United States
Environmental Protection
Agency
Office of Air
and Radiation
Washington DC 20460
November 1986
&EPA
Air
Motor Vehicle Tampering
Survey — 1985
V
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United States Environmental Protection Agency
Office of Air and Radiation
MOTOR VEHICLE TAMPERING SURVEY - 1985
November 1986
FIELD OPERATIONS AND SUPPORT DIVISION
OFFICE OF MOBILE SOURCES
Washington, D.C.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY 1
Introduction 1
Conclusions 3
BACKGROUND 9
SURVEY METHODS 12
Site Descriptions 14
RESULTS 20
Vehicle Tampering 20
Site and Aggregate Totals 20
Tampering Trends 1978-1985 22
Types of Tampering 27
Vehicle Characteristics and Tampering 30
Vehicle Type 30
Vehicle Age 32
Manufacturer 40
I/M Programs and Geographic Bias , 43
Effect of I/M Programs on Tampering 44
Tampering Trends for Selected Sites 49
Effectiveness of ATP-Only - Houston 55
Correlation Between Tampering and Idle Emissions 56
Fuel Switching 63
Fuel Switching Indicators and Overlap 63
Fuel Switching Rates 65
Fuel Switching by Vehicle Type 69
Fuel Switching and Vehicle Age 69
Catalyst Tampering and Fuel Switching 72
Gasoline Lead Concentrations 74
APPENDICES
A. Relevant Portions of Clean Air Act 75
B. Survey and Data Recording Procedures 76
C. Emission Cutpoints for I/M Areas 90
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LIST OF FIGURES
1. Component specific tampering rates:
1979-1985 surveys 5
2. Overall and catalyst tampering by vehicle model
year - 1985 survey •••• • 7
3. Breakdown of surveyed vehicles by condition and
extent of tampering 21
4. Cumulative tampering prevalence as a function of
vehicle age for the 1978-1985 surveys 36
5. Cumulative catalyst tampering rates as a function
of vehicle age for the 1978-1985 surveys 37
6. Comparison of catalyst and overall tampering rates
with vehicle age as a function of survey year 39
7. Tampering rates by manufacturer - 1985 survey 41
8. Tampering prevalence by manufacturer for the
1978-1985 surveys 42
9. Comparison of tampering found in three locations in
the same geographic area - 1985 suvrey 45
10. Converter tampering as a function of vehicle age for
vehicles covered by different programs - 1985 Survey .. 51
11. Comparison of data from 1985 survey sites that had
been surveyed previously (Figs. 11(a) thru (d)) .... 53-54
12. Distribution of survey sample among tampering, fuel
switching, and idle test categories 58
13. Overlap of tampering and carburetor misadjustment
among conventionally carbureted vehicles - 1985
survey 60
14. Overlap of fuel switching indicators among unleaded
vehicles - 1985 survey 66
15. Overlap of catalyst tampering and fuel switching
among catalyst-equipped vehicles - 1985 survey 73
16. Lead concentrations in fuel sampled from misfueled
vehicles 73
_ 11 _
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LIST OF TABLES
1. Tampering Prevalence by Vehicle Type for
Critical Control Components 7
2. 1985 Tampering Survey Summary 23
3. Classification of Vehicle Condition by Survey
Site 24
4. Trends in vehicle Condition Classification 25
5. Comparison of 1985 Survey Sample to Actual
Nationwide vehicle Fleet 25
6. Prevalence of Tampering by Component and Survey
Year 28
7. Component-Specific Tampering Rates (percent) by
Survey Location - 1985 Survey 29
8. Prevalence of Arguable Tampering by Component
and Survey Year 31
9. Tampering Prevalence (and Sample Size) by Model
Year and Vehicle Age at Time of Survey 33
10. Percentage of Catalyst Removal (and Sample Size)
among Catalyst-Equipped Vehicles by Model Year
and Vehicle Age at Time of Survey 34
11. Tampering Prevalence in I/M and non-I/M Areas 47
12. Component-Specific Tampering by Inspection Program
Type - 1985 Survey 47
13. Catalyst Tampering among Vehicles for each Model
Year covered by a Particular Program Type 50
14. Comparison of Tampering Rates in Houston for
Components and Model Years covered by Antitamper ing
Program 57
15. Idle Test Failure Rates (percent) by
Pollutant and Vehicle Condition 62
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16. Mean Idle Emissions by Vehicle Condition 62
17. Fuel Switching Rates among Unleaded Vehicles by
Site and Indicator - 1985 Survey 67
18. Fuel Switching Prevalence among Unleaded vehicles
in I/M and non-I/M Areas 68
19- Fuel Switching Rates among Unleaded Vehicles by
Indicator and Survey Year 68
20. Combined Tampering and Fuel Switching
Rates - 1985 Survey 70
21. Percentage of Fuel Switching (and Sample Size)
among Unleaded vehicles by Model Year and Vehicle
Age at Time of Survey 71
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EXECUTIVE SUMMARY
INTRODUCTION
Under the direction of the Field Operations and Support
Division (FOSD) of the Environmental Protection Agency (EPA),
contract personnel from Colorado State University (CSU)
conducted a survey of light-duty motor vehicle tampering in
15 cities between April and September, 1985. The areas surveyed
and the total number of vehicles inspected are listed below.
Kansas City, MO 469
Kansas City, KS 475
Fresno, CA 466
Charlotte, NC 430
Raleigh, NC 501
Louisville, KY 456
Wilmington, DE 502
Portland, ME 436
Northern Virginia 380
Long Island, NY 305
Philadelphia, PA 446
Cleveland, OH 383
Baton Rouge, LA 438
Houston, TX 450
Albuquerque, NM 449
TOTAL 6,586 vehicles
The objectives of this survey were:
1. To make local measurements of the types and extent of
tampering and fuel switching.
2. To extend and update the knowledge gained from earlier
surveys on:
a. The rates of overall and component-specific
tampering and fuel switching.
b. The distribution of tampering by vehicle age,
type, manufacturer, and other variables of
interest.
c. The relationship between tampering and vehicle
idle emissions.
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d. The effect of vehicle inspection and maintenance
(I/M) programs and antitampering programs (ATPs)
on tampering and fuel switching.
To achieve these objectives, the inspection teams
visually examined emission control devices and measured the
idle hydrocarbon (HC) and carbon monoxide (CO) emissions of
each vehicle. To provide information on fuel switching, the
inspectors sampled gasoline from the tanks of vehicles (for
later laboratory lead analysis), tested for lead deposits in
tailpipes using Plumbtesmo® test paper, and checked the
integrity of the fuel filler inlet restrictors. Four cate-
gories were used to summarize the condition of the inspected
vehicles:
1. Tampered - at least one control device removed or
rendered inoperative
2. Arguably Tampered - possible but not clear-cut
tampering (i.e., may have resulted from malmaintenance)
3. Malfunctioning
4. Okay - all control devices present and apparently
operating properly
These brief but thorough inspections were performed with the
consent of the vehicle owners in a variety of settings more
fully detailed elsewhere in this report.
While the data from a survey such as this seem to invite
inferences regarding program effectivenes, trends, etc., this
approach can easily lead to incorrect conclusions. The sample
size is reasonably adequate for evaluating tampering prevalence
in any particular site, but the sampling of sites is neither
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large nor random. Simple comparisons of site tampering
rates across control program categories, for example, can
overlook a variety of confounding factors. These may include
geographical variability, fleet age structure and vehicle
mix, variations in program maturity, coverage, history, and
management, and the interactions among these factors. Straight-
forward experimental control of these variables, difficult
to achieve under the best of circumstances, becomes impossible
in a situation where site selection is driven by programmatic
considerations unrelated to the experimental questions.
CONCLUSIONS
For consistency with past surveys, the surveyed vehicles
were classified as follows: tampered - 20%; arguably tampered
- 27%; malfunctioning - 1%; okay - 52% (overall survey averages),
This gross classification, while useful for some comparisons,
is less informative concerning the emissions impact of
tampering than an examination of component-specific rates.
The 20% overall tampering rate is less than the rates found
in 1984 and 1983 but greater than the rates from the other
large surveys of 1978, 1979, and 1982. The apparent decrease
in tampering activity may be an artifact of site-to-site
variations in geographic location, truck proportion, and
other characteristics, as well as disproportionate selection
of sites with I/M and ATP programs. This decline may have
emerged in part because this survey's sample is composed of
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vehicles whose average age is somewhat lower than in the last
survey, a trend discussed further in the body of this report.
Component-specific tampering for selected critical
components is shown in Figure 1. The results shown have not
been weighted to compensate for I/M program representation;
these rates probably underestimate the actual nationwide rates.
Tampering with evaporative and PCV systems has increased
since 1984, while the rates for other components have fluctuated
The catalytic converter removal rate for the 1985 survey
was 5% overall. Catalytic converter removal increases HC and
CO emissions by an average of 475% and 425%, respectively.!
For vehicles equipped with three-way catalysts, substantial
increases in NOX emissions would also be expected to occur.
The fuel inlet restrictor, air pump system, and exhaust
gas recirculation (EGR) system were the most frequently
tampered components (7%). EGR system tampering can increase
NOX emissions by an average of 175%.
Fuel Switching
Fuel switching, defined as the presence of any of the
three indicators2, was found in 9% of the unleaded vehicles in
1 The emissions increases mentioned in this report are from a
study of three-way catalyst vehicles presented in Anti-Tampering
and Anti-^Misfueling Programs to Reduce In-Use Emissions from
Motor Vehicles, EPA-AA-TTS-83-10, December 31, 1983.
2 The three fuel switching indicators are: a tampered fuel
filler inlet restrictor, a positive Plumbtesmo® tailpipe test,
or a gasoline lead concentration of more than 0.05 gram per
gallon.
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Component or System
Catalytic Convertor
Evaporative System
Air Pump System
Inlet Restrictor
PCV System
EGR System
ss ssss ss ss ss/A 82
1979
1981
1982
1983
1984
1985
] 13Z
Tampering Rato (%)
Figure 1. Component-specific tampering rates:
1979 - 1985 surveys.
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the 1985 survey. The fuel switching rate weighted by program
status was 11%. The pattern of overlap among the three misfuel-
ing indicators is discussed in detail later in this report.
While the emissions impact of fuel switching depends upon its
duration and certain vehicle characteristics, emission increases
of 475% for HC and 425% for CO can easily occur.
Age of Vehicle
The probability that a vehicle has been tampered with is
clearly related to its age, as has been shown in previous
surveys. This is evident in Figure 2, which shows the rates
by model year for both overall tampering and catalyst removal.
These age-specific rates are investigated more thoroughly later
in this report.
Vehicle Types
The tampering rates for light-duty trucks were equal to
or higher than for automobiles in every tampering category, as
shown in Table 1. The difference in catalytic converter
tampering is particularly striking—over twice as prevalent
for light-duty trucks as for passenger cars (10% vs 4%).
Overall tampering and fuel switching rates among trucks mirror
the general decline from 1984 rates observed in the survey as
a whole.
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Tampering Rate (2)
Qvwal 1
Tampering
Catalyst
Tanparing
20 •
10 •
1965 1984 1983 1982 1981 1980 1979 1978 1877 1976 1975
Vehicle Modal Year
Figure 2. Overall and catalyst tampering by
vehicle modal yeai— 1985 survey.
TABLE 1
Tampering Prevalence by Vehicle Type for
Critical Control Components
Tampering Rate (%)
Component/System
Catalytic Converter
Filler Neck Restrictor
Air Pump System
PCV System
Evaporative Control
System
EGR System
OVERALL
Trucks
10
10
11
5
4
8
22
Cars
4
7
6
5
4
7
19
Overall
5
7
7
5
4
7
20
Fuel Switching
13
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I/M Programs and Tampering
While the tampering rates in non-I/M areas were clearly
equal to or greater than those with control programs for every
critical component, such comparisons across program categories
should be made very carefully. The classification of sites
into program categories is necessarily somewhat rough.
