EPA-460/3-77-018
September 1977
      EVALUATION OF POTENTIAL
       INSPECTION/MAINTENANCE
           BENEFITS ON VEHICLES
   OPERATED AT HIGH ALTITUDE
     U.S. ENVIRONMENTAL PROTECTION AGENCY
         Office of Air and Waste Management
      Office of Mobile Source Air Pollution Control
        Emission Control Technology Division
           Ann Arbor, Michigan 48105

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                            EPA-460/3-77-018
  EVALUATION OF POTENTIAL
  INSPECTION/MAINTENANCE
     BENEFITS ON VEHICLES
OPERATED AT HIGH ALTITUDE
                   by

            Alan P. Berens and Michael Hill

           University of Dayton Research Institute
              300 College Park Avenue
               Dayton, Ohio 45469
              Contract No. 68-03-2384
            EPA Project Officer: Lois A. Platte
                 Prepared for

         ENVIRONMENTAL PROTECTION AGENCY
           Office of Air and Waste Management
         Office of Mobile Source Air Pollution Control
           Emission Control Technology Division
             Ann Arbor, Michigan 48105

                September 1977

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This report is issued by the Environmental Protection Agency to report
technical data of interest to a limited" number of readers. Copies are
available free of charge to Federal employees, current contractors and
grantees, and nonprofit organizations - in limited quantities - from the.
Library Services Office (MD-35), Research Triangle Park, North Carohna
27711; or, for a fee, from the National Technical Information Service,
5285 Port Royal Road, Springfield, Virginia 22161.
This report was furnished to the Environmental Protection Agency by
the University of Dayton Research Institute, 300 College Park Avenue,
Dayton, Ohio 45469, in fulfillment of Contract No. 68-03-2384. The
contents of this report are reproduced herein as received from the
University of Dayton Research Institute. The opinions, findings, and
conclusions expressed are those of the author and not necessarily those
of the Environmental Protection Agency. Mention of company or product
names is not to be considered as an endorsement by the Environmental
Protection Agency.
Publication No. EPA-460/3-77-018
ii

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ABSTRACT
Inspection/Maintenance (I/M) is one of the transportation
control strategies available to state planners. Although I/M
is needed in over 25 air quality control regions (AQCRs), it has,
to date, been effectively implemented in only a small subset of
these regions. At the present time, an effective I/M program
has not been implemented in a high altitude region.
Recently, the EPA published in the Federal Register two
significant supporting documents for I/M. The first document
was a Notice of Proposed Rulemaking on the 207(b) Clean Air Act
Warranty. The second document was a Notice of Proposed Rule-
making on Appendix N to the State Implementation Plan Guidance
Document. Appendix N presents I/M credits for various types of
I/M programs. Although both of these documents are expected to
apply equally to high and low altitude regions, the majority of
the data used to develop these documents have been collected at
low altitude.
This report presents a thorough analysis of data collected
at high altitude. The data were not collected in a real life
I/M program; they are laboratory data. As such, they can be
compared with laboratory data taken at low altitude and, in some
subject areas, they can extend the general understanding of the
costs and effectiveness of maintenance programs at both high and
low altitude. The prime analysis objectives of this study were
threefold: to estimate the effectiveness of I/M, to evaluate
the correlation between the Federal Test Procedure (FTP) and
various short inspection tests, and to examine any relationships
which exist between emissions, engine condition, and vehicle
usage.
iii

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SECTION
1
2
3
TABLE OF CONTENTS
INTRODUCTION
SUMMARY OF RESULTS

2.1 Expected Benefits of Hiah Altitude I/M
2.2 Relationship Between FTP and Short Test
Emissions
2.3 Correlation of Emissions with Engine Condition
and Usage
TECHNICAL DISCUSSION
3.1
Data Base
3.2
Selection of Vehicles
Test Procedures
Basic Parameters Measured and
Stratifications to be Used

Effectiveness of I/M
3.1.1
3.1.2
3.1. 3
3.3
3.2.1 Estimation of Idle (N) I/M Program
Effectiveness
3.2.2 Comparison of After Maintenance
Emissions with Passed Vehicle
Emissions
3.2.3 Correlation of Changes in Emissions
with Before Maintenance Levels,
Engine Displacement, and Vehicle
Mileage
3.2.4 Correlation of Change in FTP Emissions
with Change in Short Test Emissions
3.2.5 Effect of Relative HC to CO Failure
on I/M Effectiveness
3.2.6 Costs, Frequency, and Types of Repair
3.2.7 Variability of Replicate Short Tests

FTP/Short Test Correlation
3.4
Linear Regression Relationships
Contingency Table Correlation
Ability of the Short Test to Identify
the Highest FTP Emitters

Relationships Between Emissions/Engine
Condition/Usage

3.4.1 Causes for High FTP Emissions
3.4.2 Maladjusted Vehicle Systems
3.4.3 Relationships Between Maladjustments
and Emissions
3.3.1
3.3.2
3.3.3
v
PAGE
1
4
4
9
11
15
15
15
17
19
24
25
27
28
30
31
32
35
38
38
41
46
48
48
49
51

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SECTION
3.4.4
3.4.5
3.4.6
TABLE OF CONTENTS, concluded
Relationship Between Maladjustments
and Owner Practices
Engine Parameter Settings
Relationship of Engine Parameter
Settings with Emissions
vi
52
53
54

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FIGURE
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
3.12
3.13
3.14
3.15
3.16
3.17
3.18
LIST OF FIGURES
Phase I Flow Diagram of Denver Inspection/
Maintenance Evaluation Task Vehicles

Phase II Flow Diagram of 470 Vehicles Used in
the Denver Inspection/Maintenance Evaluation
Task
Before Maintenance FTP HC versus After Maintenance
FTP HC

Before Maintenance FTP CO versus After Maintenance
FTP CO
Before Maintenance FTP NOX versus After Maintenance
FTP NOX

Before Mainenance Fuel Economy versus After
Maintenance Fuel Economy

Percent Reduction in 1975 FTP HC Emissions due to
Maintenance - All Phase I
Percent Reduction in 1975 FTP CO Emissions due to
Maintenance - All Phase I

Percent Reduction in 1975 FTP NOX Emissions due to
Maintenance - All Phase I
Percent Reduction in Fuel Economy due to Maintenance -
All Phase I

1975 FTP HC versus Hot Start HC -- Before Maintenance,
All Phase I Vehicles
1975 FTP CO versus Hot Start CO -- Before Maintenance,
All Phase I Vehicles

1975 FTP NOX versus Hot Start NOX -- Before Mainten-
ance, All Phase I Vehicles

1975 FTP HC versus Federal Short Cycle HC - Before
Maintenance, All Phase I Vehicles
1975 FTP CO versus Federal Short Cycle CO - Before
Maintenance, All Phase I Vehicles

1975 FTP NOX versus Federal Short Cycle NOX - Before
Maintenance, All Phase I Vehicles

1975 FTP HC versus Federal Three Mode (50 mph) HC -
Before Maintenance, All Phase I Vehicles
1975 FTP CO versus Federal Three Mode (50 mph) CO -
Before Maintenance, All Phase I Vehicles
vii
PAGE
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73

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FIGURE
3.19
3.20
3.21
3.22
3.23
3.24
3.25
3.26
3.27
3.28
3.29
3.30
3.31
3.32
3.33
LIST OF FIGURES, concluded
1975 FTP NOX versus Federal Three ~1ode (50 mph) NOX -
Before Maintenance, All Phase I Vehicles

1975 FTP HC versus Federal Three Mode (30 mph) HC -
Before Maintenance, All Phase I Vehicles

1975 FTP CO versus Federal Three Mode (30 mph) CO -
Before Maintenance, All Phase I Vehicles

1975 FTP NOX versus Federal Three Mode (30 mph) NOX -
Before Maintenance, All Phase I Vehicles

1975 FTP HC versus Federal Three Mode (N) HC - Before
Maintenance, All Phase I Vehicles

1975 FTP CO versus Federal Three Mode (N) CO - Before
Maintenance, All Phase I Vehicles

1975 FTP NOX versus Federal Three Mode (N) NOX - Before
Maintenance, All Phase I Vehicles

1975 FTP HC versus Idle (2250) HC - Before Maintenance,
All Phase I Vehicles
1975 FTP CO versus Idle (2250) CO - Before Maintenance,
All Phase I Vehicles
1975 FTP NOX versus Idle (2250) NOX - Before Maintenance,
All Phase I Vehicles 83

1975 FTP HC versus Idle (N) HC - Before Maintenance, All
Phase I Vehicles

1975 FTP CO versus Idle (N) CO - Before Maintenance, All
Phase I Vehicles
1975 FTP NOX versus Idle (N) NOX - Before Maintenance,
All Phase I Vehicles

1975 FTP HC versus Idle (N) HC - Before Maintenance, All
Phase I Vehicles
1975 FTP CO versus Idle (N) CO - Before Maintenance, All
Phase I Vehicles
viii
PAGE
74
75
76
77
78
79
80
81
82
84
85
86
87
88

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TABLE
2.1
2.2
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
3.12
3.13
3.14
3.15
3.16
LIST OF TABLES
Percent Benefit from I/M Programs Based on the
Idle (N) Short Test

Estimated Percent Benefit from I/M Program with
40 Percent Stringency Factor

Number of Test Vehicles by Model Year, Phase, and
Pass/Fail Status

Average 1975 FTP Emissions and Fuel Economy Before
and After Maintenance

Standard Deviations of 1975 FTP Emissions and Fuel
Economy Before and After Maintenance

Percent Benefit in an I/M Program with a 10 Percent
Stringency Factor - 1975 FTP

Percent Benefit in an I/M Program with a 20 Percent
Stringency Factor - 1975 FTP

Percent Benefit in an I/M Program with a 30 Percent
Stringency Factor - 1975 FTP

Percent Benefit in an I/M Program with a 40 Percent
Stringency Factor - 1975 FTP

Percent Benefit in an I/M Program with a 50 Percent
Stringency Factor - 1975 FTP

Comparison of Estimated High Altitude Percent
Benefits with First Year Percent Benefits of
Appendix N

Percent Benefit in an
Stringency Factor -

Percent Benefit in an
Stringency Factor -

Percent Benefit in an
Stringency Factor -

Percent Benefit in an
Stringency Factor -

Percent Benefit in an
Stringency Factor -

Percent Benefit in an
Stringency Factor -

Percent Benefit in an I/M Program with a 20 Percent
Stringency Factor - Cold Transient Emissions
I/M Program with a 10 Percent
Idle (N) Emissions

I/M Program with a 20 Percent
Idle (N) Emissions

I/M Program with a 30 Percent
Idle (N) Emissions

I/M Program with a 40 Percent
Idle (N) Emissions

I/M Program with a 50 Percent
Idle (N) Emissions

I/M Program with a 10 Percent
Cold Transient Emissions
lX
PAGE
5
6
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104

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TABLE
3.17
3.18
3.19
3.20
3.21
3.22
3.23
3.24
3.25
3.26
3.27
3.28
3.29
3.30
3.31
3.32
3.33
LIST OF TABLES, continued
Percent Benefit in an 11M Program with a 30 Percent
Stringency Factor - Cold Transient Emissions

Percent Benefit in an 11M Program with a 40 Percent
Stringency Factor - Cold Transient Emissions

Percent Benefit in an 11M Program with a 50 Percent
Stringency Factor - Cold Transient Emissions

Percent Benefit in an 11M Program with a 10 Percent
Stringency Factor - Cold Stabilized Emissions

Percent Benefit in an 11M Program with a 20 Percent
Stringency Factor - Cold Stabilized Emissions

Percent Benefit in an 11M Program with a 30 Percent
Stringency Factor - Cold Stabilized Emissions

Percent Benefit in an 11M Program with a 40 Percent
Stringency Factor - Cold Stabilized Emissions

Percent Benefit in an 11M Program with a 50 Percent
Stringency Factor - Cold Stabilized Emissions

Average Percent Reductions in 1975 FTP Emissions
Due to Maintenance

Comparisons of After Maintenance Emissions with
Passed Vehicles' Emissions
Regression Equations for Absolute Change in FTP
Emissions as a Function of Pre-Maintenance
Emissions Level, Engine DisplaceMent, and Vehicle
Mileage - All Phase I

Regression Equations for Predicting Absolute Change
in FTP Emissions as a Function of Before Mainten-
ance Short Test Emissions - All Phase I Vehicles

Regression Equations for Predicting Absolute Change
in FTP Emissions as a Function of Change in Short
Test Emissions - All Phase I Vehicles

Short Test Cutpoints Based on Combination of
Emittants Assuming Stringency Factors of 10%, 20%
30%, 40%, and 50% '

Idle (N) Cutpoints and Number of Failures for
Various HC/CO Ratios at a 30% Stringency Factor

Comparison of Estimated Percent Benefits for
30% Stringency Factor and Various HC/CO Ratios

Tune Up Information, All Phase I Vehicles
x
PAGE
105
106
107
108
109
110
III
112
113
114
115
116
117
118
119
120
121

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TABLE
3.34
3.35
3.36
3.37
3.38
3.39
3.40
3.41
3.4~
3.43
3.44
3.45
3.46
3.47
3.48
3.49
3.50
3.51
3.52
3.53
LIST Of TABLES, continued
Tune Up

Tune Up
Phase
Information, Passing Phase I Vehicles

Information, Failing Phase I/Failing
II Vehicles
Tune Up Information, All Phase I Vehicles,
1975-1976 Model Year

Tune Up Information, Passing Phase I Vehicles,
1975-1976 Model Year
Tune Up Information, Failing Phase I/Failing
Phase II Vehicles, 1975-1976 Model Year
Tune Up Information, All Phase I Vehicles
Tune Up Information, Passing Phase I Vehicles
Tune Up Information, Failing Phase I/Failing
Phase II Vehicles     
Vehicle Tuneup Cost Summary by Model Year, All
Phase I Vehicles

Vehicle Tuneup Cost Summary by Model Year,
Passing Phase I Vehicles

Vehicle Tuneup Cost Summary by Model Year,
Failing Phase I/Failing Phase II Vehicles

Vehicle Tuneup Cost Summary by Hanufacturer,
All Phase I Vehicles
Vehicle Tuneup Cost Summary by Manuf~cturer,
Passing Phase I Vehicles

Vehicle Tuneup Cost Summary by Manufacturer,
Failing Phase I/Failing Phase II Vehicles

Vehicle Tuneup Cost Summary by Mileage, All Phase I
Vehicles

Vehicle Tuneup Cost Summary by Mileage, Passing
Phase I Vehicles
Vehicle Tuneup Cost Summary by Mileage, Failing
Phase I/Failing Phase II Vehicles

Vehicle Tune-Up Cost Summary by Stringency Factor,
All Phase I Vehicles
Correlation Coefficients for Percent Change in FTP
Emissions Versus Costs of Maintenance

Standard Deviations of Replicate Short Test Values -
All Phase I Vehicles
Xl
PAGE
122
123
124
125
126
127
127
128
129
129
130
131
131
132
133
134
135
136
137
138

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TABLE
3.54
3.55
3.56
3.57
3.58
3.59
3.60
3.61
3.62
3.63
3.64
3.65
LIST OF TABLES, continued
Standard Deviations of Replicate Short Test Values -
Passing Phase I and Failing Phases I and II

Student's t Statistics for Evaluating Significance
of Average Difference of Replicate Determinations -
All Phase I

Regression Equations for Predicting Pre-Maintenance
FTP Emissions as a Function of Pre-Maintenance
Short Test Emissions - All Phase I Vehicles

Regression Equation for Predicting Pre-Maintenance
FTP Emissions as a Function of Pre-Maintenance
Short Test Emissions - Passing Phase I Vehicles

Regression Equations for Predicting Pre-Maintenance
FTP Emissions as a Function of Pre-Maintenance
Short Test Emissions - Failing Phases I and II
Vehicles
Reg~ession Equations for 1975 FTP Emissions as a
Function of Short Test Emissions - Low Altitude
Data

Partial Correlation Coefficients of Mileage Term in
Predicting FTP Emission from Short Test Emissions
and Mileage

Short Test Cutpoints for Individual Emittants at
Stringency Factors of 10%, 20%, 30%, 40%, 50%

Errors of Omission and Commission, Idle (N), All
Phase I Vehicles, 1972-1974 Model Year

Errors of Ommission and Commission, Idle (N), All
Phase I Vehicles, 1975-1976 Model Year

11M Impact Measure for Stringency Factors of 10%,
20%, 30%, 40%, and 50%, Idle (N) Short Test

11M Impact Measure for Stringency Factors of 10%,
20%, 30%, 40%, and 50%, Federal Short Cycle
Short Test
3.66 Mean 1975 FTP HC Emissions, All Phase I Vehicles,
 1972-1974 Model Year Vehicles  
3.67 Mean 1975 FTP HC Emissions, All Phase I Vehicles,
 1975-1976 Model Year Vehicles  
3.68 Mean 1975 FTP CO Emissions, All Phase I Vehicles,
 1972-1974 Model Year Vehicles  
3.69 Mean 1975 FTP CO Emissions, All Phase I Vehicles,
 1975-1976 Model Year Vehicles  
xii
PAGE
139
140
141
142
143
144
145
146
147
148
149
149
150
150
151
151

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TABLE
3.70
3.71
3.72
3.73
3.74
3.75
3.76
3.77
3.78
3.79
3.80
3.81
3.82
3.83
3.84
3.85
3.86
3.87
3.88
LIST OF TABLES, continued
PAGE
Mean 1975 FTP NOX Emissions, All Phase I Vehicles,
1972-1974 Model Year Vehicles
152
Phase I Vehicles,
Mean 1975 FTP NOX Emissions, All
1975-1976 Model Year Vehicles

Mean 1975 FTP HC Emissions, All
1972-1974 Model Year Vehicles

Mean 1975 FTP HC Emissions, All Phase I Vehicles,
1975-1976 Model Year Vehicles
152
Phase I Vehicles,
153
153
Mean 1975 FTP CO Emissions, All
1972-1974 Model Year Vehicles

Mean 1975 FTP CO Emissions, All
1975-1976 Model Year Vehicles

Mean 1975 FTP NOX Emissions, All Phase I Vehicles,
1972-1974 Model Year Vehicles
Phase I Vehicles,
154
Phase I Vehicles,
154
155
Mean 1975 FTP NOX Emissions, All Phase I Vehicles,
1975-.1976 Model Year Vehicles

Mean Cold Transient HC Emissions in Grams, All
Phase I Vehicles, 1972-1974 Model Year
155
156
Mean Cold
Phase I

Mean Cold
Phase I
Transient
Vehicles,

Transient
Vehicles,
HC Emissions in Grams, All
1975-1976 Model Year

CO Emissions in Grams, All
1972-1974 Model Year
157
156
Mean Cold Transient CO Emissions in Grams, All
Phase I Vehicles, 1975-1976 Model Year

Mean Cold Transient NOX Emissions in Grams, All
Phase I Vehicles, 1972-1974 Model Year
157
158
Mean Cold Transient NOX Emissions in Grams, All
Phase I Vehicles, 1975-1976 Model Year

Mean Cold Stabilized HC Emissions in Grams, All
Phase I Vehicles, 1972-1974 Model Year
158
159
Mean Cold Stabilized HC Emissions in Grams, All
Phase I Vehicles, 1975-1976 Model Year

Mean Cold Stabilized CO Emissions in Grams, All
Phase I Vehicles, 1972-1974 Model Year
159
160
Mean Cold
Phase I

Mean Cold
Phase I
Stabilized CO Emissions in Grams, All
Vehicles, 1975-1976 Model Year

Stabilized NOX Emissions in Grams, All
Vehicles, 1972-1974 Model Year
161
160
xiii

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TABLE
3.89
3.90
3.91
3.92
3.93
3.94
3.95
3.96
3.97
3.98
3.99
LIST OF TABLES, continued
Mean Cold Stabilized NOX Emissions in Grams, All
Phase I Vehicles, 1975-1976 Model Year

Emissions for 10% to 50% Worst Emitting Vehicles

Clayton Causes of High HC Emissions

Clayton Causes of High CO Emissions

Percent of Vehicles Failing Federal HC Standards
with High HC Emissions on Federal Three Mode
Test for 1972-1974 Model Year Vehicles

Percent of Vehicles Failing Federal CO Standards
with High CO Emissions on Federal Three Mode
Test for 1972-1974 Model Year Vehicles
Percent of Vehicles Failing Federal HC Standards
with High HC Emissions on Federal Three Mode
Test for 1975-1976 Model Year Vehicles

Percent of Vehicles Failing Federal CO Standards
with High CO Emissions on Federal Three Mode
Test for 1975-1976 Model Year Vehicles
Percentage of Vehicles with Maladjusted or
Disabled Emission Systems or Components

Percentage of Vehicles with Maladjusted/Disabled
Emission Systems/Components by Manufacturer,
1975-1976 Model Year Vehicles

Percentage of Vehicles with Maladjusted/Disabled
Emission Systems/Components by Mileage,
1972-1974 Model Year Vehicles
3.100 Percentage of Vehicles with Maladjusted/Disabled
Emission Systems/Components by Mileage,
1975-1976 Model Year Vehicles

3.101 1975 FTP All Phase I Vehicles with Maladjustments/
Disablements by Manufacturer, 1975-1976 Model
Year Vehicles
3.102 1975 FTP All Phase I Vehicles Without Ma1adjustments/
Disablements by Manufacturer - 1975-1976 Model
Year Vehicles

3.103 1975 FTP All Phase I Vehicles with Maladjustments/
Disablements by Mileage - 1972-1974 Model Year
Vehicles
3.104 1975 FTP All Phase I Vehicles Without Ma1adjustments/
Disablements by Mileage - 1972-1974 Model Year
Vehicles
xiv
PAGE
161

162
163
164
165
166
167
168
169
170
171
172
173
174
175
176

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TABLE
3.105
3.106
3.107
3.108
3.109
3.110
3.111
3.112
3.113
3.114
3.115
3.116
3.117
LIST OF TABLES, continued
PAGE
1975 FTP All Phase I Vehicles with Maladjustments/
Disablements by Mileage - 1975-1976 Model
Year Vehicles

1975 FTP All Phase I Vehicles Without Maladjustments/
Disablements by Mileage - 1975-1976 Model Year
Vehicles
177
178
Student t Statistics for Testing Mean Emissions
With and Without Maladjustments and Disablements
by Manufacturer, 1975-1976 Vehicles, Phase I
Vehicles

Student t Statistics for Testing Mean Emissions
With and Without Maladjustments and Disablements
by Mileage and Model Year, Phase I Vehicles

Percentages of Vehicles by Owner Response to
Questionnaire that have Maladjusted or Disabled
Systems/Component, All Failing Phase II

Percentages of Vehicles by Owner Response to
Questionnaire that have Maladjusted or Disabled
Systems/Component, 1972-1974 Model Year, Failing
Phase II Vehicles
179
180
181
182
Percentages of Vehicles by Owner Response to
Questionnaire that have Maladjusted or Disabled
Systems/Component, 1975-1976 Model Year, Failing
Phase II Vehicles

Percentages of Vehicles with Engine Parameters
Outside of Specification Tolerances by Manufacturer,
1975-1976 Model Year
183
184
Percentages of Vehicles with Engine Parameters
Outside of Specification Tolerances by Mileage,
1975-1976 Model Year

Percentages of Vehicles with Engine Parameters
Outside of Specification Tolerances by Engine
Displacement, 1975-1976 Model Year

1975 FTP All Phase I Vehicles Timing and Idle RPM
Within and Outside Specification Tolerances,
1975-1976 Model Year

1975 FTP All Phase I Vehicles Idle CO Within and
Outside Specification Tolerances, 1975-1976 Model
Year
185
186
187
188
1975 FTP Passing Phase I Vehicles Timing and Idle RPM
Within and Outside Specification Tolerances,
1975-1976 Model Year
189
xv

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TABLE
3.118
3.119
3.120
3.121
3.122
3.123
LIST OF TABLES, concluded
1975 FTP Passing Phase I Vehicles Idle CO
Within and Outside Specification Tolerances,
1975-1976 Model Year

1975 FTP Failing Phase I/Failing Phase II Vehicles
Timing and Idle RPM Within and Outside Specifi-
cation Tolerances, 1975-1976 Model Year

1975 FTP Failing Phase I/Failing Phase II Vehicles
Idle CO Within and Outside Specification
Tolerances, 1975-1976 Model Year

Student's t Values for Average Emissions of Vehicles
Outside Tolerances Minus Average Emissions of
Vehicles Within Tolerances

Correlation Coefficients for Percent Change in
Emissions and Fuel Economy Versus Change in Engine
Parameters Following Maintenance -- All Phase I
Vehicles
Multiple Correlations for Percent Change in Emissions
Versus Change in Engine Parameters During Main-
tenance, All Phase I Vehicles
xri
PAGE
190
191
192
193
194
195

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SECTION 1
INTRODUCTION
There are two principal methods of reducing the motor
vehicle contribution to a regional emission inventory or emission
hot spot. One method is to reduce the pollutants which are
emitted from each vehicle on a per mile traveled basis, while the
second method is to reduce the total number of miles traveled by
motor vehicles, either nationally, regionally, or in a specific
problem location. Although emission standards and compliance
strategies associated with the manufacture of vehicles with
properly operating emission control systems have normally been
effected on a national level, transportation control strategies
have been implemented on a state or local basis. National
strategies include new car certification, assembly line testing,
and recall of properly maintained vehicles which are substan-
tially above emission standards. Regional strategies include
inspection/maintenance (I/M), parking controls, vehicle miles
traveled reduction strategies, improvements/incentives for
public transportation, mandatory maintenance, roadside emission
checks, etc. In this way, regions with more severe air quality
problems can implement more comprehensive control strategies.
The effectiveness of I/M as a regional control strategy is
based upon two key factors. First, vehicle emissions deteriorate
with age. This deterioration is due partly to a gradual wearing
of engine components and partly to lack of proper maintenance.
I/M can reduce overall deterioration by ensuring that vehicles
are properly maintained. Secondly, I/M is based upon being able
to properly identify vehicles which can benefit from emission
related repair. This identification can be based upon short
emission tests, short diagnostic tests, or a general requirement
for mandatory emission related maintenance. However, since I/M
affects a large population in a given region, its implementation
must be reasonable in both cost and time commitments from the
public.
1

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11M programs have been the subject of several studies but most
of the EPA effort, to date, has centered on low altitude regions of
the country. Until 1977, vehicles sold at high altitude were built
to be similar to those sold at low altitude. However, vehicle
engine operation at high altitude differs from that at low altitude
in that, at the same parametric settings, vehicles run rich at high
altitude. The rich operation results in increased hydrocarbon (HC)
and carbon monoxide (CO) emissions. This difference in vehicle
operation at high altitude could result in different 11M benefits
than those projected at low altitude.

Previous studies at low altitude have included the collection
of FTP and short test data as well as the assessment of vehicle
repair effectiveness. These data have been formulated into a
simulation model which projects 11M benefits over the life of a
vehicle. In addition, cost of repair information has been acquired.
Several operational 11M programs exist at low altitude and these
programs have been able to characterize the real world costs and
short test measured benefits of 11M. At present, a major EPA test
program is being performed to assess the real world effectiveness
of an operational 11M program at low altitude. Since a real world
11M program does not exist in a high altitude location, this study
attempted to address those aspects of 11M that could be measured in
a laboratory environment. Three major question areas were examined:
the effectiveness of 11M, the correlation between FTP and various
short inspection tests, and the relationships which exist between
emissions, engine condition, and vehicle usage. The information
obtained from these analyses will be used by the EPA to develop a
high altitude version of the 11M simulation model. That work will
be published in a separate EPA report.
The data were collected in two phases on a random sample of
in-use vehicles from the population of 1972 through 1976 model year
vehicles. In Phase I, 193 vehicles were subjected to the Federal
Test Procedure (FTP) and a series of short tests. Every vehicle
then received an emission oriented tune-up, factory recommended
2

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maintenance if due, and the restoration of maladjustments and
disablements. All emissions tests were then repeated. The
Phase I data were then used to establish a pass-fail criteria on
the basis of the idle in neutral (Idle (N» short test which was
designed to fail 35-40 percent of the vehicles in each of two
model year groupings: 1972-1974 model years and 1975-1976 model
years. An additional random sample of 470 vehicles from the
population of the same model year vehicles was then obtained and
this sample was designated as Phase II. Each of the vehicles in
Phase II was given the Idle (N) short test and those which passed
the idle test were not tested further. Those vehicles which failed
were then given the same set of tests and maintenance actions as
was given to the Phase I vehicles. The two phases provided a
sample of 382 vehicles which were subjected to FTP and short test
emission evaluations before and after maintenance actions. For
all of these vehicles, complete records were maintained on the
type and costs of maintenance actions, the condition of the vehicle
as received, and other pertinent data. A complete description of
the vehicle selection and testing procedure can be found in
Reference I and a summary is provided in Paragraph 3.1 of this
report.
Section 2 of this report will present a summary of the major
conclusions of the study, while Section 3 will contain a technical
discussion of methodology and results. Both sections will be
divided into the three major study areas. Within each study area,
a series of problem statements have been formulated. The presen-
tation of results by study area and specific problem areas has
been used in order to effectively present the large amount of data
analysis which has been performed.
3

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SECTION 2

SUMMARY OF RESULTS
A summary of the major results in each of the three primary
interest areas is presented in this section. The data and
analyses supporting these conclusions are presented in Section 3.
2.1
EXPECTED BENEFITS OF HIGH ALTITUDE 11M
1.
Estimation of Idle (N) 11M Program Effectiveness
Table 2.1 presents estimates of the average first year
effectiveness for different stringency factors in an 11M program
based on the Idle (N) short test. At high altitudes, the NOX
emissions and fuel economy are unaffected by 11M while significant
reductions in HC and CO emissions are possible. To compare the
potential 11M pollutant reductions of this program with those of
previous high altitude programs and the Appendix N estimates,
Table 2.2 presents the estimated benefits for a 40 percent strin-
gency factor. The 1975-1976 model year percentage reductions
obtained from this study are in close agreement with those of the
Reference 3 Colorado report. The CO reductions of this report
are within the range of those of Appendix N for both model year
groupings. The HC reductions are within the range of those of
Appendix N for 1972-1974 model years, but are greater than those
of Appendix N for the 1975-1976 model years.
With respect to the benefits to be gained and the com-
parison with the Appendix benefits, it should be noted that the
maintenance actions in Denver were performed by trained contractor
mechanics. However, the emissions oriented tune-up performed on
the vehicles in this program returned the vehicle to a manufacturer
recommended condition for low altitude regions which is not optimum
for high altitude operation. Therefore, the maximum possible
emission reductions are not achieved during the maintenance actions.
The net effect of this factor on any comparisons is unknown.
4

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TABLE 2.1
PERCENT BENEFIT FROM IIM PROGRAMS
BASED ON THE IDLE (N) SHORT TEST
 Stringency    
Model Years Factor HC CO NOX F.E.
1972-1974 10 6 3 1 0
 20 8 8 0 0
 30 10 12 0 -1
 40 12 15 1 -1
 50 14 18 1 -1
1975-1976 10 8 10 1 0
 20 14 16 2 0
 30 19 20 4 0
 40 23 25 5 0
 50 28 27 7 0
5

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TABLE 2.2

ESTIMATED PERCENT BENEFIT FROM I/M PROGRAM
WITH 40 PERCENT STRINGENCY FACTOR
         Fuel
      HC CO NOX Economy
12/73 Colorado Report (Ref. 2)    
1964-1967 Models    4.4 2.4 2.3 -0.8
1968-1973 Models    18.0 10.8 1.1 1.4
3/76 Colorado Report (Ref. 3)    
1975 Models    24.6 24.3 4.7 1.0
Appendix N* (Ref. 4)      
1972-1974 Models    8-13 14-22  
1975 Models    12-15 23-32  
Current Report       
1972-1974 Models    11.7 15.1 0.9 -1.0
1975-1976 Models    23.4 25.0 4.8 0.1
* First year benefit without mechanic training.
6

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2.
Comparison of After Maintenance Emissions with Passed
Vehicle Emissions
Average Idle (N) emissions of repaired vehicles were below
the cutpoints for each stringency factor but the repaired vehicle
Idle (N) averages tend to be greater than the averages of vehicles
which passed the short test. For 1972-1974 model year vehicles,
repair of failed vehicles yielded FTP HC averages which were
greater than those of passed vehicles and FTP CO averages which
were lower than those of passed vehicles. For 1975-1976 model
years, the average FTP HC and CO emissions of repaired vehicles
were still greater than those of vehicles which originally passed
the short test.
3.
Correlation of Changes in Emissions with Before Main-
tenance Levels, Engine Displacement, and Vehicle Mileage
A multiple regression analysis was performed for predict-
ing change in FTP and short test emissions as a function of the
before maintenance value, engine displacement, and mileage. The
change in emissions was uncorrelated with mileage for all three
emissions and all short tests. On occasion, the contribution
from the CID term was significantly nonzero but for practical
purposes this term could also be ignored in the predictive equa-
tions. Thus, of the factors considered, change in emissions was
correlated with pre-maintenance emission levels and the ability
to predict the change depended on the pollutant and short test.
A regression analysis was also conducted to predict
change in FTP emissions as a function of pre-maintenance short
test emission levels. The observed correlations were stronger
for the Hot FTP and Federal Short Cycle tests than for the
Federal Three Mode and Idle tests.
4 .
Correlation of Change in FTP Emissions with Change in
Short Test Emissions
A regression analysis
in FTP emissions as a function
for each of the short tests.
was performed to predict change
of change in short test emissions
The relationship was strongest for
7

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the Hot FTP test (r~0.90) and weakest for the Idle (N) test
(0.50
-------
1972-1974 vehicle was $44. For a 1972-1974 vehicle passing the
Idle (N) short test (Phase I vehicles) this cost was $39.50 while
for a failing 1972-1974 vehicle (Phases I and II), it was $41.50.
The correlation of percent change in FTP emissions and
maintenance cost was analyzed. The costs of maintenance are
unrelated to percent emissions reductions for the 1975-1976
vehicles and are significantly (but weakly) correlated with
reductions in the 1972-1974 ~odel years.
7.
Variability of Replicate Short Tests
Replicate determinations of all of the short tests were
performed as a part of the test procedure. A pooled estimate of
the standard deviation of the replica~e determinations provided
a measure of the repeatability of the various short tests. As a
percentage of the mean, there was less repeatability for 1975-
1976 vehicles than for the 1972-1974 vehicles. No consistent
patterns of variability were observed
pollutants, and model year groupings.
variation (100 Six) are approximately
5 percent and a high of 100 percent.
in comparing short test,
Typical coefficients of
20 percent with a low
2.2
RELATIONSHIP BETWEEN FTP AND SHORT TEST EMISSIONS
1.
Linear Regression Relationships
A regression analysis was performed to assess the ability
of the short test emissions to predict the FTP emissions. The Hot
FTP and the Federal Short Cycle emissions displayed a strong
correlation with the FTP emissions, with correlation coefficients
greater than 0.93 and 0.84, respectively, for each model year-
pollutant combination. The predictive ability of the Federal
Three Mode Test was intermediate (0.60~r~0.88) while that of the
Idle (N) short test was weak (0.19~r~0.71). The observed
correlations were generally consistent with those observed in
vehicles operating at low altitudes but the predictive equations
were significantly different. The correlation of FTP emissions
9

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with short tests was not improved by the addition of a term for
vehicular mileage.
2.
Contingency Table Correlation
The discriminatory ability of the short tests was
investigated through a contingency table analysis. Using the
short test pass-fail criteria and the Federal Standards for
defining high and low FTP emissions, the percentage of vehicles
erroneously classified by the short test cutpoint can be
determined. An error of commission is defined as a short test
rejection when the FTP emissions are less than the Federal
Standard.
An error of omission is defined as a short test
acceptance when the FTP emissions are greater than the Federal
Standard. The percentage errors of commission and omission were
calculated for all short tests and for stringency factors of 10,
20, 30, 40, and 50 percent for both model year groups. In the
Denver area, very few errors of commission occurred since most
in-use vehicles fail the Federal Standards for CO and/or HC. In
the 1972-1974 model years, none passed the CO standard and seven
percent passed the HC standard. In the 1975-1976 model years,
ten percent passed the CO standard and 32 percent passed the HC
standard. Therefore, when the pass-fail criteria are based on
all three emissions, the errors of commission are negligible and
the percent errors of omission can be approximated by the per-
centage that passes the short test (the compliment of the
stringency factor). The errors are reversed when only NOX is
considered. In Denver, 95 percent of 1975-1976 and 83 percent of
1972-1974 vehicles pass the Federal Standards for NOX. Thus, NOX
errors of commission are very common. For all four combinations
of passing and failing the Idle (N) short test and Federal Stand-
ards, the means and standard deviations of FTP emissions are
presented in the tables of Section 3 for the five stringency
factors.
An impact measure was defined in terms of the percentage
of excess emissions that are identified by the short tests at each
10

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stringency factor. For the !dle (N) and Federal Short Cycle tests
at 40 percent stringency factors, approximately 65 percent of the
emissions which exceed the Federal Standards will be identified by
the short test. The Federal Short Cycle test had higher impact
measures than did the !dle (N) test and the 1975-1976 vehicles
had higher impact measures than the 1972-1974 vehicles.
3.
Ability of Short Test to Identify the Highest FTP
Emitters
To determine if the failed fraction of the population has
significantly higher emissions than the passed as determined by the
Idle (N) or Federal Short Cycle tests, the average emissions at
each stringency factor were calculated for the four categories of
pass/fail and FTP/short test. For all stringency factors, both
model year groupings and both short tests, the average HC and CO
emissions were significantly greater for the failed vehicles than
for the passed vehicles.
The average emissions at each stringency factor of the
failed vehicles were also compared with the corresponding worst
x percent of the population. For stringency factor of 30 percent
or more, the HC and CO averages of vehicles failed by the Federal
Short Cycle test are 90 percent or more of the worst emitters'
average. Similar averages for vehicles failed by the Idle (N)
test are 80 percent or more of the worst emitters' average.
2.3
CORRELATION OF EMISSIONS WITH ENGINE CONDITION AND USAGE
1.
Causes for High FTP Emissions
A sequence of diagnostic tests defined by the Clayton
Manufacturing Company was applied to the emissions from the modes
of the Federal Three Mode test. The diagnostics indicated that
approximately 50 percent a the vehicles failing the federal HC
standard had abnormally high HC emissions in the modes associated
with failure of an ignition system component. Similarly, approxi-
mately 50 percent of the vehicles which failed the Federal CO
11

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standard had abnormally high CO emissions in modes whose cause is
a gross error in the carburetor idle air fuel mixture.
2.
Maladjusted Vehicle Systems
In the high altitude regions, maladjustment and/or dis-
ablement of emission related systems is common. The data from
all Phase I test vehicles indicate that approximately 70 percent
of the vehicles have at least one system maladjusted and/or dis-
abled. This percentage is lower (66 percent) for the vehicles
which pass the Idle (N) short test and, thus, higher (86 percent)
for those which fail. Maladjustments and/or disablements are
most common to the limiter caps and the timing (about 50 percent
in the Phase I vehicles) and relatively rare for other systems
(6 percent or less). The percentage of vehicles with maladjusted
and/or disabled limiter caps, timing, and at least one system
malperformance were obtained by manufacturer for 1975-1976
vehicles and by vehicular mileage for the model year groupings.
No noteworthy differences were observed among these percentages.
3.
Relationships Between Maladjustments and Emissions
The average standard deviation of the FTP emissions and
fuel economy of the vehicles with and without maladjustments and/or
disablements were obtained and compared for various groupings of
the total data set. Most of the comparisons regarding manufactur-
ers and vehicular mileage increments indicated no difference in
emissions and fuel economy between the categories. However, fuel
economy was higher for vehicles with timing maladjusted and lower
for those with limiter caps maladjusted and/or disabled. Also,
average CO was significantly larger for vehicles with maladjust-
ments and/or disablements in at least one system.
No relationship was determined for identifying vehicles
with FTP emissions greater than the Federal Standards with the
various types of maladjustments and/or disablements. Similarly,
no relationship was found between engine related owner responses
to a questionnaire and the various types of maladjustments and
disablements.
12

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4 .
Relationship Between Maladjustments and Owner Maintenance
Practices and Owner Perceived Performance Problems
A questionnaire regarding owner practices with regard to
vehicle maintenance and performance problems was completed for
each vehicle. The percentage of vehicles with maladjustments
and/or disablement of the limiter caps, timing, or at least one
emission related system and/or component was calculated for each
response to pertinent questions. The comparisons did not indicate
differences in owner maintenance practices or owner perceived
performance problems for vehicles with maladjusted or disabled
limiter caps, timing, and/or any other examined component.
5 .
Engine Parameter Settings
Percentages of vehicles with the engine parameters of
timing, idle RPM, and idle CO outside of defined tolerances were
determined for various data groupings. Among the all Phase I
and passing Phase I vehicles, fewer General Motors vehicles were
outside specifications than the other manufacturers. This
difference did not hold for the failing vehicles, however. Thus,
among General Motors vehicles engine parameters provide a degree
of discrimination as to passing or failing the Idle (N) test that
is not present in the vehicles of other manufacturers. These
percentages were also determined for increments of engine displace-
ment and vehicular mileage, but no conclusive trends were
identified.
6 .
Relationship of Engine Parameter Settings with Emissions
Averages and standard deviations of emissions and fuel
economy were calculated for vehicles within specification toler-
ances and outside specification tolerances for many groupings of
the test data. For Phase I the HC and CO emissions for vehicles
outside timing and/or RPM tolerances were significantly larger
than for the vehicles within these tolerances. The differences
were not significant in the passing Phase I vehicles or failing
Phases I and II vehicles. Thus, the timing and idle RPM settings
13

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tend to discriminate between the pass-fail vehicles. For vehicles
inside and outside idle CO tolerances, however, the differences
in average He and co emissions were significant for the all phase I
and passing Phase I groups. Insufficient data were available for
comparison in the failing Phases I and II groups of vehicles.
The correlation between changes in emissions due to
maintenance and the change in adjustments of timing, idle RPM, and
idle co was investigated by a regression analysis. The correlations
were poor although significantly different from zero.
14

