpoints as did okay vehicles (35% vs. 8%). The
majority (63%) of the vehicles that either had been fuel switched or had their catalysts
removed also exceeded HC or CO limits. Conversely, 37% of the vehicles with missing
catalysts or classified as fuel switched were still able to pass an idle emissions test. A
significant number of arguably tampered vehicles also produced excess idle emissions.
The effectiveness of idle emissions testing on "new" technology vehicles can also
be seen in Table 13. The data in Table 13 actually underestimate 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 previous
surveys, idle emissions testing is more effective in identifying tampering in 1980 and older
vehicles than on 1981 and newer vehicles. For example, 40% 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 as effective a
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
14 by program type. The classification of survey sites is the same as was described in
Figure 5, with two alterations. The data from Anchorage and Fairbanks are listed in a
separate category (I/M (CO only)) because these programs have no HC cutpoints. The
remaining I/M and I/M + ATP sites have been combined into die "I/M" category.
The mean idle emissions from tampered vehicles were considerably greater than
from untampered vehicles (Table 14). Overall, HC and CO emissions from tampered
vehicles were over five times greater on average than from okay vehicles. Untampered
vehicles in Anchorage and Fairbanks (which don't have HC cutpoints) had surprisingly
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Motor Vehicle Tampering Survey -1989
Page 36
TABLE 14
Mean Idle Emissions for Tampered and Okay Vehicles Within Each
Program 'type
HC emissions (ppm) CO emiviinna ( %)
Program Type Tampered Okay
non-I/M
VM*
I/M (CO-only)"
ATP-only
390
254
232
274
68
64
71
32
Tampered
2.6
1.7
1.2
2.2
Okay
0.5
0.4
0.3
0.2
OVKRALL 325 62 2.2 0.4
* Includes any program where idle emissions are checked, including I/M + ATP
areas.
** Consists of vehicles surveyed
emissions are checked.
in
Anchorage and
Fairbanks, where
only CO
low HC and CO emissions, particularly in comparison to the El Paso vehicles surveyed
in 1988 (which also were not subject to HC outpoints). The low idle rates found in Alaska
are consistent with the low tampering rates found there, and provide further evidence
of their program effectiveness.
B. FUEL SWITCHING
1. Fuel Switching Indicators and Overlar
Fuel switching is more easily defined than measured, since no single indicator can
completely characterize its prevalence. 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
determine 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.
Measuring fuel switching is somewhat unusual because two of the three indicators
(positive Plumbtesmo and leaded fuel in the tank) disappear with a series of subsequent
proper fuelings. Positive Plumbtesmo results disappear slowly, while leaded gasoline is
quickly diluted with subsequent tanks of unleaded fuel A vehicle which has one or both
of these transient indicators, however, has recently used or is currently using leaded
gasoline. The presence of a tampered inlet restrictor provides no information about the
immediacy of the fuel switching. A fuel switching rate derived from the two transient
indicators would thus measure how many vehicles have recently used leaded gasoline,
while all three indicators together provide a more accurate indication of long-term fuel
switching behavior with its associated catalyst destruction and elevated emissions.
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Motor Vehicle Tampering Survey -1989 Page 37
The presence of any of these three indicators suggests that a given vehicle has been
misfueled; their absence, however, does not rule it out. For example, fuel samples could
only be obtained from 76% of the unleaded vehicles surveyed, limiting the scope of this
variable. A vehicle with an untampered fuel filler inlet restrictor may also have been
fueled at a leaded pump equipped with a smaller nozzle, or by using a funnel or similar
device. The tailpipe lead test may also fail to identify misrueling, particularly if older
vehicles have had their tailpipes replaced since last operated on leaded fuel As the lead
phasedown program has lowered lead levels in leaded gasoline, the incidence of false
negative Ptumbtesmo results may be increasing. The uncertainty in these measures,
then, is always toward underestimating the number of vehicles misfueled.
The limitations of the fuel switching indicators can be seen in their incomplete
overlap. The Venn diagram (Figure 9
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Motor Vehicle Tampering Survey -1989
Page 38
Positive Plumbtesmo
(69 Total)
(a)
Tampered Inlet Only '''
(70%)
Leaded Fuel in Tank
(56 Total)
Tampered Inlet
Rettrictor
(283 Total)
Leaded Gaa Only (3%)
All Three Indicators
(9%)
Inlet (5%)
Ptumbtatmo + inlet
Plumbtaarno + Ga* (1%)
(b)
Flgura 9(a). Overlap of fu«t swttchlng Indteator* among
v«hlclM lor which all thr«* Indicators wnr« Inipoctad.