Fresno, for instance, has a biennial I/M + ATP program that
has not been in effect long enough for all of the affected
vehicles to have been inspected for the first time. Because of
restricted program coverage aimed at newer vehicles (those
less likely to be tampered with because of warranty status and
age) the impact of a newly implemented program may not be
observable for several years.
A simple comparison of rates by program status would
mislead one to conclude that antitampering programs are of
doubtful utility when added onto I/M tailpipe programs. A
different picture emerges, however, when we look at a group of
sites roughly matched by geographical location, but varying in
program status: Raleigh, Louisville, and Charlotte. Raleigh
(non-I/M) has the highest rates of the three for catalyst and
inlet tampering and fuel switching, followed by Louisville
(I/M-only). Charlotte, which shares the geographical background
of the other two cities but has an antitampering program augmenting
its I/M program, has the lowest tampering rates of the three
for the components specified. The effects of control programs
on tampering are discussed in greater detail elsewhere in this
report.
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BACKGROUND
Motor vehicle emissions in urban areas account for nearly
90% of the total carbon monoxide (CO) and airborne lead, over
30% of the hydrocarbons (HC), and nearly 40% of the oxides of
nitrogen (NOX) emitted into the atmosphere. As a result, a major
focus of the nation's efforts to achieve compliance with clean
air standards has been the control of emissions from mobile
sources. The first pollution control devices were installed on
vehicles in 1962, and most light-duty vehicles manufactured
since 1968 have been equipped with a variety of emission control
devices to meet required emissions standards.
The 1977 amendments to the Clean Air Act (sections
203(a)(3)(A) and (B), found in Appendix A) make it illegal for
automobile dealers, repair and service facilities, and fleet
operators to disconnect or render inoperative emission control
devices or elements of design. Regulations issued under section
211(c) of the Act (40 CFR Part 80) prohibit retailers and
wholesale purchaser-consumers from introducing or allowing the
introduction of leaded gasoline into vehicles labeled "unleaded
gasoline only". The EPA's Field Operations and Support Division
(FOSD), formerly the Mobile Source Enforcement Division (MSED),
is responsible for enforcing the tampering and misfueling
provisions of the Act.
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Before 1978, the EPA had data suggesting that tampering
with emission control devices and misfueling of "unleaded only"
vehicles with leaded gasoline was occurring. Variability in
the inspection procedures, however, prevented an accurate
assessment of the nature and extent of the tampering. As a
result, the Agency began conducting nationwide tampering
surveys of light-duty motor vehicles in 1978 to determine the
rates and types of tampering and fuel switching. These surveys
were conducted in 1978*, 19792, 198l3, 19824, 19835, and 1984$,
either by FOSD directly, by EPA's National Enforcement
Investigations Center (NEIC) under the direction of FOSD, or by
EPA contractors supervised by FOSD personnel. Consistent
inspection procedures were used throughout these surveys to
permit comparisons and identification of trends.
1 Motor Vehicle Tampering Survey (1978), U.S. Environmental
Protection Agency, Mobile Source Enforcement Division,
November 1978.
2 Motor Vehicle Tampering Survey (1979), U.S. Environmental
Protection Agency, National Enforcement Investigations
Center, May 1980, EPA-330/1-80-001.
3 Motor Vehicle Tampering Survey - 1981, Chattanooga, Tennessee
and Houston, Texas, U.S. Environmental Protection Agency,
National Enforcement Investigations Center, March 1982,
EPA-330/1-82-001.
4 Motor Vehicle Tampering Survey - 1982, U.S. Environmental
Protection Agency, National Enforcement Investigations
Center, April 1983, EPA-330/1-83-001.
5 Motor Vehicle Tampering Survey - 1983, U.S. Environmental
Protection Agency, Field Operations and Support Division,
August 1984, EPA-460/1-84-001.
6 Motor Vehicle Tampering Survey - 1984, U.S. Environmental
Protection Agency, Field Operations and Support Division,
October 1985, EPA-460/1-85-001.
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The uses for the tampering surveys have evolved since the
first survey was conducted in 1978. Since 1983, the tampering
survey results for some locations have been used to calculate
credits for State Implementation Plans (SIPs), the measures
taken by State and local governments to achieve ambient air
quality standards by reducing mobile source emissions. Data
from the surveys is also used in the default database for the
Agency's mobile source computer model (MOBILES) to estimate
both the emissions loading impact and the reductions that may
be achieved by various control programs. Sites for the surveys
are chosen in light of the need for data on specific areas
either currently operating or considering programs, as well as
the continuing need to monitor the types and extent of tampering
and fuel switching nationwide.
The 1985 tampering survey was conducted for FOSD by the
National Center for Vehicle Emissions Control and Safety,
Colorado State University (CSU). The inspection procedures
used were consistent with those of previous surveys, and are
described in detail in the next section of this report.
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SURVEY METHODS
The 1985 tampering survey was conducted in 15 cities between
April and September, 1985. A goal of inspecting at least 300
vehicles in each location was established to ensure a statistically
meaningful database; 6,586 total vehicles were actually inspected.
The mix of vehicles inspected was assumed to be a self-weighting
sample, and no attempt was made to approximate the national
vehicle mix.
Each inspection team consisted of at least four members:
three CSU personnel, one or two EPA representatives, and fre-
quently a State or local agency representative. The CSU personnel,
assisted by the State or local person, performed the actual
inspections, while the EPA representative(s) supervised the survey.
Each vehicle inspection included the following:
1. basic vehicle identification data recorded (year,
make, model)
2. all emission control systems checked
3. idle HC and CO emissions measured
4. fuel sample collected from unleaded-only vehicles for
lead analysis
5. tailpipe tested for lead deposits using Plumbtesmo®6
test paper
6. integrity of fuel inlet restrictor checked
6 Plumbtesmo® is a registered trademark, and appears hereafter
without the ®. It is manufactured by Machery-Nagel, Duren, W.
Germany, and marketed by Gallard-Schlesinger Chemical Corp.,
Carle Place, New York.
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The inspection and recording procedures are detailed in
Appendix B. The survey database has been reviewed by CSU,
EPA, and the major automobile manufacturers to ensure its
accuracy.
The tampering survey included only 1975 and newer
light-duty cars and trucks fueled with gasoline. For the
purposes of the tampering surveys, a vehicle is considered
to be "unleaded" if a dash label, tank label, or filler
inlet restrictor is observed at the time of the inspection.
A vehicle's designation as "unleaded" or "leaded" may be
changed upon subsequent review of the data. Fuel switching
rates are thus calculated based only on the unleaded vehicles
surveyed. Similarly, tampering rates for specific components
are based only on the vehicles originally equipped with the
component.
The inspections were performed with the consent of the
vehicle owners at either roadside pullovers or inspection
stations. The survey was designed to minimize the refusal
rate of potential survey participants. A high refusal rate
increases the uncertainty in the data gathered, and indivi-
duals who have tampered with or misfueled their vehicles are
less likely to allow their vehicles to be surveyed. The
overall refusal rate was relatively low (7%), but some
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survey sites had high refusal rates (see below). The tampering
and misfueling rates at these particular locations might be
significantly higher than reported here. A brief description
of each survey site follows.
Kansas City, Missouri - non-I/M
Dates: April 22 - 26, 1985
Vehicles Surveyed: 469
Fuel Samples: 384
Refusal Rate: • 9%
The Kansas City Police Department and Missouri State
Highway Patrol provided officers to stop potential survey
participants, and the inspectors solicited permission to
conduct the inspections. Locations for pullovers were changed
daily.
Kansas City, Kansas - non-I/M
Dates: April 29 - May 3, 1985
Vehicles Surveyed: 475
Fuel Samples: 386
Refusal Rate: 5%
Roadside pullovers were conducted with the help of the
local law enforcement officers of municipalities in the Kansas
City area. Inspection locations were changed daily and
included Kansas City (two days), Shawnee, Overland Park, and
Olathe.
Fresno, California - I/M + ATP
Dates: May 20 - 24, 1985
Vehicles Surveyed: 466
Fuel Samples: 297
Refusal Rate: 5%
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The California Highway Patrol provided officers to assist
with the roadside pullovers. The California Bureau of
Automotive Repair conducted a survey of driver's perceptions
about emission control concurrently with the tampering
inspections. Survey locations were changed daily. Fresno has
had a decentralized biennial I/M and antitampering program
since November, 1984; consequently less than 30% of the vehicles
in Fresno had been inspected at the time of the survey.
Charlotte, North Carolina - I/M + ATP
Dates: June 3-7, 1985
Vehicles Surveyed: 430
Fuel Samples: 324
Refusal Rate: 12%
Roadside pullovers were conducted with the assistance
of the Charlotte Police Department. Survey locations were
changed daily. Charlotte (Mecklenburg County) enacted an
annual decentralized I/M + ATP in December, 1982 which covers
the last twelve model years.
Raleigh, North Carolina - non-I/M
Dates: June 10 - 14, 1985
Vehicles Surveyed: 501
Fuel Samples: 399
Refusal Rate: 7%
The North Carolina Department of Motor Vehicles provided
officers to assist with the roadside pullovers. The surveys
were conducted at five locations in the Raleigh metropolitan
area.
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Louisville, Kentucky - I/M-only
Dates: June 18 - 21, 1985
Vehicles Surveyed: 456
Fuel Samples: 415
Refusal Rate: 7%
The Louisville survey was conducted at four centralized
inspection stations in the metropolitan Louisville area. The
inspection team set up and conducted the survey at the entrance
to the inspection lane each day. The centralized annual I/M
program in Louisville (Jefferson County) was enacted in
January, 1984.
Wilmington, Delaware - I/M-only
Dates: June 24 - 28, 1985
Vehicles Surveyed: 502
Fuel Samples: 417
Refusal Rate: 8%
The Wilmington survey was conducted with the assistance
of the Delaware State Police, New Castle County Police, and
Wilmington Police Department. The roadside pullover locations
were changed daily, and were all located in the metropolitan
Wilmington area. Wilmington (New Castle County) enacted an
annual centralized I/M program in January, 1983.
Portland, Maine - non-I/M
Dates: July 8-12, 1985
Vehicles Surveyed: 436
Fuel Samples: 376
Refusal Rate: 6%
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The Portland survey was conducted at four locations in
Portland and one location in South Portland. The inspection
team was assisted by the Maine State Police, City of Portland
Police, and the South Portland Police.
Northern Virginia - I/M + ATP
Dates: July 15-19, 1985
Vehicles Surveyed: 380
Fuel Samples: 332
Refusal Rate: 10%
The Northern Virginia survey was conducted in the Virginia
suburbs of Washington, D.C. The Virginia State Police assisted
with the roadside pullovers. Northern Virginia's annual
decentralized I/M + ATP was enacted in December, 1981, and
covers the previous eight model years.
Long Island, New York - I/M + ATP
Dates: July 22 - 26, 1985
Vehicles Surveyed: 305
Fuel Samples: 256
Refusal Rate: 12%
The survey was conducted in three New York State
counties surrounding New York City: Suffolk, Nassau (2 days),
and Westchester. The last day of the survey (in Rockland
County) was cancelled because of inclement weather conditions.
The New York State Environmental Conservation Police, Long
Island Park Police, New York State Police, and Nassau County
Police assisted with the roadside pullovers. The greater New
York metropolitan area has had an annual decentralized I/M +
ATP since January, 1982.
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Philadelphia, Pennsylvania - I/M-only
Dates: August 5-9, 1985
Vehicles Surveyed: 446
Fuel Samples: 361
Refusal Rate: 6%
The Philadelphia survey was conducted in Philadelphia
four days and in Cheltenham township one day. The Philadelphia
Highway Patrol and Cheltenham Township Police assisted with
the roadside pullover. The greater Philadelphia metropolitan
area has had a decentralized annual I/M program since June,
1984.