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SECTION 3
TECHNICAL DISCUSSION
This section contains a detailed description of the data base,
analysis procedures, data summaries, and results of the study.
First, the data available for analysis are discussed in terms of
their source, range of applicability, and type. There are three
primary objectives of the program and each of these is presented
as a major subsection. The major objectives of the program are
to determine the effects of inspection and maintenance on
emissions, to determine the effectiveness of short tests in identi-
fying high emitters, and to characterize maintenance and repair
actions and costs.
3.1
DATA BASE
As part of its Emission Factor Programs, the EPA has measured
the emissions and fuel economy of in-use light duty vehicles in the
Denver area for several years. The Denver segment of the fiscal
year 1974 (FY74) Emission Factor Program was expanded for this
study to provide data relevant to the evaluation of inspection and
maintenance programs. While a detailed description of the FY74
Denver Emission Factor Program can be found in Reference 1, a brief
summary of the elements of the program which have impact on the
interpretation of the 11M data analysis is presented in the follow-
ing paragraphs. A description of the basic parameters that were
measured and the data stratifications that will be used is also
presented.
3.1.1
Selection of Vehicles
Considerable care is exercised to insure that the
vehicles selected for testing in the Emission Factor Programs
form a representative sample of the in-use vehicle population. In
the FY74 Emission Program, the total sample was not representative
of the total population of in-use vehicles but, rather, was
15

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selected to provide a representative sample of vehicles within each
model year. This sampling philosophy was adopted to provide a large
sample of 1975 and 1976 model year cars, thereby providing
sufficient data for an early characterization of the newer genera-
tion of emission control devices. Thus, as a part of the FY74
Emission Factor Program, a random sample of Denver vehicles were
selected from each of the 1972, 1973, and 1974 model years
(Technology I vehicles), and 1975/76 model years (Technology II
vehicles) .
A profile of the in-use vehicles was produced based on
national vehicle sales which characterized a representative sample
by make, engine size, carburetor type, and transmission type for
each of the model years. The test sample of in-use vehicles was
then found by matching this profile as closely as possible using
the following guidelines: (1) all vehicles were to be of the
correct make and model; (2) at least 90 percent were also to be
of the engine displacement specified; and (3) at least 70 percent
were to be an exact match to the profile specifications.
Vehicle procurement was achieved primarily through mail
contact with a large random sample of car owners in the Denver area.
Every nth name on a computer file of vehicle owners in selected
postal zip code areas received mailings which explained the pro-
gram and provided a reply data card. The responses to mailed
questionnaires provided information about the owner's vehicle and
also indicated owner willingness to participate in the program.
Approximately 85 percent of the test vehicles were selected through
this procedure and the remainder (which had to meet a narrowing
range of specific requirements) were located through the news media,
automobile repair organization service files, used car lots, and
other sources. Approximately 30 mailings were required for each
vehicle finally selected.
The initial sample of Denver Emission Factor Program
vehicles consisted of 117 automobiles. This sample was increased
in two stages. First, an additional random sample of 77 automobiles
were added to the 1975/76 model years and these cars were treated
16

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as Emission Factor Program vehicles. One of these vehicles was
eliminated from the analyses of this report due to questionable
emission values. This group of 193 vehicles comprise the sample
defined as Phase I vehicles. Second, an additional representative
sample of 470 vehicles representing the 1972-1976 model years was
obtained through a selection procedure identical with that of the
Phase I Emission Factor Program vehicles. This latter sample is
defined as the Phase II vehicles.
Pass-fail selection criteria to identify high emitters
(which will be discussed later) were developed and applied to all
vehicles in Phase II. The criteria were selected to fail approxi-
mately 40 percent of the vehicles. The same pass-fail criteria
were applied to the Phase I vehicles to obtain a failed sample
similar to that of the Phase II sample. The number of automobiles
that resulted in each combination of phase, model year, and pass-
fail status is shown in Table 3.1. All Phase I vehicles were given
a complete set of emission tests before and after maintenance as
will be described in the next paragraph. However, only those
Phase II vehicles which failed the selection criteria were given
the complete set of emission tests. The Phase II vehicles which
passed the criteria were immediately returned to their owners,
and since no further evaluations of these vehicles were performed,
they are not included in any of the analyses of this report.
3.1.2 Test Procedures
Each Phase I test vehicle was inspected upon delivery
to the laboratory to insure that it could be safely run on the
dynamometer and to determine its compliance with sample require-
ments. A few vehicles were rejected at this initial point. After
acceptance, a sample of the fuel was taken for lead content analysis
and pre-test operations were performed. The vehicle was then
subjected to the before maintenance Evaluation Test Sequence. The
Evaluation Test Sequence consisted of a variety of test procedures
but for the 11M analysis the pertinent steps of the sequence areas
follows:
17

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1.
2.
3.
4 .
5.
6.
7.
8 .
1975 Federal Test Procedure
Hot Start Federal Test Procedure
Federal Short Cycle
Two Speed Idle Test
Federal Short Cycle (replicate)
Federal Three Mode Test
Two Speed Idle Test (replicate)
Federal Three Mode Test (replicate)
Following the before maintenance Evaluation Test
Sequence, an emission related Maladjustment and Disablement Inspec-
tion was performed. This inspection consisted of visual and func-
tional tests of emission related components and systems to determine
the extent of maladjustment and disablement to which the test vehicles
had been subjected. Engine diagnostic checks were also performed to
determine the condition of the electrical components (timing, dwell,
spark plugs, ignition wiring, points, condenser, spark coil, etc.)
and the engine vacuum system (vacuum signal lines, PCV valve, etc.).
This diagnostic procedure also included an emission analysis to
determine the amount of HC and CO in the exhaust at idle and at a
no-load condition of 2250 rpm. Maintenance was then performed by
the laboratory personnel on the vehicle which included restoring
disabled components or systems, performing required periodic main-
tenance if appropriate and performing an emission oriented tune-up.
In performing the maintenance, a limitation of $100 was placed on
total emission related parts replacement and labor. The emission
related tune-up returned the vehicle to emission specifications as
appearing on the EPA required Engine Emission Control Specification
label and in the service manuals. Since these specifications are
primarily for low altitude regions, the emissions oriented tune-up
was not necessarily optimum for the high altitude of the Denver
region.
Following maintenance, the vehicles were again subjected
to the Evaluation Test Sequence to determine the FTP and various
short test emission levels. Upon completion of the after main-
tenance test sequence, the vehicles were returned to the owners.
18

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Figure 3.1 presents a flow diagram of the Denver 11M Program pro-
cedures for Phase I vehicles.
The handling procedures for the Phase II vehicles
differed from those of the Phase I vehicles only to the extent that
an inspection test was performed to screen the low emitters from
further testing. This test was similar to the Two Speed Idle Test
except NOX emission measurements were not taken. The failure
limits were based only on the HC and CO emission measurements at
the low speed idle condition (curb idle in neutral). All vehicles
which passed the limits were returned immediately to their owners
with no further tests. Those which failed the limits were then
subjected to the same handling procedures as those of Phase I.
Figure 3.2 gives the flow diagram for Phase II vehicles.
3.1.3
Basic Parameters Measured and Stratifications to be
Used
high
The basic data set relevant to the evaluation of a
altitude 11M program consists of six types of parameters:
1. FTP emissions
2. Fuel economy
3. Short test emissions
4. Maladjusted and disabled system identifications
5. Engine parameters
6. Cost of maintenance and repair
The purpose of this subsection is to define the general stratifica-
tions that are maintained throughout the study and to present
pertinent comments regarding the basic data parameters.
The vehicles included in the sample represent the 1972
through 1976 model years. Since the vehicles of these model years
involve both Technology I and Technology II emission control systems
and since the two types have different emission characteristics,
the data will always be stratified in terms of model year. The
1975 and 1976 model year vehicles are always grouped together due
to the relatively few 1976 model year vehicles and due to the fact
19

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that both of these model year vehicles employ Technology II systems.
The 1972, 1973 and 1974 model year vehicles are presented both
separately and combined. All vehicles of these model years have
Technology I systems, but the 1972 models were not certified to
meet NOX standard. All three years had identical HC and CO
Federal Standards. Combining the 1972-1974 model year vehicles
into a single subpopulation provides a homogeneous subgroup of the
total sample of cars since the HC and CO emissions of the Denver
test vehicles do not differ significantly among the three model
years and since the average NOX emissions for all three model years
were below the 1973/74 standard.
As discussed in the previous paragraph, the test vehicles
were obtained in two phases. All Phase I vehicles went through a
before and after maintenance Evaluation Test Sequence, but only those
Phase II vehicles which failed the screening test were subjected to
any Evaluation Test Sequence. Thus, Phase II data only consist of
failing vehicles and can only be combined with the failing vehicles
of Phase I to form an unbiased sample of vehicles which fail the
screening test.
Three samples of interest in the analysis of the Denver
I/M data have been used throughout most of this report. All of the
Phase I vehicles provide a representative sample of the Denver in-
use vehicles for the four model years. The passing vehicles of
Phase I provide a representative sample of all vehicles for each
model year which meet the screening criteria. Finally, the com-
bination of the failing vehicles of Phases I and II are combined
to form a random sample of the population of vehicles which fail to
pass the screening criteria.
Obviously, the last two of these populations are greatly
dependent on the pass-fail screening criteria. The analysis of
this study is dependent for the most part on a screening criteria
designed to fail approximately 40 percent of the vehicles on the
basis of HC and CO emissions obtained from the Idle (Neutral) Short
Test. Specifically, a vehicle failed the inspection test if
20

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either the HC or CO Idle (N) emissions exceeded the following
limits or cutpoints;
Model Year
1972-1974
1975-1976
Idle HC
400 ppm
250 ppm
Idle CO

5.5%

2.0%
The planned failure percentage which is assumed for
any I/M program is known as the stringency factor. The effect on
the change of emission levels for several stringency factors is
considered for the Idle (N) test in Paragraph 3.2.1. It should be
noted that different results would be expected if the pass-fail
criteria were established in terms of one of the other short tests
or if diffe~ent cutpoints were used on the Idle (N) test. The
method used in determining the cutpoints will also be discussed in
Paragraphs 3.2.1 and 3.2.5.
The stratifications that result from model year, phase,
and pass-fail categorizations as described above are generally
maintained throughout the analysis. As a convenient reference,
the number of vehicles in each relevant combination is as follows:
 All Phase I Passing Phase I Failing Phase I
 Vehicles Vehicles and Phase II Vehicles
1972 25 14 50
1973 27 16 53
1974 30 22 31
1972-1974 82 52 134
1975-1976 III 72 124
The basic or standard exhaust emission test was per-
formed in accordance with the Federal Test Procedure. The FTP
is comprised of cold transient, cold stabilized and hot transient
portions. The 1975 FTP weightings were used in the calculation of
the emissions for all vehicles. Similarly, when emission levels
were compared to Federal Standards, the 1975 FTP equivalent of the
1973/74 standards were applied to all 1972-1974 vehicles
21

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(even though no NOX standard was in effect in 1972). The 1975
standards were applied to the 1975-1976 vehicles. For reference,
the applicable Federal 49 State Standards are as follows:
Model Year FTP HC CO
  -  
1972  1972 3.4 39.0
1973/74 1972 3.4 39.0
1975/76 1975 1.5 15.0
NOX
-
3.0
3.1
A conversion between the 1972 FTP and the 1975 FTP depends upon
vehicle mix, but approximately equivalent values for the 1972-1974
model year vehicles are:
HC
-
co
NOX
1972 FTP
1975 FTP
3.4
3.0
39
34
3.0
3.1
In conducting the emission tests for a particular
vehicle, the amount of C02 emitted was measured in addition to
the pollutants of HC, CO, and NOX. Since a fixed quantity of
gasoline contains a known amount of carbon and the total carbon
emitted was measured, the amount of gasoline used to traverse a
fixed distance may be determined by the carbon balance method.
The fuel economy data for each vehicle were calculated and
recorded in terms of miles per gallon. The average fuel economy
for a group of vehicles is defined as total miles divided by
total fuel consumption. Since all vehicles are driven the same
distance in the tests, it can be shown that average fuel economy
in miles per gallon is the harmonic mean of the fuel consumed
during the tests of the individual vehicles. Therefore, average
fuel economy is reported in terms of harmonic means and standard
deviations. Reference 5 gives further information on the method
of statistical inference regarding the fuel economy parameter.
Emissions were also obtained using the Hot Start FTP,
the Federal Short Cycle, the Federal Three Mode, and the Two
Speed Idle Tests in each Evaluation Test Sequence. These latter
22

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emission tests are referred to as the short tests in this report and
statements concerning their measurements will always identify the
specific short test. It should be noted that while all of these
tests are faster and cheaper than the full FTP, there is a wide
range in their length and complexity. The following paragraphs
give a brief description of each of these tests.
The Hot Start FTP is a mass emissions test similar to
the FTP except that exhaust sampling is initiated from a hot
engine start. Hot Start FTP emissions are comprised of the sum of
the emissions from the transient and stabilized test portions of
the full FTP divided by the distance traversed during the test
portions (7.5 miles).
The Federal Short Cycle is a 9 mode mass emission test
which uses the CVS measurement procedure. The test is preceded
by a six minute soak period which begins after a sustained period
of vehicle operation. The Federal Short Cycle test time is
125 seconds at an average speed of 21.7 mph (0.7536 mi.). The
dynamometer loading and transmission shift points are identical to
those of the FTP.
The Federal Three Mode Test employs tailpipe sampling
by volumetric procedures at each of three modes of vehicle opera-
tion. The three steady state modes simulate the average power
which occurs at high speed (50 mph) , low speed (30 mph) , and idle
(neutral). The results from each of the three modes are measured
separately.
The Two Speed Idle Test is a two mode test which
entails volumetric HC, CO and NOX emission measurements while the
engine is operated at approximately 2250 rpm with no load and at
idle in neutral. The engine is operated in each of these modes
until the emissions are stable. The idle mode of the Two Speed
Idle Test was used to screen the Phase II vehicles as to its
exclusion (pass) or inclusion (fail) in further testing.
In addition to the measured emission levels as
determined by the tests, data were collected defining those
23

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emission control systems which had been maladjusted and/or dis-
abled on each vehicle. Analysis of this data was performed in
an attempt to determine the effect of maladjustments and disable-
ments of specific components and systems on emissions and fuel
economy. Certain engine parameter settings were also obtained
during the inspection and maintenance task, both before and after
maintenance. The engine parameters were used in an attempt to
isolate high emission vehicles and to correlate emissions with
data on the extent of maladjustment of emission components.
Finally, estimates were recorded for the emission related tune-up
costs, maladjustment and disablement costs and the manufacturers
recommended maintenance costs.
3.2
EFFECTIVENESS OF 11M
In the evaluation of the effectiveness of an 11M program in
reducing automobile pollutants, seven distinct areas of analysis
were established. These include:
1. The determination of first year effectiveness for idle
11M programs with different stringency factors.
2. The comparison of after maintenance emissions with
emissions of vehicles passing the cutpoints.
3. The correlation of changes in emissions with before
maintenance levels, engine displacement, and mileage.
4. The relationship between changes in FTP emissions with
changes in short test emissions.
5.
The effect of relative HC to CO failures on 11M effect-
iveness.
6.
passing
The cost, amount, and type
or failing the short test.
The variability of FTP and
of repairs as a function of
7 .
short test results.
The following paragraphs address each of these areas by present-
ing a statement of the objectives followed by the analysis and
the conclusions.
24

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3.2.1
Estimation of Idle (N) I!~ Program Effectiveness
Objective: Determine the average first year maintenance
effectiveness for different stringency factors in an riM program
based on the Idle (N) short test.
The basic data pertinent to this analysis include the FTP
emission and fuel economy data taken before and after maintenance.
Tables 3.2 and 3.3 present the average and standard deviations,
respectively, for all three populations and the model year group-
ings. The percent effectiveness values given in Table 3.2 are
equivalent to those expected in a mandatory maintenance program
since all vehicles received maintenance. Tables 3.4 to 3.8 have
been generated by assuming stringency factors of 10 percent to 50 per-
cent. In each case, the Phase I vehicles were used to determine the
appropriate idle test cutpoints. Cutpoints were determined by assum-
ing that a vehicle that is twice the short test standard for HC is
equally as bad as a vehicle which is twice the short test standard
for CO. The short test standard is obtained by regressing the FTP
emissions on the idle emissions (using Phase I and Phase II vehicles)
and finding the idle equivalent value of the FTP standards. The
short test standards are given below along with the number of HC and
CO failures observed in the Phase I data.
Stringency
Factor
10
20
30
40
50
Model Combined Cutpoints Actual No. of Failures
Year HC CO NOX HC CO  NOX
72-74 739 9.99  7 4  0
75-76 1199 5.59  1 10  0
72-74 599 8.19  9 10  0
75-76 1199 3.49  1 22  0
72-74 599 6.29  9 21  0
75-76 1199 2.39  1 32  0
72-74 389 5.39  15 31  0
75-76 394 1.69  5 43  0
72-74 314 4.29 III 18 35  1
75-76 299 0.99  8 56  0
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It should be noted that in calculating the standards this way,
the 40% stringency factor is not equivalent to the one used as
a screening criteria for Phase II. Although there are an infinite
number of combinations of HC/CO short test cutpoints which could
give a 40% stringency factor, the one given in the table above is
equivalent in concept to the assumption used in the formulation
of Appendix N. Table 3.9 contrasts the results of the previous
tables with the first year benefits listed in Appendix N. Tables
3.10 to 3.24 present similar information for the idle test
emissions, the cold bag emissions of the FTP, and the stabilized
bag emissions of the FTP. Examination of these tables indicates
that effectiveness measures are dependent upon the driving sequence
of concern. In CO hot spots, the FTP may not be the driving cycle
of most interest.
In addition to the comparisons of before and after
maintenance emission levels, two other comparisons are of interest
which are more difficult to make. It is of interest to determine
if the Technology II vehicles benefit more or less than the
Technology I vehicles from an I/M program. Further, given that
both HC and CO are reduced by an I/M program, the comparative
amount of reductions of the two need to be established. A set of
statistics that would account for the variability in observed
percentage changes is required to perform these comparisons. The
means and standard deviations of the percent change in each
vehicle was calculated and these values are presented in Table
3.25 for all three groups of data.
First, consider the question of whether Technology I
and II vehicles benefited equally from the maintenance actions.
This hypothesis can be tested by a comparison of average percent
differences for 1972-1974 vehicles against those of the 1975-1976
vehicles. This test indicates that in the all Phase I and passing
Phase I populations, the average percent reductions of both HC
and CO were not significantly different between the Technology I
and II vehicles. In the failing Phases I and II vehicles, how-
ever, the Technology II vehicles experienced a significantly
26

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greater average percent reduction than did the Technology I
vehicles for both the HC and co. These tests were conducted at
the 95 percent level of confidence. Thus, failing 1975-1976
model year vehicles benefit more from the maintenance action
than do the failing 1972-1974 vehicles.
In the comparisons of the HC reductions to the co
reductions, the conclusions depended on the model years. In
1975-1976 model year vehicles, the average percent reductions
were not significantly different for HC versus co emissions for
all three populations of vehicles. In the 1972-1974, however, the
average percent reduction for co is significantly greater than
that of HC for all three populations. This analysis indicates
that HC and co benefits of Technology II vehicles due to main-
tenance are equal while those of Technology I vehicles are greater
for co than HC. Since this latter conclusion held for the group
of all passing vehicles as well as the group of all failing
vehicles, the result is independent of the screening ability of
the Idle (N) short test.
3.2.2
ComEarison of After Maintenance Emissions With
Passed Vehicles Emissions
Objective: Determine if the vehicles are repaired to
just pass the short test standards, to the FTP standards, or to
the mean of the passed vehicles.
This study does not simulate a real 11M program in
that the prescribed maintenance included the repair of diagnosed
maladjustments and disablements as well as an emission related
tune-up. Thus, mechanics were not merely attempting to get a
vehicle to pass a specific set of short test standards. As a
result, the repaired vehicle emissions measured in this study
could be expected to be lower than those that would occur in a real
world 11M program. With this in mind the tables presented earlier
(Tables 3.4 - 3.24) were examined to determine how the repaired
emissions compared to those of the passed vehicles. The results
are summarized in Table 3.26 for HC, CO, and NOX emissions of
27

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the FTP, Idle (N), cold transient, and cold stabilized by ~odel
year groupings.
Several conclusions can be drawn from the comparison
of average emissions of failed vehicles after repair with those
of the passed vehicles, the short test cutpoints, and the appli-
cable standards. The means of the Idle (N) emissions of repaired
vehicles are below the cutpoints but the repaired vehicle
Idle (N) means tend to be greater than the passed vehicle
Idle (N) means. All average FTP HC and CO means exceed Federal
Standards while the NOX averages are all less than Federal
Standards. For the 1972-1974 model year vehicles, repair of
failed vehicles yield HC averages which were greater than
those of the passed vehicles for the FTP and cold stabilized
portion and less than those of the passed vehicles for the
cold transient portion of the test. The average FTP, cold
transient, and cold stabilized CO emissions, however, were
less in the repaired vehicles than in the passed vehicles.
For the 1975-1976 model year vehicles, all average HC and
CO emissions were greater for the repaired vehicles than for
those which passed. The repair for both model year groupings
did reduce the average FTP, cold transient, and cold stabilized
NOX emissions below that of the passed vehicles.
Correlation of Changes in Emissions with Before
Maintenance Levels, Engine Displacement, and
Vehicle Mileage

Objective: Determine the relationship between the

changes in FTP and short test emissions due to maintenance

with the before maintenance levels, the vehicle engine displace-

ment (CID), and the vehicle mileage.
3.2.3
An examination of the emission reductions of each
vehicle which received maintenance indicates that these reduc-
tions vary widely from vehicle to vehicle. This is displayed
in the standard deviations of the average percent reductions
given in Table 3.25, the before versus after maintenance values
28

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of Figures 3.3 through 3.6, and the histograms of percent change
in emissions and fuel economy of Figures 3.7 through 3.10.
The diagonal lines on Figure 3.3 through 3.6 repre-
sent no change due to maintenance. It is obvious from Figures
3.3 and 3.4 that not all vehicles benefit from the maintenance
action. (The degree of repeatability of the FTP test is being
ignored. This assumes that the scatter from replicated tests
is balanced in the total presented picture even though indivi-
dual data points could be in error.) Approximately 25 percent
of the vehicles had higher HC and/or higher CO after mainten-
ance than before. It is also interesting to note that some
higher emitters, as well as lower, had their emissions increased.
The histograms of percent change in emission and fuel economy
reductions due to maintenance of Figures 3.7 through 3.10
display the distributions of the observed percent reductions
for the two model year groupings. The histograms for the
1972-1974 vehicles display less variation than those of the
1975-1976 vehicles but this may be attributed to the higher
before maintenance emissions of the 1972-1974 vehicles.
Any ability to predict which vehicles will obtain
the greatest reduction from maintenance would enhance the
attractiveness of an I/M program. (This analysis could also
examine specific diagnostic parameters or parametric changes
but these have been treated separately in a later problem
statement.) A regression analysis was performed on the rela-
tionship between the absolute change in emissions and the
before maintenance level, engine displacement, and mileage.
This analysis was performed for each FTP pollutant, short
test pollutant, and FTP fuel economy. A stepwise regression
analysis was calculated in which the dependent variable is
first estimated by the strongest correlating independent
variable (if significant) and more terms are added to the
equation if they provide a significant increase in the predic-
tive ability of the regression equation. The results of this
29

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analysis indicated the reduction of pollutant levels are cor-
related with the pre-maintenance emission measurement, are not
correlated with vehicle mileage, and are weakly correlated with
CID for some short tests and emissions. Table 3.27 presents
the significant regression results for each pollutant and for
fuel economy for the two model year groupings for all Phase I
vehicles. A similar analysis was performed to determine if
percent reduction could be predicted as a function of pre-
maintenance value and CID. For every pollutant, model year, and
test the correlation of percent reduction was weaker than that
for absolute reduction.
A regression analysis was also performed to deter-
mine if absolute change in FTP emissions could be predicted as
a function of pre-maintenance short test emission levels. These
results are summarized in Table 3.28 which presents the regres-
sion equations and correlation coefficients for each pollutant,
model year grouping and short test combination for all Phase I
vehicles. In this analysis the multiple modes of the Federal
Three Mode and Idle tests were combined in a single equation.
Due to the use of the Idle (N) short test in screening high
emitters, a separate equation was also calculated for this
single mode of the Idle short test. All observed relationships
were significant except for predicting the change in FTP NOX
emissions as a function of the Idle (N) short test values. The
relationships are generally stronger for the Hot FTP and Federal
Short Cycle tests than for the Federal Three Mode and Idle tests.
For HC and CO, between 45 and 75 percent (100 r2) of the varia-
tion in change in FTP levels is explained by the correlation
with the Hot FTP and Federal Short Cycle tests. Less than 25 per-
cent of the variation in NOX reduction is explained by the pre-
maintenance short test values.
3.2.4
Correlation of Change in FTP Emissions with Change
in Short Test Emissions -
Objective: Determine the relationship between change
in FTP emissions due to maintenance with change in the short test
emissions.
30

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The ability of a short test to predict the FTP is
considered to be a measure of the FTP/ST correlation. The question
posed here is a different one. It is possible to predict changes
in the FTP from changes in the short test and still not be able
to predict absolute FTP levels. Such a situation can readily
occur if FTP change and short test change are not highly
correlated with their pre-maintenance emission levels.
The results of this analysis are summarized in Table
3.29 which presents the regression equations for all combinations
of model year groupings, short tests, and pollutant for all
vehicles of Phase I. The correlation coefficients of this table
are in every case greater than the corresponding correlation
coefficients of Table 3.28 for predicting change in FTP emission
as a function of the pre-maintenance short test level. Thus, the
ability to predict absolute FTP levels is enhanced if the pre-
diction is based on a change in short test emission rather than
on pre-maintenance short test level.
3.2.5
Effect of Relative HC to CO Failure on I/M
Effectiveness
Objective: For a fixed overall stringency
30%, determine the effect of relative changes in HC/CO
on the first year inspection/maintenance benefits.
factor of
failures
In the development of the first year I/M benefits
given in Paragraph 3.2.1, the stringency factor cutpoints were
determined by a complex procedure. For each short test emission
value from each vehicle, a normalized score was developed by
dividing the observed short test value by a "standard". For each
emittant and model year grouping, the "standard" was defined as
the predicted short test value at the Federal Standard when aver-
age short test values are predicted as a linear function of FTP
values. All normalized values for the three emittants were
combined,
cutpoints
the exact
ordered, and the desired percentile determined. The
for each of the emittants were determined from that of
percentile determined (e.g., a CO value) and from the
31

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nearest normalized values of the other emittant which lie above
the exact percentile. If an emittant is not represented in this
latter group, the cutpoint is independent of that emittant at
that stringency factor. The cutpoints that were obtained based
on the combination of emittants are presented in Table 3.30.
Again, note that the cutpoints calculated by this method for
the Idle (N) 40 percent stringency are not those used in the
screening of the values into pass-fail populations.

Many other schemes could be devised for deriving
cutpoints based on a combination of emittants which will fail
the desired number of vehicles. To examine the effect of chang-
ing these criteria, a single stringency factor of 30% was
selected. The HC normalized score was multiplied by the following
factors: 10, 5, 2, .5, .1. In each case, a new set of 30 per-
cent stringency factor cutpoints were determined. Table 3.31
displays the cutpoints and Table 3.32 summarizes the benefits for
the different cases. Very little change in overall benefits
occurred as a result of changing the HC/CO ratio.
3.2.6
Costs, Frequency, and Types of Repair
Objective: Determine the difference between costs,
frequency: and types of repair as a function of vehicle pass/fail
status.
Due to the scarcity of vehicles which passed the FTP
standards, an analysis based on stratification defined in terms
of the Federal Standards would be meaningless. Therefore, the
data were stratified in terms of passing or failing the Idle (N)
short test and analyzed with respect to cost, frequency, and
type of repair.
The maintenance actions performed on each vehicle
during tune-up were summarized to indicate the type of action
required for each system. Tables 3.33, 3.34, and 3.35 display
the summaries for all vehicles in the Phase I, pass Phase I, and
32

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failing Phases I and II g~oups, respectively. As expected, the
rates of component replacement, repair and adjustment are
greater for the failing Phases I and II vehicles.
Sufficient maintenance actions were performed on
the idle RPM, idle air/fuel ratio, and dwell to warrant a
further division of these systems by manufacturer (for 1975-1976
model year vehicles) and by the two model year groupings. These
data are presented in Tables 3.36 through 3.41. The observed
differences in percentages of vehicles which required the
various categories of tune-up action were not significant when
comparisons were made among manufacturers, model years, or the
pass-fail grouping.
The costs incurred in performing the maintenance
actions were categorized as being either for parts, labor and
total as applied to emission related tune-up cost, maladjust-
ment and/or disablement costs, and manufacturer recommended
maintenance costs. For each of the Phase I and II groupings of
vehicles, the mean and standard deviation for all of these costs
were calculated for each model year, for each manufacturer, and
for vehicle mileage by model year groupings. These data are
presented in Tables 3.42 through 3.50. The average total main-
tenance cost of the passing Phase I vehicles is not significantly
different from that of the failing Phases I and II vehicles. The
newer Technology II vehicles cost less on the average (about $26)
to maintain than did the Technology I vehicles (about $44).
Labor represented approximately 75 percent of the total costs.
Costs for repairing maladjustments and/or disablements are small
compared to the total maintenance cost.
With respect to manufacturer, the average cost of
maintaining the foreign vehicles was less than that of the
American vehicles among the all Phase I and passing Phase I
groups. None of the differences among manufacturers was
significant for the failing Phases I and II vehicles.
33

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When the cost data are considered by vehicular
mileage, the 1972-1974 vehicles with more than SOrOOO miles
have higher average costs for the tune-up than the lower
mileage vehicles (which display an increasing trend with
mileage). Note that the cost of manufacturer recommended
maintenance influences total costs so that these comparisons
should be made on the basis of tune-up cost. Among the
1975-1976 vehicles, the general trend of increasing tune-up
costs with mileage is also present in the all Phase I and
passing Phase I groups, but the average tune-up costs
for the all failing 1975-1976 vehicles by mileage increments
are not significantly different.
Given a population of vehicles, the data from
these tables can be used to estimate the cost of an inspec-
tion/maintenance program for a given stringency factor.
Table 3.51 presents a summary of the tune-up costs for the
passed and failed Phase I vehicles as determined for different
stringency factors and the Idle (N) short test. For either
model year grouping the tune-up costs are greater for the
failed vehicles than for the passed vehicles at all strin-
gency factors. The difference between average pass and fail
costs for 1975-1976 vehicles, however, is approximately con-
stant for all stringency factors. For the 1972-1974 vehicles,
however, the difference increases as the stringency factor
decreases. For the 1972-1974 vehicles, the greatest polluters
(as determined by Idle (N) emissions) tended to require more
expensive maintenance.
An analysis was performed to determine the relation-
ship of the percent change in FTP emissions and fuel economy with
the three components of maintenance cost and the total main-
tenance cost. The results of this analysis are presented in
Table 3.52 which contains the correlation coefficients for each
34

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combination of the emissions and cost element for the two model
year groupings and the stratifications of vehicles by Phase I,
passing Phase I, and failing Phases I and II. The correlations
which are significantly non-zero at the 95 percent level of
confidence are indicated by an asterisk. The correlation of
maintenance costs with percent emission reduction is, in general,
very weak. For the failing Phases I and II vehicles and for any
group of 1975-1976 vehicles, there is virtually no correlation of
maintenance costs with percent emission reduction or percent
change in fuel economy. For the 1972-1974 vehicles of all
Phase I and passing Phase I groups, the correlation with tune-up
costs, manufacturers recommended maintenance costs, and total
costs is fairly consistently significant, although weak. There-
fore, the costs of maintenance are unrelated to percent emission
reductions of the relatively new 1975-1976 model year vehicles
and are significantly (but weakly) correlated with reductions
in the 1972-1974 model year vehicles.
3.2.7
Variability of ReElicate Short Tests
Objective: Estimate the degree of variability
when the short tests are repeated under identical conditions.
Determine if this vehicle variability is a function of absolute
level, mileage, or maintenance state.
As a part of the test sequence performed on each
of the vehicles, replicate determinations were made for each
short test. (The hot portions of the FTP were treated as a
replicate of the Hot FTP test.) These replicates were used
to estimate the variability that is present when the short
tests are repeated under identical experimental conditions.
Before estimating the variability, however, preliminary
analyses were performed to determine the appropriate measure
of the variability.
35

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To determine if the replicate variability was a function
of absolute level, the standard deviation of each pair of Hot FTP
and Idle (N) measurements was calculated and plotted as a function
of the average of the two points. A plot of the standard deviation
divided by the average versus the average was also generated. These
figures indicated that the degree of variability is not a function
of the emission level for the Hot FTP and Idle (N) short tests.
Further, the ratios of individual standard deviations to averages
tend to provide a biased measure of the variability as those ratios
are larger for the lower average emissions.
The preliminary analysis led to the use of a pooled
estimate of the standard deviation of replicate measurements.
This standard deviation was calculated by estimating the variance
of each vehicle and then pooling the estimates to obtain a single
overall value. This procedure accounts for the differences that
are present between the vehicles and depends on the assumption that
the within vehicles (replicated) standard deviation is equal for
all vehicles.
Table 3.53 presents the replicate standard deviations
and coefficients of variation for the three pollutant measure-
ments from all short tests and the two model year groupings for
the all Phase I vehicles. The coefficient of variation was cal-
culated as the ratio of the pooled standard deviation to the grand
average of both measurements from all vehicles. In the prelimi-
nary analysis, some of the replicated values from eight vehicles
were identified as outliers and these eight vehicles were not
included in further replicate analyses. To indicate the influence
of the outliers, Table 3.53 also contains the replicate standard
deviations and coefficients of variation for the 1975-1976 Phase I
vehicles with three vehicles eliminated. (No 1972-1974 Phase I
vehicles were identified as containing outliers.) The Idle (N)
short test reflects a large reduction in the variance for HC and
CO due to eliminating the three outliers but all other variances
are essentially unchanged. Therefore, the exclusion of
36

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the outlier vehicles will provide a more realistic estimation of
the replicate variation without influencing the conclusions drawn
in the analyses.
A comparison of the replicate variability for model
year groupings indicates that the 1975-1976 vehicles have greater
variability in the CO measurements than do the 1972-1974 vehicles
for all short tests. This conclusion holds in an absolute sense
as measured by the standard deviations and, since the CO emissions
are lower in the 1975-1976 vehicles, in the relative sense as
measured by the coefficients of variation. In most cases for HC,
the 1975-1976 vehicles had less variability than the 1972-1974
vehicles in the absolute value but approximately equivalent varia-
bility when expressed as a percentage of the mean. The Hot FTP and
Federal Short Cycle HC determinations were more repeatable for the
1972-1974 vehicles. The Idle (N) HC determinations were more
repeatable for the 1975-1976 vehicles in absolute measure but
approximately equal in relative variance. The replicate variability
of the NOX measurements from the two model year groupings was
approximately equal for the Hot FTP and Federal Short Cycle tests,
was less for the 1975-1976 vehicles for the Federal Three Mode, and
was greater for the 1975-1976 vehicles for the Idle tests.
Table 3.54 compares the replicate variability of the
vehicles which passed the Idle (N) short tests with those that
failed. For the HC determinations, the passing vehicles displayed
greater repeatability than the failing vehicles for the Federal
Short Cycle and Idle tests, but the results were mixed for the
Hot FTP and Federal Short Cycle tests. The replicate variability
of the CO and NOX measurements indicate that the results of
pass-fail comparison depend on the particular short test and model
year combination. The Federal Three Mode had less variation in
determinations for passing 1972-1974 model year while the 1975-1976
order was not consistent for all three modes. The Hot FTP and
Federal Short Cycle CO variability was less for failing vehicles
than for passing for both model year groupings. The Idle (N) CO
37

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determination variability was less for passing vehicles than
for failing.
To test for a possible bias between the replicate short
test determination, a Student's t statistic was calculated for
the average difference between first and replicate determination.
The observed Student t values are presented in Table 3.55. The
pollutant, model year grouping, and short test combinations which
indicated a statistically significant bias are indicated on the
table. In particular, there was a consistent bias observed for
the Idle (N) and Idle (2250) determinations of HC and CO in
which the second determination was larger than the first. No
explanation could be found for the possible biases observed in
these data.
3.3
FTP/SHORT TEST CORRELATION
A key feature in the application of an inspection and
maintenance problem is the ability to identify the vehicles which
are high emitters and which will benefit from an emissions oriented
maintenance. In recent years, all new automobiles have been sub-
jected to Federal emission standards which are expressed in terms
of FTP emissions. Since all new vehicles were designed to be
capable of meeting these standards, the FTP standards provide
natural pass-fail criteria for determining the vehicles which
should benefit from the maintenance actions. FTP emissions,
however, are time consuming and relatively expensive to measure.
Thus, the use of the FTP in a large scale inspection program
would be impractical. Several short tests are available which
could be used in a large scale program. However, their ability to
identify the high FTP emitters in high altitude areas needs to
be established.
3.3.1
Linear Regression Relationships

Objective: Assess the strength of the relationship
pre-maintenance short test emissions and the pre-
FTP emissions. Determine if this relationship is
the ability to pass the Idle (N) screening criteria.
between the
maintenance
affected by
38

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Plots of before maintenance FTP and short test emissions
are presented in Figures 3.11 through 3.31. These figures provide
an indication of the strength and functional form of a predictive
FTP/short test relationship. The FTP/short test relationship was
measured quantitatively by a regression analysis assuming a linear
model.
There are two common quantitative measures of the
strength of the relationship between variables. The correlation
coefficient, r, is a standardized index between II which summarizes
the degree of linear relationship. Values close to plus or minus
one indicate strong relationships (the sign is indicative of the
sign of the slope) and values close to zero indicate weak linear
relationships. A useful interpretation of the correlation
coefficient can be inferred from the fact that lOOr2 is the
percent reduction of the variance of the FTP emissions after
accounting for the linear relationship. A second measure is the
estimate s(e), the standard deviation of differences between the
predicted and observed values. Approximately 68 percent of the
FTP emissions would be expected to lie within one s(e) of the
predicted value and approximately 95 percent would be expected
to lie within 2s(e). As r decreases in absolute value, s(e)
increases rapidly to the standard deviation of the FTP emissions.
Tables 3.56 through 3.58 present the results of the
regression analysis for the Phase I, passing Phase I, and failing
Phases I and II vehicles, respectively- The equations of Table 3.56
are representative of the in-use population of vehicles for these
model years. The tables of passing and failing vehicles are
presented for comparative purposes.
The correlations displayed in Table 3.56 indicate a
strong relationship between FTP emissions and the Hot FTP and
the Federal Short Cycle emissions. At least 85 percent (r2) of
the variability of the FTP emissions is explained by the correla-
tion with the Hot FTP short test emissions for all pollutants and
both model year groupings. At least 71 percent (r2) of this
39

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variability is explained by the correlation with the Federal Short
Cycle emissions. The Federal Three Mode test provided as good or
better predictions of the FTP results than the Idle tests for all
pollutants and both model year groupings. The Federal Three Mode
test, however, did not equal the predictive ability of the Hot FTP
or Federal Short Cycle tests for any pollutant by model year com-
bination. The standard errors, s(e), provide a direct measure of
the uncertainty of a prediction and indicate the possible discrepan-
cies that could result from a prediction of an FTP level from a
short test measurement. The results for 1972-1974 are generally
consistent with those for 1975-1976 vehicles. The equations
reflect the differences in overall emission levels between the
groupings and generally the correlation coefficients agree.
FTP HC versus Federal Three Mode HC correlation is less for
1975-1976 vehicles and the Idle and Idle (N) CO correlations are
less for 1972-1974 vehicles.
The
In comparing the relationships for vehicles which
fail the Idle (N) short test with those that pass (Tables 3.57
and 3.58), no general conclusion results. For the Hot FTP and
Federal Short Cycle tests the correlation coefficients are
larger for the failing vehicles but the standard errors are not
necessarily smaller for the failing vehicles. This can result
due to a larger degree of variability of the FTP emissions for
the population of failing vehicles. For the Federal Three Mode,
Idle, and Idle (N) short tests there is no consistent pattern
between the passing and failing vehicles.
Table 3.59 presents a summary of regression results
obtained from an analysis of 1975 model year vehicles operating
at low altitudes, Reference 6. The strength of the FTP/short
test correlation is approximately equal for the high and low
altitudes. The resulting regression equations, however, are
significantly different with respect to slopes and intercepts.
40

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It is apparent from Figures 3.11 through 3.31 that,
except for possibly the.Hot Start FTP and Federal Short Cycle tests,
other sources of variability will have to be accounted for to
improve the predictive capability. In an effort to determine if
vehicular mileage had a significant influence on this predictive
capability, a regression analysis was performed with FTP emissions
being predicted as a function of short test emissions and mileage.
The results of this analysis are summarized in Table 3.60 in which
the partial correlation coefficients of mileage with FTP emissions
are presented, after accounting for the correlation with short
test emissions. As a group, this relationship is strongest for
CO emissions in 1975-1976 model year vehicles, but in no case did
the addition of the mileage term significantly increase the
predictive ability of the short test. For example, the largest
partial correlation coefficient is 0.25 which occurred three times.
The increases in the multiple correlation coefficient obtained by
adding the mileage term for these cases were 0.01, 0.03 and 0.03.
Increases of this magnitude would have no significant influence on
predictive capability. Therefore, a more extensive summary of
these results is unwarranted.
3.3.2
~ontingency Table Correlation
Objective: Contingency table analysis is useful if
the correlation of interest involves the ability to predict
whether an observation belongs to a specific group rather than to
predict its exact value. In FTP/short test relationships, the
ability to predict FTP passage or failure based on a knowledge of
the short test value is of most interest. The determination of
the number of errors and the percent of vehicles which are
properly identified for various stringency factors is part
contingency table approach for correlation estimation.
of the
The Federal Standards apply to FTP emissions and can
be used to divide the vehicles of a particular group (e.g. 1972-
1974 model years) into two categories, pass or fail. Similarly,
the cutpoints of a short test will divide the vehicles into
41

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categories of pass and fail. When the Federal Standards and the
short test cutpoints are applied simultaneously, the vehicles are
divided into four categories: pass short test, pass FTP; pass
short test, fail FTP; fail short test, pass FTP; fail short test,
fail FTP.
Such groupings can be visualized quite readily in
Figures 3.11 through 3.31. To demonstrate, Figures 3.32 and 3.33
again show the FTP versus Idle (N) HC and CO emissions plots, this
time the cutpoints used in this program and the 1975 FTP equiva-
lents of the 1973/1974 Federal Standard are superimposed. The
Federal Standards and short test cutpoints divide the plane into
the four regions as defined in the previous paragraph. Since
vehicles to the right of the vertical cutpoint line fail the
short test, reducing the stringency factor shifts the vertical cut-
point line to the right (i.e. fail fewer vehicles) .