9(b). Breakdown of mlafu«l«d vahtolM In 9(a) by pr«val«ne«
of each Indicator combination.
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Motor Vehide Tampering Survey -1989
Page 39
2-Fuel Switching Trends
Of the vehicles requiring unleaded fuel, 6% were identified as misfueled by at least
one of the indicators discussed above. The fuel switching incidence by survey site is listed
in Table 15. The data in Table 15 again show that inlet restrictor tampering is easily the
most prevalent indicator of misfueling. This is not surprising, since inlet tampering is
the most persistent indicator of past misfueling, even when the vehicle has been properly
fueled for sometime.
TABLE 15
Fuel Switching Rates among Unleaded Vehicles by Site
Leaded Tampered
Survey Fuel in Inlet
Location Tank(%) Restrictor (%)
San Diego, CA
Bakcrsfield, CA
Phoenix, AZ
Dallas, TX
Baton Rouge, LA
Jacksonville, FL
Detroit, MI
Cincinnati, OH
Cleveland, OH
Springfield, MO
Milwaukee, WI
Missoula,MT
Anchorage, AK
Fairbanks, AK
Denver, CO
OVERALL
Note: The overall fuel (witching rate
of the (lightly different population t
for all three indicator*).
0
0
0
5
1
1
1
1
1
2
0
2
1
1
1
1
4
8
4
10
6
4
2
5
4
9
2
9
2
5
3
5
and Indicator
Positive Overall Fuel
Plumbtesmo Switching
(%) (%)
0
1
2
5
1
1
0
0
1
3
0
2
1
3
1
1
4
8
5
11
7
4
2
5
5
9
2
8
2
7
3
6
may actually be lower thaa the nte for any one indicator because
ne* for each indicator {i*, not all vehicle* were able to be tested
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Motor Vehicle Tampering Survey -1989
Page 40
Table 16 presents the combined tampering and fuel switching rates for the 1989
survey. The percentage of unleaded vehicles that were tampered or fuel switched was
18%, and the percentage of unleaded vehicles with missing or. damaged converters was
7%. Table 16 thus suggests that nearly 40% 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
much tampering.
TABLE 16
Combined Tampering and Fuel Switching Rates
Catalyst-Equipped Vehicles
Survey with Catalysts Removed or
Location that were Fuel Switched (%)
San Diego, CA
Bakersfield, CA
Phoenix, AZ
Dallas, TX
Baton Rouge, LA
Jacksonville, FL
Detroit, MI
Cincinnati, OH
Cleveland, OH
Springfield, MO
Milwaukee, WI
Missoula,MT
Anchorage, AK
Fairbanks, AK
Denver, CO .
OVERALL
5
9
5
16
8
7
3
7
7
13
2
11
3
8
4
7
Unleaded Vehicles
either Tampered or
Fuel Switched (%)
11
17
25
30
19
16
14
16
22
25
14
21
8
16
14
18
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Motor Vehicle Tampering Survey -1989
Page 41
Table 17
Prevalence of Fuel Switching Indicators by Program Type
Percentage by Program Type
Fuel Switching Indicator non-I/M ATP-only I/M-only I/M + ATP
Tampered Inlet Restrictor
Positive Plumbtesmo
Leaded Fuel in Tank
Overall Fuel Switching
9
3
2
9
2
0
0
2
4
0
0
4
3
0
1
3
Table 17 presents the prevalence of each fuel switching indicator by program type.
The classification of survey sites is the same as was described for Figure 5. Table 17 shows
that the prevalence of each fuel switching indicator was considerably greater in the
non-I/M areas than in areas with control programs.
Table 18
Prevalence of Fuel Switching Indicators by Vehicle lype
Percentage of each Indicator
Fuel Switching Indicator LDV LDT^
Tampered Inlet Restrictor 5 6
Positive Plumbtesmo 1 2
Leaded Fuel in Tank 1 2
Overall Fuel Switching 5 7
3. Fuel Switrhmg hy Vehicle Type
The prevalence of each fuel switching indicator by vehicle type is presented in Table
18. Overall fuel switching among trucks was slightly higher than for passenger cars (7%
vs. 5%) and the prevalence of each indicator was higher in trucks as well Fuel switching
data from the heavy-duty trucks was not included in Table 18 because of an insufficient
sample of unleaded HDTs.