Cleveland, Ohio - non-I/M
Dates: August 12 - 16, 1985
Vehicles Surveyed: 383
Fuel Samples: 343
Refusal Rate: 9%
Roadside pullovers were conducted with the help of local
law enforcement officers in the municipalities in the Cleveland
area. Inspection locations changed daily and included Cleveland
(two days), Parma Heights, Garfield Heights, and Westlake.
Baton Rouge, Louisiana - non-I/M
Dates: August 19 - 23, 1985
Vehicles Surveyed: 438
Fuel Samples: 405
Refusal Rate: 3%
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The Louisiana State Police provided officers to assist
with the roadside pullovers. Inspection locations changed
daily, and included Baton Rouge, East Baton Rouge, West Baton
Rouge, Erwinsville, and Denham Springs. Baton Rouge was a
non-I/M area at the time of the survey, but implemented an
ATP only in September, 1985.
Houston, Texas - ATP-only
Dates: August 26 - 30, 1985
Vehicles Surveyed: 450
Fuel Samples: 369
Refusal Rate: 6%
The Houston survey was conducted at four locations in
Houston and one location in South Houston. The Texas Department
of Public Safety supplied officers to assist with the roadside
pullovers. An annual decentralized ATP-only program was
implemented in Houston (Harris County) in July, 1984.
Albuquerque, New Mexico - non-I/M
Dates: September 9-13, 1985
Vehicles Surveyed: 449
Fuel Samples: 410
Refusal Rate: 6%
The Albuquerque survey was conducted with the assistance
of the New Mexico State Police. Survey locations were changed
daily, and included Albuquerque (3 days), North Valley, and
South Valley. Albuquerque is currently a non-I/M area, but
had an I/M program from January, 1983 to March, 1984.
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RESULTS
A. VEHICLE TAMPERING
1 . Site and Aggregate Totals
The vehicles surveyed have been classified into four
categories established by previous surveys: tampered,
arguably tampered, malfunctioning, and okay. Each vehicle
was classified by the worst state of any component in the
vehicle- For example, a vehicle would be classified as
"tampered" if any one component had been tampered, even if
all other components were functioning properly. A vehicle
classified as "okay" must have all observed components
functioning properly 1. The criteria used for component
classification are presented in Appendix B. This overall
tampering rate is useful only as a rough indicator of the
emissions impact of a tampering problem, since the different
components making up the rate may have widely varying emissions
implications.
The proportion of inspected vehicles with at least one
tampered component was 20%. Nearly half of the vehicles
surveyed (48%) displayed some form of malfunction, arguable
tampering, or clear tampering of emission control components.
The specific distribution of surveyed vehicles among these
categories is depicted in Figure 3.
1 An "okay" vehicle, however, may still be classified as
fuel switched (see section B.I., Fuel Switching Indicators
and Overlap of this report).
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Arguably Tampered
Malfunctioning
Tampered
OK ay
four or more (ll/O
three (10%)
-two (21%)
-one (58%)
NJ
I-1
I
Condition of Surveyed Vehicles
Number of Tampered Components
Figure 3. Breakdown of surveyed vehicles by
condition and extent of tampering.
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The frequency distribution of tampering instances for
those vehicles classified as "tampered" is also shown in
Figure 3. Forty-two percent of the tampered vehicles had
multiple components tampered, of which 11% had four or more
instances of tampering.
Tables 2 and 3 summarize the 1985 survey data by site.
Table 2 is a general survey summary, while Table 3 shows
the vehicle condition classification by site. As in the
1984 survey, the overall tampering rates in 1985 vary
considerably from site to site. This can be attributed to
the variety of program configurations among the cities
surveyed and to geographic differences.
Table 2 also contains the refusal rate at each survey
site. While the overall refusal rate for the survey was
relatively low (7%), three survey sites had refusal rates
equal to or exceeding 10%. The actual tampering rates at
these sites were probably higher than is reported here,
since individuals who tamper with or misfuel their vehicles
are less likely to allow their vehicles to be surveyed.
2. Tampering Trends 1978-1985
Table 4 shows the overall rates found in each of the
seven tampering surveys. The overall tampering rate
declined to 20% from the 22% and 26% rates found in 1984
and 1983, respectively. Such direct comparisons between
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Survey
Location
Kansas City, MO
Kansas City, KS
Fresno, CA
Charlotte, NC
Raleigh, NC
Louisville, KY
Wilmington, DE
Portland, ME
N. Virginia
Long Island, NY
Philadelphia, PA
Cleveland, OH
Baton Rouge, LA
Houston, TX
Albuquerque, NM
OVERALL
TABLE 2
1985 Tampering Survey Summary
Number of Tampering Misfueling Survey Refusal
Vehicles Rate (%) Rate (%) Type* Rate (%)
469
475
466
430
501
456
502
436
380
305
446
383
438
450
449
21
25
21
19
18
23
14
12
15
20
13
22
32
18
24
10
12
9
6
14
10
5
5
4
7
3
8
21
7
11
R
R
R
R
R
C
R
R
R
R
R
R
R
R
R
9
5
5
12
7
7
8
6
10
12
6
9
3
6
6
6,586
20
*R = roadside pullovers, C = centralized I/M stations,
-------
-24-
TABLE 3
Classification of Vehicle Condition by Survey Site
Tampered Arguably Malfunctioning Okay
Survey Site
Kansas City, MO*
Kansas City, KS
Fresno, CA
Charlotte, NC
Raleigh, NC
Louisville, KY
Wilmington, DE
Portland, ME
N. Virginia
Long Island, NY
Philadelphia, PA
Cleveland, OH
Baton Rouge, LA
Houston, TX
Albuquerque, NM
( % )
21
25
21
19
18
23
14
12
15
20
13
22
32
18
24
Tampered ( %)
24
24
31
25
21
37
28
24
25
21
29
26
25
28
27
( %)
1
1
2
1
1
1
2
2
1
3
0
2
1
0
2
(%)
55
50
46
56
60
39
56
61
59
56
57
49
42
53
47
OVERALL 20 27 1 52
*The rates do not total 100% for some sites because of rounding
-------
-25-
TABLE 4
Trends in Vehicle Condition Classification
Survey
Year
1978
1979
1981*
1982
1983
1984
1985
Tampered
(%)
19
18
14
17
26
22
20
Arguably
Tampered (%)
48
47
45
38
30
29
27
Malfunctioning
(%)
2
2
3
1
3
4
1
Okay
(%)
31
33
38
44
42
46
52
*Because the 1981 survey involved only two sites and a very
limited sample size, these results may exhibit more variance
than the other larger surveys.
TABLE 5
Comparison of 1985 Survey Sample to Actual Nationwide
Vehicle Fleet
Program Percentage within
Type Survey Sample (%)
non-I/M
I/M-only
I/M + ATP
ATP-only
(Houston)
48
21
24
7
Approx. Percentage of
Nationwide Fleet (%)**
75
13
11
1
** Based on 1986 vehicle population data gathered from EPA
Regional and State contacts.
-------
-26-
survey years, however, are not entirely appropriate. The
surveys, for example, covered different sites, and had
*
different age and car/truck distributions. More importantly,
because of the 1985 survey's specific goals, it greatly
overrepresents the percentage of the national vehicle fleet
under local control programs (see Table 5). I/M and I/M +
ATP areas comprised 45% of the survey sample, while only
approximately 24% of the national vehicle fleet were under
such programs.
This discrepancy can be corrected to some degree by
applying a weighting factor to the tampering rates found
under each program type. The 1985 tampering rate weighted
for program representation is 21%. The 1985 weighted tampering
rate can be compared to the weighted rates from the 1984,
1983, and 1982 surveys (26%, 28%, and 19%, respectively.)
Applying weighting factors to the 1981 and earlier surveys
would be difficult, since some surveys contained no I/M
areas. For the sake of clarity, only the actual, unweighted
rates found during the surveys will be reported. Useful
comparisons, however, can still be made between program types
within a given year (e.g., I/M vs. non-I/M) or between the
same program type in different years (e.g., non-I/M in 1984
and 1985) .
-------
-27-
3. Types of Tampering
The tampering rates for specific emission control
components and systems for the various survey years are
presented in Table 6. The component-specific tampering
rates for the 1985 survey are presented by survey site in
Table 7. The arguable tampering percentages by component
for the 1978-1985 surveys are presented in Table 8. Only
those vehicles originally equipped with a particular
component are considered when computing the tampering or
arguable tampering rate for that component. The heated
air intake was the only component that could be classified
as either tampered or arguably tampered, based on its
condition in a surveyed vehicle (see Appendix B).
Table 6 shows that tampering with some major components
(e.g., filler inlet restrictor and catalytic converter)
has decreased since the 1984 survey. Tampering with the
PCV, aspirator, and evaporative systems has increased
since the 1984 survey. Tampering in general remained higher
than in the 1982 and earlier surveys.
Table 7 shows the wide variation in tampering rates
for any given component from site to site. Catalytic
converter removal, for example, ranged from 2% in Fresno
to 14% in Baton Rouge. This range is partly due to the
effectiveness of I/M and antitampering programs and geo-
graphic differences, as will be discussed later in this
report.
-------
-28-
TABLE 6
Prevalence of Tampering by Component and Survey Year
Survey Year
Component/System
Catalytic Converter
Filler Neck
Restrictor
Air Pump System
Air Pump Belt
Air Pump/Valve
Aspirator**
PCV System
Evaporative
Control System
EGR System
EGR Control Valve
EGR Sensor
Heated Air Intake
Vacuum Spark
Retard
Idle Stop
Solenoid
Oxygen Sensor
1978
1%
3
7
6
3
***
3
3
13
12
5
1
11
1
***
1979
1%
4
5
4
2
2
3
2
10
5
7
1
2
1
* * *
1981*
4%
6
4
4
4
0
2
2
5
5
5
0
1
0
* * *
1982
4%
6
5
5
4
1
3
2
10
7
7
1
0
0
***
1983
7%
7
7
7
3
1
5
5
13
9
12
1
1
1
0
1984
7%
10
7
7
4
1
2
3
10
7
6
1
5
1
0
1985
5%
7
7
4
6
2
5
4
7
6
4
1
***
** *
0
*The 1981 survey was of limited scope, covering only two
sites and 399 vehicles.
**Vehicles with aspirated air systems are not equipped with
other listed air-injection components, nor do conventional
systems include aspirators.
***
Component not checked during survey.
-------
TABLE 7
Component-Specific Tampering Rates (percent) by Survey Location - 1985 Survey
Emission Control Component or System
Survey
Location
Kansas City, MO
Kansas City, KS
Fresno, CA
Charlotte, NC
Raleigh, NC
Louisville, KY
Wilmington, DE
Portland, ME
N. Virginia
Long Island, NY
Philadelphia, PA
Cleveland, OH
Baton Rouge, LA
Houston, TX
Albuqueroue, NM
OVERALL
Catalytic
Converter
7
10
2
3
8
6
3
4
1
5
2
6
14
5
5
5
Inlet
Restrictor
9
10
9
5
11
8
3
4
4
4
2
7
17
5
9
7
Air Pump
System
6
11
4
3
4
10
4
2
5
8
5
7
19
8
12
7
PCV
System
3
5
7
7
2
6
4
2
3
5
5
7
7
5
7
5
EGR
System
6
11
7
8
4
6
6
4
5
6
5
8
14
9
6
7
Evaporative
System
3
4
4
4
2
3
3
3
3
4
3
4
10
4
5
4
Any
Component
21
25
21
19
18
23
14
12
15
20
13
22
32
18
24
20
I
to
-------
-30-
Table 8 shows that idle limiter caps/sealed plugs remain
the item most frequently arguably tampered (42%). The arguable
tampering with limiter caps and sealed plugs, however, has
continued to decline from a high of 83% in 1981. This is
probably due to the widespread use of sealed plugs instead of
limiter caps in recent years to deter carburetor adjustments.
The sealed plugs are much more difficult to remove than the
plastic limiter caps were. Arguable tampering with the
heated air intake doubled in 1985, and tank label removal
also remained high.