If the objective is to identify those vehicles which
exceed the Federal Standards, the vehicles in the pass-pass (PP)
and fail-fail (FF) regions have been correctly identified. How-
ever, the vehicles in the other two regions have been erroneously
classified. An error of commission (EC) is defined as that of
failing a vehicle on the basis of the short test when the FTP
emissions are less than the Federal Standard. An error of
omission (EO) is defined as passing a vehicle on a short test
when the FTP emissions exceed the Federal Standard. As can easily
be realized from Figure 3.33, few errors of commission are possible
on 1972-1974 model year test vehicles since most cars of these
model years exceed the CO Federal Standard. Since errors of
commission might cause needless maintenance expenses and since
errors of omission would fail to identify the high emitters for
maintenance, an analysis was conducted to determine the frequency
of these errors for all of the short tests and five stringency
factors. This analysis is referred to as the contingency table
analysis. In addition, the percentage of the total pollution
contribution to be removed from the air by correctly identifying
high emitting vehicles at a particular cutpoints is the air
42

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quality impact at that cutpoint. The air quality impact is
investigated for various cutpoints.
Before presenting the results of the contingency table
analysis, several comments are in order concerning the method of
determining the cutpoints for specific stringency factors. Only
the set of all Phase I vehicles was used in the derivation of the
cutpoints. The Phase II vehicles were not used since they were
pre-screened and are representative only of the population of
vehicles that would fail a 40 percent stringency factor Idle (N)
short test. The same procedure was used to determine cutpoints
for each of the short tests so no distinction among short tests
is necessary in describing the methodology.
Cutpoints were determined to obtain stringency factors
of 10, 20, 30, 40, and 50 percent for each emittant considered
individually and for the emittants considered collectively.
When the emittants are considered individually, the cutpoints were
simply determined by ordering or ranking the values from a short
test and recording the values which correspond to 10 percent
exceeding that value, 20 percent exceeding that value, etc. That
is, the cutpoints are merely the non-parametric sample estimates
of the percentiles of the observed distribution of emissions.
The cutpoints for the individual emittants, the short tests and
the model year groupings are presented in Table 3.61.
A more complex procedure was required to derive cut-
points which will fail a given percentage of the total population
based on a combination of emittants. This procedure was described
in detail in Section 3.2.5 and summarized in Table 3.30.
The above procedures for determining cutpoints will
fail the prescribed percentage of vehicles on the short test. The
contingency table for each stringency factor will provide esti-
mates of the percentage of vehicles in the four combinations of
passing or failing the short test and FTP standards. To measure
the potential impact on pollutant levels by performing maintenance
43

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on those vehicles which fail the short test, a measure of the
aggregate emission behavior of the vehicles in each category of
the contingency table is required. An impact measure as described
in Reference 6 was calculated for each stringency factor of the
Idle (N) and Federal Short Cycle Tests for the two model year
groupings. This impact measure is computed by the following
steps:
(1) Each emission is divided by its Federal Standard
to provide a dimensionless emission level. Use of dimensionless
emissions allows aggregation of different emissions.
(2) Each dimensionless emission is reduced by 1.0.
This provides a measure of the excess over the standard.
(3) All negative values are set equal to zero. This
recognizes that all cars which meet the federal standards (i.e.
have negative scores) have legal emissions and are assigned
equal impact.
(4) Within a pass-fail category, the total impact
score is obtained by summing the scores of all vehicles within
the category.
(5) For the vehicles which failed the short test at
each stringency factor, the impact is defined as the ratio of the
summation in the FF category to the total of the FF and EO
categories. (Since no 1972-1974 vehicles and only eight 1975-
1976 vehicles passed the Federal Standards, the impact measures
for the PP and EC categories were not calculated.)
This definition of the impact for a short test-stringency factor
combination essentially measures the emissions from vehicles which
fail the short test as a proportion of the total emissions from
all vehicles which exceed the Federal standards. The actual
reduction in emissions also depends on the efficacy of the main-
tenance actions in reducing the emission levels.
44

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Tables 3.62 and 3.63 present the errors of omission
and commission that would be made in the use of the Idle (N) test
at various stringency factors for the 1972-1974 and 1975-1976 model
years, respectively. Due to the extent of the high HC and CO FTP
emissions in the Denver area, errors of commission for these
emittants are extremely rare with respect to HC and did not occur
for co. Since all vehicles exceeded the Federal CO standards,
the cutpoints merely separate these vehicles into two categories
for the 1972-1974 model year vehicles: fail short test and FTP
and errors of omission. The same separation also occurs on the
combined emittants table since the co value always exceeds the
standard. For these model years, approximately the same phenomena
occurs for HC emissions since the vehicles are separated into three
categories and the pass-pass category contains only six vehicles
(7.3 percent).
Similar results were obtained for the 1975-1976 model
year vehicles, but the errors of omission are reduced somewhat
due to the fact that more of the 1975-1976 vehicles passed the
Federal Standards. At the 50 percent stringency rate for the
combined emittants discrimination, errors of omission occurred
in 41 percent of the vehicles.
The errors of commission are hiah and errors of
omission are low when the cutpoints are determined on the basis
of NOX only. This merely reflects the fact that FTP NOX emissions
in Denver are generally low as compared to the Federal Standard.
These tables indicate that in the Denver area, errors
of commission will be at an acceptable level for HC, CO, and all
pollutants combined regardless of the desired stringency factor.
Further, it would appear that the stringency factor would be
approximately equal to the compliment of the percentage errors of
omission for HC, CO, and all pollutants combined.
The impact measure as defined above was calculated for
the Idle (N) and Federal Short Cycle for stringency factors of
45

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10, 20, 30, 40, and 50 percent. The resultins values are presented
in Tables 3.64 and 3.65. As the stringency factor increases, the
proportion of detected aggresate emissions exceeding Federal Stand-
ards also increases as was expected. The change in the impact
measure was greater, however, for a change in stringency from 10
to 30 percent than for a change from 30 to 50 percent. The Federal
Short Cycle test had higher impact measure than the Idle (N) test
and the 1975-1976 vehicles had higher impact measures than the
1972-1974 vehicles.
3.3.3 Ability of the Short Test to Identify the Highest FTP
Emitters
Objective: Demonstrate that the emissions from the
failed vehicles of the population were significantly larger than
those of the passed vehicles.
If it is assumed that for cost or public reactions,
an I/M program will force maintenance on some fraction of the
entire population, a question of interest is whether the failed
fraction of the population has significantly higher emissions
than the passed fraction. To address this question, means and
standard deviations of the emissions at each stringency factor
were calculated for the four categories of FTP and Short Test
pass/fail. The results for the Idle (N) test are summarized in
Tables 3.66 through 3.71 and for the Federal Short Cycle test
are summarized in Tables 3.72 through 3.77 for each model year
grouping and for failure rates based on the combined pollutants.

The average HC and CO emissions are significantly
greater for the vehicles that failed the short test than for
the vehicles that passed for all stringency factors, for both
model year groupings, and for both short tests. The average NOX
emissions are equivalent for the failed and passed vehicles as
determined by the Idle (N) test but the passed vehicles of the
Federal Short Cycle test have larger average NOX emissions than
do the failed vehicles.
46

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To present similar data for the cold portions of the
FTP tests, Tables 3.78 through 3.83 present averages and standard
deviations of the cold transient emissions for each stringency
factor as determined by the Idle (N) short test and the four
categories of pass-fail. Tables 3.84 through 3.89 present
analogous data for the cold stabilized emissions. For the average
cold transient emissions, the distinction between passing and fail-
ing average HC and CO of the 1972-1974 vehicles was not significant
at the high stringency factors. The difference was significant for
the 1975-1976 vehicles at all stringency factors. The NOX average
cold transient emissions were also not significantly different for
the two populations of vehicles. For the cold stabilized emissions,
average HC and CO were significantly larger for the failed vehicles
for all stringency factors and both model year groupings. NOX
averages, however, tended to be larger for the passing vehicles
than for the failing.
The previous analyses demonstrate that the vehicles
which fail the short tests have higher FTP, cold transient, and
cold stabilized HC and CO emissions than those which pass the short
test. It is also of interest to compare the average emissions at
each stringency factor of vehicles which fail the short tests with
the average emissions from corresponding stringency factor defined
in terms of the FTP, cold transient, and cold stabilized emissions.
That is, the worst x percent emitting vehicles were identified by
using the combined pollutant method on the FTP emissions and the
averages and standard deviations of each pollutant were calculated
for these vehicles. The process was repeated using the cold
transient and cold stabilized emissions to define the worst pollu-
ting vehicles. Table 3.90 presents the resulting averages and
standard deviations for each pollutant and model year for stringency
factors of 10, 20, 30, 40, and 50 percent. These averages repre-
sent the FTP emissions of the worst polluters (as determined on
the FTP) and their comparison with Tables 3.66 through 3.89 pro-
vide an indication of whether or not the highest emitters are
being detected.
47

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The HC and CO ave~ages at each stringency factor
of the Federal Short Cycle test compares favorably with that of
the worst emitters. For stringency factors of 30 percent or more,
the Federal Short Cycle average is 90 percent or more of the worst
emitters' average. For the Idle (N) test, the HC and CO averages
tend to be less than the corresponding averages using the Federal
Short Cycle as the discriminating short test, and, hence, there is
more difference between the worst emitters and those identified by
the Idle (N) short test at the stringency factors. For stringency
factors of 30 percent or more, the Idle (N) averages are at least
80% of the worst emitters' average for the FTP and cold stabilized
emissions. The agreement for the cold transient emissions is not
as good, particularly for the 1972-1974 model year vehicles. The
NOX averages display the typical high altitude trends. The worst
emitters (as determined previously by HC and CO) have lower NOX
average emissions than the averages as determined for the
corresponding Federal Short Cycle stringency factors. The
Federal Short Cycle NOX averages, in turn, are less than those of
the Idle (N) NOX averages.
3.4 RELATIONSHIPS BETWEEN EMISSIONS/ENGINE CONDITION/USAGE
In addition to the basic data on the emissions and costs of
maintenance actions, data was also collected which defines the
state of each vehicle before and after maintenance actions. The
analyses of these data are presented in the following paragraphs.
3.4.1
Causes for High FTP Emissions
Objective: Determine the causes for high FTP emissions
to provide proper mechanic training inputs, and determine
whether future technology vehicles will be more resistant to areas
that have caused previous problems.
In an effort to determine the probable causes of high
FTP emissions, the diagnostic tests similar to those defined by
the Clayton Manufacturing Company were applied to the vehicles
48

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which failed the Federal Standards. These Clayton diagnostics are
expressed in terms of failures of specific modes of the Clayton
Key Mode Test. Although this test was not performed on most of
the Denver IIM vehicles, the diagnostic criteria were applied to
the emissions from the Federal Three Mode test. Both the Federal
Three Mode and the Clayton Key Mode are loaded steady state tests.
The diagnostics and the identification of the causes are presented
in Tables 3.91 and 3.92 for HC and CO, respectively.
As can be seen from Table 3.91, the use of the
diagnostics requires a determination of "abnormally high" HC and
CO emissions in all three modes of the Federal Three Mode test.
In the following analysis, "abnormally high" is
90th percentile of the respective pollutant for
which passed the 1975 Federal Standard for that
defined as the
only those vehicles
pollutant.
The results of this analysis categorizes the vehicles
into probable causes of high emissions and are presented in
Tables 3.93 and 3.94 for the 1972-1974 vehicles, and in Tables
3.95 and 3.96 for the 1975-1976 vehicles. With respect to vehicles
failing the HC standard, approximately 50 percent also had abnormally
high He emissions in the modes associated with the type 2 causes
(failure of an ignition system component). This was true for the
vehicles of both model year groupings. Approximately 50 percent
of the vehicles failing the Federal CO standard also had abnormally
high CO emissions in the modes associated with type 3' causes and
approximately 30 percent had abnormally high CO emissions in the
modes associated with type l' causes. Since gross error in the
carburetor idle air fuel mixture adjustment is associated with both
of these type causes, it is concluded that this is the probable
cause of the high CO emissions.
3.4.2
Maladjusted Vehicle Systems
Objective:
emission performance to
vehicle systems.
Investigate the causes of poor field
provide input for the design of improved
49

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A common phenomenon in the high altitude regions is
for vehicles to have engine systems adjusted differently from
manufacturers' specifications or to be totally disabled. Infor-
mation was recorded on the maladjustment or disablement of
certain engine systems on the vehicles of this study. Table
3.97 presents the percentages of vehicles which had maladjusted
and/or disabled systems for all Phase I vehicles, passing
Phase I vehicles, and failing vehicles of Phases I and II.
Approximately 50 percent of the Phase I vehicles had the
limiter caps and/or the timing out of adjustment, and 70 per-
cent had at least one of the components or systems maladjusted
and/or disabled. Since individual vehicles may have had more
than one component or system maladjusted and/or disabled, the
categories are not mutually exclusive. The failing vehicles
of Phases I and II had a significantly higher percentage of
vehicles with maladjusted/disabled limiter caps and timing
than did the passing Phase I vehicles.
The number of vehicles with maladjustments and
disablements of the limiter caps and timing was large enough to
permit comparisons between manufacturers and between increments
of vehicle mileage. Table 3.98 presents the percentage of
vehicles of each manufacturer that had maladjusted and/or dis-
abled emission-related system/components. The differences in
these percentages between the vehicles of different makes are
not significant. The sample sizes for some comparisons,
however, are too small for definite conclusions.
The percentage of vehicles with maladjusted or
disabled limiter caps and/or timing are presented by vehicular
mileage increment for the model year groupings due to the
large discrepancy in mileages between these populations. This
added, but necessary, stratification reduced sample sizes even
further. The percentages are presented in Tables 3.99 and
3.100. No distinct mileage trends were detected in either of
the model year groupings.
50

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3.4.3
Relationships Between ,Malad~ustme~ts and Em~ssions

Objective: Determine if the maladjustments can be
related to emission levels and fuel economy to provide informa-
tion for public and mechanic training and to assess the possible
use of a diagnostic emissions inspection.
To compare the emissions of vehicles with disable-
ments and/or maladjustments of limiter caps, timing, and at least
one system in a vehicle to those without, the average and standard
deviations of the emissions and fuel economy of these two groups
were calculated for the Phase I vehicles. The data were strati~ied
by manufacturer and also by vehicular mileage for each model year
grouping. These data are presented in Tables 3.101 through 3.106.
Many comparisons can be made using these tables, but the with
versus the without maladjustments and disablements comparison for
manufacturers is summarized in Table 3.107 and for mileage incre-
ments and model year groupings in Table 3.108. These tables pre-
sent values of the Student t statistic for the test of significance
of the equality of two means. Those comparisons which indicate
a significant difference at a 95 percent level of confidence have
been indicated with an asterisk. Positive values indicate the
average with maladjustments and disablements is greater than the
average without. Most of the comparisons resulted in the con-
clusion that the differences were not statistically significant.
For the sample of all vehicles, fuel economy was significantly
higher for vehicles with timing maladjusted and significantly
lower for those with limiter caps maladjusted and/or disabled.
The average CO emissions were significantly larger for vehicles
with maladjustments and/or disablements in at least one compon-
ent/system and for vehicles with disabled limiter caps.
An attempt was made to use discriminant analysis to
determine whether the various types of maladjustments and disable-
ments were correlated with high FTP emissions where high FTP
emissions were defined as those greater than the Federal Standards.
This analysis was not conducted beyond the initial stages for two
51

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reasons. First the number of vehicles which had FTP HC and CO
emissions below Federal Standards was far too small for meaningful
analysis. The categorical type variables on which discrimination
depended would have required much larger sample sizes than those
available. Secondly, comparatively few of the vehicles had mal-
adjustments and/or disablements of systems other than the limiter
caps and timing. Any discrimination would have to come from these
systems and a preliminary analysis showed that percentages of
vehicles with and without,maladjustments and disablements were
approximately equal for vehicles with emissions above and below
the Federal Standards. Therefore, this type of multivariate
analysis was not pursued further.
3.4.4
Relationship Between Maladjustments and Owner
Practices
Objective: To assess the possible
education program, determine if maladjustments
related to owner practices.
efficacy of a public
or disablements are
As part of the data collection procedure each owner
was required to complete a questionnaire regarding use, mainten-
ance, and engine characteristics of the vehicle. The percentage
of vehicles with maladjustments and/or disablements of the limiter
caps, timing, or at least one system was calculated for each
response. The questions related to engine performance for which
enough diversity of answers were given to provide comparisons are
summarized in Table 3.109 for all failing Phase II vehicles and
in Tables 3.110 and 3.111 for the 1972-1974 and 1975-1976 model
years, respectively. Note also that all answers to a question
are not necessarily included. This questionnaire was only com-
pleted by the Phase II vehicle owners so the vehicles represented
by these questionnaire responses have failed the Idle (N) short
test. None of the comparisons of percentages for different
responses are noteworthy. In fact, there is a high degree of
consistency across all of the questions.
52

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3.4.5
Engine Parameter Settin~s

Objective: Determine if the extent of maladjustments
of the engine parameter settings of timing, idle RPM, and idle CO
displays significant trends with respect to manufacturer, CID,
or mileage.
The engine parameters of timing, idle RPM, and idle
CO measured before maintenance were compared to fixed levels to
determine the number of vehicles which were within the specifica-
tion tolerances. If timing and idle RPM were within f2 degrees
and f150 RPM, respectively, of manufacturers' recommended settings,
the parameter was defined as within specification tolerances. Idle
CO was defined as within tolerances if the tailpipe idle CO measure-
ment was less than 0.5 percent.
The percentage of 1975-1976 vehicles with the pre-
maintenance timing, idle RPM, and idle CO outside tolerances were
calculated for each manufacturer, for each of five vehicular mileage
increments and for each of three classes of engine displacement.
These percentages are presented in Tables 3.112, 3.113, and 3.114
for each of the three samples of vehicles. Among the all Phase I
and passing Phase I vehicles, fewer General Motors vehicles were
outside specification tolerances than the other manufacturers.
Among the failing Phases I and II vehicles, however, the General
Motors vehicles have approximately the same percentages outside
tolerances as do the other manufacturers.
The outside tolerance percentages are presented in
Table 3.113 for vehicles in vehicular mileage increments. The
only distinct trend among the mileage categories is the decreas-
ing percentage outside of tolerances for the Idle RPM parameter.
However, due to the small number of vehicles which do not meet
the tolerances for this parameter and the relatively small number
of vehicles in each mileage increment, this trend can only be
considered tentative.
53

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The percentage of vehicles outside engine parameter
tolerances by engine displacement groups are presented in
Tables 3.114. Again, the results are inconclusive.
3.4.6
Relati"onship o"f "Engine Parameter Se"ttin"gs with
Emissions
Objective: For use in estimating repair benefits,
investigate the relationships between emissions and average
engine parametric settings.
Tables 3.115 through 3.120 present the averages and
standard deviations of FTP emissions and fuel economy for 1975-
1976 vehicles within specification tolerances and outside of
specification tolerances for each manufacturer, a composite for
all vehicles and for all three populations. In general, tests
for the difference of means for the individual manufacturers would
not be meaningful due to small sample sizes. Student's t values
for testing significance for all pairs in which there were ten or
more vehicles in both averages are presented in Table 3.121. An
asterisk indicates a significant difference at the 95% level of
confidence. For the all Phase I vehicles, the average He and CO
emissions were significantly larger for vehicles outside the
timing and idle RPM tolerances and also for vehicles outside the
idle CO tolerances. When only those vehicles which passed in
Phase I are considered, the differences in the averages for these
are not significant for the vehicles within and outside timing and
idle RPM tolerances, but are for the idle CO. Similarly, for all
failing vehicles, the differences in the average emissions are not
significant for the vehicles within and outside timing and idle
RPM tolerances. Insufficient vehicles within tolerance prohibit
the significance test for the idle CO tolerance averages.
The correlation between percent change in emissions
and fuel economy before and after maintenance with the changes in
adjustments of timing, RPM, and idle CO was determined by means of
a stepwise regression. Tables 3.122 and 3.123 summarize the
54

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results of this analysis for all the Phase I vehicles. First, in
Table 3.122, the simple correlations of change in parameter
setting with percent change in emissions is presented for the FTP,
short tests and fuel economy. The stepwise regression analyses
selected significant engine parameters for predicting the percent
change in emissions. The multiple correlation coefficients for
these equations and the identification of the engine parameters
and the order of their importance are presented in Table 3.123.
None of the correlations have a good predictive capability and
changes in all three engine parameters are significantly related
to at least one of the FTP pollutants. The correlations with
the percent changes in the Idle (2250) short test emissions are
particularly weak.
55

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Preliminary Compliance/
Safety/Exhaust System
Inspection
193*
Accepted
Vehicles
Rejected Vehicle
As Received
Fuel Lead (Pb) Analysis
& Pre-test Operations
Evaluation Test
Sequence #1
Documentation of
En~!ne Status,
Dia~~~~ce,#~nd
D~sa tion
isabP~~~ehRa~\~ab„Dn,
Re~~geaep8r~@g~C
D,M lft~~~abtes~n9~q
t:fu'i M~1;,.Om~epion
Disablement
stora t '
, erlodic
~~a1u~emanc@e~hd
seqy~eoj~ented
Tu
Eva~fter es
s~tl8l=~@Uriest
.~.
* ~D;;~~ ndt-. ciJn.alude one
thiS report due to qu
ehicle eliminated from t
tionable e '
After-Test
* Does Procedures
this not include one veh; 1
report due to questi~n:b~;i:~~:t~d from the anal si

Figure 3.1. phase I Flow Diagram Bl96&nver Inspectfon'
Maintenance Evaluation Task Vehicles.
of
Figure 3.1.
56
Phase I Flow D'
M ' lagram of D
alntenance Evaluat' enver Inspection/
lon Task Vehicles-

-------
Preliminary Compliance/     470    
 .....  Accepted  
Safety/Exhaust System  '   
Inspection    Vehicles  
        ,   
Rejected      Inspection Test
Vehicle        t  
   ,If      
 Passed Vehicles   Failed Vehicles
 65 Percent   35 Percent 
        ,   
      As Received 
     Fuel Lead (Pb) Analysis
     & Pre-test Operations
        , '  
      Evaluation Test
      Sequence #1
        , I  
      Documentation of
   ,   Engine Status,
 Documentation of   Diagnostics, and
 Engine Status  Disablement Inspection
 & As Rec'd Fuel        
 Lead Analysis     ,~  
     Disablement Restoration,
      Required periodic
      Maintenance and
      Emissions-Oriented
       Tune-Up  
         ~  
      Evaluation Test
      Sequence #2
,~        ~  
Return Vehicle ~   After-Test
to Owner    Procedures
Figure 3.2.
Phase II Flow Diagram of 470 Vehicles Used in
the Denver Inspection/Maintenance Evaluation
Task.
57

-------
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LEGEND

1 = 1972-1974 vehicles
2 = 1975-1976 vehicles
/
/
12
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,~ I I I
, ~ II I 'i
I, I e \Ia ,I I II'
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BEFORE MRINTENRNCE FTP CO
200.00
(GM/M IJ
~
280.00
320.00
Before Maintenance FTP CO versus After Maintenance
FTP CO.
59

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1 = 1972-1974
2 = 1975-1976
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I
0.80 1.60 2.~0 3.20
BEFORE M~INTENRNCE FTP NOX
1.\10
Figure 3.5.
11.00
lGM/MIJ
11.80
S.SO-
Before Maintenance FTP NOX versus After Maintenance
FTP NOX.
60

-------
 Q   LEGEND          
 Q 1  1972-1974 vehicles        
 .,; =        
 ... 2  1975-1976 vehicles        /
  =       
 Q              
 Q              
 cD              
 N              
<.:J               
Q..Q              
~Q              
 ;.              
~N              
~               
C               
Z               
CO              
w~              
(.&JQ         a I    
 N        2 ')Y 12    
-J         I 1zZ' 2    
(.&J            
~        2  II 2    
       2    
u..0        12 l    
 0           
Q..~        l      
,....-        II      
u..         22      
(.&J               
Wo    l          
zo              
a:";              
z-              
(.&J               
,....               
z               
a:Q              
~~              
 III              
a:               
(.&J               
,....               
u..               
a:o              
 0              
 .;              
 Q              
 0              
   '1.00 8.00 l2.00 l6.00  20.00 2'1.00 28.00 32.00
    BEFORE MAINTENf:lNCE FTP FUEL ECONOMY IHPGJ  
Figure 3.6.
Before Maintenance Fuel Economy versus After
Maintenance Fuel Economy.
61

-------
0'1
IV
"
GI
....
U
...
.c
~ 30
ow
o
..
"

120
z
50
40
10
-125 -100 -75
Figure 3.7.
50
1972-1974 model year
40
.
"
....
u
...
.c
"
>
ow 30
o
..
"
1
z
20
10
-50 -25 0 25 50
Percent Reduction
-50
-25 0 25 50
Percent Reduction
75
-125 -100 -75
100
1975-1976 model year
75
100
Percent Reduction in 1975 FTP HC Emissions due to Maintenance -
All Phase I

-------
CJ\
W
II
GI
....
o
...
-;30
:>
....
o
~
GI
120
z
50
40
10
-125 -100 -75
Figure 3.8.
50
40
1972-1974 model year
II
GI
....
o
...
.c
II
:>
... 30
a
~
II
1

z
1975-1976 model year
20
10
-50 -25 0 25 50
Percent Reduction
5
100
-125 -100 -75
-50
-25 0 25 50
Percent Reduction
75
100
Percent Reduction in 1975 FTP CO Emissions due to Maintenance -
All Phase I

-------
    50
  50  
    1975-1976 model year
  40  40
 '"  '" 
 II  .. 
0'\ ..... 1972-1974 model year ..... 
u u 
~ .04  ... 
 .c  .c 
 III  . 
 > 30 > 30
 ow  ow 
 0  0 
 ...  ... 
 CI/  .. 
 1  1 
 :z:  :z: 20
  20
10
-100 -75
Figure 3.9.
10
-50 -25 0 25 50
Percent Reduction
75
100
125
-125 -100 -75
-50 -25 0 25
Percent Reduction
Percent Reduction in 1975 FTP NOX Emissions Due to Maintenance -
All Phase I

-------
  50  50
    1975-1976 model year
  40 1972-1974 model year 40
0'1 III  . 
U1 II  II 
 ....  .... 
 0  0 
 ...  ... 
 'i 30 'i 30
 >  > 
 ....  .... 
 0  0 
 ...  ... 
 CII  . 
 ~ 20 ~ 20
 z  z 
10
10
,-----.,
-125 -100 -75
-50
-25 0 25 50
Percent Reduction
75
100
-125 -100 -75
-50
-25 25 50
Percent Reduction
75
100
Figure 3.10.
Percent Reduction in Fuel Economy due to Maintenance -
All Phase I

-------
o
o
.
o
N
LEGEND
1 = 1972-1974
2 = 1975-1976
model yea!!
model year
o
o
ID
-
o
o
.
CD
-
o
o
.
="
-
o
o
N
-
,
..-1
S 0
-"""0
S .
~ ~
u
:r:
Il< 0
E-4 ~
r... ID
I
I
o
o
II
1111
11
,11"ltl
, 11 I"', 1
, I I ,.
11 ,1. ~ II
Il'til I

, , 21.tl"
at ~.'2
'!Jl12
~22

N ~]~, 2
.'1'
o zc-.
o
I 1
2
I
o
o
.
CD
o
o
="
.
9J ...aO
2 ...aO
~.oo 6.00 8.00
Hot Start HC (gm/mi)
10.00
12.00
111.00
Figure 3.11. 1975 FTP HC versus Hot Start HC -- Before
Maintenance, All Phase I Vehicles.
66

-------
- 0
..-1 0
e Q
" \/'I.
e -
0'1
o cg
u .
o
~ ~
E-t
rz.:
o
o

o
0,
(0\'
o
o
o
,...
N
o
o
o
,..
N
o
o
o
-.
N
o
o

o
Ga.
o
o
O.
aJ
l
1
Iii
l ~ 1
l \ 1 I
1 1,1 1
Ilfr l
2 2 f If~2} 11
2 2 211 1- 2
221t~1 I

~2 2
2 "
2 . it 12 2
1 -ll2
2 2{ '''222
~~ 2
2 2j2
21 2 2
52
o
o
o
Ia
o
o
.
o
(0\
o
o
.
0.00
30.00
80.00 90.00 120.00
Hot Start CO (gm/mi)
2 1 0 ..6tI
1
2 1121
Lz 2 1 1

2 1
2
2
LEGEND
1 = 1972-1974 model year
2 = 1975-1976 model year
2
2
1
1
1
1
2
2
150.00
180.00
Figure 3.12.
1975 FTP CO versus Hot Start CO -- Before
Maintenance, All Phase I Vehicles.
67

-------
 o 
 aI 
 . 
 ~ 
 1 1
 o 
 N 
 . 
 ~ 
.r-!  
e  
-"""0 
e U1 
tJ'I. 
_crI 
X  
0  
Z 0 
~ GO 
E-4 N 
r...  
 0 
 - 
 . 
 N 
o
o
.
,...
o
crI
\D
o
\D
.
U1
o
~
.
-
o
,...

o
L~GEND
1 = 1972-1974 model year
2 = 1975-1976 model year
2
2
1 1
11
Z
2
2
~ ~
1
2 1 11'
1 ~
11 I 'l Z
1
,
'2 ~2
2 ~2
i\2t Z
Zl~, 2
a2 iJ; I
u J". z
z Z;tlZI
~
."
Z
o
o
.
91.00
3.00
1f.00
5.00
&.oa
7.00
L.OO
l.oa
Hot Start
NOX (gm/mi)
Figure 3.13.
1975 FTP NOX versus Hot Start NOX - Before
Maintenance, All Phase I Vehicles.
68

-------
o
o
.
o
N
o
o
CD
LEGEND

1 = 1972-1974 model
2 = 1975-1976 model
year
year
o
o
.
CD
-
o
o
~
o
o
.
N
2
....
eo
,-0
eo
0'1-
-
U
:I::
o
~o
E-4 .
~CD
o
o
U)
f
12
I
I
I
I II II
I I
~n 1 I
I I
2 lal~1 I~ I
2 I 12 I' I ' I
12 'J, I r
"if tIll 2 1
I 2~ h
2 1 2 '2. I 2
o 2 2~1
o 2 2 2
. 2 2
N ~A~'2
il~1Ji
o ~2 2

o
2
o
o
.
~
.
9:1. 00
2.00
11.00
6 ...eo
8.00
10.00
12.00
111.00
Federal Short Cycle HC (gm/mi)
Figure 3.14.
1975 FTP HC versus Federal Short Cycle HC -
Before Maintenance, All Phase I Vehicles.
69

-------
o
- 0
.~ 0
e '"
.......... -
e
t7'
- 0
o
o .
(J ~
Il<
E-4
rz..
o
o

o
o
<"
LEGEND
1 = 1972-1974 model
2 = 1975-1976 mod~l
year
year
o
o
o
l"-
N
o
o

o
:r
N
o
o
o
-
N
o
o
o
CD
,
1
,
,
21111 ,
1 1 1 1 1
I "
" ~ 1
1..1 1
lif 1
\ I' I
, ,,1 1
~ 2 2,1 .f'al\ z' ' ,
:; ,~ I-~:J

, :' ~;. , l 1
o , ;V.f~
~ ~~z.~,,' ,
<" , ~l
o
o
,
.
o
en
1 1
l
l
2
o
o
91.00
80.00 120.00 160.00 200.00
Federal Short Cycle CO (gm/mi)
21&0.00
110.00
280.00
Figure 3.15.
1975 FTP CO versus Federal Short Cycle CO -
Before Maintenance, All Phase I Vehicles.
70

-------
...-1
s~
......... .
s...,
C1
x
00
Z~
N
~
8
~
o
o
.
,....
LEGEND

1 = 1972-1974 model
2 = 1975-1976 model
o
...,
.

-------
o
o
.
o
C\I
o
o
.
CD
-
LEGEND
1 = 1972-1974 model
2 = 1975-1976 model
year
year
o
o
.
UI
-
o
o
.
~
-
o
o
C\I
-
I
o
- 0
...-. .
e: ~
.........
&
u g
::I: .
CD
~
~
rz..
I I
I
I
I
I
I
,
o
o

C£I
I I
o
o
~
I, I I I I
I I
'1 'II d I
I II I
, tl I I I I
I I I I I II I
I I f , "1
I I , 1 . I'
, 'I Lit I , II I I
, I ,I ~. I'
o I :I I I'
o , II' " IU .' "
N ,22 " I'
P'I I " ,
I ~ 2 21,'
",, '
u,ij, ,
o zI"
o
,
I
z2
I
.
9J.OO
70.00 I~O.OO 210.00 280.00 350.00 ~20.00
Federal Three Mode (50 mph) HC (ppm)
1190.00
Figure 3.17.
1975 FTP HC versus Federal Three node (50 mph) HC -
Before Maintenance, All Phase I Vehicles.
72

-------
 o                      
 0                      
 0                LEGEND   
 0                  
 C'I'I                      
               1 = 1972-1974 model year 
               2 = 1975-1976 model year 
 0                    
 0                      
 .                      
 0                      
 ,....                      
 N                      
 0                      
 0                      
 0                      
 :2"                      
 N                      
 0                      
 0                      
 .                      
 0                      
 N                      
 0                      
 0                      
 .                      
 0                      
 CD                      
.,-i 0                  l   
S 0                      
" .                      
0                      
S II)                      
tJI -                      
0       2               
CJ 0                      
0                      
~ 0   II     2             
8 N         1             
-          1            
~                      
             1          
     2 1  1 1    2           
  Z                  
 0  1 I 211    1            
 0      2   2 Z 2         
 0  1 . 2                 
 OJ   1 2   1   Z           
    1 1 1                
    a 11 1 1 1                
  1 1 1                
   2 1 1 1 1  2                
 0 1 2 I 2 It                 
 0    , 2 1 r  2       
 . 1 1 1 I 11 2  2 2            
 0 l 2f ~ 2  2     22          
 ID   I             
   I 1         2         
  11~1222~2Z        I         
 0 ~ 2; II 2 2 z2              
 0 2 2 Ii 2 2~ 1 2 2 2              
 0     Z            
 C'I'I \'2 2az 2 2                 
  2  ,~ ~       2   2       
 0   2                   
 0                      
 .                      
 91.00   2.00   4.00   6.00 8.00 10.00 12.00 14.00
       Federal Three Mode (50 mph) CO (%) 
Figure 3.18.
1975 FTP CO versus Federal Three Mode (50 mph) CO -
Before Maintenance, All Phase I Vehicles.
73

-------
CI
CI
,...
.f"i
S CI
.......... 111
S .
t1' (PI
x
o CI
Z «)
~ N
E-1
rz..
CI
(PI
'"
CI
'"
111
CI
CJI
.
~
CI
N
~
LEGEND
1 = 1972-1974 model
2 = 1975-1976 model
2 1
2 1
1
2
1 2
CI
-
2
1
2 ~ 2 11
\ ~ 2i 2 2 2
I\.~ 22 2 12
2 ~ 1 a
12,"':1112 2 "'12211
1 1 2 1, r2 2 2
~alt 2 1
,1 12 2 1
2. \121
2 'z 11 12 '2 2
.211,\ 22 2 \
2 2 1
2 2 Z 22
1
2 , 2
2
year
year
2
2
1
1
1
2
2
1
1
2
.
N
2
CI
~
- /1
CI
,...
o 1
2
 2 .
2  
 22 
2,  
2 
CI
CI
.
91. DD
6 no 1 2 0 0 1 ~ 00 2 II 00 ) n I . () "H.I) ()
Federal Three Mode (50 mph) NOX (ppm)
'.:! on
Figure 3.19.
1975 FTP NOX versus Federal Three Mode (50 mph)
NOX - Before Maintenance, All Phase I Vehicles.
74

-------
o
o
.
o
N
LEGEND

1 = 1972-1974 model
2 = 1975-1976 model
year
year
o
o
II)
-
o
o
.
CD
o
o
.
2"
o
o
.
N
2
o
o
- .
-.-I 0
= -
.........
=
0'1
o
t> ~
:I:: II)
~
8
~
II
2
o
o
CD
I
I I I I I

2 I I I
I 'I II I I
2 I 1211 1\ I
11111211'2
"I 'I
2... 2~ 112 I
12 1I I 2 I II I 2 1
2 2 tR2 2 22 1
2 2 2 l 21 I
2 212 a 2 12
o 2 '2 ~ 2
~ 2:: 2 L2z f
a& 22 2 ~ 2
W2~
o j2h
o
2
o
o
2"
2
2
2
2
2
2
.
CU . 00
1 n n ~ () 0 ) 0 0 q 0 n :. /1 0 (, () f)
Federal Three Mode (30 mph) HC (?pm)
7nn
Figure 3.20.
1975 FTP HC versus Federal Three Mode (30 mph) HC -
Before Maintenance, All Phase I Vehicles.
75

-------
a              
a              
.           LEGEND  
a            
a              
(11     1  =  1972-1974 model year
     2  = 1975-1976 model year
a              
a              
.              
a              
,..              
N              
a              
a              
 .             
a             
~             
N             
a             
0             
a             
N             
a             
0             
a             
CD             
-             
..... a             I
eo             
......... .             
&~             
0     I        
UO             
 a     ,I       
ilia           
E-tN     I        
rz..-   I         
          I    
  I     I'  .   
 a   II  I    I I  
 a  , I'     I ,   ' 
 a  . I    I     
 en           
  II  I I    I    
   III I I II    
 a I i. ~I, ~ I     Iz  
 a ~ ~' IU"  I I   I
  I I, ,  "  
 a & , I GIz'I    ,   
 cD     ,   
   , I     I      
  Iz h&II~1    Z    
   I-     
 a I & II ,"         "  
  I       ,   
 0 Ii. I ~ Ii,   I     
 a   "      
 (11 IZZ.} ,        
  I? '    z ,     
   ,         
a
a
z
9J . 00
2.00 ~.OO 6.00 8.00 10.00
Federal Three Mode (30 mph) CO (%)
12.00
111.00
Figure 3.21.
I
1975 FTP CO versus Federal Three Mode (30 mph) CO -
Before Maintenance, All Phase I Vehicles.
76

-------
 o 
 C\I 
 . 
 ~ 2
OM  
e:  
"  
e: 0 
tJ'I U1 
- CI'I 
:><:  
0  
z  
~ 0 
III 
E-i C\I 
~ 
o
o
.
,...
LEGEND
1 = 1972-1974
2 = 1975-1976
o
CI'I
model year
model year
.
CD
2
o
CD
U1
2
o
aI
~
2
2
12 L
1
I
~
1
2
2 L 2

2 ~ Z I 11
2 ~ 122 2 2.. 2 2
2 2""i! 2 2 1
2 2f 2 ~
2 I 2 2
22 1
222 i12 i2L22 I,
~ 2 '-2 L I 1 1 22 1
.,-, 1 2 2 1
21 2 2 1 L 1
21 ~2 tL
: tli~

2 ~'I 1
~ 2 222 2
. 2 21 11
o Ir2
a
2
2
o
2
.
C\I
2
22
2
o
o
.
91.00
')01) iOOO 15()() ~()('() 2')(10 )000
Federal Three Mode (30 mph) NOX (ppm)
3500
Figure 3.22.
1975 FTP NOX versus Federal Three Mode (30 mph) NOX -
Before Maintenance, All Phase I Vehicles.
77

-------
.,-i
e 0
-""""0
&~
CJ
:z::
p.. 0
E-4 ~
rz.. III
o
o
.
o
N
LEGEND
1 = 1972-1974
2 = 1975-1976
o
o
III
o
o
.
co
-
o
o
.
~
-
o
o
N
-
z
o
o
.
co
I
, ' ,
, '
I 2"" I
" :L
~" 't"', 21
". 2'
I "'J' 't
2 II, 't II , II
,I, . \. "
, 2 .2 ~
~ 2 I, II
III
2
4'2;. It II

II II
a II
II 1/
1/
o
o
.
~
II
o
o

N
o
o
.
".00
model year
model year
,
II
II
2
300
600 900 1200 1500
Federal Three Mode (N) HC (ppm)
2100
11300
Figure 3.23.
1975 FTP HC versus Federal Three Mode (N) HC -
Before Maintenance, All Phase I Vehicles.
78

-------
 o               
 0       LEGEND     
 .           
 0               
 0    1  1972-1974 model   
 (PI    = year 
     2 = 1975-1976 model year 
 0               
 0               
 .               
 0               
 ,...               
 (\I               
 0               
 0               
 .               
 0               
 ~               
 (\I               
 0               
 0               
 0               
 (\I               
 0               
 0 1              
 0               
 II)               
               1
- 0              2
.~ 0               
e: 0               
" II)               
e: -               
~                
               2
o 0               
0               
CJ .              2
o             
 (\I               
~ -               
~                
~                
   2      1   2 1   It
 o     1    1    2 1 
 0       22  2 2  
 0      2   21      
 OJ       21       
   II      2       
   1    1 1       1 1 
   1  1 2     2    1
     tl    1  
 0  2 1    2 1      2 2
 o II .  d 2 II  2 . 12.  21
 .   
 0     . 212212 1       
 ID  . 2  1 12 .        
   . t la 21 22      2    
   2 1        2
   2 i2 1  1        21 2 
    2 .        
   2            . 
g 1
C lz 21
(PI 2 2 2
2 2
2 ~
~
2
2
22
2
2
o 2
o
.
9J.OO
2.00
11.00
6.00
8.00
10.00
12.00
111.00
Federal Three Mode (N) CO (%)
Figure 3.24.
1975 FTP CO versus Federal Three Mode (N) CO -
Before Maintenance, All Phase I Vehicles.
79

-------
I:)
I:)
.
r-
LEGEND
1 = 1972-1974 model
2 = 1975-1976 model
year
year
o
1"1
.
CD
12
o
CD
In
2
 I:)  
 en  
 .  
 ~  
  II 
 0  
 N  
 ~ 2 
.....  I
fa I:)  II
In  2
......... . 
&1"1  2
I
  I 
:<
o I:)
z ~
N
p..
E-4
~
o
-
I I'
, 21 I
I I 2
I 2
2 2 I I I 2

22 II. I 2
I .0121 2.
N 2 f2-/
22 1, I 2 2
.,. j II
& ~.",C} '2' 2
~ I II It 2 2
2 -. III 2
- 2 a. 1'1 I
, 2111 2 I I
221,.. ,2,.
I' It/Ila ;, ,
ill ,
:=' z.i ,
. I I
o laZZ 'I
,
2
,
,
I:)
o
91.00
50.00 LOO.OO 1 0.00 200.00 250.00
Federal Three Mode (N) NOX (ppm)
300.00
3150.00
Figure 3.25.
1975 FTP NOX versus Federal Three Mode (N) NOX -
Before Maintenance, All Phase I Vehicles.
80

-------
o
o
LEGEND

1972-1974 model year
1975-1976 model year
.
o
N
o
o
CD
o
o 1
co
o
o
~
 o  
 0  
 N  
 -  
  2 
...-1   
E 0  
""'-0  
E .  
tJ'I~  
U   
~   
p.. 0  
0  
E-t .  
~ CD  
   1
  } 1
 o  
 0  
 CD 1 
   12
 ~  
o
o
.
N
o
o
.
9).(
2(1()
/, () ()
(, '1 ()
:: (' (\
1 ~ (~n
] ') n r)
I II (II'
Idle (2250) HC (ppm)
Figure 3.26.
1975 FTP HC versus Idle (2250) HC - Before
Maintenance, All Phase I Vehicles.
81

-------
o   
0   
0   
0   
(t'J   
0   
0   
0  
,..   
N  
 0  
 0  
 0  
 ,.  
 N  
 0 
 0 
 0 
 - 
 N 
 0 
 C 
 0 
 CD 
 - 
oM   
fa 0 
'0 
fa . 
\:11~ 
- - 
0  I
U  0 
~  0 211
E-t  c
r...  N 
 - 
LEGEND
1 = 1972-1974 model
2 = 1975-1976 model
year
year
z
     z ~ Z 
0 2  1 ~ 11 
0   I ~  
0 11  IJ II  
at    
 ~ 11     
    \1 1 1  
0 1 \1 I I 1 I I 2 I
o ',1\ 111 I 1 I 1 2 
. 
0     I I  
CD 2221 I II II  
 ~ 2 I Z
    Z 
 21~111 211 2 
0 I,      
0      
. II I z, I  
0   2    
(t'J 22 2   
 I I     
 I  I    
o
o
91.00
2.00
11.00
6.00
8.00
10.00
12.00
111.00
Idle (2250) CO (%)
Figure 3.27.
1975 FTP CO versus Idle (2250) CO - Before
Maintenance, All Phase I Vehicles.
82

-------
o
o
LEGEND

1 = 1972-1974 model year
2 = 1975-1976 model year
,...
o
(T'I
2
<:  
0  
z  
~ 0 
E-4 CD 
. 
rz.. N 
11
I 12
I I
2
I 2
I
.i I I
2
I
2\ I ~ I
. ~q2~2 2
N 2r 2 2z
2~' 2 2i I
I- II \ 2 2
~a\' 2t I
~ „~ I 2 I
22 I i!> I 2 12 2
1122 I~ I
21.62~'
2°rS 2 212
at' i21 i 21
~ 2 2 ~2
. 'II
o Ii} i
o
2
21
2
o
o
.
91.00
2 (, I J
I, f) I)
(,O()
:: r' ( I
I ;, ,; r;
l~n!"')
I I, II "
Idle (2250) NOX (ppm)
Figure 3.28.
1975 FTP NOX versus Idle (2250) NOX - Before
Maintenance, All Phase I Vehicles.
83

-------
o
o
.
o
N
LEGEND

1 = 1972-1974" model
2 = 1975-1976 model
year
year
o
o
.
ID
-
o
o
.
CD
-
.
- N
.~ -
e
..........
6, 0

- 0

CJ 2
:I:

Po.
8
!:&.I 0
o
ID
2
,
o
o
CD
I
I ~ 'I
I ,,' I
.J ~\ Ill, , I
o ~ II
o II ,I,
. I d! I I
,. i. I 111'1 I ,
,I~, t H l ~
14.', \ ~
g ,,~:
N ~ i 2
2
,
2
o
o
.
9J. 00
300
GO,)
900 1200
Idle (N) HC (ppm)
1'500
leno
2LOO
Figure 3.29.
1975 FTP HC versus Idle (N) HC - Before Maintenance,
All Phase I Vehicles.
84

-------
 CI
 CI
 CI
 CI
 CI'I
 CI
 CI
 .
 CI
 r-
 N
 CI
 CI
 CI
 ,.
 N
 CI
 CI
 CI
 N
 CI
 CI
 .
 CI
 CD
-ri 0
S 0
,.
S ~
0'1-
o 0
u 0
~ 0
N
8 -
~ 
 1
 2
 o
 CI
LEGEND

1 = 1972-1974 model year
2 = 1975-1976 model year
2
.
CI
en
2
2
21
    2  
    I 
     2 I
I   2 1 1 
12 i 2 12     
I      
2     II 
2 1\2 2 2   
2      
 2 I   
2      
 2     
I
a

II I 21
I I
12 I
CI 2
CI 111 Z I
Z 211
I Z 2
212 Z . J
Z 2
li1212Z~2 22.