4. Fuel Switching and Catalvsf TV
Consumers and mechanics remove catalytic converters for a number of reasons, but
some of their motivation may be related to fuel switching. The vehicle owner may remove
the catalytic converter either prior to misfueling, or after some misfueling if the vehicle's
driveability has been adversely affected by a catalyst damaged from the repeated misfuel-
ing. The data from this survey cannot be used to distinguish between these two situations,
but can be used to examine the extent to which these types of abuse occur in conjunction.
Figures 10(a) and (b) examine the relationship between converter tampering and
two of the three misfueling indicators (positive Plumbtesmo and tampered inlet restrictor).
Vehicles included in Figures 10(a) and (b) had to meet two criteria. First, only those
vehicles that have not been subject to an ATP with Ptumbtesmo testing were included.
Second, the sample population was further restricted to those vehicles in which all three
parameters were inspected during the survey. The three parameters examined in Figures
10(a) and (b) have been incorporated into a number of antitampering programs to
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Motor Vehicle Tampering Survey -1989
Page 42
determine if a converter is missing or damaged. A vehicle failing the Plumbtesmo test or
inlet restrictor inspection in some of these programs (e.g., Phoenix) is required to have its
converter replaced.
Figure 10(a) shows the value of these programmatic criteria in detecting missing or
lead-poisoned converters. A simple inspection of the converter, for example, would catch
74% of the group of vehicles which lack functional converters (converter either missing
or presumed to be disabled from lead exposure). Inspecting both the convener and inlet
restrictor, however, would detect 98% of these vehicles. The usefulness of Plumbtesmo
in detecting damaged converters appears to be limited, since only 2% of the vehicles in
Figure 10(b) failed for Plumbtesmo only. In 1984, prior to lead phasedown, 17% of the
vehicles failing one of these programmatic criteria failed for Plumbtesmo only. Plumbtes-
mo may still be effective, however, in deterring fuel switching.
Poatttvt Phjmbtwmo
(60 Total)
Misting Catalytic
Convwtw
(243 Total)
Tampered tnlvt
flwtrtctor
(215 Total)
Cat«ty«tOnty<3«)
Tampered mMt Orty
(21%)
PtumbtMmo + Ctf.
Plumtot tamo Only (2%)
Alt Thrw Indicator! (13%)
Wit +• Prumbtaamo (2%)
Cat + mm (29%)
(b)
Flgur* I0(a). Overlap of Indicator* used by ATP* to dtteet mlMbig/dtnwg«d
catalyst*. Only mcltid** v*hlcl** for which all thra* Indicator* war*
ln*p«ctad and ar* not covarod by *n ATP with plumbtaamo tetttng.
10(b). Braakdown of vthlda* In 11 (a) by pr*val*nc* of aach Indicator
combination.
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Motor Vehide Tampering Survey -1989 Page 43
Of the vehicles identified as misfueled by any of the three misfueling indicators,
83% were using unleaded gas when surveyed (i.e., their gasoline lead concentration was
less than 0.05 gram per gallon (gpg)). These vehicles, then, were identified as fuel
switched by a tampered inlet rcstrictor and/or a positive Plumbtesmo lest. Figure 11
presents the distribution of lead concentrations of 0.05 gpg or more in misfueled vehicles
for the 1984-1989 surveys. The impact of lead phasedown can be clearly seen in Figure
11. Not only has the overall prevalence of leaded gas in unleaded vehicles declined, but
the distribution of lead concentrations in the leaded gasoline has shifted dramatically.
In the 1989 survey, for example, none of the misfueled vehicles had a gasoline lead
concentration of 0.2 gpg or higher, compared to 17% in 1987 and 53% in 1984.
Of the leaded light-duty vehicles surveyed, a significant percentage (43%) were
using unleaded gasoline, and 32% of the leaded heavy-duty trucks were using unleaded
gasoline as well. Such high percentages of unleaded fuel use may be due to unavailability
of or higher pricing of leaded gas, the vehicle owners' decision to change fuels, or the
service stations marketing leaded" gasoline that actually contained less than 0.05 gpg of
lead. The distribution of lead concentrations among both light-duty and heavy-duty
leaded vehicles using leaded fuel is consistent with the distribution of lead concentrations
found in the misfueled unleaded vehicles. While this would be expected, it also suggests
that the addition of concentrated lead additives to the gas tank by consumers is not
widespread.
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Motor Vehicle Tampering Survey -1989
Page 44
Percentage of
Misfueled Vehicle*
100
90 -
80 -
20 -
10 -
lead concentration
range (gpg.)