4. Vehicle Characteristics and Tampering
The next section of this report investigates the impact
on tampering of three vehicle characteristics: type (car
or truck), age, and manufacturer.
Vehicle Type. The tampering prevalence for light-duty
trucks was higher than for automobiles, as was mentioned
previously (Table 1). The tampering rate for each emissions
component on trucks was equal to or greater than on passenger
cars, continuing the pattern observed in previous surveys.
The catalytic converter tampering rate for trucks was more
than double that for automobiles (10% vs. 4%). The fuel
switching rate for trucks (13%) was also considerably higher
than for automobiles (8%).
-------
-31-
TABLE 8
Prevalence of Arguable Tampering by Component
and Survey Year
Survey
Year
1978
1979
1981
1982
1983
1984
1985
Limiter Cap/
Sealed Plugs
65%
62
83
54
54
49
42
Fuel Tank
Cap
0%
1
1
2
3
1
1
Tank
Label
5%
4
4
4
9
12
10
Dash
Label
1%
1
0
1
1
3
2
Heated Air
Intake
9%
8
9
6
14
8
16
-------
-32-
Vehicle Age. Table 9 relates vehicle age and model
year with tampering prevalence for the 1978-1985 surveys.
Catalytic converter removal rates are similarly related to
vehicle age and model year in Table 10. The results from
any given survey are entered diagonally in each table.
The results in Tables 9 and 10 indicate that vehicle
tampering increases directly with vehicle age. Examining
Table 9 diagonally (by survey) shows a fairly linear increase
in the tampering rate with vehicle age for each survey. In
the 1985 survey, for example, the tampering rate increases
from 2% for first year (1985) vehicles to 54% among the 1975
model year vehicles surveyed. Table 10 shows a similar,
though less pronounced, increase in catalyst removal. Examin-
ing these tables in this manner has the advantage of comparing
data collected during one survey in one set of locations, but
ignores the possible effects of model year differences (i.e.,
technology) on tampering.
Two additional ways of analyzing Tables 9 and 10 address
the impact of model year on tampering rates. Analyzing the
tables horizontally (holding the model year constant) provides
a look at the tampering rates over time for the vehicles of
a particular model year. This approach shows the same distinct
increase in tampering with vehicle age for all model years
since 1975. (The 1974 and 1973 data sets are too small to
-------
TABLE 9
Tampering Percentage (and Sample Size) by Model Year and Vehicle &je at Time of Survey
Year of Vehicle Life
Model
Year
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
First
2(816)
1(462)
7(182)
1(250)
2(57)
6(371)
7(298)
Second Third
2(1001)
4(471) 6(710)
4(226) 7(466)
7(448) 13(206)
5(63) 9(454)
9(59)
14(502)
10(457) 15(476)
18(395)
Fourth Fifth
9(621)
15(458) 11(607)
15(211) 18(516)
18(477) 31(288)
15(79) 21(430)
21(66)
19(374)
22(274) 22(271)
33(276)
Sixth Seventh Eighth Ninth Tenth Eleventh
25(564)
28(503) 37(673)
39(238) 34(559) 37(562)
26(316) 44(190) 41(408) 48(452)
29(52) 26(317) 40(171) 39(385) 49(369)
32(22) 37(183) 55(89) 46(197) 54(194)
27(242)
32(253) 36(251)
-------
TABLE 10
Percentage of Catalyst Removal (and Sample Size)
among Catalyst-equipped Vehicles by Model Year and Vehicle Age at Time of Survey
Model
Year
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
First
0(808)*
0(462)
1(179)
0(250)
0(57)
0(326)
0(291)
Second
0(978)
2(471)
1(225)
2(441)
2(61)
0(445)
1(417)
Third
0(686)
2(465)
5(204)
2(428)
4(55)
1(417)
2(377)
Year of Vehicle Life
Fourth Fifth Sixth Seventh Eighth Ninth Tenth Eleventh
2(597) £
6(457) 3(567)
3(200) 6(487) 6(522)
6(429) 12(252) 10(455) 12(572)
0(71) 4(362) 8(213) 8(486) 10(472)
2(59) 2(271) 11(166) 14(357) 17(379)
2(305) 10(48) 6(257) 12(139) 12(314) 15(291)
2(242) 2(204) 26(19) 12(139) 23(75) 16(174) 21(130)
*Tampering rates have been rounded to the nearest whole percent. A zero does not necessarily indicate a total
absence of tampering, but rather a level of tampering that rounded to zero.
-------
-35-
perrait any conclusions.) For example, the tampering incidence
for 1979 vehicles increased from 6% in their first year to
37% by their seventh year of use. This increase in tampering
with vehicle age also seems to lessen once the vehicles of a
model year are five years old or more, with the tampering
rates leveling off at higher levels in older model years.
This type of analysis involves observations made from different
survey sites at different times; nevertheless, the relationship
between tampering rate and vehicle age is readily apparent.
Tables 9 and 10 can also be analyzed vertically (holding
vehicle age constant), which provides a look at the tampering
rates for different model year vehicles of the same age.
This approach suggests that improvements in automotive tech-
nology, such as closed loop emission control systems, may
initially affect overall tampering rates. Vehicle tampering
by the second year, for example, was only 2% for 1984 vehicles
compared to 10% for 1977 vehicles. A similar vertical analysis
of Table 10, however, shows that catalytic converters are as
susceptible to tampering on newer models as on older ones at
a given vehicle age. Vertical analysis of Tables 9 and 10
introduces the same variability as the horizontal analysis.
The influence of vehicle age on tampering can be more
clearly seen when the data in Tables 9 and 10 is presented
graphically. Figures 4 and 5 plot the overall and catalyst
-------
60
50 -
40 -
30 -
20 -
10 -
Rate (%) S
O A
A/ \
"
a
^^
o
0 B D
A 7\
^L, LJ
5*0
§ A
* @
* S a
o 9 ° A
TT /*\ A
® A s
BA
i i i i i i i i i i
urvey Year
1978
*
1979
O
1981
a
1982
A
1983
O
1984
D
1985
D 123456789 10 11 12 A
lo Age (years)
Figure 4. Cumulative tampering prevalence as a
function of vehicle age for the
1979 - 1985 surveys.
CTl
I
-------
Tampering Rate (%)
60
50
40
30
20
10
a
o
A
Vehicle Age (years)
Figure 5. Cumulative catalyst tampering rate as
a function of vehicle age for the
1978 - 1985 surveys.
Survey Year
1978
*
1979
O
1981
a
1982
A
1983
O
1984
D
1985
-------
-38-
tampering rate, respectively, as a function of vehicle age
for the 1978-1985 surveys. This is equivalent to the diagonal
method of analysis used for Tables 9 and 10 that was outlined
previously. Figure 4 demonstrates that the relationship
between tampering rate and vehicle age is not only linear,
but has remained nearly constant since the first survey in
1978. The strong correlation is obvious despite the different
sizes, vehicle compositions, and locations of the surveys.
In Figure 5 the catalyst tampering rate remains negligible
for the first two to three 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 similar delay
in overall tampering would also be expected, but is not
readily apparent in Figure 4.
The link between tampering prevalence and vehicle age
was shown to influence the survey averages for tampering in
the 1984 report. Previous survey samples have been comprised
of increasingly older vehicles, contributing to the increase
in overall tampering among surveyed vehicles. Figure 6 shows
that the proportion of older vehicles (five or more years
old) in the survey declined in 1985 for the first time, down
to 52% from a high of 58% of the vehicles surveyed in 1984.
-------
Percent
60
50 -
40 -
30
20
10
0
Percent of Vehicles
5 Years Old or More
o
Tampering Rate
—B—
Catalyst Tampering
Rate
U)
l£
I
1978 1979 1980
Figure 6.
1981
1982
1983
1984
1985
Survey Year
Comparison of catalyst and overall
tampering rates with vehicle age as
a function of survey year.
-------
-40-
This decline may represent a stabilizing of the proportion of
older vehicles surveyed, since the 1985 survey population
encompassed 82% of the cars and 74% of the light-duty trucks
currently in use.2 The lower proportion of older vehicles in
the survey may have thus contributed to the decline in tampering
Manufacturer. Figure 7 presents the 1985 tampering
rates for each major manufacturer. Since the number of
vehicles surveyed for each individual foreign manufacturer
is small, foreign vehicles have been combined into two
groups, European and Japanese. As in previous surveys, the
tampering rate is higher among domestic than foreign
manufacturers.
Figure 8 shows the trend in tampering rates for each
manufacturer over time. The American vehicles are at or
consistently above the overall tampering rate, while the
European and Japanese vehicles have a tampering incidence
consistently lower than the overall rate.
A number of factors might explain the discrepancy in
tampering among manufacturers. Differences in design may
make some vehicles more tamper-prone than others. Changing
market share history results in different age distributions
for vehicles of different makes, and vehicle age is clearly
related to tampering prevalence. Tampering rates probably
vary with geographic location and socioeconomic background,
2 based on model year distribution data used in MOBILES.
-------
-41-
American Motors
General Motors
12%
Japanese
7%
Tampering Rate (%)
Figure 7. Tampering rates by manufacturer -
1985 survey.
-------
Tampering Rate (%)
40
20 -
10 -
0
7
*y
X
X
x
X /
X /
X /
X /
X /
x
X
x/
X /
K
d^
/
X /
x /
x
x
x
x
x/fr
x/v
X/s
x/^
x/^
^
/ ^
/ s
/ s
/ s
/ s
/ s
/ v
/ s
/ \
/ s
/ \
/ \
Figure 8.
Manufacturer
Tampering prevalence by manufacturer
for the 1978 - 1985 surveys.
-------
-43-
so the owner demographics for different makes may affect
the likelihood of tampering. Finally, certain types of
vehicles (trucks, for instance) are more likely to be
tampered, and thus manufacturers with production concen-
trated in these types can be expected to have higher
tampering rates.
5. I/M Programs and Geographic Bias
Before examining the impact of I/M and antitampering
programs on tampering and misfueling, the influence of
geography on the survey data should first be discussed.
Previous surveys have shown that tampering is historically
higher in southern states than in northern states, which
complicates any evaluation of I/M and antitampering program
effectiveness. To illustrate this phenomenon the 1985 survey
sites are listed below by program type.
Non-I/M I/M-Only I/M + ATP
Kansas City, MO Louisville, KY Fresno, CA
Kansas City, KS Wilmington, DE Charlotte, NC
Raleigh, NC Philadelphia, PA Northern Virginia
Portland, ME Long Island, NY
Cleveland, OH
Baton Rouge, LA
Albuquerque, NM
The sites for the 1985 survey are fairly well distributed
geographically among program types, lessening any geographic
bias. The influence of geography can still be seen, however,
in the tampering rates for the 1985 survey sites. The three
areas surveyed with the lowest tampering rates were all
northern cities (Portland, Philadelphia, and Wilmington).
-------
-44-
Portland's low tampering rate (12%) is particularly noteworthy
because it is a non-I/M area, and its tampering rate was
considerably less than was found in Louisville (23%) , a
southern I/M area, and Baton Rouge (32%), a southern non-I/M
location.
One way to minimize geographic bias when evaluating
program effectiveness is to compare programs within the same
geographic region. Figure 9 compares catalyst tampering and
fuel switching in three southern cities with different program
types - Raleigh (non-I/M), Louisville (l/M-only), and Charlotte
(I/M + ATP). This data shows that when geographic bias is
minimized the effectiveness of I/M and I/M + ATP becomes
apparent. While such comparisons as these overlook other
variables such as program design and administration, the
geographical location of a survey site is nonetheless a
contributing factor to an area's tampering prevalence.