CI ~il 2 I 2 2 I I
~ 2 2..AZ
o 2 l""2
CI'I Z 2
Z 2
Z
o
cg
. 2
.21
I, I
2
i
2
2
o i
CI
.
9J.OO
2.00
1.1.00
6.00
8.00
10.00
12.00
11.1.00
Idle (N) CO (%)
Figure 3.30.
1975 FTP CO versus Idle (N) CO - Before Maintenance,
All Phase I Vehicles.
85

-------
.
....
LEGEND
1972-1974 model
1975-1976 model
year
year
C)
C)
C)
c<'I
l
.
UJ
C)
UJ
2
.
tIJ
c
g)
7
 C)              
 C\I              
 ;,   2           
.~               
S C)          1 1   
........ tIJ             l
& c<'I            l  
><               
0 C)      1  t     
Z CD     1      
 .     II 1 '  2     
 C\I          
Po<         1     
E-4       1  2     
~     2     1 2     
   l    2      
 c   2 2~ 1 I   2~    
 -   21 z2 2 1 , 2 ,  2 2
 C\I 2        
     2 a"  1 2   2
    2 ~ 2 , ~   
     2 2 \  121a  1   
    a .. 12, 1 /  '2    
 c  1 1 2 II e       , ,
 , ~  21'#1.      1 2
  .        
    I' 1 Iz \ 2  2  I    
  2 ,I 2  #i     
   2 212,2"      I  
      ~I 1 22  1 "     
    2    2  ' 
    1      
 C)  Z 2  2 \ 2      
 ....         
  . 1  I        
 c  a 22  2    I     
      2        
c
C)
91.00
30.00
60.00
90.00
L20.00
150.00
180.00
~10.00
Idle (N) NOX (ppm)
Figure 3.31.
1975 FTP NOX versus Idle (N) NOX - Before
Maintenance, All Phase I Vehicles.
86

-------
o
o
o
N
LEGEND

1 = 1972-1974 vehicles
2 = 1975-1976 vehicles
o
o
.
CD
o
o
72-74 Model Year Idle (N)
Cutpoint
.
IC
o Pass-Fail
~ (Errors of
=: Omission)
Fail-Fail
o
o
_N
-
-
%:
......
%:
<..:)0
.....0
2
o
U
:I:
(l.0
~~
IL.CD
2
o
o
IC
.
~
2
o
o
72/73 Federal Standard
in '75 FTP Equivalent
2
.
N
o
o

c:'
2 Pass-
Pass
30
IDLE
Fail-Pass
(Errors of Commission)
600
(NEUTRAL)
900
12 0
1500 1800
HC (PPM)
-'
Figure 3.32.
1975 FTP HC versus Idle (N) HC - Before Maintenance,
All Phase I Vehicles.
87

-------
1 1 1 ,I
1 I
o ~ I , I ,
~ ~1 , I , , It 1 2t
01 ,,111
ca ~" 1.1
, ,
~12 I, ,12 2"
o 1_, .... II
~ i clt' 2
q.~. ,
'"' ,/ 2 I
2
I
o
o

o
o
'"'
o
o

o
r-
N
o
o
.
o
,
N
o
o
.
o
N
o
~ I
o
--ca
....-
2:
......
2:0
<.:)0
-0
\I)
c
u
o
o
~ .
o
.... N.
LL.-
o
o
o
GI
o I
o
.
9J. 00
LEGEND

1 = 1972-1974 vehicles
2 = 1975-1976 vehicles
72-74 Model Year Idle (N)
Cutpoint
Pass-Fail
(Errors of
Omission)
Fail-Fail
2
2
I
, I
I
,
2
1 1
I,
,
2
H
I
1z1 2
I
12
1
2
,I 1
11
2
2
2
1 II'
2
2
72/73 Federal Standard
~n '75 FTP Equivalent
2
2
Pass-Pass
Fail-Pass
(Errors of Commission)

8-:00 10.00 12.00
CO (Xl
1 ~ . 00
2.00 11.00
IDLE (NEUTRAL)
6'.00
Figure 3.33.
1975 FTP CO versus Idle (N) CO - Before Maintenance,
All Phase I Vehicles.
88

-------
TABLE 3.1
NUMBER OF TEST VEHICLES BY MODEL YEAR, PHASE,
AND PASS/FAIL STATUS
  Phase I phase II
Model Year Pass Fail Pass Fail
1972  14 11 47 39
1973  16 11 52 42
1974  22 8 47 23
  - - - -
1972-1974 52 30 146 104
1975-1976 72 39 135 85
Total  124 69 281 189
Population I All Phase I    193 vehicles
Population II All Passing Phase I   124 vehicles
Population III All Failing Phases I and II 258 vehicles
89

-------
TABLE 3.2
AVERAGE 1975 FTP EMISSIONS AND FUEL ECONOMY BEFORE AND AFTER MAINTENANCE
\0
o
    HC   CO   NOX   F.E. 
 Model    ,   ,   ,   ,
 Year N Before After Reduction Before After Reduction Before After Reductio!,\ Before After Reduction
All 72 25 6.53 4.16 36 84.47 59.07 30 2.68 2.61 3* 14 .20 14.26 0*
Phase I 73 27 4.60 4.01 13 80.99 58.59 28 2.06 2.11 -2* 13.70 14.00 -2*
 74 30 5.15 4.12 20 83.67 59.13 29 1.85 1.87 -1* 13.63 13.88 -2*
 72-74 82 5.39 4.10 24 83.03 58.94 29 2.17 2.17 0* 13.82 14.04 -2*
 75-76 111 2.31 1.69 27 50.25 35.75 29 1.72 1.59 8* 14.31 14.30 0*
Passing 72 14 4.42 4.18 5* 68.66 62.63 9* 2.96 2.82 5* 13.90 13.45 3*
Phase I 73 16 3.95 3.81 .4* 70.82 55.62 21 2.04 2.15 -5* 12.50 12.61 -1*
 74 22 5.44 4.24 22 81.36 58.28 28 1.88 1.94 -3* 13 . 20 13.46 -2*
 72-74 52 4.71 4.09 13 74 .20 58.64 21 2.22 2.24 -1* 13.15 13.18 0*
 75-76 72 1.72 1.43 17 36.53 30.80 16 1. 75 1.63 7* 14.41 14 .32 1*
Failing 72 49 7.01 5.06 28 92.35 60.60 34 2.40 2.36 2* 15.11 15.39 -2*
Phases 73 53 6.25 4.98 20 95.52 65.15 32 1. 76 1.74 1* 14.42 14.77 -2.
I and II 74 31 5.83 4.62 21 89.26 63.18 29 1.82 1.64 10* 14.80 14.92 -1.
 72-74 133 6.44 4.92 24 92.89 62.99 32 2.01 1.95 3* 14.76 15.03 -2.
 75-76 124 3.54 2.08 41 78.35 47.04 40 1. 52 1.31 14 13.84 13.79 O.
. Not a significant reduction at 95' level of confidence

-------
TABLE 3. 3
STANDARD DEVIATIONS OF 1975 FTP EMISSIONS AND FUEL ECONOMY
BEFORE AND AFTER MAINTENANCE
1.0
......
 Model  HC CO NOX  F.E. 
 Year N Before After Before After Before After Before After
 -. -        
All Phase I 72 25 5.67 0.95 42.31 25.95 1.22 1.16 3.41 3.92
 73 27 1. 61 1.40 32.73 20.62 1.26 1.07 3.49 3.66
 74 30 2.74 1. 05 38.54 14.80 0.84 0.86 3.52 3.29
 72-74 82 3.70 1.14 37.53 20.17 1.15 1.06 3.45 3.56
 75-76 III 1.43 0.90 37.85 20.80 0.86 0.79 3.74 3.60
Passing 72 14 0.84 0.82 26.21 33.37 1.40 1.41 3.54 3.90
Phase I 73 16 0.95 1.15 19.37 15.54 1.04 1.13 2.62 2.61
 74 22 3.07 1.14 36.74 14.78 0.90 0.93 2.85 2.85
 72-74 52 2.18 1.06 29.58 21.26 1.17 1.17 2.93 3.03
 75-76 72 0.84 0.83 19.69 15.43 0.94 0.88 3.63 3.59
Failing 72 49 4.28 2.41 27.49 25.47 0.93 0.90 2.68 4.15
Phases I 73 53 6.40 3.32 39.67 29.78 1.00 0.78 4.00 4.21
and II 74 31 2.80 1.73 33.16 20.03 0.99 0.67 4.44 4.01
 72-74 133 3.64 2.67 37.24 25.21 1.01 0.86 3.99 4.13
 75-76 124 2.09 1.05 40.22 27.38 0.63 0.55 3.26 3.15

-------
PERCENT BENEFIT
TABLE 3. 4
IN AN IIM PROGRAM WITH A 10
STRINGENCY FACTOR - 1975 FTP
PERCENT
   HC CO NOX F.E.
1972-1974    
Mean of Passed Cars  4.81 80.33 2.19 13.64
Mean of Failed Cars before Maint. 8.95 95.92 1.89 15.40
Population Mean (10' Failures) 5.22 81.89 2.16 13.82
Mean of Failed Cars after Maint. 5.83 73.66 1.76 15.40
Population Mean (10' Failure) 4.91 79.66 2.15 13.82
Percent Benefit   6 3 1 0
1975-1976      
Mean of Passed Cars  2.11 45.07 1.73 14.35
Mean of Failed Cars before Maint. 4.14 97.60 1.36 13.71
Population Mean (10' Failure) 2.31 50.32 1.69 14.29
Mean of Failed Cars after Maint. 2.18 49.49 1.23 14.01
Population Mean (10, Failure) 2.12 45.51 1.68 14.32
Percent Benefit      
   8 10 1 0
92

-------
TABLE 3.5
PERCENT BENEF IT IN AN I/U PROGRAM ~lITH A 20
STRINGENCY FACTOR - 1975 FTP
PERCENT
1972-1974   HC CO NOX F.E.
Mean of Passed Cars  4 67 76 AS 2 21 13.63
Mean of Failed Cars before Maint. 7 84 97 54 , 88 15.11
Population Mean (20% Failures) 5 30 80 99 2.14 13.93
Mean of Failed Cars after Maint. 5 62 66 61 , 88 15.45
population Mean (20% Failure) 4 86 74.80 2.14 13.99
Percent Benefit   8 8   
   0  0
1975-1976       
Mean of Passed Cars  1 q.:1 .:1n.:11 1 7.:1 1.:1.:1.:1
Mean of Failed Cars before Maint. 3 78 89 57 1 42 13 77
Population Mean (20 % Failure) 2.31 50.24 1. 68 14.31
Mean of Failed Cars after Maint. 2.10 49.32 1. 22 13.85
Population Mean (20% Failure) 1.97 42.19 1.64 14.32
Percent Benefit       
   14 16 2  0
93

-------
PERCENT BENEFIT
TABLE 3.6
IN AN 11M PROGRAM WITH A 30 PERCENT
STRINGENCY FACTOR - 1975 FTP
  HC CO NOX F.E.
1972-1974  
Mean of Passed Cars 4.66 75.28 2.27 13.31
Mean of Failed Cars before Maint. 6.96 96.80 1.92 14.92
Population Mean (30% Failures) 5.35 81.74 2.17 13.85
Mean of Failed Cars after Maint. 5.11 64.28 1.92 15.29
Population Mean (30 % Failure) 4.80 71.98 2.17 13.96
Percent Benefit     
  10 12 n -1*
1975-1976     
Mean of Passed Cars 1. 79 37.96 1.77 14 42
Mean of Failed Cars before Maint. 3.65 84.98 1.46 13.88
Population Mean (30 % Failure) 2.35 52.07 1.68 14.26
Mean of Failed Cars after Maint. 2.17 49.79 1.25 13.88
Population Mean (30 % Failure) 1.90 41.51 1.61 14.26
Percent Benefit     
  19 20 4 0
* Negative percent decrease resulted from increased fuel economy.
94

-------
PERCENT BENEFIT
TABLE 3.7
IN AN I/t1 PROGRAM \'lITH A 40

STRINGENCY FACTOR - 1975 FTP
PERCENT
1972-1974   HC CO NOX F.E.
Mean of Passed Cars  4 66 74 07 2 27 12.92
Mean of Failed Cars before Maint. 6 65 95.26 2 02 14.77
Population Mean (40% Failures) 5 46 82.55 2.17 13.66
Mean of Failed Cars after Maint. 5 05 64.06 1.97 15.10
population Mean (40% Failure) 4.82 70.07 2.15 13.79
Percent Benefit        
   , ') 1 c;  1  -,*
1975-1976        
Mean of Passed Cars  1.63 33.87 1. 76 14.28
Mean of Failed Cars before Maint. 3.52 81. 26 1. 51 14.02
Population Mean (40 % Failure) 2.39 52.83 1.66 14.18
Mean of Failed Cars after Maint. 2.12 48.28 1. 30 13.98
Population Mean (40 % Failure) 1. 83 39.63 1. 58 14.16
Percent Benefit        
   23 25  5  0
* Negative percent decrease resulted from increased fuel economy.
95

-------
PERCENT BENEFIT
TABLE 3.8
IN AN IIM PROGRAM WITH A 50 PERCENT
STRINGENCY FACTOR - 1975 FTP
1972-1974  HC CO NOX F.E.
Mean of Passed Cars 4.63 72.65 2.12 13.17
Mean of Failed Cars before Maint. 6.51 94.72 2.08 14.45
Population Mean (50% Failures) 5.57 83.69 2.10 13.81
Mean of Failed Cars after Maint. 4.97 64.73 2.03 14.70
Population Mean (50% Failure) 4.80 68.69 2.08 13.94
Percent Benefit     
  14 18 1 -1 *
1975-1976     
Mean of Passed Cars 1.51 31.93 1.77 13.79
Mean of Failed Cars before Maint. 3.44 76.26 1.55 14.16
Population Mean (50% Failure) 2.48 54.10 1.66 13.98
Mean of Failed Cars after Maint. 2.06 46.56 1.32 14.08
Population Mean (50% Failure) 1.79 39.25 1. 55 13.94
Percent Benefit I    
 28 27 7 0
* Negative percent decrease resulted from increased fuel economy.
96

-------
TABLE 3. 9

COMPARISON OF ESTIMATED HIGH ALTITUDE PERCENT BENEFITS
WITH FIRST YEAR PERCENT BENEFITS OF APPENDIX N
  HC  CO 
 Stringency Appendix High Appendix High
 Factor N* Altitude N* Altitude
1972-1974 0.10 3-6 6 7-11 3
Model Years 0.20 4-9 8 9-16 8
(Technology I)
 0.30 7-12 10 12-20 12
 0.40 8-13 12 14-22 15
 0.50 8-14 14 15-23 18
1975-1976 0.10 4-9 8 10-17 10
Model Years 0.20 6-13 14 17-26 16
(Technology II)
 0.30 10-14 19 21-30 20
 0.40 12-15 23 23-32 25
 0.50 13-16 28 2 5 -- 33 27
* ~ange of first year benefit. Low number represents no
mechanic training and high number represents full mechanic
training. These values are the most recent EPA estimates
as of December, 1977.
97

-------
PERCENT BENEFIT
TABLE 3.10

IN AN IIM PROGRAM WITH

STRINGENCY FACTOR
IDLE (N) EMISSIONS
A 10 PERCENT
1972-1974  HC CO NOX
Mean of Passed Cars 200.0 3.59 56.12
Mean of Failed Cars before Maint. 1129.6 6.69 35.30
Population Mean (10% Failures) 293.0 3.90 37.38
Mean of Failed Cars after Maint. 524.7 2.12 56.16
population Mean (10% Failure) 232.5 3.44 37.39
Percent Benefit  21 12 0
1975-1976    
Mean of Passed Cars 91.3 1.26 56.06
Mean of Failed Cars before Maint. 349.8 7.17 45.55
population Mean !10% Failure) 117.2 1.85 55.01
Mean of Failed Cars after Maint. 102.4 0.84 62.81
population Mean (10% Failure) 92.4 1.22 56.74
Percent Benefit  21 34 -3
98

-------
TABLE 3.11
PERCENT BENEFIT
IN AN 11M PROGRAM WITH
STRINGENCY FACTOR
IDLE (N) EMISSIONS
A 20 PERCENT
     I
1972-1974  HC CO NOX 
Mean of Passed Cars 179.2 3.25 56.68 
Mean of Failed Cars before Maint. 824.8 7.11 39.23 
Population Mean (20% Failures) 308.3 4.02 53.19 
Mean of Failed Cars after Maint. 430.0 2.02 60.24 
Population Mean (20% Failure) 22.94 3.00 57.39 
Percent Benefit     
  26 25 -8 
1975-1976     
Mean of Passed Cars 71.9 0.87 57.08 
Mean of Failed Cars before Maint. 298.3 5.94 47.29 
Population .Mean (20% Failure) 117.2 1. 88 55.12 
Mean of Failed Cars after Maint. 94.1 0.84 64.52 
Population Mean (20% Failure) 76.3 0.86 58.57 
Percent Benefit  35   
  54 -6 
99

-------
PERCENT BENEFIT
TABLE 3.12

IN AN 11M PROGRAM WITH A 30
STRINGENCY FACTOR

IDLE (N) EMISSIONS
PERCENT
1972-1974  HC  CO NOX
Mean of Passed Cars 161 5 2.63 56.63
Mean of Failed Cars before Maint. 648.1 7.15 43.09
Population Mean (30% Failures) 307.5 3.99 52.57
Mean of Failed Cars after Maint. 336.0 1. 83 62.94
Population Mean (30 % Failure) 213.8 2.39 58.52
Percent Benefit     
  30  40 -11
1975-1976     
Mean of Passed Cars 64.0 0.61 56.12
Mean of Failed Cars before Maint. 272.7 5.46 48.81
Population Mean (30 % Failure) 126.6 2.07 53.93
Mean of Failed Cars after Maint. 89.7 0.87 64.95
Population Mean (30 % Failure)' 71.7 0.69 58.77
Percent Benefit     
  43  67 -9
100

-------
PERCENT BENEFIT
TABLE 3.13

IN AN IIM PROGRAM WITH

STRINGENCY FACTOR
IDLE (N) EMISSIONS
A 40 PERCENT
1972-1974   HC  CO NOX
Mean of Passed Cars  143.4 2.08 55.84
Mean of Failed Cars before Maint. 575.1 6.70 45.50
Population Mean (40% Failures) 316.1 3.93 51.70
Mean of Failed Cars after Maint. 329.2 1. 79 64.91
Population Mean (40% Failure) 217.7 1.96 59.47
Percent Benefit      
   31  50 -15
1975-1976      
Mean of Passed Cars  .1R Q 0 1R 113 Q.1
Mean of Failed Cars before Maint. 258 9 4.96 50.64
Population Mean  (40% Failure) 132.9 2.21 52.62
Mean of Failed Cars after Maint. 86.2 0.86 66.00
Population Mean (40% Failure) 63.8 0.57 58.76
Percent Benefit      
   52  74 -12
101

-------
PERCENT BENEFIT
TABLE 3.14
IN AN IIM PROGRAM WITH

STRINGENCY FACTOR
IDLE (N) EMISSIONS
A 50 PERCENT
   HC CO NOX
1972-1974   
Mean of Passed Cars  , ':t c; 1 1 78 55_59
Mean of Failed Cars before Maint. 540 8 6.44 45.65
Population Mean (50% Failures) 338.0 4.11 50.62
Mean of Failed Cars after Maint. 311. 2 1.76 65.19
Population Mean (50% Failure) 223.2 1.77 60.39
Percent Benefit     
   34 57 -19
1975-1976     
Mean of Passed Cars  38 6 0 18 57.06
Mean of Failed Cars before Maint. 233.4 4.36 49.15
Population Mean (50% Failure) 136.0 2.27 53.11
Mean of Failed Cars after Maint. 83.5 0.81 64.53
Population Mean (50% Failure)' 61.0 0.50 60.80
Percent Benefit     
   55 78 -14
102

-------
TABLE 3.15
PERCENT BENEFIT IN AN I/M PROGRAM WITH A 10 PERCENT
STRINGENCY FACTOR
COLD TRANSIENT EMISSIONS (gm/mi)
1972-1974   HC CO NOX
Mean of Passed Cars  6.82 102.23 2.66
Mean of Failed Cars before Maint. 10.13 108.90 2.36
Population Mean (10% Failures) 7.15 102.90 2.63
Mean of Failed Cars after Maint. 7.93 103.94 2.03
Population Mean (10% Failure) 6.93 102.40 2.60
Percent Benefit     
   3 0 1
1975-1976     
Mean of Passed Cars  3.41 67.18 2.12
Mean of Failed Cars before Maint. 5.50 110.08 1. 77
Population Mean (10% Failure) 3.62 71.47 2.09
Mean of Failed Cars after Maint. 4.09 83.87 1. 58
Population Mean (10% Failure) 3.48 68.85 2.07
Percent Benefit   4 4 1
103

-------
TABLE 3.16
PERCENT
BENEFIT IN AN I/M PROGRAM WITH A20

STRINGENCY FACTOR
COLD TRANSIENT EMISSIONS (gm/mi)
PERCENT
1972-1974   HC CO NOX
Mean of Passed Cars  F; 74 99.64 2 68
Mean of Failed Cars before Maint. q 13 107.97 2.37
Population Mean (20% Failures) 7.22 101.31 2.62
Mean of Failed Cars after Maint. 7.40 94.67 2.20
Population Mean (20% Failure) 6.87 98.65 2.58
Percent Benefit     
   5 3 1
1975-1976     
Mean of Passed Cars  3.25 62.64 2.13
Mean of Failed Cars before Maint. 5.09 104.49 1.87
Population Mean (20% Failure) 3.62 71.01 2.08
Mean of Failed Cars after Maint. 3.88 81.58 1.61
Population Mean (20% Failure)' 3.38 66.43 2.03
Percent Benefit     
   7 6 3
104

-------
TABLE 3.17

PERCENT BENEFIT IN AN I/M PROGRAM

STRINGENCY FACTOR
COLD TRANSIENT EMISSIONS
WITH A 30 PERCENT
( grn/rni )
1972-1974   HC CO NOX
Mean of Passed Cars  6.89 101.44 2.73
Mean of Failed Cars before Maint. 8.22 106.18 2.42
Population Mean (3~ Failures) 7.29 102.86 2.64
Mean of Failed Cars after Maint. 6.79 90.89 2.27
Population Mean (30 % Failure) 6.86 98.28 2.59
Percent Benefit     
   6 4 2
1975-1976     
Mean of Passed Cars  3.05 60.38 2.14
Mean of Failed Cars before Maint. 4.99 100.38 1.95
Population Mean 00 % Failure) 3.63 72.38 2.08
Mean of Failed Cars after Maint. 4.02 82.85 1.67
Population Mean GO % Failure) 3.34 67.12 2.00
Percent Benefit     
   Q 7 .1
105

-------
TABLE 3.18
PERCENT BENEFIT IN AN I/M PROGRAM WITH A 40
STRINGENCY FACTOR
COLD TRANSIENT EMISSIONS (gm/mi)
PERCENT
I    I
1972-1974  HC CO NOX
Mean of Passed Cars 7.03 102.94 2.69
Mean of Failed Cars before Maint. 8.04 106.81 2.54
Population Mean (40' Failures) 7.43 104.49 2.63
Mean of Failed Cars after Maint. 6.85 91.80 2.36
Population Mean (40, Failure) 6.96 98.48 2.56
Percent Benefit    
  6 6 3
1975-1976    
Mean of Passed Cars 2.93 56.87 2.15
Mean of Failed Cars before Maint. 4.80 96.99 1.98
Population Mean (40' Failure) 3.68 72.92 2.08
Mean of Failed Cars after Maint. 3.88 80.35 1. 70
Population Mean (40' Failure) 3.31 66.26 1.97
Percent Benefit    
  10 9 5
106

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TABLE 3.19
PERCENT BENEFIT IN AN I/M PROGRAM WITH A 50 PERCENT
STRINGENCY FACTOR
COLD TRANSIENT EMISSIONS (gm/mi)
1972-1974    HC CO NOX
Mean of Passed Cars  7 17 110? c;f; ? c; 1
Mean of Failed Cars before Maint. 7 RR 110f; 92 2.59
Population Mean (50 % Failures) 7 1:)3 104.74 2.55
Mean of Failed Cars after Maint. 6 73 92.82 2.41
Population Mean (50 % Failure) 6.95 97.69 2.46
Percent Benefit      
   8 7 4
1975-1976      
Mean of Passed Cars  2 85 55.91 2.15
Mean of Failed Cars before Maint. 4.78 92.37 2.02
Population Mean (50 % Failure) 3.82 74.14 2.09
Mean of Failed Cars after Maint. 3.74 76.97 1. 75
Population Mean (50 % Failure) 3.30 66.44 1.95
Percent Benefit      
    14 10 6
107

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TABLE 3.20

PERCENT BENEFIT IN AN IIM PROGRAM WITH A 10

STRINGENCY FACTOR
COLD STABILIZED EMISSIONS (gm/mi)
PERCENT
1972-1974  HC CO NOX
Mean of Passed Cars 4.21 77.18 1.69
Mean of Failed Cars before Maint. 9.27 97.59 1.44
Population Mean 0.0 % Failures) 4.72 79.22 1.67
Mean of Failed Cars after Maint. 5.43 64.33 1.44
Population Mean (1.0 % Failure) 4.33 75.90 1.67
Percent Benefit    
  8 4 0
 .   
1975-1976    
Mean of Passed Cars 1.65 37.85 1.41
Mean of Failed Cars before Maint. 3.97 102.72 1.02
Population Mean (10 % Failure) 1.88 44.34 1.37
Mean of Failed Cars after Maint. 1.56 36.69 0.98
Population Mean (10 % Failure) 1.64 37.73 1.37
Percent Benefit  13  
  15 0
108

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TABLE 3.21
PERCENT BENEFIT IN AN I/M PROGRAM WITH A 20 PERCENT
STRINGENCY FACTOR
COLD STABLIZED EMISSIONS (gm/mi)
1972-1974   HC CO NOX
Mean of Passed Cars  4.04 72.75 1.71
Mean of Failed Cars before Maint. 7.90 101. 46 1. 41
Population Mean (20 % Failures) 4.81 78.49 1.65
Mean of Failed Cars after Maint. 5.17 57.94 1. 52
Population Mean (20 % Failure) 4.27 69.79 1. 67
Percent Benefit     
   11 11 -1
1975-1976     
Mean of Passed Cars  L4f\ 32 88 1 41
Mean of Failed Cars before Maint. 3.57 91.81 1.07
Population Mean (20 % Failure) 1.88 44.67 1. 34
Mean of Failed Cars after Maint. 1.51 36.15 0.96
Population Mean (20 % Failure) 1.47 33.53 1. 32
Percent Benefit     
   22 25 2
109

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TABLE 3.22
PERCENT
BENEFIT IN AN I/M PROGRAM WITH A 30

STRINGENCY FACTOR
COLD STABILIZED EMISSIONS (gm/mi)
PERCENT
1972-1974   HC CO NOX
Mean of Passed Cars  3.94 69.45 1. 77
Mean of Failed Cars before Maint. 6.93 101.05 1.44
Population Mean (30% Failures) 4.84 78.93 1.67
Mean of Failed Cars after Maint. 4.64 55.72 1.55
Population Mean (30% Failure) 4.15 65.33 1.70
Percent Benefit     
   14 17 -2
1975-1976     
Mean of Passed Cars  1. 31 30.20 1.44
Mean of Failed Cars before Maint. 3.40 86.39 1.10
Population Mean (30 % Failure) 1.94 47.06 1. 34
Mean of Failed Cars after Maint. 1.58 36.79 0.98
Population Mean (30 % Failure) 1. 39 32.18 1. 30
Percent Benefit     
   28 32 3
110

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TABLE 3.23
PERCENT BENEFIT IN AN I/M PROGRAM WITH A40 PERCENT

STRINGENCY FACTOR
COLD STABILIZED EMISSIONS (gm/rni)
1972-1974   HC CO NOX
Mean of Passed Cars  3.88 66.80 1. 78
Mean of Failed Cars before Maint. 6.52 98.52 1. 52
Population Mean (40 % Failures) 4.94 79.49 1. 68
Mean of Failed Cars after Maint. 4.52 55.09 1. 58
Population Mean (40% Failure) 4.14 62.12 1. 70
Percent Benefit     
   16 22 -1
1975-1976     
Mean of Passed Cars  1.09 25.20 1. 42
Mean of Failed Cars before Maint. 3.27 82.09 1.17
Population Mean (40 % Failure) 1.96 47.96 1. 32
Mean of Failed Cars after Maint. 1. 55 35.87 1.03
Population Mean (40 % Failure) 1. 27 29.47 1. 26
Percent Benefit   35 39 
   4
111

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TABLE 3.24
PERCENT BENEFIT IN AN I/M PROGRAM WITH A 50 PERCENT
STRINGENCY FACTOR
COLD STABILIZED EMISSIONS (gm/mi)
  HC CO NOX
1972-1974  
Mean of Passed Cars 3.82 64.43 1.67
Mean of Failed Cars before Maint. 6.36 97.76 1.57
Population Mean (50 % Failures) 5.09 81.10 1.62
Mean of Failed Cars after Maint. 4.43 55.62 1.62
Population Mean (50 % Failure) 4.13 60.03 1.65
Percent Benefit    
  19 26 -2
1975-1976    
Mean of Passed Cars 0.94 22 h4 ] 4h
Mean of Failed Cars before Maint. 3.14 76.21 1.18
Popu1ationMean (50 % Failure) 2.04 49.43 1.32
Mean of Failed Cars after Maint. 1.51 34.77 1.04
population Mean (50 % Failure) 1.23 28.71 1.25
Percent Benefit    
  40 42 5
112

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TABLE 3.25
AVERAGE PERCENT REDUCTIONS IN 1975 FTP EMISSIONS DUE TO MAINTENANCE
         ALL PHASE 1 VEHICLES          
         PERCE~T REUUCTION          
MI'flll   HVOR'lCARllnNS ex)  CAR£lUN HnNOXloF (I)  NIJX (I)    FUel ECn~OHY (S) 
Y E AP t! H[At! SO MIN MAX RANGE MEAN SO HIN MAX RANGE MEA'" 50 HIN HAX RANGE HEAN SO HtN MAX RANGE
\'}12 25. 10 2"1 -29 91 121 21 29 -35 72 107 -2 31 -110 53 164 -1 9 -24 13 38
1973 27 10 19 -47 41 89 23 21 -28 53 111 -9 30 -71 55 127 -2 6 -15 9 25
1"174 30 12 111 -11 73 114 22 20 -10 69 110 -h 32 -103 49 In -1 8 -29 13 42
77-14 112 13 22 -47 91 139 2Z 23 -35 72 107 -6 31 -110 55 166 -2 8 -7.9 13 43
75-16 111 17 30 -100 116 187 17 33 -117 85 202 4 7.3 -105 8L 186 0 0 -62 21 £14
r-o                         
r-o          PASSI~G PHASE \ VEHIClES         
W          PERCFNT REOUCTION          
 HI'n( L   HY(IRrICAROONS I I)  CAROON MoNOXIDE II)    WIX es)    FUEL ECn~mHY IS) 
 YFAR N MEAN 50 MIt! HAX RANGE "EAN SO Hl'j MAX RANGE HE AN  SO H(tj HAX RANGE MEAN SO HIN MAX RANCE
 1172 14 4 II> -29 28 5£1 7 26 -35 43 19 4 16 -24 29 5/t 2 6 -7 L3 2L
 1'113 16 2 20 -47 3L 78 19 21 -28 53 01 -LO 30 -50 44 94 -1 6 -9 9 18
 1974 22 13 70 -11 73 0" 22 19 -10 6"1 110 -10 36 -103 49 153 -2 9 -29 13 42
 72-14 57. 7 19 -41 73 120 17 22 -35 69 104 -6 30 -103 49 U3 0 7 -29 L3 43
 75-76 72 9 7.9 -100 66 167 9 31 -L 17 74 192 4 22 -47 OL 120 0 9 -1>2 21 114
         FAIL (NG PHASE 1 I r A III NL PHASE 2 VEHICLES      
         PERC[NT REOUCTION           
M"nrl   HYIIRUC IIRRnns (XI  CIII\I3(IN HIINnxlflE (%I    wJX (S)    FUEl ECONOHY es) 
Vr AP N HEAt! Sf! HHI MAX RANGE "E AN SI) MHI MAX PA'~GE MEAN S'1 MIN HAX RANGE lIE AN  SO MIN HAX RANGE
1"172 50 11} 33 -104 "II 196 28 30 -1}6 72 IbO  -3 31 -110 53 164 -2 0 -24 19 43
1')13 0;) 10 71 -42 hO 102 27 23 -20 72 '12  -7 31 -155 59 7.14 -2 0 -30 15 46
\ ')14 11 17 .5 -11 55 6b 24 20 -4 1\ 16  1 211 -53 68 122 0 0 -14 26 4L
1/-1'4 134 10 25 -104 91 l')b 71 25 -96 12 1"0  -4 H -155 68 224 -7. 0 -30 26 57
75-16 174 3" 7" -!l6 1}2 IH B 39 -287. 85 3h7  9 76 -105 59 165 0 7 -7.1 36 57

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COMPARISONS
OF AFTER
TABLE 3026
MAINTENANCE EMISSIONS
WITH
PASSED VEHICLES'
EMISSIONS
I-'
I-'
.c:.
  ~T  ..... ,..... lie... ......lred -... ....ed MI!." ltepelred -... ...... Ne... ".pelr" _.n ,...ed M.." lI.pelred 
8t.. In,.nc  cutpolnt8  rTl'0   rTl'0   ..1. fN,.. 1418 Ult.. Cold Tr.".tent- Cold 'rr....t...t. Cold .tabUhed° Cold n.bUhed° 
r.etol' III: CO 110. lie CO 110. III: CO MOl lie CO 110. III: CO 110. III: CO 110. IIC 1"O - lie CO 110. IIC CO 110. 
1. 739 ,." - '.11 ".U 1.1' 5.U n." 1.71 I" J.st ".1 1115 1.11 ".1 '.11 181.U I." 7.n 181.14 1.81 '.11 11.11 1.19 5.U ".n 1." 
10 5" ..U - '.'7 7'." 1.11 5.11 ".'1 1." 17. J.1t ".1 M: t:~ :~i: '.74 It." I." 1." 14.11 1.1' .... 11.75 1.71 5.17 51." 1.51 
JO 5" '.11 - .... 75.1' 1.11 5.11 ".18 1.91 112 I.U ,... .... 181." I.n '.19 to." 1.11 J.t4 II." 1.11 . ... 55.11 1.55 
to ]" 5.39 - .... 74.01 1.11 5.tS ..... 1.11 lU I." 55.' ~:: !.~! !'~! 7.!: !!~.!~ ~.:! ..., 11." 1.)1 J." II." 1.18 '.51 55." 1.58 i
50 n. '.11 111 '.13 n.15 1.11 '.11 ".n 1.0) U5 1.18 55.' .n 91.11 1.41 J.II ".4) 1.11 '.4) 55.'1 1.12
           1'75-1111 _1 '..1'8             
10 11" 5.st - I.U ".01 1. n I.f' ..... I.U .1.J 1.21 ".1 01 .... 12.' J.n 11.11 1.11 .... U.01 1.58 1.15 n." 1.41 1." J..., .... 
10 11" J.n - I." ".41 1.74 1.1' ".n 1.11 n.' '.01 51.1 '.1 .... ".5 J.15 12." I.U J." 81.58 1.'1 1.41 n." 1.n 1.51 J'.U '.tI 
JO 11" 1.39 - I. 7. n." 1.11 1.17 ".19 Lit .... '.11 ".1 .:1 '.01 .... J." ".J' 1.14 '.'1 II." 1.11 1.)1 )8.1. 1.44 1.58 n.19 .... 
'0 39. loll - l.U n.n 1.1' 1.11 ".1' 1.)8 .... '.)8 tJ.' '.1 .... .... I.t) ,..11 1.15 J." ".)5 1.18 1." 15.10 l.tI 1.55 )t.n 1.0) 
5. I" 0." - 1.51 J1.n 1.11 I." ...,. 1.)1 )8.' '.1' 51.1 J.5 '.'1 ".5 I." 55.'1 1.15 J.1I 11.11 1.75 '.14 II." 1.41 1.51 JI.11 1..' 
un-l'74 _1 ".u.
"71-1'14 8tand,nda .n FT, RquI".181tt
1.,5 Standa..d..
8C
J.'
1.5
1"O
JI
15.'
1101
J.l
J.l
. ""Ita 8... ""-. for tIC. CO" .NI 1108.
..URIt. .... pp8/h.. for lie and 810., .... . 101' CO.

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TABLE 3.27

REGRESSION EQUATIONS FOR ABSOLUTE CHANGE IN FTP EMISSIONS AS A
FUNCTION OF PRE-MAINTENANCE EMISSIONS LEVEL, ENGINE DISPLACEMENT, AND
VEHICLE MILEAGE - ALL PHASE I
......
......
\JI
      HC    CO    NOX 
    r a b c r a b c r a b c
1972-1974                 
FTP    0.95 -3.85 0.953 . 0.84 -34.04 0.700 . 0.47 -0.28 0.294 -0.001
not FTP   0.94 -3.61 0.945 . 0.72 -27.61 0.656 . 0.45 -0.58 0.269 .
Fed. Short Cycle 0.92 -3.03 0.971 . 0.66 -14.93 0.587 . 0.46 -0.57 0.308 .
Fed. Three Mode(50) 0.94 -137 0.950 . 0.51 -0.71 0.376 . 0.47 -774 0.338 1.178
Fed. Three Mode(30) 0.93 -186 0.952 . 0.71 -1.04 0.577 . 0.55 -390 0.490 .
Fed. Three Mode(N) 0.82 -233 0.753 0.457 0.86 -0.97 0.818 . . . . .
Idle (2250)   0.89 -239 1.02 0.439 0.55 -0.43 0.394 . 0.61 -84 0.455 .
Idle (N)   0.75 -299 0.686 0.696 0.94 -1. 59 0.933 0.002 0.37 -38 0.473 .
1975-1976                 
FTP    0.79 -1. 29 0.660 0.001 0.84 -19.76 0.682 . 0.42 -0.29 0.244 .
Hot FTP   0.85 -1. 22 0.744 0.001 0.85 -16.92 0.690 . 0.39 -0.28 0.228 .
Fed. Short Cycle 0.90 -0.81 0.838 . 0.88 -11.42 0.749 . 0.53 -0.30 0.320 .
Fed. Three Mode(50) 0.40 -14 0.308 . 0.41 -0.56 0.314 . 0.51 -252 0.370 .
Fed. Three Mode (30) 0.49 -23 0.384 . 0.58 -0.79 0.536 . 0.58 -108 0.340 .
Fed. Three Mode(N) 0.79 -69 0.783 . 0.82 -0.66 0.825 . 0.54 -27 0.475 .
Idle (2250)   0.65 -12 0.447 . 0.83 -0.40 0.681 . 0.61 -41 0.434 .
Idle (N)   0.77 -55 0.548 0.149 0.93 -0.80 0.875 0.002 0.61 -39 0.625 .
  Fuel Economy: 1972-1974: No significant correlation     
      1975-1976: r '" 0.53, a = -50.6, b = 2.03, c = 0.07 
Change'" a + b(pre-maintenance value) + c(CID): mileage term was non-significant. 
. Indicates non-significant contribution to regression equation.     