1984 1965 1986 1987 1988
Survey Year
Figure 11. Distribution of lead concentrations In leaded fuel sampled
from fuel switched vehicles: 1984 - 89 surveys. Percentages
based on all fuel switched vehicles, Including those using
unleaded fuel («XOS gram per gallon (gpg.)).
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Motor Vehicle Tampering Survey -1989 Page 45
APPENDIX 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.
APPENDIX B
SURVEY AND DATA RECORDING PROCEDURES
1. Explanation of Survey Forms
The 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 property 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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Motor Vehicle Tampering Survey -1989 Page 46
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 b noa-I/M
area).
9-12 Manufacturer of vehicle
13-23 Engine Family - as recorded on the underhood emission label.
24-34 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.
35-38 • Displacement - as recorded on the underhood emission label.
39-40 Vehicle Model Year
41 Originally Catalyst Equipped - as recorded on the underhood emission label or
the driver's door post.
42 Engine Status - is coded 'V if the engine is the one originally installed in the
vehicle; and is coded 'Z' if the vehicle: has a different gasoline engine than was
originally equipped; was originally equipped with a diesel engine and currently
has a gasoline engine; was converted to operate on a fuel other than gasoline or
diesel fuel (i.e., propane); or is a "gray market" imported vehicle.
43 Air Cleaner -is coded 'A', 'B', or T.
44 Heated Air Intake - provides warm air to the carburetor during cold engine
operation. The heated air intake is coded '0*, T, 3', '4\ 7* (stovepipe hose), '9'
(vacuum override), or 'B' (custom air cleaner).
45 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 T, "3', '4' (fresh air hose), T, "9", or 'B' (includes fuel economy
devices).
46 Exhaust Gas Redrculation (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. The EGR system is
coded 'V, T, T, T, '4', '51, T, or '9".
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Motor Vehicle Tampering Survey • 1989 Page 47
47 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
T, T (carburetor line), '4' (tank line), '5', '6' (air cleaner unsealed), T, 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. Two types of air injection systems are currently
used. One type uses a belt-driven air pump to direct air 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.
48 Aspirated Air Injection System (PAIR) - coded '0* (If air pump system or none), T,
'4',T,or'9'.
49 Air Pump Belt - is coded '0' (if PAIR or none), T, T, or '8* (loose belt).
50 Air Pomp System - for the purposes of this variable, consists of the air pump and
control valve and is coded '0* (if a PAIR or none), T, "3', '4' (other than belt
removal), T, or *9*(frozen pump).
51 Exhaust Manifold - coded 'A' or 'B'.
52 Oxygen and Related Sensors - The oxygen sensor controls the air-fuel mixture
going into the engine of vehicles equipped with three-way catalytic conveners. A
vehicle's computerized engine and emissions control system 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. These sensors are coded 'CK, T, T, '4' (unscrewed),
'6',orT.
53 Carburetor Type - is coded T (fuel injected), 'A' (stock carbureted), or 'B' (non-
stock carbureted).
54 Turbocharger - coded 'ff, 'A', 'B', or 'D'.
Form B - Rear
1-4 ID Number • Same as on Form A.
5-8 Make
9-12 Model
:13 Vehicle Type - coded as follows: C = car, T = light-duty truck, H = heavy-duty
truck.
14-15 License Plate -State abbreviation
16-19 Program Jurisdiction - the city or county of the vehicle's registration is entered
(if the vehicle is covered by a control program).
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Motor Vehicle Tampering Survey -1989 Page 48
20-23 Exhaust gas HC concentration (in ppm) at curb idle.
24-26 Exhaust gas CO concentration (in percent) at curb idle.
27-29 Exhaust gas COi - concentration (in percent) at curb idle.
30-32 Exhaust gas Oj - concentration (in percent) at curb idle.
33-35 Odometer - mileage in thousands
36 Dash Label - displays the fuel required and is coded '0' (for leaded vehicles), T, or '7'.
37 Catalytic Converter - oxidizes the HC and CO to water and CCh in the exhaust gas.
Later model catalysts also reduce oxides of nitrogen. The converter is coded '0',
'!', T (entire catalyst canister removed), or 'B' (aftennarket catalyst present).
38 Exhaust System - if as originally equipped an 'A' is coded. If non-stock a "B' is coded..
39 Exhaust System Integrity. the condition of the exhaust system is coded' 1' (no
obvious leaks) or *9* (leaks evident).
40 Tank Cap * seals the fuel tank during normal operating conditions and is coded T,
'T, or "9* (loose cap). A separate entry (see below) is made to indicate whether
the tank cap is stock or non-stock ('A' or 'B').