6. Effect of I/M Programs on Tampering
Inspection and maintenance (I/M) programs require vehicles
to meet specific idle emission standards. Vehicles registered
in areas with these programs are required to be periodically
tested to assure that they comply with the specific idle
emission cutpoints established by these jurisdictions. In
addition to reducing emission levels by stimulating better
owner maintenance, I/M programs may deter some tampering with
emission control components. Data from previous surveys has
-------
Tamponing RatQ (%)
20
15
10
8%
3%
8%
5%
10%
6%
Catalytic
Convert^
Restr
ictor
s,itching
Raleigh. NC
(non-I/M)
Louisville. KY
(I/M-only)
Charlotte. NC
(I/M + ATP)
Compongnt
FigurQ 9. Comparison of tampQring found in thrQQ
locations in tho samQ goographic
region - 1985 survey.
-------
-46-
tended to support this proposition, since tampering in I/M
areas has historically been lower than in non-I/M areas.
Some I/M 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 in 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.
Throughout this report the survey sites are classified very
generally as seven non-I/M areas, three I/M-only areas, four
I/M + ATP areas, and one ATP-only area (Houston). Houston
was the only city in 1985 to have an antitampering program
and no I/M program; similar programs, however, were implemented
in other areas in January, 1986. The survey results from
Houston will be discussed separately from the other survey
sites.
Table 11 compares the tampering rates in non-I/M, I/M-only,
and I/M + ATP areas to earlier surveys. The tampering rates
in non-I/M areas are considerably lower than in the previous
two surveys, while tampering in I/M + ATP areas is higher
than in previous surveys. It thus appears from the data for
this particular survey that I/M programs and I/M + ATPs are
-------
-47-
TABLE 11
Tampering Prevalence in I/M and non-I/M Areas
Survey
Year
1978
1979
1981**
1982
1983
1984
1985
non-I/M
19
20
14
19
29
31
22
Tampering
I/M-only
*
13
*
15
24
17
17
Rate (%)
I/M + ATP
*
*
*
10
16
11
19
Overall
19
18
14
17
26
22
20
*none surveyed
**1981 survey was of limited scope, covering only two sites and
399 vehicles
TABLE 12
Component-Specific Tampering by Inspection Program Type
1985 Survey
Tampering Rate (%)
Component non-I/M I/M-only I/M+ATP
Catalytic Converter 8 32
Inlet Restrictor 9 56
PCV System 556
Air Pump System 964
Evaporative System 4 34
EGR System 867
-------
-48-
only slightly more effective than no I/M program at all.
Similar results are reflected in the 1985 component-specific
tampering rates for each program type, as shown in Table 12.
These observations are not due to any decrease in program
effectiveness, but rather to the generalizations inherent in
the way programs are categorized in this survey.
Tampering programs vary generally in their model year and
component coverage. Long Island, for example, is classified
as an I/M + ATP site because 1984 and newer vehicles are
subject to an antitampering inspection. Vehicles manufactured
between 1975 and 1983, however, are subject only to an I/M
test. Long Island is thus predominantly an I/M-only site.
Also, all emission control components are not covered by the
I/M + ATP inspection programs. For example, Charlotte does
not inspect the evaporative system. Finally, Fresno is
classified as on I/M + ATP area even though the tampering
survey was conducted only six months after the start of a
biennial inspection program.
As this discussion suggests, the I/M + ATP rates reported
above do not accurately reflect actual program effectiveness
in controlling tampering with particular components in covered
model years. In order to more appropriately assess the
effectiveness of tampering inspection programs, the catalyst
tampering rate will be analyzed. It is appropriate to focus
on the catalyst rate for several reasons. The catalyst is
the primary HC and CO emission control component and thus
-------
-49-
represents the largest portion of the emission benefit
attributable to tampering inspection programs. Also most of
the survey vehicles were originally equipped with catalysts.
Table 13 presents the model year specific and overall
catalyst tampering rates for non-I/M, I/M only and I/M + ATP
areas. All out-of-state vehicles were excluded from the I/M
and I/M + ATP figures because those vehicles are not subject
to the local programs. The New York vehicles were split by
model year with the 1984 and newer vehicles appearing in the
I/M + ATP rates and the 1975 to 1983 vehicles in the I/M only
rates. To show the program impacts graphically, regression
techniques were used to fit a separate power curve for each
program type to the date in Table 13. These curves are presented
in Figure 10.
Figure 10 and Table 13 suggest that, for the sites
surveyed, I/M and I/M + ATP areas have lower catalyst rates
than non-I/M areas. The deterrence and correction of tampering
in I/M + ATP areas is also readily apparent.
7. Tampering Trends for Selected Sites
The impact of I/M and antitampering programs in specific
locations can be examined by comparing the 1985 survey data
with that from earlier surveys. Comparisons made between
surveys widely spaced in time, however, must take into con-
sideration the differences in average vehicle age in each
survey. The average miles traveled per vehicle surveyed in
1985, for example, is 62% greater than it was in the 1978
-------
-50-
TABLE 13
Catalyst Tampering among Vehicles for each Model
Year Covered by a Particular Program Type
Vehicle Tampering Rate (%) for each Program Type
Model Year
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
non-I/M
0
0
1
2
4
9
17
14
25
22
32
I/M-only
0
1
0
2
2
4
7
7
9
12
13
I/M+ATP
0
0
0
1
0
2
4
4
3
2
10
TOTAL
-------
Converter Tamponing (%)
50
40
30
20
10
0
0
non-I/M
Power Curve
Regression Analysis
7
8
10
11
12
Vehicle Ago (years)
Figure 10. Converter tampering as a function of
vehicle age for vehicles covered by
different programs - 1985 survey.
-------
-52-
survey. Since vehicle age is directly related to tampering
prevalence, a substantial increase in tampering might be expected
to have occurred between 1978 and 1985, if all other factors
remain constant (car/truck distribution, owner demographics,
etc.) Inferences regarding program effects must thus be made
cautiously.
Figures ll(a)-ll(d) depict overall tampering rates for
four sites surveyed in 1985 and earlier years. Figure ll(a)
compares tampering in northern Virginia as found in the 1978
and 1985 surveys. In 1978 northern Virginia was a non-I/M
area. Figure ll(a) suggests that low tampering rates in
northern Virginia predate the advent of an I/M + ATP, and that
there has been essentially no change in overall tampering in
northern Virginia since 1978. When the increase in average
vehicle miles from 1978 to 1985 is considered, however, it is
quite possible that tampering rates in Virginia in 1985 are
much lower than they would have been without a control program.
A similar comparison can be made in Wilmington over the same
time period (Figure ll(b)). In 1978 Wilmington was also a
non-I/M area, but had tampering rates that were much higher
than in northern Virginia at that time. The institution of an
I/M program in Wilmington has apparently had a significant
impact on overall tampering, since the 1985 rates (for higher
mileage vehicles) in Wilmington are equal to or lower than they
were in 1978, when vehicle mileage was much lower.
-------
-53-
Tampering Rate (2)
25
20
15
10
Ovaroll
142
152
22
42
02
12
22
Fual S-ic^^ conve ^ Ra6trictor
a) Northern Virginia
Tampering Rate (2)
25
20
15
10
232
142
52 52
32 32
52
32
b) Wilmington. DE
Figures 11 (a) and (b). Comparison of data from
1985 survey sites that had been
surveyed previously.
•Fual switching rates in 1978 do not Include
plumbtosmo results
1978
-------
-54-
Tcnparlng Rota tt)
35
30
ZS
20
15
10
5
0
323.
252
212
132
142
72
c) Baton Rouga, LA
172
^ 1982
D1985
Tanpwlng Rota
25
20
15
10
20X
162
Fual
132
142
72
Foal in
42 42
d) New York Metropolitan Area
Figures ll(c) and (d). Comparison of data from
1985 survey sites that had been
surveyed previously (cont'd).
7Z* 1384
222 (Now York C11
(NYC Suburbs)
-------
-55-
Baton Rouge was surveyed in 1982 and 1985, and the
results from those surveys can be found in Figure 11(cK
Baton Rouge has always been a non-I/M area, and Figure 11(c)
depicts a substantial increase in tampering in the absence of
any control program. This difference may also in part be due
to the higher average mileage of surveyed vehicles in 1985
than in 1982, and the greater proportion of trucks surveyed
in 1985. Baton Rouge instituted an ATP-only in September,
1985, and is scheduled to be surveyed in 1986.
Figure 11(d) shows the survey results for New York City
in 198*4 and its suburbs in 1985. The most interesting aspect
of this comparison is the large decrease in the percent of
vehicles with leaded fuel in their tanks. This may be attri-
buted to a concentrated Agency and local effort to curb
widespread unleaded gasoline contamination in the New York
City area last year.
8. Effectiveness of ATP-Only - Houston
As was mentioned earlier, Houston (Harris County) was
the first area to adopt an antitampering program without an
idle emissions test. Started in July, 1984, this program
includes a tampering check of the PCV, evaporative, air pump,
and EGR systems for 1975 and later vehicles, and also a check
of the converter, inlet restrictor, and Plumbtesmo for 1980
and later vehicles. To investigate the effectiveness of
Houston's program, the 1985 tampering data for the components
-------
-56-
and model years covered can be compared to similar data from
the 1983 survey in Houston (see Table 14). The data presented
in Table 14 is from all vehicles surveyed in Houston, including
any non-Harris County vehicles that were surveyed. It is
obvious that Houston's ATP program has noticeably reduced
tampering for almost every component covered. As more
antitampering-only programs are enacted nationwide, their
effectiveness will be carefully evaluated.
9. Correlation between Tampering and Idle Emissions
As was mentioned previously, vehicles which are subject
to an I/M program must meet specific idle emissions cutpoints.
To assess the relationship between tampering and fuel switch-
ing and idle failure rates, the idle emissions from vehicles
have been tested against the cutpoints established by the
I/M program where they were sampled. Vehicles in non-I/M
areas were tested against the cutpoints specified by the New
Jersey I/M program. The cutpoints for each I/M area are
listed in Appendix C.
The results of the idle tests are presented in Figure 12
for vehicles in the various tampering and fuel switching
categories. Only 14% of the surveyed vehicles that were free
of tampering and fuel switching failed an idle test, while
65% of the tampered and fuel switched vehicles failed that
test. These results indicate that a substantially larger
-------
-57-
TABLE 14
Comparison of Tampering Rates in Houston* for Components
and Model Years covered by Antitampering Program
Survey Year
Component and Model Years 1983 1985
Catalytic Converter 1980+ 6% 2%
Inlet Restrictor 1980+ 1 1
Positive Plumbtesmo 1980+ 7 2
PCV System 1975+ 9 5
Evaporative System 1975+ 8 4
Air Pump System 1975+ 9 8
* averages include any non-Harris County vehicles that were
surveyed. The 1985 rates for Harris County vehicles only
are egual to or lower than those listed abovp
-------
Figure 12
Distribution of Survgy Sample Among Tampering*,
Fuel Switching, and Idle Test Categories
Entire survgy
samp 1e
100%
Okay
52%
Arguably
tampergd
Not fuel
sw i tched
Fuel
switched
1%
Pass
B6X
Fail
14%
Not fuel
sw i tchiQd
98%
88%
Fail
12%
Pass
59%
Fail
41%
TamperGd
20%
00
Not fuel
switched
63%
Fuel
switched
377.
Pass
51%
Fail
49%
Pass
35%
Fail
65%
*excludes malfunctioning vehicles (1% of total)
-------
-59-
proportion of tampered and fuel switched vehicles than of
okay vehicles fail an idle test at typical I/M cutpoints.
This is partly due to the tendency for tampered vehicles to
have misadjusted carburetors, as is shown in Figure 13. This
Venn diagram shows that 73% of the tampered vehicles with
conventional carburetors also had missing sealed plugs or
limiter caps. It must be noted from Figure 12, however, that
35% of the tampered and fuel switched vehicles were still
able to pass the idle test.
Table 15 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 signifies closed loop emissions control, which
came into widespread usage in 1981 model year vehicles.