-------
TABLE 3.28

REGRESSION EQUATIONS FOR PREDICTI~ABSOLUTE CHANGE IN FTP EMISSIONS
AS A FUNCTION OF BEFORE MAINTENANCE SHORT TEST EMISSIONS -
ALL PirA3B I VEIUCLI:S
 Model       Correlation
Pollutant Year Short Test Reqres.ion Equation* Coefficient
HC 1972- Hot FTP  Y . 3.59 + 1.00x   0.87
 1974 Fed. Short Cycle . -3.39 + 1.15x   0.84
  Fed. Three Mode . -1.67+0.0118xl+0.0016x2+0.0013x3 0.86
  Idle   . -0.74 + 0.0036xl + 0.0046x2 0.65
  Idle (N)  . -0.61 + 0.0065x   0.57
HC 1975- Hot FTP  Y . -0.68 + 0.64x   0.77
 1976 Fed. Short Cycle . -0.41 + 0.63x   0.74
  Fed. Three Mode . 0.01+0.00374Xl+0.00142x2+0.00125x3 0.36
  Idle   . 0.07 + 0.00284xl + 0.00314x2 0.46
  Idle (N)  . 0.20 + 0.0036x   0.44
CO 1972- Hot FTP  Y . -28.20 + 0.70x   0.77
 1974 Fed. Short Cycle . -14.46 + 0.68x   0.66
  Fed. Three Mode . -13.42+4.41xl+4.63x2+3.39x3 0.58
  Idle   . 2.26 + 3.86xl + 3.26x2 0.45
  Idle (N)  . 6.34 + 4.38x   0.42
CO 1975- Hot FTP  Y . -14.55 + 0.63x   0.81
 1976 Fed. Short Cycle . -7.80 + O.71x   0.78
  Fed. Three Mode . .6.18+2.43xl+1.52x2+5.11x3 0.60
.    
  Idle   . -4.30 + 5.70xl + 6.68x2 0.71
  Idle (N)  . -2.00 + 9.28x   0.66
NOX 1972- Hot FTP  Y - 0.49 + 0.23x   0.38
 1974 Fed. Short Cycle . -0.44 + 0.25x   
    0.36
  Fed. Three Mode . -0.43 + 0.0004x2 + 0.0006x3 0.37
  Idle   . -0.21 + 0.0016xl - 0.0027x2 0.38
  Idle (N)  . -0.18 + 0.0033x   0.09**
NOX 1975- Hot FTP  Y . -0.25 + 0.23x   0.41
 1976 Fed. Short Cycle . -0.24 + 0.26x   
    0.47
  Fed. Three Mode . -0.06+0.0001xl+0.000lx2+0.0005x3 0.24
  Idle   . -0.03 + 0.0015xl - 0.0012x2 0.34
  Idle (N)  . 0.04 + 0.0016x   0.08**
* For Fed. Three Mode xl' x2' x3 refer to 50, 30, and N modes, respectively.
For Idle xl and x2 refer to Idle (2250) and Idle (N), respectively.
** Not aiqnificant at 95 percent level of confidence.
116

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TABLE 3.29

REGRESSION EQUATIONS FOR PREDICTING ABSOLUTE CHANGE IN FTP EMISSIONS
AS A FUNCTION OF CHANGE IN SHORT TEST EMISSIONS -
ALL PHASE I VEHICLES
 Model         Correlation
Pollutant Year Short Test  Regression Equation* Coefficient
HC 1972- Hot FTP  y - 0.28 + 1.04x   Q.91
 1974 Fed. Short Cycle '" 0.33 + l.lOx   
    0.85
  Fed. Three Mode '" 0.37 + 0.0104x1 + 0.004x3 0.85
  Idle   '" 0.43 + 0.00139x1 + 0.00724x2 0.67
  Idle (N)  '" 0.43 + 0.00842   0.66
HC 1975- Hot FTP  Y - 0.08 + 0.842x   0.91
 1976 Fed. Short Cycle '" 0.20 + 0.732x   
    0.80
  Fed. Three Mode '" 0.38+0.0071x1+0.0025x2+0.0015x3 0.52
  Idle   '" 0.21 + 0.0020x1 + 0.0073x2 0.69
  Idle (N)  '" 0.22 + 0.0077x   0.68
CO 1972- Hot FTP  Y '" 5.77 + 0.862x   0.86
 1974 Fed. Short Cycle '" 6.85 + 0.951x   
    0.82
  Fed. Three Mode '" 7.61+1.92x1+8.46x2+4.84x3 0.62
  Idle   '" 7.87 + 9.91x1 + 4.09x2  0.62
  Idle (N)  '" 8.55 + 5.42x   0.50
CO 1975- Hot FTP  Y = 1.36 +  0.886x   0.93
 1976 Fed. Short Cycle '" 3.81 +  0.895x   
     0.83
  Fed. Three Mode '" 5.88 +  10.2xl - 2.89x2 + 5.91x3 0.71
  Idle   '" l. 54 +  8.29xl + 7.62x2  0.78
  Idle (N)  '" l. 48 +  10.6x   0.71
NOX 1972- Hot FTP  Y '" 0.935x     0.94
 1974 Fed. Short Cycle '" 0.02 + 0.863x   0.84
  Fed. Three Mode '" -0.09+0.0002xl+0.0007x2-0.0014x3 0.67
  Idle   '" -0.13 + 0.0032x1 - 0.0065x2 0.56
  Idle (N)  = -0.01 - O.OOllx   0.04**
NOX 1975- Hot FTP  Y '" 0.04 + 0.885x   0.94
 1976 Fed. Short Cycle '" 0.811x     0.88
  Fed. Three Mode '" 0.08+0.0001xl+0.0005x2+0.0028x3 0.39
  Idle   '" 0.09 + 0.0024Xl + 0.0005x2 0.42
  Idle (N)  '" 0.14 + 0.0024x   0.13**
*
For Fed. Three Mode xl' x2' x3 refer to 50, 30, and neutral modes, respectively.
For Idle, xl and x2 refer to Idle (2250) and Idle (N), respectively.
** Not significant at 95 percent level of confidence.
117

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TABLE 3.30
SHORT TEST CUTPOINTS BASED ON COMBINATION OF EMITTANTS
ASSUMING STRINGENCY FACTORS OF 10%, 20%, 30%, 40%, and 50%
I-'
I-'
CD
Strinqencv Factor  10\   20\  30\  40\ 50\ 
Model Year  72-74 75-76 72-74 75-76 72-74 75-76 72-74 75-76 72-74 75-76
Hot FTP HC 29.76 -- 29.76 -- 8.49 -- 7.04 -- 7.04 --
  CO 128.09 89.06 101. 31 66.47 81. 30 54.33 77 .48 46.31 66.74 39.02
  NOX -- -- -- -- -- -- -- -- -- --
Fed. Short Cycle HC 24.56 -- 24.56 -- 7.81 -- 7.81 -- 5.81 --
  CO 112.90 66.36 82.39 46.19 62.72 36.46 57.82 29.40 46.74 22.49
  NOX -- -- -- -- -- -- -- -- -- --
Fed. Three Mode (50) HC 329 -- .214 -- 194 -- 179 164 159 144
  CO 7.39 4.79 5.29 3.69 4.59 2.89 4.59 2.39 4.59 1.99
  NOX -- -- -- -- -- -- -- -- -- --
Fed. Three Mode(30) HC 699 -- 699 -- 319 -- 319 229 269 189
  CO 4.39 4.19 3.49 3.09 3.19 2.19 2.69 1.89 2.59 1. 59
  NOX -- -- -- -- -- -- 3086 -- 2787 2364
Fed. Three Mode(N) HC 789 1999 649 899 449 899 424 459 424 289
  CO -- 7.39 9.09 4.79 7.49 3.59 6.59 2.79 5.49 1.99
  NOX 266 -- 266 -- 266 -- 266 -- 103 146
Idle (2250) HC 459 -- 319 -- 239 -- 204 249 159 249
  CO 6.99 3.49 4.69 2.09 3.79 1. 39 3.19 0.89 2.39 0.59
  NOX -- -- -- -- 871 -- 717 -- 717 --
Idle (N) HC 739 1199 599 1199 599 1199 389 394 314 299
  CO 9.99 5.59 8.19 3.49 6.29 2.39 5.39 1.69 4.29 0.99
  NOX -- -- -- -- -- -- -- -- 111 --

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TABLE 3.31
IDLE (N) CUTPOINTS AND NUMBER OF FAILURES FOR VARIOUS
HC/CO RATIOS AT A 30% STRINGENCY FACTOR
   Combined   Actual 
HC/CO Model  Cutpoints  Failures 
Ratio Year HC CO NOX HC CO NOX
10 72-74 259 -- -- 95 -- --
 75-76 149 -- -- 96 -- --
5 72-74 259 -- -- 95 -- --
 75-76 149 3.49 -- 96 82 --
2 72-74 269 8.19 -- 92 36 --
 75-76 299 2.39 -- 32 98 --
0.5 72-74 1149 6.09 -- 16 75 --
 75-76 1199 2.39 -- 1 98 --
0.1 72-74 -- 5.99 -- -- 80 --
 75-76 -- 2.29 -- -- 102 --
119

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TABLE 3.32
COMPARISON OF ESTIMATED PERCENT BENEFITS FOR
30% STRINGENCY FACTOR AND VARIOUS HC/CO RATIOS
 HC/CO Ratio HC CO NOX
1972-1974 10 9 9 2
 5 9 9 2
 2 10 10 2
 1 10 12 0
 0.5 11 13 0
 0.1 11 14 0
 Appendix N* 7-12 12-20 
1975-1976 10 22 21 4
 5 21 21 4
 2 21 20 4
 1 19 20 4
 0.5 19 20 4
 0.1 18 20 4
 Appendix N* 10-14 21-30 
* Range of first year benefit. Low number represents no
mechanic training and high humber represents full mechanic
training. These values are the most recent EPA estimates
as of December, 1977.
120

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            lJ.'i\_.~T...I ~ 3."33      
            TUNr UP INFIIRHATION      
            ALL PHASE 1 VEHICLES      
             DIAGNOSIS      
     NOT APPLICABLE SYStEH OK  REPLACED PER REPLACED PER REPA/RF.D ADJUSHn
            'iEKVltE SCHEDULE DIAGNOSIS    
  SYSTEH  ~I "  N "   N " N % N % N :I
 AIR CLEANER SFRVICE 0 0.0  In 119.6   0 0.0 6 3.1 14 7.3 0 0.0
 AIR CLEANER FILTER  0 0.0  1J8 71.5  16 8.3 39 20.2 0 0.0 0 0.0
 Alii SYS IEM 123 6).7  (>'. H.2   0 0.0 3 1.6 3 1.6 0 0.0
 AIR PUHP BElT 173 "3.7  65 H.7   0 0.0 2 1.0 0 0.0 3 1.6
 HEAT RISER VALVE 104 53.9  II] 43.0   0 0.0 0 0.0 b 3.1 0 0.0
 IDLE RpH  0 0.0  8 4.1   0 0.0 u 0.0 0 0.0 185 95.9
 IDLE A'F RATIn  1 0.5  16 8.3   0 0.0 0 0.0 0 0.0 176 91.2
 CH[lKE A( TI ON  6 3.1  1110 93.3   0 0.0 0 0.0 3 1.6 " 2.1
 (AI  156 80.8  13 6.7 21 10.9 0 0.0 0 0.0
 Pcv 5YSTEII  1 u.5  1'12 711."  14 7.3 17 8.8 8 4.1 1 0.5
 EGf( SYSTEM  18 19.7  142 13."   0 0.0 4 2.1 9 4.7 0 0.0
 EXIfAUST SY5TEII  0 1).0  191 99.0   0 0.0 0 0.0 2 1.0 0 0.0
 VAf.UU14 5Y5TEM  0 0.0  169 117.0   0 0.0 0 0.0 25 13.0 0 0.0
 El[(. IGIH T ION  87 45.1  106 5',.9   0 0.0 0 0.0 0 0.0 0 0.0
 DISTRIBUTOR (AI'  0 0.0  111 99.0   2 1.0 0 0.0 0 0.0 0 0.0
 ROTOR     0 0.0  19u 9B.'o   2 1.0 1 0.5 0 0.0 0 0.0
 POINTS    106 5',.9  62 32. I   6 3.1 7 3.6 0 0.0 12 6.2
 AOVAIIC E MECHA:>I15t1  0 0.0  1'18 97.4   0 0.0 2 1.0 3 1.6 0 0.0
 IGN/TIOI~ ~IRES  0 0.0  189 97.9   0 0.0 4 2.1 0 0.0 0 0.0
 ElECTRI(AL WIRES  0 0.0  1118 97.4   0 0.0 1 0.5 " 2.1 0 0.0
 COIL     0 0.0  192 99.5   1 0.5 0 0.0 0 0.0 0 0.0
 COIIDENSER 106 5',.9  17 39.9   4 2.l 6 3.1 0 0.0 0 0.0
 SPARK PLUGS  0 0.0  151 78.2  72 1l.4 16 8.3 0 0.0 4 2.1
 TI H WG     0 0.0  44 22.8   0 0.0 0 0.0 0 0.0 l't9 77.2
 DWFlL    1"7 55.4  34 17.6   0 0.0 0 0.0 0 0.0 52 26.9
   EHISSION (UrpOrNTS /IRE : 72-74 HODEL YR - CIJ 5.51 III 400 PPH      
       : 75-7b HrJDF.L YR - ((I 1.Ot 1ft 250 PPH      

-------
           TABLE 3.34      
           TUN£ UP INFORMATION      
           PASSINCi PHASE 1 YEHICLU     
           DUCiHIISIS       
    "I'IT APPllfADLF. sysnK OK R[PLAUD PER REPLACED PER R£"IRFD ADJUSTED
           SERVICE SCHEDULE 0 /ACiNOS IS    
  SYS TE" N "  " "   N S N S N " to! II
 AIR CLEAN[R SERVICE 0 0.0 111 9"."   0 0.0 2 1.6 , 4.0 0 0.0
 AIR CLEANER FILTER 0 0.0 91 H.4   12 9.7 21 16.9 0 0.0 0 0.0
 AIR SYSTEM "" '1.6  55 44.4   0 0.0 3 2.4 2 1.6 0 0.0
 AIR PlI"P 8El T 64 '1.6  55 44.10   0 0.0 2 1.6 0 0.0 3 2.4
 HEAT RISER YALVE 10 56.5  "iZ 41.9   0 0.0 0 0.0 2 1.6 0 0.0
 IDLE IIPM 0 0.0  1'1 6.5   0 0.0 0 0.0 0 0.0 116 n.5
 IDLE AIF UTIli 0 0.0 15 12.1   0 0.0 0 0.0 0 0.0 109 87.9
..... CHLIKE ACTION 3 2.4  III> 93.5   0 0.0 0 0.0 1 0.8 " J.2
r-.> CAR8. FlIlAT 4 3.2  117 910."   0 0.0 2 1.6 0 0.0 1 0.8
r-.> CAR8URETUR 4 3.2  107 86.3   0 0.0 0 0.0 4 J.2 9 7.3
 FUel F IL TER 0 0.0  109 '7.9   8 6.' 7 '.6 0 0.0 0 0.0
 FUEl PU"P 0 (1.0  11.'> 100,11   0 0.0 0 0.0 0 0.0 0 0.0
 r ILUR CAP 0 0.0  IlJ 99.2   0 0.0 1 0.8 0 0.0 0 0.0
 FUel SYSTEM 0 0.0  12" 100.0   0 0.0 0 0.0 0 0.0 0 0.0
 EVAP. COtITA INER 1 0.1'1  105 '''.7   6 ".8 12 9.1 0 0.0 0 0.0
 PC Y SYSTEH 0 0.0  99 79.1'1   10 '.1 10 '.1 4 3.2 1 0.8
 ECiIl SYSTEM 23 11'1.5  9'. 75.8   0 0.0 0 0.0 7 '.6 0 0.0
 EllIIAUH SYSTEM 0 0.0  122 98."   0 0.0 0 0.0 2 1.6 0 0.0
 VACUUH SYSTEM 0 0.0  101'1 87.1   0 0.0 0 0.0 16 lZ.9 0 0.0
 ElEt. ICNITION 58 46.11  66 53.2   0 0.0 0 0.0 0 0.0 0 0.0
 0lSTRI8UTOR C6P 0 0.0  122 98.4   2 1.6 0 0.0 0 0.0 0 0.0
 ROfOli   0 (1.0  112 91.4   2 1.6 0 0.0 0 0.0 0 0.0
 POINTS   66 53.2  45 36.3   3 2." 2 1.6 0 0.0 11 6.5
 ADVANCE HEeIIANI SH 0 0.0  123 99.2   0 0.0 0 0.0 1 0.11 0 0.0
 ICNITION WIRES 0 0.0  123 99.2   0 0.0 1 0.' 0 0.0 0 0.0
 ELECTIIICAL WIRES 0 0.0  110 96.8   0 0.0 1 0.8 3 2.4 0 0.0
 COIL   0 0.0  123 99.7   1 0.8 0 0.0 0 0.0 0 0.0
 CDNDENSER 66 53.2  55 44.'.   2 1.6 1 0.1'1 0 0.0 0 0.0
 SPARK PLUCS 0 0.0  100 80.6   lb 12.9 7 5.6 0 0.0 1 0.8
 TI M I NC   0 0.0  :J2 25.8   0 0.0 0 0.0 0 0.0 92 1".2
 OWHl   67 54.0  23 11'1.5   0 0.0 0 0.0 0 0.0 J4 21."
  E"I5'>ION CUTPDINTS ARE I 72-74 HOoH YR - CO 5.S!! HI. 400 PPM      
     I 75-76 MOOH YR - CO 2.0" III 250 "M      

-------
             TABLE 3.35          
             Tlmr UP INFORHATION       
             FAILING PHASE 1 I F A III NG PItASE 2 VEHICLES    
              DIIIGNOSIS          
      NOT APPIICA8lE SYSTEH 01<  II(PlACED PER REPlACHI PER REPAIRED AOJUS TE 0
             SERVICE SC HE Dill E DIAGNOSIS    
  S't'SHH II X  tj  X   N S   N X N 2; N S
 AIR ClEANER SERVICE I 0.4  lJ2  89.9   0 0.0   10 3.9 15 5.8 0 0.0
 AlII CLEANER FILTER 0 0.0  198  76.7   10 3.9   50 19.10 0 0.0 0 0.0
 AIR SYSTEH   2ZZ 111,.0  H  12.8   0 0.0   1 0.10 2 0.8 0 0.0
 AlII PUHP Bel T 222 86.0  36  110.0   0 0.0   0 0.0 0 0.0 0 0.0
 HEAT RISER VALVE 1310 51.9  116  "5.0   0 0.0   I) 0.0 8 3.1 0 0.0
 IDLE RPH   0 0.0  1  0.10   0 0.0   0 0.0 0 0.0 257 99.6
 IDLE AlF RATIO 1 0.10  2  0.8   0 0.0   0 0.0 0 0.0 255 98.8
I-' CHIIKE AC TJ ON 10 3.9  lJlI  92.2   0 0.0   0 0.0 7 2.7 3 1.2
"" CARB. flOAT   10 3.9  2100  96.1   0 0.0   0 0.0 0 0.0 0 0.0
(.oJ        
 CAIIBURETOR   10 3.9  213  82.6   0 0.0   0 0.0 110 5.4 21 B.l
 FUfl FILTER   0 0.0  224  86.8   28 10.9   6 2.3 0 0.0 0 0.0
 FUrl PUMP   0 0.0  258 100.0   0 0.0   0 0.0 0 0.0 0 0.0
 FILLER CAP   0 0.0  256  99.2   0 0.0   2 0.8 0 0.0 0 0.0
 FUn SYSTEH   0 0.0  256  99.2   0 0.0   1 0.10 1 0.4 0 0.0
 EVAP. CUNTAINf.1t 7 2.7  210  81.4   16 6.2   25 9.7 0 0.0 0 0.0
 PCV SYSTEM   3 1.2  208  80.b   16 6.2   2l 8.5 9 3.5 0 0.0
 [GII SYSTEH   66 25.6  170  b5.9   0 0.0   6 2.3 16 6.2 0 0.0
 EXHAUST SYSTEH 0 0.0  251  99.6   0 0.0   0 0.0 1 0.4 0 0.0
 VALUUM SYSTEH 0 0.0  220  85.3   0 0.0   (\ 0.0 3B 110.7 0 0.0
 H£C. IGNITIUN 122 41.3  136  !J2.7   0 0.0   0 0.0 0 0.0 0 0.0
 DISTRIBUTOR CAP 0 0.0  251  97.3   0 0.0   7 2.7 0 0.0 0 0.0
 ROTOR     0 0.0  251  97.3   2 0.8   5 1.9 0 0.0 0 0.0
 POINTS     136 52.7  83  H.2   11 4.3   16 6.2 0 0.0 12 4.7
 ADVANCE MECHANISH 0 0.0  245  95.0   0 0.0   5 1.9 8 3.1 0 0.0
 IGIUTION WIRES 0 0.0  247  95.7   0 0.0   11 4.3 0 0.0 0 0.0
 ElECTRICAL WIRES 0 0.0  257  99.6   0 0.0   0 0.0 1 0.4 0 0.0
 COil     0 0.0  258 100.0   0 0.0   0 0.0 0 0.0 0 0.0
 CDtmENSER   136 52.7  109  io2. 2   5 1.9   II 3.1 0 0.0 0 0.0
 SPARK PLUGS   0 0.0  198  76.7   22 8.5   20 7.8 0 0.0 18 7.0
 T I., I ~IG     0 0.0  3b  14.0   0 0.0   0 0.0 0 0.0 212 86.0
 OWfll     136 52.7  50  19.4   0 0.0   0 0.0 0 0.0 7Z 27.9
  E"ISSION CUTPOINfS ARE : 7Z-H HODEl VR - CII 5.51 IIC  ..00 pr"         
       : 75-76 HnOEI YR - CII 2.01 HC  250 PPM         

-------
TABLE 3.36
       TUln UP INFORMATION        
       ALL PHASE I VEHICLES        
       1975-1976 MODEL VEAl'        
          DIAGNOSIS         
    NOT APPL !C/IDLE SVSTEtI OK ItEPLACEn PER REPLACED PER REPAIRED ADJUSTED
           SERVICE SCHEDULE 0 IAGNOS IS    
 "ANUF AC TUR ER N SVS If"  N 1   N 1 N 1 N I N 1 N I
 GENERAL MOTORS ~o IDlE ItPM  0 0.0   ) 7., 0 0.0 0 0.0 0 0.0 37 92.5
  IDLE AlF RATIO 0 0.0   ) 7.5 0 0.0 0 0.0 0 0.0 37 92.5
  TI H I HG  0 0.0 16 400.0 0 0.0 0 0.0 0 0.0 H 60.0
  "WFll  ~o 100.0   0 0.0 0 0.0 0 0.0 0 0.0 0 0.0
 FORO 25 IDLE ItPM  0 0.0   I ~.O I) 0.0 0 0.0 0 0.0 24 96.0
  IDLE AlF RATIO 0 0.0   4 16.0 0 0.0 0 0.0 0 0.0 21 84.0
  TI M I NG  0 0.0   8 )2.0 0 0.0 0 0.0 0 0.0 17 68.0
  DWEll  25 100.0   0 0.0 0 0.0 0 0.0 0 0.0 0 0.0
.....                   
'" (llIIVSLER 15 IDLE ItP"  0 0.0   0 0.0 0 0.0 0 0.0 0 0.0 15 100.0
.c.  IDLE /lIF ItAT 10 0 0.0   0 0.0 0 0.0 0 0.0 0 0.0 15 100.0
  TI M I NG  0 0.0   2 13.) 0 0.0 0 0.0 0 0.0 13 86.7
  DWEll  1 5 1 00 . 0   0 0.0 0 0.0 0 0.0 0 0.0 0 0.0
 AM~RIUN MOTORS. 6 IDLE ItP"  0 0.0   0 0.0 0 0.0 0 0.0 0 0.0 6 100.0
  IDLE AlF RATIO 0 0.0   1 16.7 0 0.0 0 0.0 0 0.0 , BJ.)
  TI"ING  0 0.0   2 )).) 0 0.0 0 0.0 0 0.0 4 66.7
  DWELL  6 100.0   0 0.0 0 0.0 0 0.0 0 0.0 0 0.0
 FOIIEIGN 25 IDLE ItPM  0 0.0   4 16.0 0 0.0 0 0.0 0 0.0 21 84.0
  IDLE AlF RAT 10 I 4.0   5 20.0 0 0.0 0 0.0 0 0.0 19 76.0
  TIMING  0 0.0   6 H.O 0 0.0 0 0.0 0 0.0 19 76.0
  OWF.l L  7 28.0 10 ~0.0 0 0.0 0 0.0 I) 0.0 8 32.0
 E" I S'i JON CUTPOINrs ARE & 12-H MODel YI\ - CD '.51  IIC 400 PPM         
   : 7'-76 M(JOEl Vit - CU 2.01  H( 250 "M         

-------
TABLE 3.37
         TUIIF UP I NfORHA TI ON        
         PAS'iIN(; PHASE 1 VEHICLES       
         1975-191b HODEl YEAR        
           OI/lGNOSIS          
      NOT APPLIC/IBLE SYS HH OK  REPLACEn PER REPLACED PER REPAIRED ADJU'i TE D
              SEIIVICE SCHEDULE DIAGNOSIS    
 HANUfACTURER N C;YSTEH   N :I  N  1   1'1 II N :I N :I N 1
 GHIER/ll HOTORS 21 IOU RPH  0 0.0  3 1101   n 0.0 0 0.0 0 0.0 24 88.9
   IDLE Alf RATIO 0 0.0  3 11.1   II 0.0 0 0.0 0 0.0 Zit 88.9
   r IHING   0 0.0 12 44.4   " 0.0 0 0.0 0 0.0 15 55.b
   OWELI   21 100.0  0  0.0   " 0.0 0 0.0 0 0.0 0 0.0
 FORO 20 IOlE PPH  0 0.0  1  5.0   0 0.0 0 0.0 0 0.0 19 95.0
......   IUU AIF R/IT IU 0 0.0  " 20.0   0 0.0 0 0.0 0 0.0 lb 80.0
IV   T I HI'I(;   0 0.0  1 35.0   0 f).0 0 0.0 0 0.0 13 b5.0
U1   DW[ll   20 100.0  0  0.0   I) 0.0 0 0.0 0 0.0 0 0.0
 CHRYSlER 5 IDLE RPH  0 0.0  0  0.0   /) 0.0 0 0.0 0 0.0 5 100.0
   IDLE /lif RATIO 0 0.0  0  0.0   0 0.0 0 0.0 0 0.0 5 100.0
   TIHINl.   0 0.0  1 20.0   I) 0.0 0 0.0 0 0.0 4 80.0
   nWELL   5 100.0  0  0.0   0 1).0 0 0.0 0 0.0 0 0.0
 AH[RICAN HOTORS 2 IDLE RPH  0 0.0  0  0.0   0 0.0 0 0.0 0 0.0 2 100.0
   IDLE AIF RAT 10 0 0.0  1 50.0   0 0.0 0 0.0 0 0.0 1 50.0
   TIHINe;   0 0.0  1 50.0   0 0.0 0 0.0 0 0.0 1 50.0
   IIWEll   2 100.0  0  0.0   0 0.0 0 0.0 0 0.0 0 0.0
 fOI/EIGN 111 IDLE RPH  0 0.0  10 22.2   0 0.0 0 0.0 0 0.0 lit 17.8
   IDLE AlF R/Ir 10 0 0.0  10 22.2   0 0.0 0 0.0 n 0.0 110 77.8
   TI H I'IG   0 0.0  5 27.8'   0 0.0 0 0.0 0 0.0 13 72.2
   DWelL   " 22.2  7 38.9   0 0.0 0 0.0 0 0.0 1 38.9
 E"IHION CUTPDINTS ARE I 72-74 HOOEl YR - CU 5.51  IIC 1000 PPH         
     I H-1b HODel VR - en 2.01  lit: 250 PPII         

-------
TABLE 3.38
        TUNf UP INFORMaTION        
        FailING PHISE 1 I FaILING PHISE 2 YEHIClES     
        1975-1976 MODEL YEaR        
           DiaGNoSIS          
     NOT ArPI ICAIIlE SYSTEH OK REPLACED PER REPLACED PER REPUREO ADJUSTED
            SERVICE SCHEDULE 01 AGNOS IS    
 MaNUFACTURER N C;YSTFM   N '   N "   N ' N 1 N I N '
 GENERAL HOTOR5 5b IDLE RP"  0 0.0   I 1.8   0 0.0 0 0.0 0 0.0 " 911.2
   IDLE AlF RAT 10 0 0.0   0 0.0   0 0.0 0 0.0 0 0.0 5b 100.0
   TIHING   0 0.0 13 23.2   0 0.0 0 0.0 0 0.0 ~3 1b.1I
   nWE Ll   5b 100.0   0 0.0   0 0.0 0 0.0 0 0.0 0 0.0
~ FORD Ib IDLE RP"  0 0.0   0 0.0   0 0.0 0 0.0 0 0.0 16 100.0
IV   10l.E AlF RATIO 0 0.0   0 0.0   0 0.0 0 0.0 0 0.0 16 100.0
0\   TI " I NG   0 0.0   J 11.11   0 0.0 0 0.0 0 0.0 U 81.3
   DWEll   16 100.0   0 0.0   0 0.0 0 0.0 0 0.0 0 0.0
 CHRYSlER 29 IDLE RP"  0 0.0   0 0.0   0 0.0 0 0.0 0 0.0 Z9 100.0
   IDLE AlF RATIO 0 0.0   0 0.0   0 0.0 0 0.0 0 0.0 Z9 100.0
   flHING   0 0.0   6 20.7   0 0.0 0 0.0 0 0.0 Z3 19.3
   "wnl   29 100.0   0 0.0   0 0.0 0 0.0 0 0.0 0 0.0
 AM[RICAN HDTORS 9 IDLE RPH  0 0.0   0 0.0   0 0.0 0 0.0 0 0.0 9 100.0
   IDLE alF RAT IU 0 0.0   0 0.0   0 0.0 0 0.0 0 0.0 9 100.0
   TIHING   0 0.0   2 22.2   0 0.0 0 0.0 0 0.0 7 17.-
   "WEll   9 100.0   0 0.0   0 0.0 0 0.0 0 0.0 0 0.0
 FOREIGN .... IDLE RP"  0 0.0   0 0.0   0 0.0 0 0.0 0 0.0 H 100.0
   IDLE AIF RAT IU I 7.1   1 7.1   0 0.0 0 0.0 0 0.0 IZ 15.1
   TJ H I He   0 0.0   3 21."   0 0.0 0 0.0 0 0.0 11 18.6
   DWEll   3 21."   1 50.0   0 0.0 0 0.0 0 0.0 " 21.6
 ["15'iION CUTPOINTS IRE I 12-TIt HODEl YR - CIJ 5.51  lie "00 PPH        
    I 15-76 HODH YR - CO 2.01  He 250 PPH        

-------
        TABLE 3.39        
        TtJI'f UP I NFORHA T lor.        
        All PHASE 1 VElIlClES        
         0 IAGNIJ515        
     NOT APPllCADlE 5YSTEN OK REPLACED PER REPlUED PER REPAIRED ADJUSTED
            SERVICE SCIIEDUlE DIAGNOSIS    
  14 SYS J(H  14 %  If J    II J N S N % N 1
1912-1974 HODEL YEAR 82 IOL E RPH  0 0.0  0 0.0   0 0.0 0 0.0 0 0.0 82 100.0
   IDLE AIF RAT 10 0 0.0  3 3.7   (I 0.0 0 0.0 0 0.0 79 96.3
   TIHING  0 0.0  10 12.2   0 0.0 0 0.0 0 0.0 72 87.8
   OWEll   I', 17. I  24 29.3   0 0.0 0 0.0 0 0.0 H 53.7
1975-1976 HOOEl YEAR 111 I OL E RPH  0 0.0  8 7.2   0 0.0 0 0.0 0 0.0 103 92.8
   IDLE AIF RAT 10 1 0.9  13 11.7   0 0.0 0 0.0 0 0.0 97 87.4
   TIHING  0 0.0  3', 30.6   0 0.0 0 0.0 0 0.0 77 69.4
   DWEll   93 83.8  10 9.0   0 0.0 0 0.0 0 0.0 8 7.2
EHISSIOII CUTPOINTS ARE I 7Z-74 "0DH YR - CO 5.51
: 75-76 HOOEl YR - CO 2.01
IIC '000 PPH
IIC 250 PPH
I-'
IV
--.J
       TABLE 3.40       
       Tll/lf UP I NFOIIHA T I L"I       
       PAS~INe. PHASE 1 VlttlCLES       
        DIALNOSIS        
    tmT APPLICA8lE SYSIE/1 UK KCPl/lCEO PER REPlACEO PER REPAIREO AOJUS TEO
          SFIIVICE SC liE DUl E OIAGNOSIS    
  N SYSTEH  H 1 N  1 N ~ N 1 N 1 N J
1972-1974 HODEl YEIIR 52 IIILE P,PH  0 0.0 0  0.0 0 1).0 0 0.0 I' 0.0 52 100.0
   IOLE A/F RAT 10 0 0.0 3  5.8 0 0.0 0 0.0 0 0.0 49 9'0.2
   TIHINe.  0 0.0 ~ 11.5 0 0.0 0 0.0 0 0.0 46 88.5
   flWElL  9 17.3 II> 30.8 0 0.0 0 0.0 0 0.0 27 51.9
19H-1976 MOOH YEAR 7Z IDLE RPH  0 0.0 8 11.1 0 0.0 0 0.0 0 0.0 64 88.9
   IDLE AlF RATIU 0 0.0 12 16.7 0 0.0 0 0.0 0 0.0 60 83.3
   TIHING  0 0.0 26 3601 0 0.0 0 0.0 0 0.0 46 63.9
   DWEll.  ~O 80.6 7  9.7 0 0.0 0 0.0 0 0.0 7 9.7
EMISSION CUTPOIHTS ARE: 72-74 HODEL YR - CO 5.51
I 75-76 HnOEL YR - CO 2.01
IIC 400 PPH
HC 250 PPH

-------
TABLE 3.41
      TUNE UP INFoaHUION       
      faILING PltASE 1 I F A III NG PHASE 2 VEHICLES     
      DIAGNOSIS        
   NUT APPLICABLE SYSTEH OK ItEPLACED PEa REPLACED PEa REPAIRED ADJUSTED
        SFRVICE SCHEDULE DIAGNOSIS    
 N SYSTEH  N I N I ~I , N I N S N I
 1972-1974 HODEL YEAR 13~ IDLE ItP"  0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 134 100.0
  IDLE A/F RATIO 0 0.0 1 0.7 0 0.0 0 0.0 0 0.0 133 99.)
  TI H Hie  0 0.0 9 b.7 0 0.0 0 0.0 0 0.0 125 93.3
  nWEL L  23 17.2 41 32.1 0 0.0 0 0.0 0 0.0 be 50.7
 197'-1976 HODEL YEAR 124 'DIE RP"  0 0.0 1 0.8 0 0.0 0 0.0 0 0.0 123 99.2
~  IDLE A/F RATIU 1 0.8 I 0.8 0 0.0 0 0.0 0 0.0 122 98.4
II.)  TI"I"tG  0 0.0 27 21.8 0 0.0 0 0.0 0 0.0 97 78.2
CD  nilE II  II) 91.1 7 5.b 0 0.0 0 0.0 0 0.0 4 3.2
EHISSION eUTPOINTS ARE t 72-74 ""DEL YR - CO 5.51
t 7'-7b HODEL YR - CO 2.01
He 400 PPH
He 250 pp"

-------
    TABLE 3.42    
    VEHICLE TUNEUP COST SUMMARY BY MODEL YEAR  
    ALL PHASE 1 VEHICLES    
        MANUFACTURER  
  EMISSION RELATED riAL ADJUS TMENT / RECnMME"IDED TOTAL COSTS
MODEL  TUNEUP COS15 DISABLfMENT COSTS MAINTENANCE PER VEHICLE
YEAR N MEAN SO MEAN SO MEAN SO MEAN SO
1972 25 PARTS 12.110 14.72 1.59 7.23 3.39 9.98 17.79 17.80
 LABOR 28.40 11.16 1.08 2.84 3.40 8.34 32.89 12.09
 TOTAL 41.21 22 .82 2.67 9.25 6.79 17.34 50.67 z5.15
1973 27 PARTS 10.18 11.22 0.00 0.00 4.48 9.33 14.66 13.47
 LABOR 24.50 9.78 0.90 2.62 5.30 10.01 30.70 12."6
 TOTAL 3ft.68 18.73 0.90 2.62 9.78 19.02 45.36 23.79
1974 30 PARTS 6.65 8.43 0.28 1. 52 3.58 7.07 10.51 11.25
 LABOR 22.'.5 9.96 1.35 3.23 3./19 6.95 27.49 13.(')6
 TOTAL 29.11 15.30 1.i<)3 4.27 7.27 1.3.47 38.01 21.23
72-74 82 PARTS 9.69 11.68 0.59 4.09 3.82 11.69 14.10 14.37
 LAFIOR 24.94 10.45 1. L2 2.89 4.13 8.41 30.19 12.75
 TOTAL 34.63 19.38 1. 7l 5.88 7.95 lb.49 44.29 23.62
75-76 111 PARH 2.47 6.12 0.08 0.80 2.15 5.91 4.69 9.22
 LABOR 15.56 9.90 2.44 5.56 3.49 7.41 21.49 13.60
 TOTAL 18.02 13.57 2.52 5.76 5.64 12 .92 26.18 20.53
     TABLE 3.43    
     VEHIClE TUNEUP LOST SUMMARY BY MODEL YEAR  
     PASSING PHASE 1 VEHICLES    
          MANIJF AC TURE R  
   EMISSla~ RELATED HALAOJUSTIIENT/ RECmtHENDED TOTAL CUS TS
HODEL   TUNEUP COSTS  OISAALEMENT COSTS HUNTE/lANCE PER VEHICLE
YEAR N  HEAN SD  HEAN  SO MEAN SO HEArl SD
1972 14 PARTS 6.45 10.72 0.00  0.00 2.52 9.43 8.97 12.99
  LADOR 25.b5 9.44 0.58  2.16 2.41 9.02 28.b4 8.99
  rUTAL 32.1' 17.48 0.58  2.1b 4.93 18.45 37.61 19.38
1973 16 PARTS 6.94 8.47 0.00  0.00 '..53 7.81 11.48 12.86
  LA80R 22.53 '.59 0.59  2.36 5.110 8.61 28.52 12.92
  TOTAL 29.47 16.24 0.59  2.36 9.93 15.81 40.00 23.57
1974 7.2 PARTS 8.68 8.96 0.00  0.00 3.92 7.89 12.61 1l.99
  LAAOR 22.70 10.el 1.10  2.96 4.17 7.84 27.98 14.42
  TOTAL 31.39 16.93 1.10  2.96 11.10 15.08 40.59 23.26
72-74 52 PARTS 7.55 9. I?  0.00  0.00 3.73 8.18 1l.28 12.38
  LMOM 23.'+4 9.99 0.80  2.55 4.08 11.32 28.32 12.47
  TOTAL 30.99 16.57 0.80  2.55 7.81 16.05 39.60 21.99
7'-76 72 PARTS 1.80 5.08 0.00  0.00 2.58 6.47 4.37 9.14
  LABOR 15.47 10.82 2.55  6.35 3.69 8.00 21.71 15.52
  TOTAL 17.27 14.7.9 2.55  6.35 6.27 14.08 26.09 22.71
129

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f~LE 3.44
    VElIlClE TUNEU, COST SUMMARY BY MODEL YEAR  
    FAllINC PHASE 1 I FAILINC PHASE 2 VEHICLES  
       MANUFACTURER  
  EMISSION RELATED MAlADJUSTMENTI RECOMMENDED TDTAL COSTS
HDDEL  TUNEUP COSTS  OISARL[MENT COSTS MAINTENANCE Pelt VEHICLE
YEAR N HEAN SO  HEAN SO MEAN SO HUN SO
1972 50 PARTS 11.13 13.30 1.58 7.05 3.11 8.22 15.83 17.53
 LAkOR 26.78 10.64 0.99 2.92 3.19 6.80 30.96 11.09
 TOTAL 37.92 20.70 2.57 9.58 6.30 13.86 46.78 24.31
1973 53 PAPTS 6.91 10.04 0.07 0.47 3.84 8.56 10.82 1l.92
 LABUR 24.55 10.64 0.79 3.20 4.05 11.45 29.3' 10.14
 TOTAL 31.1t7 17.90 0.85 3.62 7.89 16.25 40.22 19.07
1974 31 PARTS 4.24 7.bJ 0.37 1.58 2.32 4.86 6.94 9.27
 LABOR 23.17 10.82 1.05 3.03 3.92 8.33 28.13 9.38
 TOTAL 27.41 15.43 1.42 4.41 6.24 11.108 35.07 16.15
72-74 13'0 PAIITS 7.87 11.19 0.70 10.101 3.22 7.69 11.7' 14.14
 lAFlUR 25.07 10.70 0.92 3.04 3.70 7.79 2'.68 10.32
 TOTAL 32.910 18.112 1.62 6.112 6.92 14.29 41.48 20.97
75-76 124 PARTS 3.03 6.710 0.07 0.711 1.51 4.64 4.61 8.69
 LABOR 20.01 8.34 0.77 2.36 3019 7.23 23.97 8.56
 TOTAL 23.04 11.56 0.84 2.U 4.70 1l.46 28.59 14.99
130