41 Tank Cap Origin - is coded 'A' if the tank cap is a stock cap. The cap is coded 'B'
if it is non-stock.
42 Tank Label - displays required fuel and is coded '0* (for leaded vehicles),'!', or T.
43 Filler Neck Restrktor - The restrictor is designed to prevent the introduction of
leaded fuel into a vehicle requiring unleaded fuel It is coded '0* (for leaded
vehicles), T, *4' (widened), '6* (nozzle adaptor present), T, or 'B' (non-stock
inlet restrictor-functioning property).
44 Phimbtesmo - Plumbtesmo paper is used to check for the presence of lead in vehicle
exhaust pipes. A positive indication is coded as 'P* and a negative as 'N1.
45 Fuel Sample - indicates if inspector was able to obtain fuel sample for later lead
analysis ('V or 'Z').
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Motor Vehicle Tampering Survey -1989 Page 49
2. Classification 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 equipped' and
'functioning properly' 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/system 234S6789B
Dash Label A
Tank Cap A M
Tank Label A
Filter Neck Restrictor T T T
Catalytic Converter T
Oxygen and Related Sensors T T T T
PCVSystem XT T M T
Heated Air Intake T A A M T
Evaporative Control System T T T T T M
Aspirated Air Injection System T T T M
Air Pump Belt . T M
Air Pump System T T T M
EGRSystem T T T T T M
T = Tampered
A = Arguably tampered
M = Malfunctioning
3. Fuel Sample Collection and Labeling Procedures
An attempt was made to take a fuel sample from each vehicle surveyed. These
samples were collected in two-ounce bottles with a hand-operated fuel pump. Once the
sample was drawn, the fuel was replaced with an equivalent amount of unleaded fuel if
the driver requested, and the pump was flushed with »n leaded 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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Motor Vehicle Tampering Survey -1989 Page 50
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.
•Note
The Plumbtesmo paper must be applied during the time that the
paper is yellow for the reaction to occur. 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 con-
tamination.
3) After removing the test paper, determine whether a color change has occurred. Red
or pink coloration indicates the presence of lead.
5. Field Quality Control
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.
Two calibration gases (Horiba) were used. These gases were a mixture of CO, HC,
and CO2 b nitrogen and were used to check the instrument twice a day. These
calibration gases were certified by the manufacturer and the RTF reference gases. Their
approximate compositions were:
8% CO
11%CO2
1560 ppm HC (Hexane equivalent)
1.6% CO
11% CO2
320 ppm HC (Hexane equivalent)
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Motor Vehicle Tampering Survey -1989
Page 51
APPENDIX C
EMISSION CUTPOINTS FOR I/M AREAS
The table below lists the emission cutpoints used by the I/M areas covered in the
1989 tampering survey. The cutpoints for pre-1975 vehicles are not included, since these
vehicles were not surveyed.
Survey Site
San Dlego/Bakersfletd, CA
Phoenix, AZ
New Jersey
Detroit, MI
Emissions Cutpoints
Model Year CO (%)
1975-79 (no CC)
1975-79 (OC, no AI)
1975-79 (OC.AI)
1975-79 (TWC)
1980+ (no CC)
1980+ (OQnoAI)
1980+ (OC.AI)
1980+ (TWC)
1975-78 (4 cyL)
1975-78 (6-8 cvL)
1979 (4 cyl.)
1979 (6-8 cyl)
1980+ (all)
1975-80
1981 +
1980
1981 +
3.5
4.5
1.5
1.5
2J
2.5
12
1.0
22
2.0
22
2.0
12
3.0
12
3.0
1.2
HC(ppm)
200
250
150
100
150
150
150
100
250
250
220
220
220
300
220
300
220
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Motor Vehicle Tampering Survey -1989
Page 52
Milwaukee, Wl
Anchorage/Fairbanks, AK
Denver, CO
1975-77
1978
1979
1980
1981 +
1975-83 (no CC)
1975-83 (OC, no AI)
1975-83
1975-83 (TWC)
1984 (all)
1975-76
1977-78
1979
1980 +
5.5
4.0
3.0
2.0
1.2
3.0
4.5
1.5
1.0
1.0
4.4
3.4
2.0
U
450
350
275
230
220
-
-
-
-
-
800
500
400
400
KEY: CC = catalytic converter (all types), CYL. = cylinder,
OC = oxidation catalytic converter, AI - air injection,
TWC = three-way catalytic converter.
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