The overall failure rate for HC from tampered vehicles
was nearly four times greater than for okay vehicles, and was
three times greater for CO emissions. Over 40% of the vehicles
that either had been fuel switched or had their catalysts
removed also exceeded HC and CO limits. Conversely, nearly
60% of the vehicles with missing catalysts or classified as
fuel switched were still able to pass an idle emissions test.
Interestingly, a significant number of arguably tampered
vehicles also produced excess idle emissions. Since the
-------
-60-
Carbureted vehicles with
some kind of tampering
(1231 total)
Carbureted Vehicles
with Arguably
Tampered Carburetors
(1648 total)
Figure 13. Overlap of Tampering and carburetor misadjustment among conventionally
carbureted vehicles - 1985 survey.
-------
-61-
majority of arguable tampering involves idle speed limiter
caps and sealed plugs, the high failure rate demonstrates the
adverse idle emissions impact of improperly adjusted
carburetors.
The effectiveness of idle emissions testing on "new"
technology vehicles can also be seen in Table 15. Idle
emissions testing is considerably more effective in identifying
tampering on 1980 and older vehicles than on 1981 and newer
vehicles. It is particularly interesting that only one-quarter
of the 1981 and newer vehicles surveyed which had missing
catalysts or had been fuel switched would fail an idle emissions
test. This suggests that idle emissions testing may not be
an effective strategy for identifying tampering and fuel
switching among "new" technology vehicles, since many vehicles
with closed loop systems are able to produce low idle emissions
even with a missing or inactive catalyst. The Agency has
consistently advised I/M programs not to rely on idle emissions
testing for these vehicles for this reason.
The mean idle emissions for tampered and okay vehicles
are presented in Table 16 by program type. The mean idle
emissions from tampered vehicles were considerably higher
than from okay vehicles. Overall, HC emissions from tampered
vehicles were more than six times greater on average than for
okay vehicles, while CO emissions were almost seven times
greater. The means for non-I/M areas were higher than for
I/M-only and I/M + ATP areas.
-------
-62-
TABLE 15
Idle Test Failure Rates (percent) by Pollutant
and Vehicle Condition
Failure Rate (%) by Pollutant
for Model Years listed
1975-80 1981+ Overall
Vehicle Condition HC CO HC CO HC CO
Okay 19 16 87 10 8
Arguably Tampered 31 38 15 16 26 31
Tampered 42 45 27 19 39 40
Catalyst Removed
or Fuel Switched 45 49 26 21 42 44
TABLE 16
Mean Idle Emissions by Vehicle Condition
Survey HC emissions(ppm) CO emissions(%)
Sites Tampered Okay Tampered Okay
non-I/M 341.0 51.9 3.0 0.3
I/M only 243.9 41.8 2.2 0.3
I/M + ATP 238.3 40.3 1.9 0.3
ATP-only 306.4 36.5 3.2 0.3
OVERALL 296.8 45.9 2.6 0.3
-------
-63-
To investigate the relationship between I/M programs and
idle emissions, the emissions from okay and tampered vehicles
in each program type can be compared (see Table 16) . The
data indicates that idle HC emissions from okay vehicles in
I/M areas were 19% lower than from vehicles in non-I/M areas.
There was no difference in this survey between idle CO emissions
from I/M areas and those from non-I/M areas. The presence of
an antitampering program further lowered idle HC and CO
emissions from okay vehicles. Idle HC and CO emissions from
tampered vehicles were 28% and 27% lower, respectively, in
I/M-only areas than in non-I/M areas, suggesting that I/M
programs may reduce idle emissions from vehicles for which
tampering is not successfully deterred.
B. FUEL SWITCHING
1. Fuel Switching Indicators and Overlap
Fuel switching is more easily defined than measured,
since no single indicator can accurately determine its
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 calculate
-------
-64-
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.
The presence of any of these three indicators suggests
that a given vehicle has been misfueled; their absence, how-
ever, does not rule it out. For example, fuel samples could
only be obtained from 83% of the unleaded vehicles surveyed,
limiting the scope of this variable. A vehicle misfueled
repeatedly with leaded gasoline may also have little detect-
able lead in its fuel tank due to subsequent proper fueling.
Similarly, a vehicle with an untampered fuel filler inlet
restrictor may have been fueled at a leaded pump equipped
with a smaller nozzle, or by using a funnel or similar device.
The tailpipe lead test, due to the difficulties of field
administration, may also fail to identify misfueling, and
older vehicles may have had their tailpipes replaced since
last operated on leaded fuel. As the lead phasedown program
lowers lead levels in leaded gasoline, the incidence of false
negative Plumbtesmo results may increase. 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 results from these
indicators would be expected to overlap significantly, since
-------
-65-
they are three indicators of the same phenomenon. This has
not held true, however, in the 1985 survey or in previous
surveys. The Venn diagram (Figure 14) illustrates the degree
of overlap in the 1985 results. For example, only 77% of
the vehicles having leaded fuel in their tank also registered
a positive Plumbtesmo test. Additionally, only 45% of the
vehicles with tampered inlet restrictors actually had leaded
gasoline in their tanks at the time of the survey. The
incomplete overlap reflects the limitations of each indicator
as well as the different aspects of fuel switching each
indicator identifies.
2. Fuel Switching Rates
Of the vehicles requiring unleaded fuel, 9% were
identified as misfueled by at least one of the indicators
discussed above. The fuel switching incidence by survey site
and program type is listed in Table 17. Non-I/M sites had
the highest fuel switching rate (12%), followed by I/M + ATP
areas and I/M-only areas. The prevalence of each fuel switching
indicator in non-I/M areas is approximately double that found
in areas with control programs.
Tables 18 and 19 compare the fuel switching rates from
the 1985 survey with those from previous surveys. As the
tables indicate, the data from this survey show a general
pattern of decline in fuel switching. Since such a pattern
could result from the selection of sites surveyed this year,
strong conclusions must await the data from subsequent surveys.
-------
-66-
Positive Plumbtesroo
(298 Total)
Leaded Fuel in Tank
(274 Total)
Tampered Inlet
Restrictor
(443 Total)
Figure 14 . Overlap of fuel switching indicators among unleaded vehicles - 1985 Survey.
-------
-67-
TABLE 17
Fuel Switching Rates among Unleaded Vehicles by Site
and Indicator - 1985 Survey
Leaded Tampered
Positive >1 Positive
Survey Fuel in Inlet Plumbtesmo
Location Tank(%) Restrictor(%) (%)
Kansas City, MO
Kansas City, KS
Raleigh, NC
Portland, ME
Cleveland, OH
Baton Rouge, LA
Albuquerque, NM
ALL NON-I/M SITES
Louisville, KY
Wilmington, DE
Philadelphia, PA
ALL I/M ONLY SITES
Fresno, CA
Charlotte, NC
N. Virginia
Long Island, NY
ALL I/M+ATP SITES
HOUSTON, TX (ATP ONLY)
ALL SITES
6
9
11
2
3
13
5
7
6
1
1
3
2
3
2
5
3
4
5
Non-I/M Areas
9
10
11
4
7
17
9
9
I/M Only Areas
8
3
2
5
I/M + ATP Areas
9
5
4
4
6
5
7
6
7
9
1
4
14
5
7
6
2
1
3
1
3
1
4
2
5
5
Indicators
(%)
10
12
14
5
8
21
11
12
10
5
3
6
9
6
4
7
7
7
9
-------
-68-
TABLE 18
Fuel Switching Prevalence among Unleaded Vehicles
in I/M and non-I/M Areas
Survey
Year
1978*
1979*
1981**
1982
1983
1984
1985
non-I/M
4
12
16
15
17
19
12
Fuel Switching
I/M only I/M
NS
3
NS
7
12
10
6
Rate (%)
+ ATP
NS
NS
NS
2*
5
8
7
Overall
4
9
16
11
14
14
9
*Plumbtesmo test not used.
**1981 survey was of limited scope, covering only two sites and
399 vehicles.
NS: None surveyed
TABLE 19
Fuel Switching Rates among Unleaded Vehicles
by Indicator and Survey Year
Survey Leaded Fuel Tampered Inlet Positive >^l Positive
Year
1978
1979
1981
1982
1983
1984
1985
in Tank(%)
4
10
7
6
7
8
5
Restrictor( %)
3
4
6
6
7
10
7
Plumbtesmo( %)
*
*
8
7
10
9
5
Indicators( %)
4
9
16
11
14
14
9
*Plumbtesmo test not used.
-------
-69-
Table 20 presents the combined tampering and fuel
switching rates for the 1985 survey. The percentage of
vehicles that were tampered or fuel switched was 21%, only
1% higher than the tampering rate alone. The substantial
overlap between the tampering or fuel switching rate and
the tampering rate alone results mainly from the inlet
restrictor tampering rates being used to calculate both
values. Table 20 also demonstrates that approximately half
of all tampering and fuel switching is composed of vehicles
in the catalyst removed or fuel switched category. This
indicates the very serious nature of most tampering.
3. Fuel Switching by Vehicle Type
As was reported previously, the fuel switching rates for
trucks was considerably higher than for passenger cars - 13%
vs. 8% (Table 1). The filler neck restrictor tampering
rates were also higher for trucks than for passenger cars
(Table 1).
4. Fuel Switching and Vehicle Age
Table 21 correlates vehicle age and model year with fuel
switching rates for the 1978-1985 surveys. This method of
analysis is identical to the one used earlier to compare
tampering rates across model years and vehicle ages. Analyzing
Table 21 diagonally shows that the rate of fuel switching
-------
-70-
TABLE 20
Combined Tampering and Fuel Switching Rates - 1985 Survey
Catalyst-equipped vehicles Unleaded vehicles
Survey wi
Location
Kansas City, MO
Kansas City, KS
Raleigh, NC
Portland, ME
Cleveland, OH
Baton Rouge, LA
Albuquerque, NM
ALL NON-I/M SITES
Louisville, KY
Wilmington, DE
Philadelphia, PA
ALL I/M-ONLY SITES
Fresno, CA
Charlotte, NC
N. Virginia
Long Island, NY
ALL I/M + ATP SITES
HOUSTON, TX (ATP ONLY)
th catalysts removed or
fuel switched (%)
Non-I/M Areas
12
12
15
6
11
20
11
12
I/M-only Areas
10
6
3
6
I/M + ATP Areas
10
6
5
9
8
9
either tampered or
fuel switched (%)
22
27
20
14
23
33
25
23
24
15
14
17
22
19
15
22
20
19
ALL SITES
10
21
-------
TABLE 21
Percentage of Fuel Switching (and Sample Size) among Unleaded Vehicles by Model Year and Vehicle Age
at Time of Survey*
Model
Year
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
First
1(816)
3(462)
5(182)
5(250)
9(57)
6(328)
2(296)
Second
2(1001)
4(471)
6(226)
7(444)
11(62)
8(451)
3(438)
Third
1(710)
6(465)
9(205)
8(447)
16(55)
9(428)
6(388)
Year of Vehicle Life
Fourth Fifth Sixth Seventh Eighth Ninth Tenth Eleventh
3(621)
8(457) 5(607)
8(210) 11(487) 9(562)
12(432) 19(269) 18(455) 15(636)
18(74) 12(377) 15(221) 24(486) 19(527)
18(60) 13(283) 23(176) 27(357) 24(420)
15(316) 37(49) 14(249) 21(147) 24(314) 27(328)
6(255) 14(213) 30(20) 17(146) 24(82) 26(174) 34(179)
*Plumbtesno not used in 1978 and 1979 surveys.
-------
-72-
increased with vehicle age in every survey taken. A similar
though less pronounced pattern can be seen when the data is
analyzed within model years (horizontally) or within vehicle
age groups (vertically).
5. Catalyst Tampering and Fuel Switching
Consumers and mechanics remove catalytic converters for
a number of reasons, but much of their motivation is related
to fuel switching. The vehicle owner may remove the catalytic
converter either prior to misfueling, or after some misfueling
if the vehicle's driveability has been adversely affected by a
catalyst damaged from the repeated misfueling. The data from
this survey cannot be used to distinguish between these two
situations, but can be used to examine the extent to which
these types of abuse occur in conjunction.