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    TABLE 3.45      
      VEHICLE TUIIEUP COST SUHHARY BY MANUFACTURER 
      ALL PHASE 1 VEHICLES    
             ~lAljUFACTURER  
   EHISSIOII RELATED  MALADJUSTMENT/ RECOMMENDED TOTAL COSTS
   TUNEUP cosrs   DISABLEMENT COSTS MAINTENANCE PER VEHICLE
PlANUFACTURER N  HEAN SD   MEAN SO  MEAN SO HEAN SO
GENERAL MOTORS 76 PAI\TS  7.73 11.12    0.00 0.00 2.94 b.99 10.b7 13.11
  LABOR  20.66 12. ',9    0.91 2.32 3.48 6.53 25.05 15.13
  TOTAL  28.39 21.31    0.91 2.32 6.42 12.58 35.71 25.71
FORD  44 PARTS  3.36 5.80    1.20 5.67 2.90 7.45 7.46 12.33
  LA80R  19.42 9.63    2.39 3.92 3.74 7.85 25.56 13.21
  TOTAL  22.78 13 .18    3.60 8.18 6.64 15.04 33.01 22.98
CHIIYSLER  25 PARTS  8.07 12.27    0.15 0.75 2.32 4.64 10.54 14.08
  LABOR  22.25 11.64    2.70 5.90 3.73 6.02 28.67 14.26
  TOTAL  30.32 20.09    2.85 5.91 6.05 9.94 39.22 22.90
AMfR1CAII /'IOTORS 9 PARTS  5.13 8.06    0.00 0.00 l.bS 4.95 6.7B 10.15
  LAt'OR  12.'10 9.;>3    4.20 5.12 3.15 ',.77 20.25 II.A7
  TUTAL  18.03 16.32    4.20 5.12 4.80 9.25 27.1)3 20.31>
FOREIG/I  39 PARTS  2018 ~.52    0.00 0.00 3.29 9.32 5.47 la.70
  LMOR  17.31 9.7.8    2. 15 7.07 4.50 11.31 23.95 12. 3B
  TUTAL  19.',9 13.'It.    2.15 7.07 7.79 2J.45 2'1.42 20.14
 EMISSION curp'lINTS ARE : 72-74 MODEL VA - r'l 5.5": HC 400 PPM    
   : 75-71> Mr'JOrL VR - CU 2.0~ Hl 250 PPM    
   T1.\BLE 3.4(-)       
     VEHICLE TUNEUP COST SUMMAR V  BY MANUFACTURER 
     PASSING PHASE 1 VEHICLES    
           MAflUFAC TURER  
  EMISqON RELATED ftALAD.IUS Tl1ENT I RECOMHENDED TOTAL COSTS
  TUNF.UP COSTS   nISABL~HENr COSTS MAINTENANCE PER VEHICLE
HAUUFACTURER N  MEAN SO   HE AN   SO  MEAN SO MEAN SO
GENERilL HOTORS 55 PARTS  t..99 9.4"   0.00  0.00 3.25 6.73 10.24 12.29
 LAnOR  20.23 12.B   0.79  2.20 3.80 1>.86 24.82 15.33
 TOTAL  27.22 19.80   0.7<)  2.20 7.05 12.94 35.06 25.57
FORD 32 PARTS  2.7', 5.32   0.00  0.00 J.t.O 8.4'1 6.34 10.83
 LABOR  lB.t.O 9.49   1.35  2.81 4.21> 8.75 24.22 14.33
 TOTAL  21.35 12.64   1.35  2.81 7.8t. 17.07 30.56 23.62
CHRVSLER 9 PARTS  3.01 7.73   0.00  0.00 0.63 1.89 3.t.4 7.1>9
 LA80R  21>.10 13.62   4.80  9.13 1.80 4.48 32.70 18.76
 TUTAL  29.11 19.7.3   4.80  9.13 2.43 4.99 3b.34 22.21
AHERICAN MOTORS 3 PARTS  2.'14 5.10   0.00  0.00 4.95 8.57 7.8'1 13.67
 LA8UR  9.45 2.70   4.05  7.01 4.50 7.79 18.00 9.95
 TUTAL  12.39 7.51>   4.05  7.01 'L45 11>.36 25.B9 21.61
FOAEICN 2~ PARH  0.54 1.62   0.00  0.00 2.6;> 7.87 3.16 7.85
 LA80R  14.47 7.Q2   3.~5  B.1>5 4.10 10.87 21.92 11.84
 TOTAL  15.01 A.35   3.35  8.65 1>.72 18.5', 25.08 17.40
EMISSION CUT~OlNTS ARE : 72-74 HODEL YR - CO 5.5%  HC 400 PPM    
  : 75-76 HIlDEl VR - CIJ 2.0"  IIC 250 PpM    
131

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   TABLE 3.47      
    VEHtClE TUNEUP CUST SUMMARY BY MANUFACTURER 
    FA 11ING PHASE 1 I FAiliNG PHASE 2 VEHICLES  
         MANUFACTURER  
  EMISSION RELATED MALADJUSTMENT I  RECOMMENDED TOTAL CUSTS
  TUNE UP COSTS DISABLEMENT COSTS MAINTENANCE PER VEHICLE
MANUFACTURER ~ MEAN SD HEAN SD  MEAN SD MEAN SD
GENERAL MOTORS 93 PARTS 5.86 9.92 0.00 0.00 3.22 1.1B 9.01 12.56
 lABOR 23.02 10.nl 0.28 1.33 3.99 8.03 21.2<1 10.61
 TOTAL 28.88 16.73 0.28 1.33 1.21 14.84 36.36 20.20
FORO 52 PARTS 5.71 9.28 1.17 7.03 2.14 5.60 9.69 14.43
 lABOR 22.33 9.48 1.86 3.85 3.25 6.89 21.43 1.18
 TOTAL 28 .10 14.11 3.63 10.03 5.31 11.10 ]1.11 11.91
CHRYSLER 58 PARTS 5.34 9.5\ 0018 0.17 1.15 4.01 1.21 11.1]
 lABOR 22.51 8.62 1.05 3.38 2.30 4.49 25.86 9.43
 TOTAL 21.85 15.61 1.23 3.95 4.05 8.01 33.13 111.26
AMERICAN MOTORS 110 PARTS 1.76 13.102 0.00 0.00 0.0<1 0.)3 1.85 13.37
 LA80R 23.34 14.02 1.113 3.65 2.02 4.06 27.19 12.61
 TOTAL 31.10 24.65 1.83 3.65 2.11 4.33 35.04 23.68
FOREIGN 101 PARTS 4.0<1 '.0<1 0.00 0.00 2.59 1.83 6.61 10.45
 LABOR 22.09 10.94 0.26 1.22 4.61 10.76 26.91 11.23
 TOTAL 26.18 16.51 0.26 1.22 7.20 11.13 )].64 19.98
EMISSION CUTPOINTS ARE : 12-710 MODEL YR - CD 5.''1 HC 400 PPM    
  : 15-76 Mr:JDEL VA - CO 2.0'1 Hf 250 prM    
132

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      TABLE 3.40      
       VEHICLE TUNEUP cas T SUMMARV BY MILEAGE  
       All PHASE 1 VEHICLES    
       1972-1974 Monn VeAR    
              MANUFACTURER  
    EMISSION RELATED MALAOJUSTMENTI RECOMMENOED TOTAL COSTS
    TUNEUP COSTS   DISAALEMENT COSTS MAINTENANCE PER VEHICLE
MILEAGE  N   MEAN 50   MEAN SD  MEAN So MEAN SO
LESS THAN 20000 23 PARTS  ".98 6.87    0.36 1. 74 4.82 10.09 10.16 12.62
   LA80R  20.48 8.68    1.23 3.28 5.22 8.9B 26.94 13.29
   TOTAL  25.47 11.2',    1.60 4.59 10.04 1 A.13 37.10 21.13
20000 TO 30000 13 PARTS  6.71) 8.74    0.00 0.00 7.21 11.66 13.90 lZ.69
   LAIIOR  25.96 11.lb    0.83 2.03 8.b2 13.56 35.41 13.29
   TOTAL  32.66 17.92    0.83 2.03 15.82 25.07 49.31 24.83
30000 TO 40000 7.0 PARTS  10.90 14.37    1.80 8.07 2.14 5.23 14.84 18.23
   LA80R  24.91 12.47    1.01 3.12 3.10 6.86 29.02 15.21
   TOTAL  35.80 24.70    2.112 10.34 5.24 11.67 43.86 30.07
40000 TO 50000 14 PARTS  9.68 10.77    0.00 0.00 4.71 10.07 14.40 13.25
   LA80R  24.30 7.18    1.16 2.94 3.18 5.04 28.64 9.22
   TOTAL  33.98 14.Q7    1.16 2.94 7.90 14.81 43.03 19.117
GREATER THAN 50000 12 PARTS  19.96 12.60    0.31 1.08 0.00 0.00 20.27 13.,)2
   LABOR  33.19 8.37    1.35 2.88 0.00 0.00 34.54 A.)7
   TOTAL  53.15 16.89    l.b6 3.08 0.00 0.00 54.81 15.94
       VEHICLE TUNI;UP COST SUMMARV BY MILEAGE  
       ALL PHAse 1 VEHICLES    
       1975-1976 MonEL YEAR    
              MANUFACTURER  
    EMISSION RELATED I1AlA(1,fUSTMENTI RECOMME~IUED TOTAL COSTS
    TUNE UP COSTS   OISABLEMENT COSTS MAI~TENA~CE PER VEHICLE
IIJLEAr.E  N   MEAN 0;0   t,EAN so  MEAN SO tiE AN  50
LESS THAN 5001') 12 PARTS  0.63 2.19    0.00 0.00 0.00 0.00 0.63 2.1')
   LAIIOR  14.06 7.97    2.25 3.75 0.34 1.17 Ib.65 10.11
   TOTAL  14.69 7.75    2.25 3.75 0.3', \.17 17.28 9.7b
5000 TO 10000 J3 PARTS  0.78 3.19    0.00 0.00 0.1'3 0.76 0.91 3.25
   l A [! OR  13.09 7.03    3.44 7.62 1.84 3.30 18.37 9.89
   TUTAL  13.07 7.76    3.44 7.62 1.97 3.58 19.28 10.74
10000 TO 15000 25 PARTS  2.76 6.52    0.00 0.00 4.66 7.62 7.42 1 \.29
   LA80R  15.17 9.79    2.54 3.88 6.48 10.31 24.19 13.85
   TOTAL  17.93 14.80    2.54 3.88 11.14 17.50 31.61 23.98
15000 TO 20000 23 PARTS  3.99 6.67    0.37 1.77 0.30 1.19 4.66 6.99
   LAIIOR  16.01 9.77    2.58 !J.n 0.88 2.92 20.07 14.28
   TUTAL  20.1>0 11.48    2.95 7.18 1.18 3.35 24.13 11>017
GREATER THAN 7.0000 18 PARTS  4.47. 9.35    0.00 0.00 6.16 9.94 10.511 14.03
   LAROP.  20.25 14.22    0.45 1. 39 7.80 10.89 211.50 17.65
   TI1TAL  24.67 21.5\)    0.45 1. 39 13.96 20.43 39.08 30.46
 EMISSION CUTPOItHS .\RE : 72-74 ~OOEl VR - cn 5.5:': He 400 PP'1    
    : 75-76 HOnEl VR - 1:0 2.0~ HI: 250 PPH    
133

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      TABLE 3.49     
       VEHICLE TUNEUP COST SUHHARY BY MILEAGE  
       PASSING PHASE 1 VEtIIClES    
       1972-197~ H~DEl VEAR    
          HANUFACTURER  
     EHISSIO~ RELATED HAL ADJUSTMENT I  ReeOHHE NDED TOTAL CUSTS
     TUtlEUP COSTS DISABlfHENT COSTS MA I NTENAflCE PER VEHICLE
MILEAGE  N  MEAN SO HEAN So MEAN SO HEAN SO
lBS THAN 20000 111 PARTS 11.31 7.711 0.00 0.00 11.13 11.70 12.43 14.10
    LAROR 19.57 e.l11 1.10 3.01 5.32 9.58 25.99 11.94
    TOTAL 25.88 11.62 1.10 3.01 11.44 20.89 38.42 22.46
20000 TO 30000 10 PARTS 8.70 9.08 0.00 0.00 4.70 7.85 13.40 11.14
    LABOP 25.78 12.03 0.54 1.71 6.62 10.88 32.94 11.94
    TOTAL 34.49 19.77 0.54 1.71 11.32 18.66 46.34 21.97
30000 TO 40000 12 PARTS 3.82 5.11 0.00 0.00 2.35 5.51 6.17 9.27
    LABOR 20.n 10.04 0.90 3.12 3.82 1.34 25.115 16.40
    TOTAL 24.7" 13.40 0.90 3.12 11.18 13.51 31.82 23.83
..0000 TO 50000 9 PAnTS 7.75 10.41 0.00 0.00 2.32 5.64 10.06 13.16
    LA80R 25.05 1.49 0.00 0.00 1.65 3.43 26.70 9.'6
    TOTAL 32.80 16.58 0.00 0.00 3.97 8.96 36.76 20.'4
GREATER 7HAN 50000 5 PAR TS 17.79 13.93 0.00 0.00 0.00 0.00 17.79 n.9]
    LAlOR 31o.2? 5.37 1.62 3.112 0.00 0.00 35.91 '.37
    TOTAL '2.08 16.02 1.62 3.62 0.00 0.00 53.70 13.76
       VEHICLE TUNEUp COST SUMMARY BY MILEAGE  
       PASSING PHASE 1 VEHICLES    
       1975-19711 MODEL VEAR    
          MANUFACTURER  
     EMISSION RELATED MALADJUSTMENTI ReeOHHENlIED TOTAL COSTS
     TUNEUp COSTS DISARLEHENT COSTS HAHITENANCE PER VEHICLE
MILEAGE  N  MEAN SO HEAN SO HE AN  SO HEAN SO
lESS THAN 5000 10 PARTS 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
    LA!lOR 15.25 8.25 2.02 3.78 0.40 1.28 17.68 10.73
    TOTAL 15.25 8.25 2.02 3.78 0.40 1.28 17.118 10.73
5000 TO 10000 21 PARTS 0.08 0.35 0.00 0.00 0.21 0.95 0.2' 1.00
    LAIIOR 10.?9 5.010 4.05 9.20 1.48 2.56 16.52 10.62
    TOTAL 11.07 5.17 4.05 9.20 1.69 3.12 16.80 10.79
10000 HI 15000 15 PARTS .. .19 8.12 0.00 0.00 5.64 7.69 9.13 12.90
    lAIOR 111.74 10.77 1.98 3.85 7.74 11.46 26.46 15.87
    TOTAL 20.93 17.52 1.98 3.85 13.38 l'J . 60 36.29 27.79
15000 TO 20000 14 PARTS 2.72 ...89 0.00 0.00 0.40 1.51 3.12 4..88
    lUO" 16.49 11.59 2.19 7.37 1.16 3.62 20.510 17.65
    TOTAL 19.21 13.36 2.89 7.37 1.56 4.10 23.66 18.92
GREATER THAN 20000 12 PARTS 2.2'1 6.03 0.00 0.00 7.51 11.31 9.12 13 .16
    LABOR 20.70 16.111 0.67 1.111 11.21 12.07 29.59 20.01
    TOTAL 22.9'1 21.85 0.67 1.118 15.79 23.09 39.41 32.34
  EMISSION CUTpOINTS ARE : 72-7.. MOOH YR - CO 5.51 He 400 ppH    
     : 75-16 HOllEL VR - co 2.01 He 250 PpH    
134

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      TABLE 3.50      
       VEHICLE TUNEUP LOST SUMMARY BY MILEAGE  
       FAILING PHASE 1 I FAILING PHASE 2 VEHICLES  
       1972-1974 MODFL YEAR    
            MANUFACTURER  
    EMISSION RELATED MALAD,IUS TMENT I RECOMMENUED TOTAL COSTS
    TUNI'UP COSTS   DISA~LEMENT COSTS MAINTENANCE PER VEHICLE
MILEAGE  N   MEAN SO   HEliN  SO MEAN SO MEAN SO
LESS THAN 20000 21 PARTS  5.79 11.11   0.92  2.15 1.40 3.78 8.11 11.91
   LA80R  24.36 9.96   2.44  5.54 2.96 5.77 29.7b 12.44
   TOTAL  30.15 111.46   3.36  7.34 4.3b 7.98 37.87 20.42
201)00 TO 30000 33 PARTS  4.01 5.73   0.00  0.00 4.15 8.80 8.1b 9.14
   LABOR  21.76 10.11   0.41  1.33 5.93 11.53 28.10 9.59
   TOTAL  25.77 12.98   0.41  1.33 10.09 18.b5 36.27 Ib.bO
30000 TO 40000 30 PARTS  9.24 13. 91   2.37  9.01 3.59 8.05 15.21 20.39
   LABOR  2b. n 11.27   1.03  3.34 3.55 5.77 31.32 10.23
   TOTAL  35.97 20.92   3.40  12. II 7.15 13.22 4b.53 Zb.24
.0000 TO 50000 ,21 PARTS  9.8b 11.32   0.00  0.00 7.47 11.07 17.33 12.60
   LA80R  23.59 10.75   0.80  2.43 6.24 8.62 30.03 9.311
   TOTAL  33.45 19.23   0.80  2.43 13.71 18.55 47.9b 18.55
GR[ATER THAN 50000 29 PARTS  10.91 11.87   0.13  0.70 0.00 0.00 11.04 12.15
   LA80R  28.68 10.52   0.37  1. 35 0.00 0.00 29.05 10.59
   TOTAL  39.59 20.15   0.50  1.00 0.00 0.00 40.09 20. J4
       VEHICLE TUNEUP COST SUMMARY BY MILEAGE  
       FA !lING PHASE 1 I FAILING PHASE 2 VEHICLES  
       1975-197b MODEL YEAR    
            MANUFACTURER  
    EMISSION RELATED MALAD,IUS TMENT I RECOMMENUEO TOTAL COSTS
    TUNFUP COSTS   DISABLEMENT COSTS MAINTENANCE PER VEHICLE
MILEAGE  N   MEAN SO   MEliN  SO MEAN SO MEA~I SO
LESS THAN 5000 " PIIRTS  1.90 3.79   0.00  0.00 0.00 0.00 1.90 3.79
   LA80R  14.85 8.10   1.69  3.37 0.00 0.00 16.54 6.83
   TOTAL  16.75 6.77   l.b9  3.37 0.00 0.00 18.43 4.2B
5000 TO 10000 27 PARTS  2.47 4.6b   0.00  0.00 0.00 1).00 2.47 4.6b
   LA80R  21.60 9.9b   1.05  2.66 1.10 3.11 23.75 8.85
   TOTAL  24.07 11.32   1.05  2.bb 1. I/') 3. II 2b.22 10.64
10000 TO 15000 2B PARTS  1.05 3.33   0.00  0.00 l.b7 4.76 2.72 5.67
   LABOR  18.22 7.58   1.21  2.83 2.89 5.85 22.32 7.05
   TOTAL  19.27 8.15   1.21  2.83 4.56 10.26 25.04 10.78
15000 TO 20000 27 PARTS  4.81 10.44   0.31  1.63 0.54 1.56 5.66 10.69
   LAFIOR  20.00 8.75   0.85  2.83 1.75 ..89 22.60 7.48
   TOTAL  24.81 15.50   1.16  It.35 2.29 6.43 28.26 15.86
GREATER THAN 20000 38 PARTS  3.7b 6.60   0.00  0.00 3.32 11.87 7.08 10.82
   LA80R  20.75 7."7   0.11  0.66 6.25 11).47 27.11 9.40
   TOTAL  24.5/) 10.62   0.11  0.66 9.57 16.85 3't.18 18.b5
 EIUSSION CUTPOINTS APE : 77-74 MODEL YR - eo 5.511  fie 400 PPM    
    : 75- 76 MODE 1 YR - eo 2.01  He 250 "PM    
135

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TABLE 3.51
VEHICLE TUNE-UP COST SUMMARY BY STRINGENCY FACTOR
ALL PHASE I VEHICLES
 1972-1974 MODEL YEARS 1975-1976 MODEL YEARS 
 PASS IDLE (N)    PASS IDLE (N) 
Stringency      StrJ.ngency    
Factor N  Mean S.D. Factor N  Mean S.D.
10 73 Parts 12.57 13.05 10 100 Parts 4.12 8.53
  Labor 29.03 12.31   Labor 21.23 13 .87
  Total 41. 61 22.48   Total 25.34 20.18
20 66 Parts 11. 57 12.71 20 88 Parts 4.04 8.68
  Labor 28.90 12.61   Labor 21.13 14 .35
  Total 40.47 22.72   Total 25.16 21.14
30 57 Parts 11. 55 12.48 30 78 Parts 4.07 8.85
  Labor 29.27 12.82   Labor 21.32 15.02
  Total 40.82 22.55   Total 25.39 21. 98
40 47 Parts 12.33 12.54 40 66 Parts 3.27 7.03
  Labor 29.24 12.60   Labor 21.03 15.03
  Total 41.57 22.13   Total 24.29 20.22
50 41 Parts 13.33 13.02 50 54 Parts 2.92 6.74
  Labor 29.30 12.96   Labor 20.40 14.41
  Total 42.63 23.15   Total 23.32 19.30
 FAIL IDLE (N)    FAIL IDLE (N) 
10 9 Parts 26.45 19.11 10 11 Parts 9.90 13.42
  Labor 39.60 12.98   Labor 23.93 11.17
  Total 66.05 22.47   Total 33.83 23.10
20 16 Parts 24.53 16.46 20 23 Parts 7.19 10.89
  Labor 35.52 12.26   Labor 22.89 10.41
  Total 60.05 21.16   Total 30.08 17.87
30 25 Parts 19.91 16.83 30 33 Parts 6.17 10.04
  Labor 32.29 12.59   Labor 21.89 9.65
  Total 52.20 24.57   Total 28.06 16.76
40 35 Parts 16.47 16.41 40 45 Parts 6.78 11. 49
  Labor 31.47 13.01   Labor 22.17 11. 32
  Total 47.94 25.35   Total 28.95 20.89
50 41 Parts 14.87 15.73 50 57 Parts 6.37 10.86
  Labor 31. 08 12.62   Labor 22.52 12.84
  'rotal 45.95 24.26   Total 28.90 21. 45
136

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.....
W
-...J
TABLE 3.52

CORRELA TION COEFFICIENTS FOR PERCENT CHANGE IN FTP EMISSIONS
VERSUS COSTS OF MAINTENANCE
  1972-1974   1975-1976 
 HC CO NOX FE HC CO NOX FE
All Phase I        
Tune-up 0.31* 0.27* 0.21* 0.25* 0.05 O. 10 0.08 0.03
Maladj. /Disabl. o. 16 0.03 0.26* 0.02 0.10 0.05 0.27* 0.05
Man. Rec. MTCE O. 12 O. 18 O. 30* O. 18 0.03 0.03 0.02 O. 13
Total O. 38* O. 36* O. 32* 0.33* 0.08 0.09 O. 12 O. 12
Passing Phase I        
Tune-up 0.20 0.22 0.27* 0.25* 0.04 0.28* O. 13 O. 13
Maladj. /Disabl. O. 11 0.05 O. 15 O. 14 0.04 O. 16 0.43* O. 16
Man. Rec. MTCE O. 17 0.24* 0.26>''' 0.27* O. 13 0.04 0.05 0.17
Total 0.28* O. 34* O. 38* 0.36* 0.07 O. 19 O. 18 0.23*
Failing Phases I and II        
Tune-up 0.01 0.03 0.05 0.02 0.06 o. 16* 0.02 0.02
Maladj. /Disabl. 0.03 0.07 0.19* 0.05 O. 11 0.08 0.06 0.17*
Man. Rec. MTCE 0.07 0.05 o. 12 0.00 O. 10 0.06 0.02 0.02
Total 0.07 0.02 0.07 0.00 0.05 0.07 0.02 0.03
*Significantly non-zero at 95 percent level of confidence.

-------
TABLE 3.53

STANDARD DEVIATIONS OF REPLICATE SHORT TEST VALUES -
ALL PHASE I VEHICLES
       THREE VEHICLES
    ALL VEHICLES  ELIMINATED
   1972-1974 1975-1976 1975-1976
   S.D. C.V.* S.D. C.V.* S.D. C.V.*
HC        
 Hot FTP 0.28 5.8 0.39 19.3 0.40 19.1
 Fed. Short Cycle 0.49 10.2 0.62 39.6 0.63 39.0
 Fed. Three Mode(50) 27.3 15.0 11.7 13.3 11.8 13.1
 Fed. Three Mode(30) 26.8 10.8 19.0 18.4 19.2 18.2
 Fed. Three Mode(N) 97.7 30.7 63.8 35.9 64.7 35.5
 Idle (2250) 35.0 17.7 36.4 50.9 36.9 50.3
 Idle (N) 78.8 26.8 134.6 100.4 39.7 31.0
CO        
 Hot FTP 4.98 6.6 7.48 16.4 7.58 16.2
 Fed. Short Cycle 5.84 10.5 7.90 26.4 8.01 26.1
 Fed. Three Mode(50) 0.34 13.2 0.38 18.1 0.39 17.8
 Fed. Three Mode(30) 0.24 10.0 0.72 37.8 0.73 37.3
 Fed. Three Mode(N) 0.42 9.1 0.65 25.4 0.66 25.1
 Idle (2250) 0.49 20.4 0.97 66.7 0.99 65.9
 Idle (N) 0.44 10.7 0.86 43.6 0.59 30.1
NOX       
 Hot FTP 0.11 5.0 0.12 7.0 0.12 6.9
 Fed. Short Cycle 0.12 6.6 0.09 6.7 0.10 6.5
 Fed. Three Mode ( 50) 308 22 132 13.3 134 13.1
 Fed. Three Mode(30) 276 28.6 98 16.6 100 16.4
 Fed. Three Mode(N) 11.5 20.9 8.3 16.3 8.4 16.1
 Idle (2250) 62.4 28.8 49.7 35.2 50.3 34.6
 Idle (N) 7.1 13.3 10.9 20.3 10.2 22.2
*
C.V. = Coefficient of Variation = 100(S.D./Avg)
138

-------
TABLE 3.54

STANDARD DEVIATIONS OF REPLICATE SHORT TEST VALUES -
PASSING PHASE I AND FAILING PHASES I AND II
~
W
\0
   PASSING PHASE I   FAILING PHASES I AND II 
  1972-1974 1975-1976  1972-1974 1975-1976 
  S.D. C.V * ~ n C.V *  ~ n (" u * ~ n " u *
HC           
Hot FTP 0.28 6.6 0.44 28.9  0.37 6.2 0.24 7.3
Fed. Short Cycle 0.49 13.5 0.77 69.1  0.32 6.5 0.54 19.1
Fed. Three Mode(50) 33.5 35.9 13.3 17.0 15.2 7.4 21.5 19.2
Fed. Three Mode(30) 24.0 11.1 19.6 22.8 39.1 13.3 20.2 14.3
Fed. Three Mode(N) 63.4 33.6 29.0 25.7 98.7 17.7 77.1 22.3
Idle (2250) 28.9 21.1 33.8 70.3 112.1 37.0 59.6 46.7
Idle (N) 26.3 16.6 34.4 60.0 145.8 27.1 73.2 27.4
CO           
Hot FTP 4.65 6.9 7.63 23.0 4.62 5.3 5.97 8.0
Fed. Short Cycle 6.66 13.2 8.39 41.9 5.41 8.6 6.83 12.3
Fed. Three Mode(50) 0.35 14.7 0.34 18.9 0.42 13.1 0.48 18.8
Fed. Three Mode (30) 0.25 11. 5 0.78 50.3 0.39 13.8 0.58 22.1
Fed. Three Mode(N) 0.43 14.9 0.23 20.2 0.67 10.1 0.78 14.0
Idle (2250) 0.54 28.8 1. 02 122.6 0.60 18.7 0.84 29.1
Idle (N) 0.45 18.5 0.43 75.0 0.60 9.7 0.73 14.9
NOX           
Hot FTP 0.11 4.9 0.13 7.2 0.12 6.2 0.11 7.2
Fed. Short Cycle 0.14 7.8 0.10 7.3 0.12 7.1 0.16 11. 9
Fed. Three Mode(50) 337 25.1 136 13.6 237  18.7 160 16.7
Fed. Three Mode(30) 307 33.6 87 15.6 182  20.7 182 30.3
Fed. Three Mode(N) 14.0 23.2 9.4 17.3 25.0 54.8 4.8 11. 8
Idle (2250) 50.0 25.8 29.2 23.9 71. 4 36.0 51. 0 32.9
Idle (N) 7.6 13.5 9.3 16.9 8.3 18.4 10.2 22.2
* C.V. = Coefficient of Variation = 100(S.D./Avg)

-------
STUDENT'S t
OF AVERAGE
TABLE 3.55

STATISTICS** FOR EVALUATING SIGNIFICANCE
DIFFERENCE OF REPLICATE DETERMINATIONS -
ALL PHASE I
    MODEL YEAR
    1972-1974 1975-1976
HC     
 Hot FTP  1. 37 -0.22
 Fed. Short Cycle  -0.41 1. 46
 Fed. Three Mode (50) 0.36 2.08*
 Fed. Three Mode (30) -0.23 0.03
 Fed. Three Mode (N) -1. 52 -0.64
 Idle (2250)  -0.61 -2.03*
 Idle (N)  -2.28* -1.41
CO     
 Hot FTP  -1.12 0.96
 Fed. Short Cycle  0.92 2.28*
 Fed. Three Mode (50) -1. 74 1. 36
 Fed. Three Mode (30) -2.66* -0.64
 Fed. Three Mode (N) 0.64 -1.30
 Idle (2250)  -3.49* -2.16*
 Idle (N)  -2.48* -2.31*
NOX    
 Hot FTP  -1. 26 -2.40*
 Fed. Short Cycle  -1.11 -1. 53
 Fed. Three Mode (50) 0.89 -2.29*
 Fed. Three Mode (30) -0.41 -1. 86
 Fed. Three Mode (N) -1.23 0.04
 Idle (2250)  -0.17 -0.36
 Idle (N)  -0.53 0.64
* Significant at 95% level of confidence.
** Negative value implies second determination was
larger.
140

-------
REGRESSION
EMISSIONS AS A
TABLE 3.56

EQUATIONS FOR PREDICTING PRE-MAINTENANCE FTP
FUNCTION OF PRE-MAINTENANCE SHORT TEST EMISSIONS -
ALL PHASE I VEHICLES
 Model          
 Year Short Test   Reqression Equation* r 8(e)
HC 1972- Hot FTP  Y . 0.22 + 1.06x  0.93 1.41
 1974 Fed. Short Cycle . 0.46 + 1.23x   
   0.89 1. 66
  Fed. Three Mode . 2.15+0.0094Xl+0.0038x2+0.0018x3 0.88 1. 79
  Idle   . 3.32 + 0.0022xl + 0.0057x2 0.63 2.92
  Idle (N)  '" 3.40 + 0.0069x  0.60 2.98
 1975- Hot FTP  Y = 0.48 + 0.901x  0.93 0.52
 1976 Fed. Short Cycle . 0.95 + 0.826x  0.84 
   0.79
  Fed. Three Mode . 0.99+0.0059xl+0.0048x2+0.0017x3 0.60 1.16
  Idle   . 1.42 + 0.0059xl + 0.0044x2 0.61 1.15
  Idle (N)  . 1.68 + 0.00527x  0.55 1. 20
CO 1972- Hot FTP  y . 4.46 + 1.06x  0.96 10.73
 1974 Fed. Short Cycle  20.46 + 1.11x  0.89 
  '"  16.90
  Fed. Three Mode '" 33.66+5.69xl+8.33x2+3.40x3 0.65 29.18
  Idle   '" 57.20 + 4.73xl + 3.77x2 0.44 34.04
  Idle (N)  = 62.19 + 5. l4x . 0.41 34.49
 1975- Hot FTP  Y '" 8.23 + 0.912x  0.96 10.49
 1976 Fed. Short Cycle '" 20.16 + 0.964x  0.86 19.25
  Fed. Three Mode . 15.95+7.04xl+l.93x2+6.38x3 0.76 25.08
  Idle   . 25.50 + 7.24xl + 8.97x2 0.76 24.87
  Idle (N)  . 28.42 + 12.28x  0.71 26.76
NOX 1972- Hot FTP  Y '" 0.10 ~ 0.95x  0.99 0.20
 1974 Fed. Short Cycle '" 0.33 + 1.04x  0.94 0.40
  Fed. Three Mode . 0.64+0.00044xl+0.00086x2+0.00144x3 0.75 0.59
  Idle   '" 1.07 + 0.00344xl + 0.00652x2 0.58 0.95
  Idle (N)  '" 1.14 + 0.0192xl  0.32 1.10
 1975- Hot FTP  Y . 0.18 + 0.926x  0.98 0.16
 1976 Fed. Short Cycle . 0.54 + 0.831x  0.87 0.42
  Fed. Three Mode '" 0.76+0.00051xl+0.00083x2-0.00063x3 0.74 0.58
  Idle   . 1.19 + 0.00400xl - 0.00109x2 0.55 0.72
  Idle (N)  '" 1.37 + 0.00621x  0.19 0.85
* For Fed. Three Mode, xl' x2' x3 refer to SO, 30, and N modes, respectively.
For Idle, xl and x2 refer to Idle (2250) and Idle (N), respectively.
141

-------
REGRESSION
EMISSIONS AS A
Model
Year
HC
1972-
1974
1975-
1976
co
1972-
1974
1975-
1976
NOX
1972-
1974
1975-
1976
TABLE 3.57

EQUATION FOR PREDICTING PRE-MAINTENANCE FTP
FUNCTION OF PRE-MAINTENANCE SHORT TEST EMISSIONS
PASSING PHASE I VEHICLES
Short Test
Hot FTP

Fed. Short ~ycle

Fed. Three Mode
Idle

Idle (N)
Hot FTP

Fed. Short Cycle

'ed. Three Mode
Idle

Idle (N)
Hot FTP

Fed. Short Cycle

Fed. Three Mode
Idle

Idle (N)
Hot FTP

Fed. Short

Fed. Three
Idle

Idle (N)
Cycle
Mode
Regression Equation *

y " 0.41 + 1.01x

" 1. 76 + 0.822x

" 2.09+0.l784xl+0.003l5x2-0.00469x3

" 4.41 - 0.00029xl + 0.00223x2
" 4.40 + 0.00200x
y " 0.42 + 0.893x
" 1.16 + 0.477x
- 1.13+0.00251Xl+0.00432x2+0.0003lx3
" 1.06 + 0.005l3xl + 0.00875x2
" 1.20 ~ 0.01005x
y " 3.32 + 1.07x
= 26.35 + 0.948x
" 40.52+5.34Xl+7.76x2+l.93X3
" 64.71 + 5.69xl + 0.176x2
" 70.22 + 1.93x
y " 9.80 + 0.809x
- 22.31 + 0.678x
a 22.57+3.64Xl+4.26x2+0.954X3
" 24.43 + 10.37xl + 11.08x2
= 28.48 + l5.97x
y a 0.14 + 0.935x

a 0.37 + 1.06x

a 0.9l+0.00048xl+0.00068x2+0.00064X3

" 1.12 + 0.004l2xl + 0.00553x2
" 0.98 + 0.222x
y = 0.18 + 0.929x
" 0.44 + 0.962x

" 0.67+0.00056xl+0.00129x2+0.00257X3
" 1.26 + 0.00843xl = 0.00936x
" 1.59 + 0.00291x 2
r
0.61
0.48
0.66
0.07**
0.07**
0.78
0.68
0.45
0.53
0.47
0.92
0.84
0.66
0.27
0.10**
0.87
0.64
0.56
0.69
0.51
0.99
0.93
0.72
0.61

0.36
0.98
0.90
0.82
0.67
o . 08**
* For Federal Three Mode, x x
l' 2' x3 refer to 50, 30, and N modes,
- For Idle, x and x f respectively.
1 2 re er to Idle (2250) and (N), respectively.

** Not siqnificantly different from zero.
Hot FTP

Fed. Short Cycle

Fed. Three Mode
Idle

Idle (N)
Hot FTP

Fed. Short Cycle

F.ed. Three Mode
Idle

Idle (N)
142
s(e)

1. 74
1. 94
1. 70
2.22
2.20
0.53
0.62
0.76
0.72
0.57
11.52
16.44
22.80
29.10
29.72
9.72
15.25
16.72
14.50
17.03
0.19
0.42
0.84
0.94

1.10
0.16
0.41
0.55
0.70
0.94

-------
TABLE 3.58

REGRESSION EQUATIONS FOR PREDICTING PRE-r1AINTENANCE FTP
EMISSIONS AS A FUNCTION OF PRE-MAINTENANCE SHORT TEST EMISSIONS -
FAILING PHASES I AND II VEHICLES
r            
 Model            
 Year Short Test   Regression Equation * r s(e)
HC 1972- Hot FTP  Y .. 0.18 + L07x    0.95 1.12
 1974 Fed. Short Cycle .. 1.03 + LOh    0.89 0.68
  Fed. Three Mode .. 1.98+0.00267xl+0.007804x2+0.00300x3 0.79 2.25
  Idle   = 4.02 + 0.00054xl + 0.0044lx2 0.58 2.98
  Idle (N)  .. 4.06 + 0.00463x   0.58 2.98
 1975- Hot FTP  Y .. 0.34 + LOb    0.97 0.54
 1976 Fed. Short Cycle = 0.25 + 1. 20x    0.92 0.84
  Fed. Three Mode .. 1.75+0.00559xl+0.00586x2+0.00112x3 0.72 1. 47
  Idle   .. 2.20 + 0.00308xl + 0.00408x2 0.44 1. 89
  Idle (N)  .. 2.41 + 0.00460x   0.41 1. 91
CO 1972- Hot FTP  Y .. 5.73 + L02x    0.97 8.53
 1974 Fed. Short Cycle  22.63 + 1.10x    0.91 15.45
  Fed. Three Mode .. 53.28+0.l01xl+7.41x2+2.99x3 0.49 32.76
  Idle   .. 61. 29 + 2.56xl + 4.01x2  0.38 34.65
  Idle (N)  = 65.15 + 4.63x    0.36 34.82
 1975- Hot FTP  Y .. 8.67 + 0.956x    0.96 10.72
 1976 Fed. Short Cycle .. 22.73 + L02z    0.88 19.16
  Fed. Three Mode .. 3l.79+6.33xl+0.963x2+5.44x3 0.63 31.50
  Idle   .. 33.45 + 4.28xl + 7.45x2  0.61 32.01
  Idle (N)  .. 35.42 + 9.31x    0.58 32.82
NOX 1972- Hot FTP  Y .. 0.07 + 0.98lx    0.97 0.25
 1974 Fed. Short Cycle .. 0.35 + 0.986x    0.91 0.43
  Fed. Three Mode .. 0.82+0.00051Xl+0.00060x2+0.00049x3 0.67 0.74
  Idle   .. 1. 37 + O. 00372xl + 0.00234x2 0.56 0.84
  Idle (N)  .. 1.64 + 0.00793x   0.16 1.00
 1975- Hot FTP  Y .. 0.17 + 0.329x    0.96 0.17
 1976 Fed. Short Cycle = 0.66 + 0.676x    0.80 0.38
  Fed. Three Mode .. 0.83+0.00041xl+0.00018x2+0.00488x3 0.62 0.50
  Idle   .. 0.99 + 0.00189xl + 0.00475x2 0.48 0.55
  Idle (N)  .. 1.12 + 0.00809x   0.32 0.59
*
For Federal Three Mode, xl' x2' x3 refer to 50, 30, and N modes, respectively.
For Idle, xl and x2 refer to Idle (2250) and (N), respectively.
143

-------
TABLE 3.59

REGRESSION EQUATIONS FOR 1975 FTP EMISSIONS AS A FUNCTION
OF SHORT TEST EMISSIONS - LOW ALTITUDE DATA
 Model      
 Year Short Test  Reqression Equation* r
HC 1975 Fed. Short Cycle y = 0.53 + 0.839x 0.78
  Fed. Three Mode = 0.55+0.0030xl+0.0071x2 0.58
      +0.0022x3 
  Idle (N)  = 0.99 + 0.0025x 0.42
CO 1975 Fed. Short Cycle y = 7.64 + l.08x 0.89
  Fed. Three Mode = 10.07+6.93xl+ll.09x2+2.85x3 0.73
  Idle (N)   12.86 + 6.99x 0.64
NOX 1975 Fed. Short Cycle y = 0.79 + 0.893x 0.81
  Fed. Three Mode = 1.13+0.0034xl+0.0004x2 0.59
      +0.0005x3 
*
For Federal Three Mode, xl' x2' x3 refer to 50, 30, and
N modes, respectively-
144

-------
TABLE 3.60

PARTIAL CORRELATION COEFFICIENTS OF MILEAGE TERM IN PREDICTING
FTP EMISSION FROM SHORT TEST EMISSIONS AND MILEAGE
....
~
VI
           FAILING 
   ALL PHASE I PASSING PHASE I PHASES I AND II
   HC CO NOX HC CO NOX HC CO NOX
1972-1974            
Hot FTP  0.07 0.06 -0.05 0.04 0.08 -0.00 0.02 0.06 -0.01
Fed. Short Cycle 0.05 0.04 0.02 -0.03 -0.04 0.11 0.04 0.14 -0.03
Fed. Three Mode 0.12 0.14 -0.10 0.13 0.04 0.01 0.06 0.05 0.03
Idle   0.09 0.16 -0.07 -0.06 0.09 -0.09 0.11 0.12 0.01
Idle (N)  0.09 0.16 -0.01 -0.06 0.06 0.06 0.11 0.12 0.01
1975-1976            
Hot FTP  -0.10 -0.12 0.16 -0.12 -0.05 0.19 0.02 -0.03 0.08
Fed. Short Cycle 0.07 -0.01 0.15 0.14 0.19 0.25 -0.13 -0.08 0.13
Fed. Three Mode 0.17 0.20 0.11 0.09 0.25 0.25 0.22 0.23 0.15
Idle   0.13 0.15 0.08 -0.01 0.23 0.15 0.15 0.21 0.16
Idle (N)  0.11 0.08 0.07 -0.05 0.16 0.10 0.14 0.18 0.15

-------
TABLE 3.61

SHORT TEST CUTPOINTS FOR INDIVIDUAL EMITTANTS AT STRINGENCY FACTORS
OF 10%, 20%, 30%, 40%, 50%
....
.c:.
0\
STRINGENCY FACTOR  10% 20%  30% 40% 50%
 MODEL YEAR 72-74 75-76 72-74 75-76 72-74 75-76 72-74 75-76 72-74 75-76
Hot FTP  7.04 3.32 5.30 2.75  4.98 2.40 4.64 2.13 4.45 1. 81
Fed. Short Cycle 5.64 2.81 4.83 2.23  4.05 1.96 3.80 1. 60 3.54 1.36
Fed. 3 Mode (50 mph) 274. 169. 199. 144.  179. 119. 169. 104. 149. 79.
Fed. 3 Mode (30 mph) 339. 194. 299. 164.  249. 134. 239. 124. 219. 89.
Fed. 3 Mode (N) 649. 389. 389. 239.  309. 204. 269. 154. 239. 109.
Idle 2250  319. 159. 179. 104.  129. 64. 119. 54. 99. 39.
Idle (N)  639. 249. 339. 189.  259. 149. 219. 89. 209. 69.
       CO      
Hot FTP  119.43 89.06 99.00 66.47 81. 30 54.30 74.04 46.31 65.29 39.02
Fed. Short Cycle 103.84 66.36 81. 80 46.19 62.66 36.46 57.82 29.40 46.47 22.49
Fed. 3 Mode (50 mph) 4.99 4.79 3.79 3.69  3.29 2.89 2.39 2.29 2.19 1.49
Fed. 3 Mode (30 mph) 4.19 4.19 3.49 3.09  2.69 2.19 2.49 1. 89 1. 99 1.59
Fed. 3 Mode (N) 9.19 7.39 7.99 4.59  6.59 3.29 5.59 2.69 4.19 1.44
Idle 2250  4.69 3.49 3.79 2.09  3.09 1. 39 2.29 0.79 1. 69 0.54
Idle (N)  8.39 4.79 7.39 3.49  5.99 2.29 4.59 1.64 3.29 0.99
      NOX      
Hot FTP  3.92 2.46 3.02 2.15  2.57 1.99 2.11 1.77 1.81 1.56
Fed. Short Cycle 3.44 2.43 2.46 1.96  2.12 1.73 1. 77 1.46 1.54 1.15
Fed. 3 Mode (50 mph) 2787. 2065. 2189. 1343. 1741. 1045. 1518. 945. 1393. 829.
Fed. 3 Mode (30 mph) 1741. 1368. 1468. 920. 1149. 675. 1120. 563. 900. 429.
Fed. 3 Mode (N) 79. 80. 69. 69.  61. 58. 56. 52. 50. 44.
Idle 2250  470. 327. 286. 212.  222. 154. 201. 123. 164. 100.
Idle (N)  78. 86. 71. 74.  64. 68. 58. 60. 54. 51.
HC

-------
TABLE 3.62
ERRORS OF OMISSION AND COMMISSION
10lE: WEUTRAl)
All PHASE 1 VEHICLES
1972-197~ MnOEl VEAR
F IlR HC qNl V
vrHIClr.s
ASSUMED FAILURE CUTPOINTS SAI1PLE FlIllURE ERRIIPS DF ERRORS OF 
RATE (%) HC RATE 17.) OMISSIIIN (~) enMMI SS IOI~ 1%)
10.  639.00 9.8 H5.4  0.0  
20.  :nq. 00 20.1 14.4  0.0  
30.  259.00 30.5 65.9  1.2  
40.  219.00 l,b. 3 50.0  1.2  
50.  709.00 50.0 4b.3  1 .2  
    FOR CO l1NlV            
 IISSJt-IED F II!L UP E eUTPlJltHS  SAMPLE FAILURE ERRORS or  ERRORS or     
 PA TF I~n (11  PATE  IX'  OMISSIIlN (%) eOMI11SSION  0"    
 10.  R.H   11.0   07.8   0.0      
..... 20.  7. 39   19.5   19.3   0.0      
~ 30.  <;.99   30.5   611.3   1).0      
-..J 40.  4.59   40.2   511.5   0.0      
 50.  3.29   50.0   It/I. 8   0.0      
    rllR tlnX IJtllV            
 ASSUI"EO FA IlURE CUTPIIIIHS  SIIMPLE r A !LURE ERRORS UF  ERRORS OF     
 RII rr (~) '1(1)(  RATE  IX)  UMISSlnN (%) COMMISSION  (7.)    
 10.  70.19   9.8   it,. 6   1.3      
 20.  11 .09   20.1   12.2   15.9      
 30.  (,',. ()9   31.1   9.11   24.4      
 40.  511.09   ,,0.2   II.S   31.1      
 50.  5', .09   51.2   4.9   39.0      
    FIlR HC, e i1, ANO NOX COM81"1EI1         
 ASSUMED r A Il'JRF - --- - -----C '-'1 PL! lilT S- - -- - - - -- - SIIMPLE FAILURE ERRORS IIF  ERRORS [JF 
 ru\ TE (~) III  ((I  Nfl X   Rfl FE (X) nMISST'1N 00 enMMI SS lOll (%1
 11).  1)9.00  9.99 99999.00  11.0  0'1.0   0.0 
 20.  599.00  8.19 <}9')99.00  19.5  flO.5   0.0 
 30.  519.00  6.2':1 ,}9999.00  30.5  69.5   0.0 
 1,0.  309.00  5.39 99999.00  42.1  ~1.3   0.0 
 50.  31'..00  4.29  111.09  50.0  '>0.0   0.0 
VALUES OF 99999.00 INDICATE NO CUTPOINT NEEDED FOR THAT POLLUTANT.