Of the catalyst-equipped vehicles surveyed, 10% were
either catalyst tampered or fuel switched (Table 20). The
rates in non-I/M, I/M-only, and I/M + ATP areas were 12%,
6%, and 8%, respectively.
Figure 15 depicts the degree of overlap between catalyst
removal and fuel switching. Vehicles with catalyst tampering
exclusive of fuel switching were relatively uncommon — only
one-third of the catalyst tampered vehicles were not fuel
switched. Fuel switching, however, is not always accompanied
by catalyst removal, since 61% of the fuel switched vehicles
still had their catalysts.
-------
-73-
Catalyst Tampering
(287 Total)
Fuel Switching
(487 Total)
Figure 15 „ Overlap of catalyst tampering" and fuel switching among catalyst-equipped
vehicles - 1985 Survey.
Percentage of Misfueled Vehicles
15
10
102
92
52
55!
42
1
62
12 12
Gasoline Lead Concentration (grams/gallon)
FigurQ 16. Lead concQntrations in fuol samplod
from misfuQled vehiclgs.
-------
-74-
6. Gasoline Lead Concentrations
Of the vehicles identified by any of the three indicators
as misfueled, 46% had only trace amounts of lead (less than
0.05 gpg) in their gasoline when inspected. These vehicles,
then, were identified as fuel switched by a tampered filler
restrictor and/or a positive Plumbtesmo test. Figure 16
presents the distribution of lead concentrations of 0.05 gpg
or more in misfueled vehicles. The impact of lead phasedown
can be dramatically seen when Figure 16 is compared to similar
data from the 1984 survey. In the 1984 survey 39% of the
misfueled vehicles had a gasoline lead concentration in
excess of 1.0 gpg, compared to 1% in 1985. The distribution
of lead concentrations in 1985 is centered on the 0.4-0.6
gpg range, which coincides with the interim lead limit of 0.5
gpg in effect between July, 1985 and December, 1985.
-------
-75-
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.
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-76-
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
1 - Functioning properly
2 - Electrical disconnect
3 - Vacuum disconnect
4 - Mechanical disconnect
5 - Incorrectly routed hose
6 - Disconnect/Modification
7 - Missing item
8 - Misadjusted item
9 - Malfunctioning
A - Stock equipment
B - Non-stock
D - Add on equipment
Y - Yes
Z - No
Additional codes were used for those components which
could not be classified into the above categories. A brief
description of each data entry follows.
-------
1985 TAMPERING SURVEY - PART A (UNDERHOOD)
48
13
M 0
4
r R
i
*
1
12
not
10 NUMBER
I/M 8TICKER(datea
•( last Inspection)
DISPLACEMENT (cubic
inch** or liters)
14
"MOTE: if (Cilia* fu. 1* Biasing
or Illegible, eon •" but Che
IMC ( dlglte of the VIM. 00
HOT COfT gPUAL NUMBEK FOIfflOII
Of VIM.
16 ENGINE FAMILY
30 HEATED AIR INTAKE
0- lot oclg. equipped
1- ruacc. properly
}- Vacuiaa disconnect
4- Mock. disconnect
7- Mlaelng Item
(otoveplp* booo)
9- Malfiwcc. Itoa
(»«c. mcrrldo)
ft- •oo-itoek(cuitoa
•ir cl«a»ir)
40 PCV SYSTEM
1- runct. proporly
3- VMUUB dlMonaoce
AA
ASPIRATED AIR
INJECTION SYSTEM
DO- Not orlg. equipped
(If conventloael
eyet» or none)
1- Fuacc. properly
((- Mich, dliconneet
7- Mlaalag lte«
9- Malfunctioning
AIR PUMP BELT
(If Aaplr.. coda "0")
0- Hot orlg. equip.
D
7-
M«ch. dUconoocc
(fruh air how)
1- Funct. properly
7- Missing Iteai
8- Hlaadjuated Itea
(loose)
46 AIR PUMP SYSTEM (lad. »«ly«)
Won-«cock(Inc. fu«l
•coaoay
D
26 VIN (If enKlne family not available)
34
41
i wn
37 ORIGINALLY CATALYST EQUIPPED?
ntoM STiacEK omen MOOD
- DOM fOJT
Y-TM
X- Can'* coll (M (ticket.
not readable. or not awncloned)
48
TURBOCHARGER
0- Not orlg. equipped
A- Stock
B- Non-stock
D- Add-on
EVAP. CONTROL
SYSTEM
1- Fuacc. properly
0- Hoc orlg. aqulppad (If
aaplrated or none)
1- fuacc. properly
4- Mech. disc, (other
than belt reawval)
7- Hlaalng Itea
9- Malfunctioning
(froseo)
48 CARBURATOR TYPE
DS- Sealed
f- fuel Injection,
A- Stock
B- Non-atock
40 LIMITER CAPS
DQ. Not orlg. aqulpp«d
(fuel Injection)
1- Funct. properly
4- Mech. disconnect
(taba broken or bone)
7- Missing Item
8- Mlsadjusted (sealed
plugs removed)
00 EGR-CONTROL VALVE
DO- Not orlg. equipped ^
1- runct. properly 7
3- Vacuua disconnect
4- Mech. disconnect
7- Hissing Item
61 EGR SENSOR
(coolant, baek-preaaure. etc.)
0- Not orlg. equipped
46
D
38 AIR CLEANER
ft- Stock
B- Non-Stock
/. Hlsalng Itea
3- VacuMi dlccon.
(carb. llM)
4- Mach. dlacoa.
(tank lino)
5- lacorr. routed hoao
7- Hlaatog Itoai
9- Halfunct. Itra (air
claaaor Mnaoalod)
47
EXHAUST MANIFOLD
DA* Stock
B- Roa-atock
OXYGEN SENSOR
DO- Mot orlg. equipped
1- functioning properly
2- Electrical disconnect
4- Keen. dlac. (unacrewed)
7- Mlaalng ltt»
D
62
1- Funct. properly
3- Vacuum dlscoaaecC
5_ Incorr. routed hoao
7- Mlaalng Iteai
COMPUTER SYSTEM
« RELATED SENSORS
D
0- Not orlg. equipped
1* Funet. properly
5- DleeoaaeetSllodlfleatloa
(oaplala)
M ••! Ml WltMUt PimullWK •' »" MPM< » IIMAICM.
-------
1985 TAMPERING SURVEY - PART B (REAR)
10 NUMBER
MAKE
£, (write out)
MODEL
(write out)
13
14
16
20
23
VE
HIC
C-
T-
is
LE TYPE
- Car
- Truck (includes vans)
LICENSE PLATE
(State)
<
i
22
19
IDLE HC
(PPM)
IDLE CO
(X)
ODOMETER
(Thou.)
25
26 DASH LABEL
Q- Not orig. equipped
1- Funct. properly
(present)
7- Missing item
27 CATALYTIC CONVERTER
31 TANK LABEL
Q- Hot orig. equipped
1- Funct. properly
(present)
7- Missing item
Q- Not orig. equipped
1- Funct. properly
(present)
7- Hissing item
28 EXHAUST SYSTEM
A- Stock
R- Non-Stock
29 EXHAUST SYSTEM
INTEGRITY
1- Funct. properly
(no obvious leaks)
9- Malfunctioning
(leaks evident)
30 TANK CAP
\- Funct. properly
7- Missing item
9- Malfunctioning
FILLER NECK
32 RESTRICTOR
Q- Not orig. equipped
1- Funct. properly
IT- Mech. disc, (widened)
7- Missing item
33 PLUMBTESMO
P- Positive
N- Negative
34 FUEL SAMPLE
Y-Yes
Z- No
I
-J
oo
leave blank
35
FUEL DATA
38
OO HOT Ull WITHOUT rtHUKIIOM Of TNI OMICI Of MtlAMCH. OCVIlOrt HI NT t THAIHIDO
-------
-79-
Form A - Underhood
1-4 ID Number - Vehicles are numbered sequentially as
they are inspected. This number is preceded by a
site identifying letter.
5-8 Month and year of last I/M inspection (left blank
if vehicle is licensed in non-I/M area) .
9-12 Displacement - as recorded on the underhood emission
label.
13-14 Vehicle Model year
15-25 Engine Family - as recorded on the underhood emission
label.
26-36 Non-serial number portion of VIN - as recorded on the
driver's side of the dash under the windshield or the
driver's door post. The VIN is recorded only if the
engine family can not be determined.
37 Originally Catalyst Equipped - as recorded on the
underhood emission label or the driver's door post.
38 Air Cleaner - is coded 'A', 'B', or '7'.
-------
-80-
39 Heated Air Intake - provides warm air to the carburetor
during cold engine operation. The heated air intake
is coded '0', '!', '3', '4', '7' (stovepipe hose),
'9' (vacuum override), or 'B1 (custom air cleaner).
40 Positive Crankcase Ventilation (PCV) system - prevents
crankcase emissions by purging the crankcase of blow-
by gases which leak between the piston rings and the
cylinder wall in the combustion chamber under high
pressures. The PCV system is coded 'I1, '3', '4'
(fresh air hose), '?', or 'B1 (includes fuel economy
devices).
41 Turbocharger - coded '0', 'A1, 'B1, or 'D'.
42 Evaporative Control System (ECS) - controls vapors
from the fuel tank and carburetor. Some systems have
two lines: from the fuel tank to the canister, and
from the canister to the carburetor or air cleaner
(for purging the canister). Other systems have a
third line connected to the carburetor. The ECS is
coded 'I1, '3' (carburetor line), '4' (tank
line), '5', '7', or '9' (air cleaner unsealed).
Air Injection System - extends the combustion process
into the engine's exhaust system by injecting fresh
air into the exhaust ports, lowering exnaust emissions
while still maintaining proper vehicle performance.
-------
-81-
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.
43 PAIR - coded '0' (if air pump system or none), 'I1,
'4', '71 , or '9'.
44 Air Pump Belt - is coded '0' (if PAIR), 'I1, '?', or
'8' (loose belt) .
45 Air Pump System - for the purposes of this variable,
consists of the air pump and control valve and is
coded '0' (if a PAIR or none), 'I1, '4' (excluding
belt removal), '?', or '9'.
46 Exhaust Manifold - coded 'A' or 'B1.
47 Oxygen Sensor - Controls the air-fuel mixture going
into the engine of vehicles equipped with three-way
catalytic converters. The sensor is coded '0', 'I1,
'2', '4' (unscrewed), or '7'.
-------
-82-
48 Carburetor Type - is coded 'S1 (sealed plugs covering
mixture adjustment), 'F1 (fuel injection), 'A1,
or 'B'.
49 Limiter Caps - plastic caps on the idle mixture screws
to limit carburetor adjustments. The limiter caps
are coded 'O1, '!', '4' (tabs broken or bent), '?',
or '8' (sealed plugs removed).
Exhaust Gas Recirculation (EGR) System - directs a
portion of the exhaust gases back into the cylinders
to reduce NOX emissions in the exhaust gas. The
standard EGR configuration consists of a vacuum line
from the carburetor to a sensor (used to detect
engine operating temperature to activate the EGR
valve), and another vacuum line from the sensor to
the EGR valve.
50 EGR Control Valve - coded '0', '!', '3', '4', or '7'.
51 EGR Sensor - coded '0', '!', '3', '5', '7'.
52 Computer Systems and Related Sensors - computerized
engine and emissions control system which receives
input from various sensors for engine condition
information, and constantly adjusts the air/fuel
ratio, distributor, and emissions devices for optimum
economy, driveability, and emissions. The system
-------
-83-
is coded '0', 'I1, or '6'. This variable includes the
entire computer system except for the oxygen sensor,
which is coded separately (see variable #47, Form A).
Form B - Rear
1-4 ID Number - Same as on Form A.
5-8 Make
9-12 Model
13 Vehicle Type - coded as follows: C = car, T = truck
14-15 License Plate - State abbreviation
16-19 Exhaust gas HC concentration (in ppm) at curb idle.
20-22 Exhaust gas CO concentration (in percent) at curb idle.
23-25 Odometer - mileage in thousands
26 Dash Label - displays the fuel required and is coded
'O1, 'I1, or '7' .
27 Catalytic Converter - oxidizes the HC and CO to water
and C02 in the exhaust gas. Later model catalysts
also reduce oxides of nitrogen. The converter is
coded 'O1, '!', or '7' (entire catalyst canister
removed).
-------
-84-
28 Exhaust System - if as originally equipped an 'A1 is coded
If non-stock a "B1 is coded.
29 Exhaust System Integrity - the condition of the exhaust
system is coded "I1 (no obvious leaks) or '9' (leaks
evident).
30 Tank Cap - seals the fuel tank during normal operating
conditions and is coded '!', '7', or '9' (loose cap).
31 Tank Label - displays required fuel and is coded '0',
'I1 , or '7' .
32 Filler Neck Inlet Restrictor (unleaded vehicles only) -
The restrictor is designed to prevent the introduction
of leaded fuel into a vehicle requiring unleaded fuel .
It is coded '0', '!', '4' (widened), or '7'.
33 Plumbtesmo - Plumbtesmo paper is used to check for the
presence of lead in vehicle exhaust pipes. A positive
indication is coded as 'Y' and a negative as "Z1 .
34 Fuel Sample - indicates if inspector was able to obtain
fuel sample for later lead analysis ('Y1 or 'Z')«
-------
-85-
2. Classification Of Component Conditions
The table below was used to classify the various system
components as 'tampered', 'arguably tampered1, or 'malfunctioning'
Only those codes which are applicable to a given component
are listed. Codes for 'not originally equipped' and 'functioning
properly1 are not included in this table- Refer to Appendix B,
Part 1 for an explanation of the codes.
Codes from form
Component/system |2|3|4|5|6|7|8|9|B|
Dash Label A
lank Cap A M
lank Label A
Filler Neck" Restrictor T T
Catalytic Converter T
Oxygen Sensor T T T
PCV System T T T T
Hsated Air Intake T A A M T
Evaporative Control T T T T M
System
Aspirated Air T T M
Injection System
Air Pump Belt T M
T = tampered
A = arguably tampered
M = malfunctioning
-------
-86-
Codes from fonn
Ccnponent/system |2|3|4|5|6|7|8|9|B
Air Pump System T T M
EGR Cbntrol Valve T T T
EGR Sensor T T T
T = tampered
A = arguably tampered
M = malfunctioning
-------
-87-
3. Fuel Sample Collection and Labeling Procedures
A fuel sample was taken from each vehicle requiring
unleaded fuel. 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 unleaded fuel.
Each bottle was identified with an adhesive label that
had the vehicle identifying survey number on it. The vehicle
identifying number was the first entry on the data forms
described in Part 1 of Appendix B.
Prior to shipment from the field, a sample tag with the
same identifying number was attached to each bottle. The
bottles were packed, labeled, and shipped to NEIC Chemistry
Branch according to the shipper's requirements and the NEIC
Policy and Procedures Manual.
-------
-88-
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 take
place. After approximately 15 seconds the yellow color
disappears and the paper is no longer effective. Excess
water also interferes with the reaction.
Care must be taken to avoid contamination of the test paper
If a person has recently handled a test paper with a
positive reaction, some lead or reactive chemical may
have been transferred to their fingers. Subsequently
handling a clean test paper may cause contamination.
3) After removing the test paper, determine whether a color
change has occurred. Red or pink coloration indicates
the presence of lead.
-------
-89-
5. Field Quality Control/Assurance
Reference and calibration gases were used to ensure the
accuracy of the emissions analyzer. Horiba gases certified by
RTF were used as reference gases. Two cylinders of reference
gas were used to validate the accuracy of the calibration gases
before they were taken to the field on each survey.
Three calibration gases (Horiba) were used. These gases
were a mixture of CO and HC in nitrogen and were used to check
the instrument at least three times daily. These calibration
gases were certified by the manufacturer and the RTF reference
gases. Their approximate compositions were:
8% CO
1560 ppm HC (Hexane equivalent)
4% CO
827 ppm HC (Hexane equivalent)
1.6% CO
320 ppm HC (Hexane equivalent)
-------
-90-
APPENDIX C
EMISSION OUTPOINTS FOR I/M AREAS
The table below lists the emission outpoints used in 1985 by
the I/M areas covered in the 1985 tampering survey. The cut-
points for pre-1975 vehicles are not included, since these
vehicles were not surveyed.
Survey Site
New York City
Metro Area
Wilmington, DE
Philadelphia, PA
Northern Virginia
Louisville, KY
Charlotte, NC
New Jersey
Model Year
Emissions Cutpoints
CO (%) HC (ppm)
1975-77
1978
1979
1980
1981 +
1975-79
1980 +
1975-79
1980
1981 +
1976-79
1980
1981 +
1975-79
1980
1981 +
1975-78
1979-80
1981 +
1975-80
1981 +
5.7
4.3
3.0
2.7
1.2
_
—
4.0
3.0
1.2
4.0
2.0
1.2
6.5
4.0
1 .2
5.0
3.0
1.5
3.0
1.2
700
500
400
330
220
600
235
400
300
220
400
220
220
650
400
220
._
-
—
300
220
U.S. GOVERNMENT PRINT ING OFFICE: 1986-
181-192/52945
-------
Unit* States Office of
Environmental Protection Public Affairs (A-107)
Agency Washington DC 20460
<«»EPA Environmental News
FCF RELEASE: MCNDAY, DECEMBER 15, 1986
Martha Casey (202) 382-4378
1985 TAMPERING The U.S. Environmental Projection Agency today
SURVEY RESULTS
issued its 1985 Motor Vehicle Tampering Survey. The
survey concludes that one out of every five light-duty
vehicles, passenger cars or light-duty trucks shows
evidence of tampering with at least one component of
the emission control system.
Fifty-two percent of the surveyed vehicles in 1985,
compared to 46 percent in 1984, were categorized by EPA
as "Okay," meaning that all of their observed components
were present and functioning properly. Twenty percent
of all light-duty vehicles fell into the "tampered"
vehicles category, which dropped from 22 percent in
1984.
Lee M. Thomas, EPA Administrator, said, "Although
incidents of tampering seem to have declined somewhat
from the previous year, they still constitute a major
environmental problem that can result in serious health
effects. Emission control systems that have been
tampered with are the predominant source of urban air
pollution and ozone. The current level of tampering
still is inexcusably high."
EPA noted that the ostensible decline in the amount
of tampering found by the 1985 survey may be attributed
in part to the fact that the average sample was composed
of newer vehicles than samples used in previous years.
This is significant because the probability that a
vehicle has been tampered with is in direct correlation
with its age. Brand new cars in 1985, for example,
have a tampering rate of two percent whereas 1975 models
have a 54-percent tampering rate.
(more)
-------
-2-
Two other categories were used in the survey. Twenty-seven percent
qualified as "arguably tampered," meaning that a determination could not
be made as to whether tampering was a conscious act. One percent were
categorized as "malfunctioning," meaning that the vehicle was not tampered
with but needed repair.
The survey also found that 10 percent of the vehicles which required
use of unleaded gasoline had been misfueled with leaded gasoline. A study
by the Motor Vehicle Manufacturers Association (MVMA) found that when
motorists try to economize and put less costly leaded gasoline in an engine
that requires unleaded gasoline, the motorist actually creates a net loss
of about 19 cents a gallon. Fuel switching also fosters more frequent
repairs and tune-ups and accelerates engine deterioration.
Tampering and misfueling can cause dramatic increases in emissions of
hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx).
Motor vehicle emissions in urban areas account for nearly 90 percent
of the total CO and airborne lead emitted into the atmosphere. In addition,
30 percent of HC emissions and nearly 40 percent of NOx emissions released
into the atmosphere annually can be attributed to motor vehicle emissions.
The most imminent and persistent environmental problem created by
pollution device tampering and fuel switching is ozone. A major element of
urban smog, ozone is formed when volatile organic compounds from gasoline
vapors, solvents and other hydrocarbons and nitrogen oxides react with sun-
light and high temperatures. Ozone can cause various adverse effects on
the human body such as impaired pulmonary functions, chronic respiratory
disease, decreased resistance to infection, impaired vision and altered blood
chemistry. In addition, low concentrations of CO can lead to mental dullness
and elevated levels of .lead in blood can lead to mental retardation, permanent
nerve damage and behavioral disorders.
i In the mid 1970's, emission control devices were installed on light-
duty trucks and passenger cars. The 1977 amendments to the Clean Air
Act made it illegal for any automobile dealer, serviceman, operator
or owner to disconnect or tamper with emission control devices. Studies
show that by removing a catalytic converter or ruining it through
misfueling, HC emissions from a given vehicle are increased by about 500
percent and CO emissions are increased by about 400 percent.
Tampering with specific components of the emission control system
has been a problem since 1974. EPA's 1985 survey found that fuel inlet
restrictors, air pump systems and exhaust gas recirculation (EGR) systems
were the most frequently tampered components. By tampering with the air
pump system, the motorist increases HC emissons by 200 percent and CO
emissions by 800 percent. EGR system tampering can increase NOx emissions
by an average of 175 percent.
(more)
R-163
-------
-3-
The tampering rates for light-duty trucks were equal to or greater
than the rates for automobiles. Catalytic converter tampering in light-
duty trucks was especially high—occurring over twice as often as on
passenger cars.
The tampering survey was conducted in 15 cities between April and
September 1985. An average of 439 vehicles per site was inspected,
amounting to a total of 6,586 vehicles.
In accordance with the requirements of the Clean Air Act, certain states
and localities have adopted vehicle inspection and maintenence (I/M)
programs, which test tail-pipe emissions, and anti-tampering programs (ATP),
in which parts are visually inspected for tampering and fuel switching.
EPA said data from areas operating emissions inspection and maintenance
programs and anti-tampering programs show that tampering with major emission
control devices is deterred by these programs. For example, in Raleigh, N.C.
(a non-I/M area), Louisville, Ky. (an I/M area), and Charlotte, N.C. (an
I/M plus ATP area), the catalytic converter removal rates were eight, six
and three percent respectively. Similarly, inlet restrictor tampering in
these three cities was 11, eight and three percent respectively.
EPA enforcement teams inspect car dealers, automobile repair
facilities, muffler shops and other facilities that may remove or tamper
with the emission control equipment. A maximum civil penalty of $10,000
per vehicle can be levied against new car dealers and manufacturers.
Commercial repair facilities and fleet operators are subject to a maximum
penalty of $2,500.
R-163
-------
TABLE 20
TAMPERING AND FUEL SWITCHING RATES - 1985 SURVEY
ALL SITES (weighted) 21
11
Unleaded vehicles
Survey
Location
Kansas City. MO
Kansas City, KS
Raleigh, NC
Portland, ME
Cleveland, OH
Baton Rouge, LA
Albuquerque, NM
ALL NON-I/M SITES
Louisville, KY
Wilmington. DE
Philadelphia, PA
ALL I/M-ONLY SITES
Fresno, CA
Charlotte, NC
N. Virginia
Long Island, NY
ALL I/M + ATP SITES
HOUSTON. TX (ATP ONLY)
Tampering
Rate (%)
Non-I/M
21
25
18
12
22
32
24
22
I/M-only
23
14
13
17
I/M + ATP
21
19
15
20
19
18
Misfueling
Rate (X)*
Areas
10
12
14
5
8
21
11
12
Areas
10
5
3
6
Areas**
9
6
4
7
9
7
either tampered or
fuel switched (I)
22
27
20
14
23
33
25
23
24
15
14
17
22
19
15
22
20
19
21
* misfueling rates are based only on the unleaded vehicles surveyed
** ATP: antitanroerinc program
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