-------
TABLE 3.63
ERRORS OF OMISSION AND COMMISSION
IIILE CIIEUTRIILI
All P\lASE 1 VEIlICU S
1975-1976 MODEL YEAR
FflR IIC !J'III.Y
VEHICLFS
.....
~
00
ASSJ'1!:O FA Il UIIF. C I!TI'III tiT S SIIMPLE FAILURE ERRORS [IF ERRORS OF 
RIIH (Xl HC 'UTF. (%1 OMISSION (Xl COMMISSION UI
10.  2'.').00 10." 56.8  0.0 
20.  189.00 2 1.6 45.9  CI.O 
30.  1 ',1 . 00 29.7 37.8  0.0 
40.  89.00 40.5 7.7.9  .0.') 
50.  69.00 51.4 19.8  3.6 
   FOR CO r)NI.Y    
ASSU~'[O fAllUR[ CUrl'OINTS SAMPLE FAILURF ERRORS UF ERRORS OF. 
RATf IXI (II RATE UI OMISSION (SI COMMISSION (:„ I
10.  4.19  9.9 80.2  0.0 
20.  1.49 19.11 70.3  0.0 
30.  ;1.29 30.6 59.5  0.0 
40.  1.64 . H.6 50.5  0.0 
50.  0.99 50.5 39.1)  0.0 
   FOR NOX ONLY    
ASSUMED FAILURE CUTPOINTS SAMPLE FAILURE ERRI1RS OF ERRORS OF 
RATE nu NIJX PATE (SI OMISSInN ISI COMMISSION (XI
10.  86.19  9.9 2.1  (101 
20.  74.19 19.8 0.9  16.2 
30.  68.09 7.9.1 0.9  2601 
41'.  60.09 40.5 0.9  36.') 
50.  51 .09 51.4 0.9  41.1 
FOR HC. CU. AND NnX COMBINED
ASS~MED FAILURF.
RATE U I
----------CUTPOINTS----------
,.C en NOX
SIIMPLE fAILURE
RATE (XI
ERRURS OF
OM I S S I ON II I
10.
20.
30.
40.
50.
1199.00
1199.00
119').00
39'..00
7.99.00
5.59
3.49
2.39
1.69
0.99
9.9
20.1
29.7
40.5
51.4
82.9
17..1
63.1
52.3
41.4
99999.00
,)9?99.00
999')9.00
9?999.00
99999.00
VALUES OF 99999.00 INDICATE NO CUTPOINT NEEDED FOR THAT POLLUTANT.
ERRORS OF
COMMISSION (II
0.0
0.0
0.0
0.0
0.0

-------
 TABLE 3. 64  
11M IMPACT MEASURE* FOR STRINGENCY FACTORS
 OF 10%, 20%, 30%, 40%, AND 50% 
 IDLE (N) SHORT TEST  
Model Stringency   
Year Factor HC CO NOX Composite
1972-1974 10   0.32 0.16 0.09 0.22
 20   0.43 0.30 0.09 0.34
 30   0.51 0.41 0.10 0.44
 40   0.60 0.53 0.30 0.55
 50   0.65 0.61 0.58 0.62
1975-1976 10   0.27 0.23 0 0.24
 20   0.49 0.42 0 0.43
 30   0.64 0.54 0 0.55
 40   0.78 0.67 0.16 0.69
 50   0.87 0.76 0.24 0.78
 TABLL 3.65  
11M IMPACT MEASURE* FOR STRINGENCY FACTORS
 OF 10%, 20%, 30%, 40%, AND 50% 
 FEDERAL SHORT CYCLE SHORT TEST 
Model Stringency     
Year Factor HC CO NOX Composite
1972-1974 10  0.35 0.26 0 0.28
 20  0.44 0.41 0 0.41
 30  0.60 0.56 0.16 0.56
 40  0.67 0.66 0.20 0.65
 50  0.73 0.73 0.50 0.72
1975-1976 10  0.32 0.27 0 0.28
 20  0.47 0.44 0 0.44
 30  0.64 0.59 0 0.60
 40  0.72 0.68 0 0.69
 50  0.81 0.79 0.19 0.79
* Contribution      
   149   

-------
TABLE 3.66
IPL[ (NEUJRAU
ALL P~AS( I VEHICLES
1972-1974 HODfL VEAR VEHICLES
IU-AN 197~ FTP IIC EMISSIONS
FAILURE KIITE Ol~ IiC ~ CI1 ~ ANU NOX
PASS SIIOI(T TEST ~ PASS Frp PASS SltOKT TEST ~ FAIL fTP
FAILURE      FAILURE     
"ATE N MEAN SD RATE N MEAN  SI)
10. 0  0.00 0.00 10. 73 4.RI 2.03
20. 0  0.00 0.00 20. 66 4.1>7 2.00
30. 0  0.00 0.00 30. 57 4.66 2.13
40. 0  0.00 0"00 40. 47 4.66 2.28
50. 0  0.00 0.00 50. 41 4.63 2.44
FAIL SttOK T  HST . PASS FTP fAIL SIIORT TE S T ~ FAIL fTP
FAILJRE      fAILURE     
~ATE N HE AN  SD RATE N HEAN  SD
10. 0  0.00 0.00 10. 9 10.13 8.55
2:>. 0  0.00 0.00 20. 16 8.36 6.70
)0. 0  0.00 0.00 30. 25 7.06 5.60
40. 0  0.00 0.00 40. 35 6.36 4.08
50. 0  0.00 0.00 50. 41 6.15 4.54
TABLE 3.67
IIJLr (NEurRALI
~LL PHASE 1 VEHICLES
1915-1976 MODEL YEAR VEHICLES
MEAN 1975 FIP HC EMISSt~NS
FAILURE RATE ON HC ~ cn ~ AND NOX
PASS SHORT HST , PASS FTP PASS SUQRT TEST ~ FAIL FTP
FA I LURE      FAILURE     
R~ If N MEAN SD RIITE N MEAN  SD
10. 8 0.'.12 0.2'. 10. 92  2.22 1.09
20. 8 0.82 0.24 20. 80  2.06 0.95
30. 8 0.1\2 0.24 30. 70  \. 91 0.82
40. 8 0.82 0.24 ,,0. 51!  1.74 0.75
50. 8 0.82 0.24 5n. 46  l.h3 0.71
FAIL SHORT TEST, PASS FTP FAIL SUORT TEST , FAIL FTP
FAILLIRE      FAILURE     
RATE N t1FAN SD RATE N MEAN  50
10. 0 0.00 0.00 10. 11  4.12 2.51
20. 0 0.00 0.00 20. 23  3.70 1.99
JO. 0 0.00 0.00 30. 33  3.53 1.77
40. 0 0.00 0.00 40. "5  3.31 1. 59
50. 0 0.00 0.00 50. 57  3.07 1.53
150

-------
TABLE 3.68
I ULE (NEUTRAL)
ALL PHASE I VEHICLES
1972-1974 MOOEL YEAR VEHICLES
MEAN 1975 FTP CO EMISSIONS
FAILURE RATE ON HC , CO , AND NOX
PASS StiORT  TEST , PASS FTP PASS SHORT  TEST , FAIL FTP
FAILURE      FAILURE      
RATE N I1E/IN  SO RATE N MF.AN  SD
10. 0  0.00 f).00 10. 73 80.33 35.22
20. 0  0.00 0.00 20. 66 76.85 31.81
30. 0  0.00 0.00 30. 57 75.28 30.69
40. 0  0.00 0.00 40. 47 74.07 29.83
50. 0  0.00 0.00 50. 41 72.65 30.61
FAIL SHORT  HST , PASS FTP I' A Il SHORT  TEST , FAIL HI'
FAILUPE      FAILURE      
RA TE N i1fllN  SI) RIITE N MF.j\N  SD
10. 0  0.00 0.00 10. 9 104.98 49.87
20. 0  0.00 0.00 20. 16 108.';4 48.55
30. 0  0.00 0.00 30. 25 100.71 45.69
40. 0  0.00 0.00 1..0. 35 95.07 43.48
50. 0  0.00 0.00 50. 41 93.'01 41.16
TABLE 3.69
II)L f (NEIHf{ALI
ALL PHAS[ 1 VFHICLE~
197<;-1976 tlOoEL YE"R VEHICLFS
11EI\f>.I 1975 FTP CO EMISSIOIIS
f"ILURf RATE UN HC , cn , AND NOX
PASS SHORT  rrs T , PASS FTP
FAIlLJRE:     
I~ II TE N '1f/lN  50
10. 8 10.85 2.55
20. 8 10.05 2.55
30. (1 10.85 7.55
40. 8 10.8~ 7.55
50. R 11).85 2.55
FA II SlInRT  Tl:ST , P/I~S rTP
FAILURE     
RA TF N MEAN  SI)
10. 0  0.00 n.oo
20. 0  0.00 0.00
10. 0  0.00 0.00
40. 0  0.00 0.00
50. 0  0.00 0.00
PASS SHORT  TEST , fAIL FTP
F"IlIJRE      
RAT[ N tifAN  SU
10. 92 48.04 25.80
70. 80 43.36 20.30
10. 70 41.06 18.91
40. 58 37 .05 15.40
50. 46 35.60 15.87
FA Il SttORT  TEST , FAIL HI'
FAILURE      
RATE N tifAN  SO
10. 11 97. 32 77 .29
20. 23 R7.RQ 58.85
30. 33 79.29 52.06
40. 45 74.76 46.61
50. 57 "7.60 43.67
151

-------
TABLE 3.10
IDLE (NEUTRAL!
ALL PHASE I VEHICLES
1912-1914 MODEL YEAR VEHICLES
MEAN 1915 FTP NOX EMISSIONS
fAILURE RATE UN HC , CO , AND NOX
PASS SHORT  TEST , p"SS FTP PASS SHORT  TEST , FAIL FTP
F A I L UP E      FAILURE      
RATE N HEAN  SO RATE N HE AN  . SO
10. 0  0.00 0.00 10. 13  2.19 1.16
20. 0  0.00 0.00 7-0. 66  2.21 1.19
30. 0  0.00 0.00 30. 51  2.21 1.7-5
40. 0  0.00 0.00 ,,0. 41  7-.?1 1.21
50. 0  0.00 0.00 50. 41  2.12 1.09
FAIL SltORT  TEST , P"S5 FTP FAIL SHORT  TEST , FAIL FTP
FA Il URE      FAILURE      
RATF N liE AN  SO RATE N MEAN  SI)
10. 0  0.00 0.00 10. 9  2.06 1.11
20. 0  0.00 0.00 20. 16  2.03 0.98
30. 0  0.00 0.00 30. 25  1.94 0.115
40. 0  0.00 0.00 40. 35  2.04 1.08
50. 0  0.00 0.00 50. 41  7..22 1.22
TABLE 3. ,71
IDLE (NEUTRAL J
ALL PHASE 1 VEHICLES
1975-1916 MOOH YEAR VEIIICLES
MEAN 1915 FTp NOX EMISSIONS
FAILURE RATE ON HC , CO , AND ~OX
PASS SHORT TE ST , PASS FTp PASS SHORT TEST   
       , FAIL FTP
FAILURE      FAILURE     
RATE N 'if AN  50 RATE N    
      MEAN SI)
10. 8  2.06 0.46 10. 92    
20. II  7..06   1.10 0.89
    0.46 20. 80  1.11 
3(). II  7-.01', 0.4b     0.94
      30. 10  1.13 0.99
40. 8  7..06 0.46    
50. II  7..06  '.0. 58  1.1.7. 1.02
    0.46 50. 46  1.12 1.05
FAIL SHORT TEST , PASS rTP FAIL SlmRT TEST   
       , FAIL FTP
FA IL URE      FAILURE     
RATE N MEliN  SO     
      RATE N MEAN  SO
10. 0 0.00 0.00 10. 11    
20. 0 0.00  1.56 0.78
      0.00 20. 23 1.63 0.63
30. 0 o.on 1).00   
40. 0 0.00  30. B 1.59 0.58
0.00   
50. 0 0.00  40. itS 1.65 0.61
      0.00 50. 51 1.61 0.12
      152     

-------
TABLE 3.72
FEDERAL SHORT CYCLE
All PHASE 1 VEHICLES
1972-1974 ~OOEl YEAR VEHICLES
MEAN 1975 FTP HC EHISSIUNS
r AllURE RA TE ON "C . cn . AND NOX
PASS SHORT  TEST . PASS FTP PASS SHORT  TEST . FA Il FTP
FAIL UR F.      FAILURE      
RAT!' N HFAN  SO RAT!' N MEAN  SO
10. 0  0.00 0.00 10. 74  4.73 1. 81
20. 0  0.00 0.00 20. 66  4.66 1.87
30. 0  0.00 0.00 30. 57  4.37 1.17
40. 0  0.00 0.00 40. 49  4.28 1.1',
50. 0  0.00 0.00 50. 41  4.30 1.12
FAIL SH(]RT  TEST . PASS FTP FAIL SHORT  TEST . FAIL FTP
FAIL UR E      FAILURE      
RATE N MEAN  SO RATE N MEAN  SO
10. 0  0.00 0.00 10. e 11.54 8.74
20. 0  0.00 0.00 20. 1(,  8.42 6.82
0\0. 0  0.00 0.00 30. 25  7.73 5.90
40. 0  0.00 0.00 40. 33  7.04 5.29
50. 0  0.00 0.00 50. 41 6.49 4.90
TABLE 3.73
FEOFRAl SHORT CYCLE
All PHASE 1 VEHICLES
1975-1976 MODEL YEAR VEHICLES
HEAN 1975 FTP HC EMISSIONS
FAILURE RArE ON HC . CO . AND NOX
PASS SHnRT  TE 5 r . PA<;S rIP
FAILURE     
RAT[ N IIEAN  S I)
10. 8  0.82 0.2/.
20. A  0.A2 0.24
30. 11  0.112 0.2/,
40. II  0.1\2 0.24
50. R  0.82 0.24
FAIL SHORT  T[ 5 T , PASS rIP
FAILURE     SO
RATf N MEAN 
10. 0  0.00 0.00
20. 0  0.00 0.00
0\0. 0  0.00 0.00
40. 0  0.00 0.00
50. 0  0.00 0.00
PASS SIIORT  TEST . rAIL FTP
FAILURE      
RATE N t1EAN  SO
10. 92  2.17 0.96
20. 81  2.07 0.90
30. 70  1. 91 0.78
40. 59  1.R3 0.79
50. 47  1.75 0.00
FAIL SHORT  TEST . FAIL FTP
FhllURE      
RATE N MEAN  5[1
10. 11  4.54 2.59
20. 22  3.72 2.13
30. 33  3.53 1.81
40. 44  3.72 1.68
50. 56  2.99 1.58
153

-------
TABLE 3.74
FEDERAL SHORT CYCLE
ALL PHASE 1 VEHICLES
191'--1914 HODEL YEAR VEHICLES
MEAN 1915 FTP CD EMISSIONS
FAILURE RATE ON HC , CO , AND NOX
PASS SIIORT  TFST , PASS FTP PASS SHan TEST , FAIL FTP
FAILURE      FAIlURE     
P.A TE N MEhN SO RATE N MEMI SO
10. 0  0.00 0.00 10. 1it 1lt.3B 25.61
20. 0  0.00 0.00 20. 66 69.QO 22.06
30. 0  0.00 0.00 30. 51 65:06 16.58
ito. 0  0.00 0.00 1,0. it9 62.31 15.06
50. 0  0.00 0.00 50. itl 60.61 13.83
FAIL SHORT  TEST, PASS FTP FAIL SHORT TEST, FAll FTP
       )     
FAIU.lRE      FAILURE     
RATE N MF.AN SU RATE N HEM..  SO
10. 0  0.00 0.00 10. 8 163.06 36.69
20. 0  0.00 0.00 20. 16 131.19 40.10
30. 0  0.00 0.00 30. 25 12it.OO 39.95
ito. 0  0.00 0.00 40. H 113.81 39.81
50. 0  0.00 0.00 50. itl 105.39 1.0. it it 
TABLE 3.75
FEOfRAL SHORT CYCLE
ALL PHASE 1 VEHICLES
1975-1916 HlIUEL YEAR VEIIICLE5
MEhN 1915 FTP CD EHISSIONS
FAILURE RATE ON HC , CU , AND NOX
PASS SIHlRT TEST, PASS FTP PASS SHORT TEST , FAIL FTP
FAILURE     FAILURE     
RATE N liF.flN 5D RATE N HEAN SO
10. 8 10.85 2.55 10. 91. 46.19 22.itl
20. 8 10.115 7.55 20. 81 '.2.24 19.85
':\0. e 10.85 7.55 30. 10 31 .76 15.54
40. 8 10.85 ;>.55 40. 59 35.111 15.62
50. 8 10.115 2.55 50. It1 H.07 lit .15
FAIL SHORT  TEST , PA')S FTP FAIL SHORT TEST, FAIL FTP
FAILURE     FAILURE     
RATE N MEAN SO RATE N MEAN SO
10. 0 0.00 0.00 10. 11 112.85 7It. 03
20. 0 0.00 0.00 20. 22 94.06 56.14
30. 0 0.00 0.00 30. H 86.29 its.31
40. 0 0.00 0.00 40. it4 16.69 it5.25
50. 0 0.00 0.00 50. 56 11.13 it 1.78
154

-------
TABLE 3.76
FEDERAL SHURT CYCLE
4LL PHASE 1 VEHICLES
1912-1974 MODEL YEAR VEHICLES
ME4N 1915 FTP NOX EMISSIONS
FAILURE RillE rJN IIC , cn , AND ~OX
PASS SHflRT  HST , PIISS FIP PASS SHORT  TEST , FAIL FTP
FAILURE      FAILURE      
RATE N MEAN  SO RillE N MEAN  SO
10. 0  0.00 0.00 10. 14  2.26 1. 18
20. 0  0.00 0.00 :?o. 66  2.31 1.22
30. 0  0.00 0.00 30. 57  2.:H 1.18
40. 0  0.0(') (').00 1,0. 49  2.',5 1.18
50. 0  0.00 0.00 50. 41  2.38 1.03
FAIL SHnRT  TEST , PIISS FTP FAIL SHnRT  TEST , FAIL FTP
FAILURE      FAILURE      
RATE N MEAN  SO RATE N MEAN  SO
10. 0  0.00 0.00 10. 8  1.39 0.34
20. 0  0.00 0.00 20. 16  1.60 0.48
30. 0  0.00 0.00 30. 25  1.86 1.03
40. 0  0.00 0.00 40. 33  1.16 0.98
50. 0  0.00 0.00 50. 41  1.96 1. 24
TABLE 3.77
r-EDF.RAL SHORT CYCLE
filL PHAsr 1 VEIIiCLES
1975-1916 MODEL YEAR VEHICLES
MEAN 191~ FTP NOX EMISSIONS
FAILURE RIITE ON IIC , CO , IIND NOX
PASS SHORT  1(S T , PIIS') FTP PASS SHORT  TEST , FAIL FTP
FAILJPE      FAILURE      
RIITE N tlEMI  SO RATE N MEliN  SO
10. 8  2.06 0.46 10. 92  1.16 0.90
20. U  2.06 0.46 10. 81  1. PO 0.94
30. 8  ;>.06 0.',6 10. 10  1. 86 0.99
40. 8  2.0h 0.46 40. 59  1.88 1.04
50. A  2.06 0.46 50. 47  1. 91 1.08
FAIL SHORT  TEST , PASS FTP FAlL SHORT  TEST , FAIL FTP
FAILURE      fAILURE      
PA TE N ~'F.IIN  ')0 RIITE N MEAN  SO
10. 0  0.00 0.00 10. 11  1.08 0.31
20. 0  0.00 0.00 ;>0. 22  1.21 0.35
30. 0  0.00 0.00 30. 33  1.33 0.42
40. 0  0.00 0.00 40. 44  1.43 0.51
50. 0  0.00 0.00 50. 56  1.50 0.62
155

-------
TABLE 3.78
IDLE (NEUTRAL)
ALL PHASE I VEHICLES
1912-1914 MUDEL YEAR VEHICLES
MEAN COLD TRANSIENT HC EMISSIONS IN
FAILURE RATE ON IIC , CO , AND NO)(
GRAMS
PASS SIiORT  TEST, PASS FTP PASS SHORT  TEST , FAIL FTP
FAILURE     FAILURE      
RATE N MEAN SO RATE N HEAN  SO
10. 0 0.00 0.00 10. 13 24.48 24.81
20. 0 0.00 0.00 20. 66 24.21 26.01
30. 0 0.00 0.00 30. 51 24.15 21.89
'.0. 0 0.00 0.00 '.0 ~ 41 25.23 30.66
~o. 0 0.00 0.00 50. 41 25.1It 32.80
FAIL SIiORT TEST, PASS FTP FAIL S llOR T  TE ST , FAIL FTP
FAILURE     FAILURE      
RATE N HEAN SO RATE N MEAN  SO
10. 0 0.00 0.00 10. 9 '.0.98... 31.93
20. 0 0.00 0.00 20. 16 3".85 25.10
30. 0 0.00 0.00 30. 25 29.19 21.28
40. 0 0.00 0.00 40. 35 21.11 18.40
50. 0 0.00 0.00 50. "I 7.6.83 11.19
TABLE 3.79
'IDLE (NEUTRAL)
ALL PHASE I VEHICLES
\915-1916 MODEL YEAR VEHICLES
MEAN COLO TRANSIEMT HC EMISSIONS IN
FAllURF RATE ON HC , CO , AND NOX
GRAMS
PASS SHORT  TFST , PASS FTP PASS SHORT TEST , FAIL FTP
FAILURE      FAILURE     
RATE N MEliN SO RATE N MEA~  SO
\0. 8  8. \0 3.35 \0. 97. 12.62 6.39
20. 8  8.10 3.35 20. 80 12.03 6.13
30. 8  II. \0 1.15 10. 10 1\.26 4.51
"0. 8  A .10 3.35 40. 511 10.86 4.6'1
50. 8  II. 10 3.35 50. 46 10.61 4.18
FAIL SHnPT TEST, PASS FTP FAIL SlfORT TEST , FAIL FTP
FA IlIJRE      FULURE     
RATE N HEliN SO RIITE N MEAN  so
10. 0  0.00 0.00 10. 11 19.38 10.99
20. 0  0.00 0.00 20. 23 11. &9 9.01
30. 0  0.00 0.00 30. 33 11.76 9.65
40. 0  0.00 0.00 40. 45 16.54 &.61
~o. 0  0.00 0.00 50. 51 15.54 8.42
      156     

-------
TABLE 3.80
II'LF. (N!:UTRAL)
ALL PIIAS[ 1 VEfllCLES
1977-197~ HODEL YEAR VEHICLFS
MEAN COLI) TRAIIISIENT CO "'USSIONSIN
FAILURE RATE (IN HC , cn , AND Nn:..
GRAMS
PASS SHnRT  TEST , PASS FTP PASS SlmRT  TEST , FAIL HI'
FAILJRE      FAILURE       
RATE N '1EAN  SO RIITE N HEAN SI)
10. 0  0.00 0.00 10. 73 367.01 189.09
20. 0  0.00 o~oo 20. 66 357.72 187.76
30; 0  0.00 0.00 30. 57 36'..16 195.60
40. 0  0.00 0.00 " (). 47 369.56 209.08
50. 0  0.00 o.ou 50. 41 368.20 220.46
FAll SHnRT  HS1 , PASS FTP FAIl. SHORT  TEST , FA IL FTP
FAILURE      rAILURE       
RATE N HfAN  sn RATE N HEAN SO
10. 0  0.00 0.00 10. 9 423.35 170.33
20. 0  0.0(1 0.00 20. 16 437.03 175.00
30. 0  0.00 0.00 30. 25 393.81 167.59
40. 0  0.00 0.00 40. 35 378.08 155.25
50. 0  0.00 0.00 50. 41 378.20 148.80
TABLE 3.81
10Lr (NEUTRAL!
ALL PHASI: 1 VEHICLES
1975-1976 HnOFL YEAR VEHICLES
HEI\~ CULD TRANSIENT CO EMISSIONS IN
FAilURE RATE ON flC , cn , AND NUX
GRAMS
PAc;s SIIIJR T  TEST , 1'1\55 FTP PASS SHrJRT  TEST I FAIL rTP
FAll UII[      FAILURE       
RATE N "EIIN  SO RflTE N MEAN SO
10. II 1,,0.94 41.86 10. 92 2'.9.118 116.70
20. 8 140.94 ',1.86 20. 80 233.7.6 100.57
3r). 8 1'.0.94 ',1.86 30. 70 275.43 93.41
40. 8 140.94 '.1.86 40. 511 7.12.90 88.96
50. 8 140.9/, 41.86 50. 46 211.10 88.04
FAll SHORT  HST , 1'1\55 FTP FAll SHnRT  TEST , FAIL FTP
FA I l UR E      FAILURE       
PATF N r'ffli~  SO RATE N MEAN 50
10. 0  0.00 0.00 10. 11 376.9" 298.97
20. 0  0.00 0.00 20. 23 368.46 230.24
30. 0  0.00 0.00 30. 33 )1,4.09 201.21
1,0. 0  0.00 0.00 40. 45 328.60 184.73
50. 0  0.00 0.00 50. 57 305.70 115.01
157

-------
TABLE 3.82
IDLE (NEUTRAlI
All PHASE I VEHICLES
197?'-1974 HnOEl YEAR VEHICLES
HEAN COLD TRANSIENT NOX F.HISSIONS IN
FAILURE RATE ON HC , CO , AND NOX
GRAMS
PA~S SHORT TEST, PASS FTP PASS s~rnRT TEST , FAil FTP
FAIL URE      FA II. liRE      
RATE N ~'EAN SO RATE N HEAN  SO
111. 0 0.00 0.00 10. n 9.57 5.21
'-0. 0 0.00 0.00 20. 66 9.61 5.33
JO. 0 0.00 0.00 30. 57 9.80 5.62
40. 0 0.00 0.00 40. 47 9."7 5."5
50. 0 0.00 0.00' 50. 41 9.00 4.94
FAil SIInRT TES I , PASS FTP FA Il SHORT TEST, FAil FTP
FAILURE      FAILURE     
!lATE N MEliN SO RIITE N HEAN  SO
10. 0 0.00 0.00 10. 9 9.07 4.38
20. 0 0.00 0.00 20. 16 9.09 It. 16
30. 0 0.00 0.00 30. 25 8."4 3.70
40. 0 0.00 0.00 40. 35 9.29 1t.67
50. 0 0.00 0.00 50. 41 10.03 5.28
TABLE 3.83
IDLE I NEUTRAlI
All PHASE 1 VEHICLES
1975-1976 HODEL YEAR VEHICLES
HEAN CULo TRANSIE~T NOX EHISSIONS
FAILURE RATE ON HC , cn , AND NOX
IN GRAMS
PASS SIIORT  TEST , PASS FTP PASS SHORT TEST , FAil FTP
FAIL UR E      r AllURE     
RATE N IIEAN SO RATE ~I HEAN  so
10. 8  7.99 1.72 10. 92 7.57 3.21
20. II  7.99 1.72 20. 110 7."0 3.3Z
30. II  7.99 1.72 30. 70 7.65 3.41
Ito. 8  7.99 1.72 40. 58 7.69 3.61
50. 8  7.99 1.1'- 50. 46 7.6A 3~80
FAIL SHORT TEST, PASS nr rAil SHORT TEST, FAil FTP
FAILURE      FAILURE     
RATE N HEA'" SO illiTE N HEAN  SO
10. 0  0.00 0.00 10. 11 7.36 3.76
20. 0  0.00 0.00 20. 23 7.33 3.07
10. 0  0.00 0.00 30. 33 7.:\1 2.92
40. 0  0.00 0.00 ito. 45 7.36 2.76
50. 0  0.00 0.00 50. 57 7.1t4 2.76
      158     

-------
TABLE 3.84
IOLE (NEUTRAL)
ALL PHASE 1 VEHICLES
1972-1974 HODEL VEAR
HEI\~ CULD SrABILIZED
FAILURE RATE ON HC ,
VEHICLES
fiC E HIS S II1NS IN GRAMS
CO , AND NOX
PASS SltnR"T TEST , PASS FTP PASS SHORT  TEST , FAIL FTP
FAILURE      FAILURE      
RATE N MEliN  SD RATE N HEAN  SO
10. 0 0.00 0.00 10. 73 16.45 5.70
20. 0 0.00 0.00 20. 66 15.7B 4.9B
30. 0 0.00 0.00 30. 57 15.42 5.10
'.0. 0 0.00 0.00 40. 47 15.16 5.15
50. 0 0.00 0.00 50. 41 14.92 5.40
FAIL SHORT TEST , PASS FTP FAIL SHORT  1[ST , FAIL FTP
FAILURE      FAILURE      
RATF N r1EAN  SO RATF N MEM..  SD
10. 0 0.00 0.00 10. 9 40.53 33.91
20. 0 0.00 0.00 20. 16 32.72 26.93
30. 0 0.00 0.00 30. 25 27.45 22.56
40. 0 0.00 0.00 40. 35 24.36 19.75
50. 0 0.00 0.00 50. 41 23.26 IB.44
TABLE 3.85
\()LE (NEIJTRAL)
IILL PHASE I VEHICLES
1975-1976 MnDEL VEAR
MEAN COLD STABILIZED
FAILURE KATE ON HC ,
VEIHCLfS
HC EMISSIONS IN GRAMS
CO , AND NOX
PASS SIIORT  TES r , PIIC;S FTP PASS SHORT  TEST , FAIL FTP
FAILJRE      Fh ItURE      
RATE N 11(AN SO RATE N MEliN  SO
10. 8  1.3', 0.54 10. 92  f1.R9 4.31
20. 8  1.3', 0.54 20. BO  6.14 3.74
30. B  1.34 0.54 30. 70  5.5', 3.39
40. 8  \ .:JIo 0.54 40. 58  4.66 2.77
50. R  1. 34 0.5', 50. 46  4.10 2.51
FAIL SHORT HST , PASS FTP FAIL SHORT  TEST , FAIL FTP
FA ILURE      FAILURE      
PATE N '1EAN SD RATE N MEliN  SD
10. 0  0.00 0.00 10. 11 15.34 8.20
20. 0  0.00 0.00 20. 23 1~.54 6.68
30. 0  0.00 0.00 30. 33 12.59 6.01
40. 0  0.00 0.00 40. 45 11.84 5.48
50. 0  0.00 0.00 50. 57 10.78 5.42
      159      

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TABLE 3.86
IDLE (NEUTRAl!
ALL PHASE 1 VEHICLES
1912-1914 MODEL YEAR
MEAN COLD STABILIZED
FAILURE RAT~ ON HC. ,
VEHICLES
CU EMISSIONS IN GRAMS
CO , AND NOX
PASS SHORT  TEST, PASS FTP PASS SlmRT TEST , FAIL FTP
FAilURE      FAILURE      
RATE N MEAN SD RATE N MEAN SD
10. 0 0.00 0.00 10. n 301.76 144.76
20. 0 0.00 0.00 20. 66 284.45 123.73
30. 0 0.00 0.00 30. 57 271.54 111.92
40. 0 0.00 o~oo 40. 47 261.19 102.70
50. 0 0.00 0.00 50. 41 251.cn 100 . Z7
FAIL SUORT TEST , PASS FTP FAil SHORT TEST, FAIL FTP
FAILURE      FAILURE      
RATE N HFAN SO RATE N MEAN SO
10. 0 0.00 0.00 10. 9 421.02 223.71
20. 0 0.00 0.00 20. 16 440.2B 218.35
30. 0 0.00 0.00 30. 25 413.60 201.14
40. 0 0.00 0.00 40. 35 386.92 IB9.48
50. 0 0.00 0.00 50. 41 371.77 180.02
TABLE 3.87
II'ILE (NEUTRAl!
ALL PHASE 1 VEHICLES
1975-1976 HODEL YEAR
MEAN COLD STA81LIZED
FAilURE RATE UN HC ,
VEHICLES
CO EMISSIONS IN GRAMS
CO , ANlJ NOX
PASS SHORT T£ST , PASS FTP
FAILURf
RATE
10.
20.
30.
40.
50.
N
MEAN
PASS SHORT TEST, FAIL FTP

FAILURE
RATE
SU
5.42
5.42
5.42
5.42
5.42
rAil SIIORT TEST, PASS FTP
FA IlURf
RA'TE
10.
20.
30.
40.
50.
8
8
8
8
8
4.14
4.74
4.74
4.74
4.74
N
MEAN
o
°
o
o
o
0.00
0.00
0.00
0.00
0.00
FAIL SHORT TEST, FAil FTP

FAILURE
RATE
SD
0.00
0.00
0.00
0.00
0.00
160
N
MEAN
SO
10.
20.
30.
40.
50.
92
80
70
58
46
160.46
140.93
131.03
111.49
103.07
105.51
88.28
84.94
66.68
69.60
N
MEAN
SO
10.
20.
30.
',0.
50.
11
23
33
45
57
409.11
347.32
305.78
284.37
254.16
291.31
222.84
200.50
182.06
172.45

-------
TABLE 3.88
IllLI' (NFIITRI\L)
I\LL PHASE I VEHICLES
\97l-1974 MODEL VEAR
I1EAN COLO STAI\ILIZEO
FAILURE RATE ON HC ,
VEHICLES
NIIX EtllSSlnN5 IN GRAMS
cn , I\NO Nnx
PASS SHnRT  TEST , PA<;S FrP PASS SHORT  TEST , FAIL FTP
FAILuRE      fl\lLURE      
RI\TE N tl[IIN  <;D R/ITE N MEAN  SO
10. 0  0.00 0.00 10. 73  b.60 3.45
20. 0  0.00 0.00 20. 66  6.60 3.53
30. 0  0.00 0.00 30. 57  6.94 3.69
40. 0  0.00 0.00 40. 47  6.94 3.4'.
50. 0  0.00 0.00 50. 4\  6.52 3.12
FAIL SHnRT  TES T , PASS FTP FA IL SYORT  TEST , FAIL FTP
FAILLIRE      FAILURE      
RAT£' N MEI\N  SU RI\TE tl MEAN  SO
10. 0  0.00 0.00 10. 9  6. 10 3.60
20. 0  0.00 0.00 20. 16  5.9B 3.12
30. 0  0.00 0.00 30. 25  5.65 2.70
40. 0  0.00 0.00 40. 35  6.02 3.44
5u. 0  0.00 0.00 50. 4\  6. 'is 3.79
TABLE 3.89
I[1LE IrH:IITRALI
/ILL PH/ISF \ VEHICLES
\975-197h MunEL YEAR
"E/IN CUll) STI\BILIZED
r A ILliRF RI\ TF UN IIC ,
VEHICLFS
NUX FtlTSSlllNS IN GRAMS
CO , AI~O NOX
PASS SllnRT  TE 5 T , P/I<;S FTP
fAlLlJRF     
RAT£' N "EMI  <;1)
1 o. e  7.'i7. 2.00
20. 8  7.57 2.00
~(). 1\  7.52 2.00
40. 8  7. 5l 2.00
')0. 0  7.57 2.00
FAIL SHORT'TEST , PASS rTP
FAILURE     
RATE N MEAN  51)
10. 0  0.00 0.00
20. 0  0.00 0.00
30. 0  0.00 0.00
40. 0  0.00 0.00
50. 0  0.00 0.00
PASS 5 tlOR T  TrST , rAIL FTP
FAILURE      
RATE N MEAN  SO
\0. n  5.33 3.55
20. 80  5.33 3.76
'~o . 70  5.43 3.95
40. 50  5.;>9 3.96
50. 46  5. ''\7 4.21
FAIL SHORT  TEST , FAIL FTP
FA ILURE      
R/ITE N MEI\N  SO
10. 11  4.53 2.43
20. 23  4.q4 2.05
~o. 33  4. A'. 2.00
40. 45  5018 2.69
50. 57  5.14 2.72
161

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TABLE 3.90
EHISSIONS FOR 10' rn 50~ WORST EHITTING VEHICLES
FEDERAL T~ST PROCE~URE
   IWOROCARnflNS    CARnON HONOXIUE    NOX   
  12-1/,  75-16  72-H  75-16  72-7'.  7')-76
 N ~IE AN SO N HEAN SO N HEAN SO N HEAN 50 tI HE AN  50 N MEAN SO
10'% 8 13.19 11.22 11 4.80 2.31 8 110.09 31.52 11 129.78 60.74 8 1.41 0.54 11 1.31 0.44
20% 16 8.91\ 7.12 22 4. 1/. 1.81t 16 I1t4.80 H.1t8 22 104.30 49.86 16 1.62 0.66. 22 1.48 0.1t2
30~ 25 7.71 5.09 13 3.63 1.611 25 127.83 35.81 33 90.91 44.76 25 1.7? 1.05 H 1.42 O. '.4
40% H 7.20 5.21 /,4 3.35 1.59 B 115.67 38.43 44 81.67 4 1 .90 H 1.75 1.03 4ft 1.39 0.43
50~ Itl 6.11 ',.85 '56 3.13 1.57 41 100.29 37.58 56 13.93 40.02 41 1.76 0.94 56 1.43 0.511
       EHISSIOtiS FOR los ,n 50~ WORST EMITTING VEHICLES      
       ClilO TRANSIENT IGMI          
f-'                    
~                    
N            MONOXIDE       
    'iYOROCARHUN5     CARRON    NOX   
   H-74  75-16  12-14  75-76  72-74  75-76
  N I~EAN 50 N MEAN SO N HEAN 511 N MEAN SO N MEA'" SO t~ MF.I\N SO
 10S II 11.40. 6'. .94 II 26.]2 11.60 8 743.11 HI. 62 11 560.05 222.57 8 5.12 2.67 11 4.95 1.67
 20'X 16 51.19 52.14 22 22.14 10.25 16 645.82 250.05 22 461.32 191.94 16 6.89 2.84 22 5.7' 1.83
 30% 25 42.2J 43.20 H 19.40 9.25 25 563.43 230.43 H 413.77 169.93 25 7.49 4.91 H 6.03 1.88
 40S H 37.26 38.51 44 17.62 8.65 33 57.1.34 213.45 lt4 381.48 157.21 H 7.59 4.65 44 6.30 2.03
 50X 41 34.21 35.08 56 16.69 8.07 41 486.04 205.07 56 349.54 153.54 41 8.19 4.86 56 ".98 3.31
      EMISSIONS FOR 10' ru 50% WORST EMITTING VEHICLES      
      CUll) STABilIZED I(;HI          
   HYOROCAAIIONS     CARRON M(1NOXIDE    NOX   
  72-14  75-76  12-74  75-76  72-7',  75-76
 N H E I\t~ SO N HEAN SO N HEAN 50 N MEAN SO N HEAN SO N "F.AN SO
10% 8 45.92 34.29 11 1" . 36 8.21 8 6117.09 139.34 11 503.56 22'.68 8 4.06 1.46 11 3.56 1.53
20S 16 37..52 2 7 . 30 22 14.911 6.02 16 57',.11.3 153.87 22 411.34 182.88 16 4.50 1.88 22 '..37 1.59
30% 25 27.80 27..51 H 13.37 5.59 15 500.08 158.72 H 351.18 171.80 25 5.7.2 2.92 H 4.14 1.48
40% H 25.62 20.36 44 12.03 5.41 33 '.51.03 164.71 44 309. 11 165.20 H 5.31 2.81 44 4.23 1. '59
50S 41 23.77. 18.70 56 10.7? 5.42 41 4111.71 161.58 56 276.11 159.41 41 5.58 2.8', 56 4.15 1.5l1

-------
TABLE 3.91

CLAYTON CAUSES OF HIGH HC EMISSIONS
Type 1 Causes
Abnormally high HC in one of the following Modes:
Idle
Idle and Low Cruise
Usual Causes
1. Vacuum leaks into the intake manifold causing a lean
mixture and subsequent misfire in some cylinders.
2. Idle circuits on 2 and 4 barrel carburetors highly
imbalanced or adjusted too lean.
3. Intermittent ignition misfire is possible but not
probable.
4 .
Grossly advanced ignition timing.
5 .
Modest compression leak through one or more exhaust valves.
6. Excessively high CO at idle can cause moderately high HC
at idle.
Type 2 Causes
Abnormally high HC in one of the following ~odes:
Low Cruise
High Cruise
High and Low Cruise
High Cruise and Idle
High, Low Cruises, and Idle
Usual Causes
1. Ignition misfire
power operation, due
component.
under higher compression pressures of
to failure of an ignition system
163

-------
TABLE 3.92
CLAYTON CAUSES OF HIGH CO EMISSIONS
Type l' Causes
Abnormally high CO in one of the following Modes:
Idle
Idle and Low Cruise
Usual Causes
Gross error in carburetor idle air fuel mixture
adjustment.
Type 2' Causes
Abnormally high CO in one of the following Modes:
Low Cruise
High Cruise
High Cruise and Low Cruise
Usual Causes
Main system carburetor malfunction. This problem cannot
be corrected by an idle adjustment only.
Type 3' Causes
Abnormally high CO in one of the following Modes:

High Cruise and Idle

High, Low Cruises, and Idle

Usual Causes
1. Gross error in carburetor idle air fuel mixture
adjustment.
2. Main system carburetor malfunction. This problem
cannot be corrected by an idle adjustment only.
164

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TABLE 3. 93

PERCENT OF VEHICLES FAILING FEDERAL HC STANDARDS WITH HIGH HC EMISSIONS
ON FEDERAL THREE MODE TEST FOR 1972-1974 MODEL YEAR VEHICLES
f-'
0\
U1
   Type 1 Cause   Type 2 Cause  
  Number of   Low   High &  High High & Low
  FTP HC  Cruise Low Hiqh Low  Cruise Cruise
Manufacturer Failures Idle & Idle Cruise Cruise Cruise & Idle & Idle
GM  33 3  3 0 21 3   3  9
Ford  19 5  0 0 21 11   11  11
Chrysler 10 0  10 0 0 20   0  50
AMC  3 33  0 0 0 67   0  33
U.S. Manu-            
facturers 65 5  3 0 17 11   5  17
Foreign            
Manufacturers 13 31  0 15 15 8   0  15
Total  78 9  3 3 17 10   4  17
PERCENT OF VEHICLES BY CAUSE
Manufacturer Type 1 Cause Type 2 Cause
GM  6   36
Ford  5   54
Chrysler 10   70
AMC  33   100
U.S. Man-    
facturers 8   50
Foreign    
Manufacturers 31   53
Total  12   51

-------
TABLE 3.94

PERCENT OF VEHICLES FAILING FEDERAL CO STANDARDS WITH HIGH CO EMISSIONS
ON FEDERAL THREE MODE TEST FOR 1972-1974 MODEL YEAR VEHICLES
   Type l' Cause Type 2' Cause  Type 3' Cause
  Number of   Low    High & High High & Low
  FTP CO   Cruise Low High Low Cruise  Cruise
Manufacturer Failures Idle  & Idle Cruise Cruise Cruise & Idle  & Idle
GM  36 8  19 6  8 6 6  44
Ford  18 33  11 0  6 17 0  33
Chrysler 10 0  30 10  0 20 10  30
AMC  3 0  33 0  0 0 0  67
U.S. Manu-           
facturers 67 13  18 4  6 10 4  40
Foreign           
Manufacturers 14 7  21 0  0 14 21  36
Total  81 12  19 4  5 11 7  40
....
0\
0'\
PERCENT OF VEHICLES BY CAUSE
Manufacturer Type l' Cause Type 2' Cause Type 3' Cause
GM 77  20   50
Ford 44  23   33
Chrysler 30  30   40
AMC 33  0   67
U.S. Manu-      
facturers 31  20   44
Foreign      
Manufacturers 28  14   57
Total 31  20   47

-------
TABLE 3.95

PERCENT OF VEHICLES FAILING FEDERAL HC STANDARDS WITH HIGH HC EMISSIONS
ON FEDERAL THREE MODE TEST FOR 1975-1976 MODEL YEAR VEHICLES
......
0'\
--.J
  Type 1 Cause   Type 2 Cause 
 Number of  Low   High & High High & low
 FTP HC  Cruise Low High Low Cruise Cruise &
Manufacturer Failures Idle & Idle Cruise Cruise Cruise & Idle Idle
GM 25 16 28 20 0 4 0 20
Ford 11 0 18 18 0 9 0 18
Chrysler 14 14 43 7 0 0 0 21
AMC 4 0 50 25 0 0 0 0
U.S. Manu-         
facturers 54 11 31 17 0 4 0 19
Foreign         
Manufacturers 21 21 14 38 0 24 0 19
Total 75 8 27 23 0 9 0 19
PERCENT OF VEHICLES BY CAUSE
Manufacturer Type 1 Cause Type 2 Cause
GM 44   44
Ford 18   45
Chrysler 57   28
AMC 50   25
U.S. Manu-    
facturers 42   40
Foreign    
Manufacturers 35   81
Total 35   51

-------
TABLE 3.96

PERCENT OF VEHICLES FAILING FEDERAL CO STANDARDS WITH HIGH CO EMISSIONS
ON FEDERAL THREE MODE TEST FOR 1975-1976 MODEL YEAR VEHICLES
          . ~ -
  Type l' Cause Type 2' Cause   Type 3' Cause
 Number of  Low    High &  High High & Low
 FTP CO  Cruise Low High Low Cruise Cruise
Manufacturer Failures Idle & Idle Cruise Cruise Cruise & Idle & Idle
GM 37 3 24 0 5 16  3  41
Ford 23 0 30 9 4 13  3  30
Chrysler 13 0 38 0 8 8  0  38
MC 5 20 20 0 0 0  0  60
U.S. Manu-           
facturers 78 3 28 3 5 13  3  38
Foreign           
Manufacturers 22 9 23 0 5 5  0  55
Total 100 4 27 2 5 11  2  42
....
0\
00
PERCENT OF VEHICLES BY CAUSE
Manufacturer Type l' Cause Type 2' Cause Type 3' Cause
GM 77  21 44
Ford 30  26 34
Chrysler 38  16 38
MC 40  0 60
U.S. Manu-    
facturers 31  21 41
Foreign    
Manufacturers 32  10 55
Total 31  18 44

-------
   TABLE 3.97    
PERCENTAGE OF VEHICLES WITH MALADJUSTED OR DISABLED
EMISSION SYSTEMS OR COMPONENTS  
       Failing Phase 1/
Emission Related All Phase I Passing Phase I Failing Phase 2
System/Component Vehicles Vehicles Vehicles
  N % N % N %
Exhaust  2 1.0 2 1.6 1 0.4
Air  4 2.1 3 2.4 1 0.4
EGR  3 1.6 2 1.6 9 3.5
Air Cleaner 11 5.7 6 4.8 16 6.2
Limiter Caps 96 49.7 53 42.7 176 68.2
Timing  94 48.7 56 45.2 162 62.8
Advance Hech. 1 0.5 1 0.8 4 1.6
Fuel  1 0.5 0 0.0 4 1.6
Per Phase 137 71. 0 82 66.1 221 85.7
Per Phase values represent the number of vehicles with at least
one maladjusted/disabled system.
169

-------
TABLE 3.98

PERCENTAGE OF VEHICLES WITH MALADJUSTED/DISABLED EMISSION SYSTEMS/COMPONENTS
BY MANUFACTURER, 1975-1976 MODEL YEAR VEHICLES
.....
'-I
o
       Failing Phase 1/
  All Phase 1 Passing Phase 1 Failing phase 2
  Vehicles Vehicles  Vehicles 
Manufacturer System/Component N % N %  N % 
General Motors Limiter Caps 16 40.0 8 29.6  42 75.0 
 Timing 12 30.0 6 22.2  37 66.1 
 Per Manufacturer 25 62.5 15 55.6  50 89.3 
Ford Limiter Caps 13 52.0 8 40.0  11 68.8 
 Timing 11 44.0 8 40.0  11 68.8 
 Per Manufacturer 17 68.0 12 60.0  15 93.8 
Chrysler Limiter Caps 10 66.7 2 40.0  21 72.4 
 Timing 8 53.3 1 20.0  20 69.0 
 Per Manufacrurer 12 80.0 3 60.0  25 86.2 
American Motors Limiter Caps 3 50.0 2 100.0  2 22.2 
 Timing 4 66.7 1 50.0  7 77.8 
 Per Manufacturer 5 83.3 2 100.0  7 77.8 
Foreign Limiter Caps 5 20.0 4 22.2  3 21.4 
 Timing 12 48.0 11 61.1  5 35.7 
 Per Manufacturer 13 52.0 11 61.1  7 50.0 
Total Limiter Caps 47 42.3 24 33.3  79 63.7 
 Timing 47 42.3 27 37.5  80 64.5 
 Per Manufacturer 72 64.9 43 59.7  104 83.9 
       - - 
Per Manufacturer category represents the number of vehicles with at least one
maladjusted/disabled emission-related system/component of any type.

-------
TABLE 3.99

PERCENTAGE OF VEHICLES WITH MALADJUSTED/DISABLED EMISSION SYSTEMS/COMPONENTS
BY MILEAGE, 1972-1974 MODEL YEAR VEHICLES
.....
--.J
.....
          Failing Phase 1/
     All Phase 1 Passing Phase 1 Failing Phase 2
     Vehicles  Vehicles Vehicles 
 Mileage  System/Component N %  N % N % 
less than 20000 Limiter Caps 11 47.8  6 37.5 14 66.7 
    Timing 10 43.5  8 50.0 8 38.1 
    Per Mileage Group 17 73.9  11 68.8 16 76.2 
20000 to 30000 Limiter Caps 9 69.2  7 70.0 23 69.7 
    Timing 8 61. 5  7 70.0 19 57.6 
    Per Mileage Group 10 76.9  8 80.0 28 84.8 
30000 to 40000 Limiter Caps 12 60.0  7 58.3 21 70.0 
    Timing 14 70.0  6 50.0 22 73.3 
    Per Mileage Group 17 85.0  9 75.0 29 96.3 
40000 to 50000 Limiter Caps 8 57.1  5 55.6 15 71.4 
    Timing 9 64.3  5 55.6 15 71.4 
    Per Mileage Group 11 78.6  7 77.8 17 81.0 
greater than 50000 Limiter Caps 9 75.0  4 80.0 24 82.8 
    Timing 6 50.0  3 60.0 18 62.1 
    Per Mileage Group 10 83.3  4 80.0 27 93.1 
Total    Limiter Caps 49 59.8  29 55.8 97 72.4 
    Timing 47 57.3  29 55.8 82 61.2 
    Per Mileage Group 65 79.3  39 75.0 117 87.3 
Per Mileage Group values represent the number of vehicles with at least one
maladjusted/disabled, emission-related system/component of any type.

-------
TABLE 3.100

PERCENTAGE OF VEHICLES WITH MALADJUSTED/DISABLED EMISSION SYSTEMS/COMPONENTS
BY MILEAGE, 1975-1976 MODEL YEAR VEHICLES
....
-..J
N
       Failing Phase 1/
  All Phase 1 Passing Phase 1 Failing Phase 2
  Vehicles  Vehicles Vehicles 
Mileage System/Component N %  N % N % 
-less than 5000 Limiter Caps 4 33.3  3 30.0 2 50.0 
 Timing 3 25.0  3 30.0 0 0.0 
 Per Mileage Group 6 50.0  5 50.0 2 50.0 
50000 to 10000 Limiter Caps 15 45.5  7 33.3 17 63.0 
 Timing 19 57.6  10 47.6 17 63.0 
 Per Mileage Group 26 78.8  15 71.4 23 85.2 
10000 to 15000 Limiter Caps 10 40.0  5 33.3 16 57.1 
 Timing 15 60.0  8 53.3 20 71.4 
 Per Mileage Group 17 68.0  10 66.7 23 82.1 
15000 to 20000 Limiter Caps 11 47.8  6 42.9 18 66.7 
 Timing 3 13.0  2 14.3 14 51.9 
 Per Mileage Group 12 52.2  7 50.0 21 77.8 
greater than 20000 Limiter Caps 7 38.9  3 25.0 26 68.4 
 Timing 7 38.9  4 33.3 29 76.3 
 Per Mileage Group 11 61.1  6 50.0 35 92.1 
Total Limiter Caps 47 42.3  24 33.3 79 63.7 
 Timing 47 42.3  27 39.5 80 64.5 
 Per Mileage Group 72 64.9  43 59.7 104 83.9 
Per Mileage Group values represent the number of vehicles with at least one
maladjusted/disabled, emission-related system/component of any type.

-------
TABLE 3.101
1975 FTP ALL PHASE I VEHICLES WITH MALADJUSTMENTS/DISABLEMENTS BY MANUFACTURER
1975-1976 MODEL YEAR VEHICLES
     IIVOIIII(I\I\RIINS (/l1(8U'1 HIltIlIX I I)[ NOli.  FUEl f(UNrmV
 H/lUUf /I( TU~ E R SYSTEM/COMPONENT I~ /1fMI SII /iC MI SI) HfAN SO HEAtl SO
 GEIIE~"l /1I1T 1111 S LIMITER CAPS II> }.I,1 I . I. 1 ~6.76 '. I, . I I, 1.1,5 0.1,3 11.13 3.52
  TIMING Il 2.51, LId 5(~. 7'1 1,0."1, 1.1,8 0.67 15.19 3.94
   PER MANUFACTURER 75 2. 19 I. '.0 5/.211 B.bS 1.51, 0.56 lit.lit 3.)2
 f01l1l  LIMITER CAPS I) 2.61 1.10 61,.85 7'..53 1.61 O.H 11.16 2.08
  TIMING II 1.'11 1.0d 1,3.89 27.70 1.05 0.18 11.18 2.09
   PER MAJ.'IUFACTURER J7 7.40 1. I, I 61. 3lt 60.71 1.61, 0.51 12.31, 2. 54
   LIMITER CAPS 10 3.1,0 I. Jt> 02.0U 311.~9 1.61 0.39 12.107 1.99
..... (.1111 VSlllI TIMING 0 3.57 1.00 711. II, 2'1.56 I.H 0.)') 12.61 1.116
...,J   
   PER MANUFACTURER 11 3.3/. 1.2J 71.<)' 16.13 1.69 0.30 11.13 1.19
W   
 AHI~ICI\II HUTUlIS LIMITER CAPS j 1.3', 0.1'1 17.84 11.03 3.93 ".2', 16.07 2.68
   TIMING I, 1.94 0.(" 21.811 111.1\1, 2.'18 0.81 17.59 2.14
   PER MANUFACTURER 5 1.70 O. I) 2'..1 U 12.60 3.50 1.15 11.00 1.55
 flU E 16N  LIMITER CAPS '.I 2. 26 0.41 1,2.10 III.H 1.1,5 0.87 20.38 3.99
   TIMING Il 2.lb 0.49 43.59 11,.02 1.76 0.91 20.13 3.19
   PER MANUFACTURER I) 2.17 0.'.7 1,7. I I, 1'.12 1.82 0.'15 20.110 3.05
 Tn'1\1  LIMITER CAPS 1,1 1.59 1.'10 61.0) 51.72 1.10 U.90 13.'" 1.30
   TIMING 1,1 £.1,1 I. 21 57. '.1, 31.21, 1.00 0.12 15.30 3.610
   PER ALL MANUFACTURERS 72 7.42 I. bll 5". 'II 1,).')1 1.71 0.86 110.)5 ).69
PER MANUFACTURER VALUES REPRESENT THE VEHICLES WITH AT LEAST ONE EMISSION-RELATED
MALADJUSTED/DISABLED SYSTEM/COMPONENT OF ANY TYPE.

-------
1975 FTP ALL
TABLE 3.102

PHASE I VEHICLES WITHOUT MALADJUSTMENTS/DISABLEMENTS BY
MANUFACTURER - 1975-1976 MODEL YEAR VEHICLES
     HYOROC AlUlUN5 CAM811N MII/UIX 1 DE NOX  fUEL ECONIIHY
 HA..UF ACTUaER SYSTEM/COMPONENT N MEAN SO HfAN 50 HEAtt SO HEAN SO
 Gttl['Ul HOTOR5 LIMITER CAPS H 1.96 0.76 105.810 20.99 '.68 1.02 tJ.97 I.n
   TIMING 28 1.97 0.9(, 10"1.25 211.)2 1.610 0.91 U.H 1.92
   PER MANUFACTURER U 2.0~ 0.83 108.90 22.12 1.67 1.19 U.Jt 1.00
 '0110  LIMITER CAPS 12 1.56 0.77 )7.89 23.?6 I.S) 0.105 12.69 1.86
   TIMING 110 2.21 2.6') 58.20 7Z.63 1.)5 0.510 11.51 2. J9
   PER MANUFACTURER . 1.31 0.105 31.87 "'.36 I.U 0."9 11.89 2.H
.....       
.......   LIMITER CAPS 5 3.17 0.7') 59.811 9.31 1.95 0.10'  
~ CIIIIY5lfR  110.01 1.95
   TIMING 1 3.09 ,,)1. 70.010 J8.B 1.71 0.105 13.36 2.101
   PIR MANUFACTURER 3 3.18 ..12 61.60 12.65 2.0" 0.106 11.88 0.5Z
 AHflUUN HOTOIIS LIMITER CAPS ) 2.109 0.100 105.96 21.60 2.56 0.010 16.9) 2.n
   TIMING 2 '.810 I. S6 )').98 10).71 10.11 3.11 110.61 0.10.
   PER MANUFACTURER I 2.95 0.00 10." 0.00 1.98 0.00 110 . II, 0.00
 fOREICN  LIMITER CAPS ZO 2.21 1.04 H.IS U.l1 1.7Z 0.82 18.96 «-.9'
   TIMING U 2.)8 1.23 H.IZ "'.Iot 1.'8 0.69 18.1t1 8.01
   PEa MANUFACTURER IZ 2.)8 1.29 31.610 110.91 1.50 0.66 18.)1, 8.29
 TOTAL  LIMITER CAPS 610 2.10 O.tH 102.)) 19.9" l.n 0.810 15.05 ).98
   TIMING 610 2.210 I. S8 U.61o U.22 ..66 0.95 13.61 )."
   PER ALL MANUFACTURERS J9 2.1& 1.05 "I.'" 20.103 I... 0.15 IIo.n 3.88
PER MANUFACTURER VALUES REPRESENT THE VEHICLES WITH NQ EMISSION-RELATED
MALADJUSTED/DISABLED SYSTEM/COMPONENT OF ANY TYPE.

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1975 FTP ALL PHASE I
TABLE 3.103

VEHICLES WITH MALADJUSTMENTS/DISABLEMENTS
1972-1974 MODEL YEAR VEHICLES
BY MILEAGE
        IIYORU(ARIIUNS (ARIION MONUXIDE NOX  FUel ECUNI1/1Y
 MILE ACE   SYSTEM/COMPONENT tl HEAN SO "[AN SD "EAN SO HEAti SO
 lESS TIIAN 20000 LIMITER CAPS  \1 4.20 1.01 81.05 H.B 1.80 0.94 12.56 3.42
    TIMING   10 4.54 1.14 76.611 22.22 1.83 1.13 13.41 2.96
    PER MILEAGE GROUP 17 4.51 1.10 78.19 7.9.14' 1.77 0.95 13.52 3.81
 20000 Tn 30000 LIMITER CAPS  9 5.82 3.30 109.02 46.55 2.11 1.'t1 12.03 2.22
    TIMING   8 5.88 3.49 105.04 1,).20 2.13 1.50 12.17 1.98
    PER MILEAGE GROUP 10 5.79 3.19 106.50 44.60 2.11 1.33 11.97 2.08
...... 30000 TO 40000 LIMITER CAPS  12 6.17 3.17 89.51 40.80 2.11 1.05 14.07 2.84
--.J    TIMING   14 6.17 2.03 85. 2Z 41.21 2.52 1.00 15.33 3.83
U1    PER MILEAGE GROUP 11 5.95 l.68 04.711 38.14 2.49 0.97 14.81 3.53
 100(100 TO 50000 LIMITER CAPS  U 0.38 9.03 910.11 14.56 2018 1.10 12.89 2.33
    TIMING   9 7. 59 9.',3 78.37 19.38 3.24 1.65 13.90 2.99
    PER MILEAGE GROUP II' 7.15 8.49 83.51 22.16 2.90 1.67 13.37 2.78
 CRfATER TIIAN 50000 LIMITER CAPS  ? 6.61 2.50 132.35 52.85 1.13 0.65 11.86 2.53
    TIMING   /) 6.30 2.35 122.90 60.02 1.51 0.23 12.29 3.02
    PER MILEAGE GROUP 10 6.51 2.37 124.98 55.01 1.14 0.61 12.23 2.82
 TOTAL   LIMITER CAPS  lo9 6.12 lo.62 99.81 102.1,) 2.13 1.01 12.11 2.16
    TIMING   lo' 6.06 ',.63 90. Z1 39.62 2.32 1.29 11.61 1.12
    PER ALL MILEAGE GROUPS 65 5.85 4.0S 92.36 1,0.58 2.20 1.18 13.32 1.21
PER MILEAGE GROUP VALUES REPRESENT THE VEHICLES WITH AT LEAST ONE EMISSION-RELATED
MALADJUSTED/DISABLED SYSTEM/COMPONENT OF ANY TYPE.

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1975 FTP ALL PHASE I
TABLE 3.104

VEHICLES WITHOUT MALADJUSTMENTS/DISABLEMENTS
1972-1974 MODEL YEAR VEHICLES
BY MILEAGE
      .IVOIIOC &II IIOt. !a  CAItUUN ItIlHOIIIOE NOX  fUEl ECONOMY
 MIlUCE  SYSTEM/COMPONENT H "£AN !aD  MEAN SD MU'. SO MEAN SD
 lHS TIIAN 20000 LIMITER CAPS  12 5.11 I.U. 11.2't 25.)1 2. II 0.99 1).'0 3.~1
   TIMING  1) ".81, 1.32 80.92 ]).9.. 2.06 0.83 12.11 3.8~
   PER MILEAGE GROUP b 5.26 1.50 81.5'0 21.89 2. st 0.81 11.8.. 2.U
 20000 '0 30000 LIMITER CAPS  I, 5.91 1.12 113.95 5.39 1.67 O.U I2.U 3.07
   TIMING  5 S.79 1.92 9'>.]) )8.10 I.n 0.~10 12.010 ].U
   PER MILEAGE GROUP ] 6.0" 2.08 11).98 ~.60 I.SIo 0.75 I2.U ].11
 ]0000 TO 40000 LIMITER CAPS  8 8.100 9."2 91.]7 610.77 1.72 0.63 1'.'6 ".26
   TIMING  6 9.15 11.08 102.00 69.90 1.810 0.96 \J.n ......
.....   PER MILEAGE GROUP 3 tJ.JS 1S.8] 121.'t7 102.H 1.]2 o.n 1).72 7.22
......  
0\          ].SI I.n 1".110 .....,
 ..OlIOO TO SOOOO LIMITER CAPS  b "."S 1."2 b7."1 H.S'
   TIMING  5 S.09 lot,] ')1).]9 32.bI 1.81 0.6" 12.59 ]."6
   PER MILEAGE GROUP ] S.O] 2.01 79.58 31.26 2. 2l 0.52 1].52 S.16
 CItLATER TItAN 5(1000 LIMITER CAPS  ] 5.bl 1.83 71.9) ]9.H 1.'" 0.]6 1)."1 6.11
   TIMING  b 6.S0 2.50 11".60 S2. 71 1.11 0.111 IZ.U ].61
   PER MILEAGE GROUP 2 S.Sb 2.S9 87.S8 SO.]9 1.2S 0.06 12.10 6.41
 TOUl  LIMITER CAPS  H S.95 ". 7'} 79. 1S 31.72 2-16 1.19 U.19 4.30
   TIMING  JS 6.03 ".16 93.72 I0Io.53 1.91 0.71 IZ. 60 3.SS
   PER ALL MILEAGE GROUPS 11 ~.82 b.51 89.]11 "~.H 1.93 0.82 12.59 ].88
PER MILEAGE GROUP VALUES REPRESENT THE VEHICLES WITH NO EMISSION-RELATED
MALADJUSTED/DISABLED SYSTEM/COMPONENT OF ANY TYPE.

-------
1975 FTP ALL PHASE I
TABLE 3.105

VEHICLES WITH MALADJUSTMENTS/DISABLEMENTS
1975-1976 MODEL YEAR VEHICLES
BY MILEAGE
       IIVOkOC AlllIlI'''S CARBUN HONO-IOE NOX  fUel ECOtIOHV
      N HEAtl SO HEAN SU HUN SO HEA" SO
 HllEAGE   SYSTEM/COMPONENT        
      " I. 8~ 1.01 106.76 )II.!)6 0.92 0.21 11o.b6 1.61
 lHS 1IIA" ~OOO LIMITER CAPS  3 1.)5 0.51 29.10 110 .03 2.01 1.19 11.40 0.35
    TIMING  6 1.50 0.93 38.810 )2 .01 1.51 0.93 15.53 2.0J
    PER MILEAGE GROUP       
      15 2.~2 1.65 55.39 102.09 l.blo 0.19 15.56 10.12
 5000 TO 10000  LI!lITER CAPS  19 2.50 1.)1 51.110 H.b~ 1.16 0.98 lb.19 10.27
    TIMING  26 2.2) I.)) 108.100 310.26 1.17 0.90 lb.35 ) .91
    PER MILEAGE SROUP     
      III 1.82 1.25 38.102 H.101 2.25 1.101 110 .10 2.1)
 10000 TO I~OOO LIMITER CAPS   2.)) 1.05 50.06 20.43 1.79 0.J9 ltt.Z1 J.n
I-'   15
-...J    TIMI~G   1..17 1.09 106.62 29.210 2.05 1.17 1...46 ).)5
   PER MILEAGE GROUP \1 
-...J             
      11 ).109 2.84 810.27 76.19 1.58 0.109 11.69 2.95
 15000 TO 20000 LIMITER CAPS  ) 3.25 1.8'. 106.11 H.b3 2.0) 0.25 110.27 5.5b
    TIMING  12 ).107 2.11 IIl.BS 1).69 1.58 0.47 12.03 3.21
    PER MILEAGE GROUP 
    LIMITER CAPS  1 2.87 1.3b 17.05 1010.32 1.66 0.39 11.35 1.06
 GREUER THAN 20000    0.92 55.11 1).56 1.73 0.108 11.9) 2.'15
   TIMING  7 2."2 
    PER MILEAGE GROUP 11 2.510 1.17 62.)2 40.05 1.12 0.100 12.10 2.53
    LIMITER CAPS  107 2.59 1.90 bl.03 51.12 1.70 0.90 11.101 ).)0
 lOJAl   TIMING  101 2."1 1.2 I !)2.1o" )\. 210 1.80 0.72 15r. 30 3.84
    PER ALL MILEAGE GROUPS 72 2.102 l.bO 510.91 103.97 1.17 0.8b 1'..)5 3.69
PER MILEAGE GROUP VALUES REPRESENT THE VEHICLES WITH AT LEAST ONE EMISSION-RELATED
MALADJUSTED/DISABLED SYSTEM/COMPONENT OF ANY TYPE.

-------
1975 FTP ALL PHASE I
TABLE 3.106
VEHICLES WITHOUT MALADJUSTMENTS/DISABLEMENTS
1975-1976 MODEL YEAR VEHICLES
BY MILEAGE
       IIYDROCAR80NS C AR801. "0,.0)( I DE "OX  FUEL ECUNOMY
 MIlUCiE   SYSTEM/COMPONENT t. HUN SO HEAN SII HE AN  SD MEAN 50
 LE S S "'AN 5000 LIMITER CAPS 0 1.9) 1.39 211.105 15.15 1.61 0.80 15.19 6.10
    TIMING 9 2 .10 1.31 36.31 28.61 1.18 O.H \10.12 5.51
    PER MILEAGE GROUP b 2.25 1.50 30.21 11.210 1.26 0.52 15.21 1.U
 5000 TO 10000 LIMITER CAPS 18 1.93 0.10 100.810 20.'15 1.61 0.'12 16. J9 3.19
    TIMING 1'0 1.18 0.910 3'0.32 25.09 t.53 0.65 15.05 3.55
    PER MILEAGE GROUP 1 2.01 0.910 10).61 21.106 1.25 0.48 11o.1io 4.17
 IOUOO TO 15000 LIMITER CAPS 15 2.20 0.95 10].91 210.05 1.18 0.'10 14.99 4.02
~    TIMING 10 1.610 1.01 21.99 19. \2 2.25 1.'5 15.29 3.16
-..J    PER MILEAGE GROUP 8 1.81 1.06 31.29 19.'16 1.19 0.61 \10.91 3.94
CO     
 15000 TO 20000 LIMITER CAPS 12 2.62 1.01 51.111 9.103 1.41 0.16 11.16 2.56
    TIMING 20 3.01 2.11 14.02 55.910 1.102 0.)9 12.48 2.14
    PER MILEAGE GROUP \I 2.56 1.04 51.92 9.116 1.102 0.31 1).49 2.J9
 GREUEIl THAN 20000 LIMITER CAPS \I 1.18 0.58 35.9) 11.51 2.110 1.l8 110.20 J.56
    TIMING \I 2.06 1. \8 4Q.51 J6.66 2010 1.28 12. J8 2.11
    PER MILEAGE GROUP 1 1.60 0.65 J5. 59 1'0.50 2.)) 1.59 \).)) J.51
 TOT Al   LIMITER CAPS 64 2.10 0.93 102.)) 19.'110 1.73 0.84 15.05 J.98
    TIMING 610 2.210 1.58 108.610 IoZ . 22 1.66 0.95 U.)1 J.5S
    PER ALL MILEAGE GROUPS J9 2.11 1.05 101.64 20.10) 1.61 0.85 !4. 3 J.88
PER MILEAGE GROUP VALUES REPRESENT THE VEHICLES WITH NO EMISSION-RELATED
MALADJUSTED/DISABLED SYSTEM/COMPONENT OF ANY TYPE.

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"'II' r
STUDENT t STATISTICS
MALADJUSTMENTS
1975-1976
TABLE 3.107

FOR TESTING MEAN EMISSIONS WITH AND
AND DISABLEMENTS BY MANUFACTURER,
VEHICLES, PHASE I VEHICLES
WITHOUT
Manufacturer System/Component HC CO NOX F.E.
General Motors Limiter Caps 1. 03 1.09 -0.98 -0.25
 Timing  1.13 0.98 -0.62 1.74*
 Per Manufacturer 0.40 0.36 -0.40 1.31
Ford Limiter Caps 1. 31 1. 24 0.39 -0.92
 Timing  -0.46 -0.68 2.99* 1.86*
 Per Manufacturer 1. 89* 1.74* 0.99 0.44
Chrysler Limiter Caps 0.41 1. 72 -1. 27 -1. 43
 Timing  0.68 0.48 -0.14 -0.67
 Per Manufacturer 0.24 1. 28 -1. 22 -1. 64
American Motors Limiter Caps -2.25 -1.93 0.99 -0.39
 Timing  0.09 0.39 -0.62 2.07
 Per Manufacturer ** ** ** **
Foreign Limiter Caps -0.30 0.70 -0.63 0.60
 Timing  -0.60 2.13* 0.53 0.69
 Per r-1anufacturer -0.53 1.75* 0.98 0.71
Total Limiter Caps 1.63 2.35* -0.18 -2.37*
 Timing  0.64 0.54 0.88 2.28*
 Per All Mfgrs. 1. 23 2.17* 0.94 0.16
* Significant at 95 percent level of confidence.
** Insufficient data for comparison.
Per Manufacturer values represent the t statistics for comparing
vehicles with at least one emission related maladjusted/disabled
system/component of any type to vehicles with no emission related
maladjusted/disabled system/component of any type.
179

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STUDENT t STATISTICS
MALADJUSTMENTS AND
TABLE 3.108

FOR TESTING MEAN EMISSIONS WITH AND WITHOUT
DISABLEMENTS BY MILEAGE AND MODEL YEAR,
PHASE I VEHICLES
......
(X)
o
    1972-1974     1975-1976  
System/Component Mileage     Mileage    
Increment IIC CO NQX F.E. Increment HC CO NOX F.E.
Limiter Cap  less than -2.04* 0.31 -0.77 -0.64 less than -0.14 0.91 -2.29 -0.45
Timing  20000  -0.58 -0.36 -0.54 0.45 5000  -1. 33 -0.58 1.18 1. 39
Per Mileage Group   -1.12 -0.24 -1.84* 1. 22   -0.93 0.57 0.57 0.08
Limiter Cap  20000 to -0.06 1. 59 0.76 -0.18 5000  1. 29 1. 22 -0.10 -0.59
Timing  30000  0.06 0.42 0.66 0.08 10000  1.79* 2.19* 0.81 1. 28
Per Mileage Group   -0.16 1. 54 0.94 -0.28   0.36- 0.39 2.05 0.86
Limiter Cap  30000 to -0.65 -0.07 2.63* -0.63 10000 to -0.82 -0.46 0.97 -0.66
Timing  40000  -0.65 -0.55 1. 43 1. 00 15000  1.65 2.40* -0.92 -0.74
Per Mileage Group   -0.81 -0.61 1.73 0.26   0.78 1. 53 0.73 -0.32
Limiter Cap  40000 to 1.12 2.16* -1. 65 -0.63 15000 to 0.96 1.14 0.83 -1.79*
Timing  50000  0.78 -0.75 2.21* 0.71 20000  0.21 -1.15 3.62* -0.55
Per Mileage Group   0.75 0.17 1.16 -0.05   1.08 1.11 0.91 -1. 24
Limiter Cap  more than 0.79 1.89 0.93 -0.43 more than 2.01* 2.40* -1.16 -2.49*
Timing  50000  -0.14 0.25 -0.87 0.08 20000  0.72 0.37 -0.87 1.12
Per Mileage Group   0.51 0.94 2.48 0.03   2.00* 2.02* -1. 00 -0.41
Limiter Cap  Total  0.16 2.24 -0.12 -1. 39 Total  1.63 2.35* -0.18 -2.37*
Timing    0.03 -0.36 1.79* 1. 34   0.64 0.54 0.88 2.28
Per Mileage Group   -0.58 0.24 1.09 .0.71   1.23 2.17* 0.94 0.16
* Significant at 95 percent level of confidence.
Per Mileage Group values represent the t statistics for comparing vehicles with at least one
emission related maladjusted/disabled system/component of any type to vehicles with no emission
related maladjusted/disabled system/component of any type.

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TABLE 3.109

PERCENTAGES OF VEHICLES BY OWNER RESPONSE TO QUESTIONNAIRE
THAT HAVE MALADJUSTED OR DISABLED SYSTEMS/COMPONENT,
ALL FAILING PHASE II
      Limiter  At least Number of
Question Responses Caps Timing One System. Response's
liard Starting?  yes   76 56 84 25
   no   70 67 88 164
Stalls?  yes   77 77 91 22
   no   69 68 87 167
Rough idle?  yes   85 67 91 33
   no   67 65 87 156
Poor Acceleration? yes   81 67 95 21
   no   69 65 87 168
No Major Problems yes   71 66 90 106
   no   70 74 86 8]
Last Tuned?  0-6 months 7J 60 89 89
   6-12 months 29 66 92 ]8
   over 12 mo. 63 71 79 38
Who Tuned?  Dealer  71 63 84 9]
   Indep. Garage 77 60 92 52
   Self   68 74 89 19
Maintained to Manufacturer yes   71 67 88 155
Recommendations? no   78 61 83 111
Unleaded Fuel Required? yes   68 71 89 79
   no   72 62 87 110
. Percentage of vehicles with at least une emission related maladjustment/disabled
system/component of any type.
181

-------
TABLE 3.110

PERCENTAGES OF VEHICLES BY OWNER RESPONSE TO QUESTIONNAIRE
THAT HAVE MALADJUSTED OR DISABLED SYSTEMS/COMPONENT,
1972-1974 MODEL YEAR, FAILING PHASE II VEHICLES
       Limiter  At Least At Least
Question  Response Caps Timing One System. Response
Hard Starting? yes    69 38 69 13
  no    75 65 90 91
Stalls? yes    83 83 83 6
  no    73 60 88 98
Rough Idl~? yes    88 65 88 17
  no    11 61 87 87
Poor Acceleration? yes    78 56 100 9
  no    74 62 86 95
No Major Problems yes    76 65 90 62
  no    71 57 83 42
LaSl Tuned? 0-6 months 75 54 86 59
  6-12 months 90 70 95 20
  over 12 mo. 50 57 71 14
Who 'funed? Dealer 73 54 78 37
  Indep. Garage 85 58 93 40
  Self    65 71 88 17
Maintained to Manufacturer yes    76 63 88 82
Recummendations? no    75 58 83 12
Unleaded Fuel Required? yes    0 0 0 1
  no    75 62 88 103
. ~ercentage of vehicles with at least one emission related maladjusted/disabled
system/component of any type.         
182

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TABLE 3.111

PERCENTAGES OF VEHICLES BY OWNER RESPONSE TO QUESTIONNAIRE
THAT HAVE MALADJUSTED OR DISABLED SYSTEHS/COMPONENT,
1975-1976 MODEL YEAR, FAILING PHASE II VEHICLES
    Limiter   At least Number of
Question  Response Caps  Timing One System. Responses
liard Starting? yes   83  75  100 12
 no   63  70  86 73
Stalls? yes   75 I 75  94 16
 no   64 I 70  87 69
Rough Idle? yes   81  69  94 16
 no   62  71  87 69
Poor Acceleration? yes   83  75  92 12
 no   63  70  88 73
No Major Problems yes   64  68  89 44
 no   68  73  88 41
Last Tuned? 0-6 months 70  70  93 30
 6-12 months 67  61  89 18
 over 12 mo. 71  79  83 24
Who Tuned? Dealer  70  70  88 56
 Indep. Garage 50  67  92 12
 Self   100  100  100 2
Maintained to Manufacturer yes   66  71  89 73
Recommendations? no   83  67  83 6
Unleaded Fuel Required? yes   69  72  90 78
 no   29  57  71 7
. perce'ltage of vehicles with at least one emission related maladjusted/disabled
system/component of any type.
183

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TABLE 3.112
PfACElIiAGE Of VflllUES IIIfH E"'I"E """EUIIS I
OIIISIUE IIf SPECIFICUIOtI tUlERANCES. BY ~UFACTURER
All PIIASE i VflllClES
i975-i97~ HUOEl YEAR
  TO'Al 'IHIII(; IDLE RP" IDLE CU FUlHIG All
HANUfA('URU N N ' N " N I I. I
GfNfRAl "0'011') 100 I" 35.0 5 12.5 16 100.0 2 5.0
FOliO  25 i~ 5".0 " i6.0 U 52.0 1 ".0
(ltRY5LER  15 il n.) 2 1).) U 1b.1 1 6.1
A"ERICAN "0 TOil S (, " 66.7 2 n.) " (,6.7 I 16.1
FOREIGN  zs U "" . 0 "' ZI.O 19 16.0 " 16.0
TOUl  III 510 108.6 20 11.0 65 58.6 9 8.1
HACUHAGE Of VEIII(LES WI'" EltGttlE 'ARAMETERS
nu'S I UE IIf srrc IF ICAf Inri TUl ERANUS. BY MANUFACTURER
PAS SINe. PIIASE i VEtil C ll:S
1975-i97(' IInOEl YEAR
......   'OrAL I 1111 NG IDLE RP" I Ol E (II fUlItlG All
CX) HANur ACJURER N H I N I N I N I
~           
 GENERAl "OTOR5 27 7 25.9 ) 11. i (, 22.2 2 1."
 FORO  20 II 55.0 ) 15.0 8 100.0 I 5.0
 (lIRY5l ER  5 ) 60.0 1 20.0 ) 60.0 I 20.0
 AMERICAN "OTUIIS 2 1 50.0 1 50.0 0 0.0 II 0.0
 rOREIGN  18 10 55.6 5 21.8 n 12.2 ) 16.1
 TOUl  72 ]2 "" ." U 18.1 3(1 H.1 1 ".1
PERCEN'AGF ur VElIlCl(!'i WI'" ENGINE 'ARAMEfEIIS
OUrslOE OF SPECIFICUION '"lERANUS. BY MANUFACTURER
FAILING PHASE 1 I failiNG PItASE 2 VEItIUf.S
191'-i976 MODEL YEAR
   TOTAL TIMWI; I DLE liP" IDLE (U FAiliNG All
"AtlUFACTURER II N II; N " N I N S
GEttfRAl "O'ORS 56 )1 55." 6 10.1 52 '12.9 2 ).6
FORD   16 " '0.0 2 12.5 12 15.0 II 0.0
CIiRYSlU  29 2i 12." 3 10.3 29 100.0 II 0.0
A"f8,rAN MOTORS 9 1 11.' I ILl . 100.0 I ...1
t Ullt .,,"  H 5 )'.1  d." ') 9~ II 2 14.)
IDTAl   1210 12 51.i 15 IZ.I .., 92.1 , "..
. TOLERANCE FOR IDLE RPM IS +150 RPM OF MANUFACTURER RECOMMENDED LEVEL.  
TOLERANCE FOR TIMING IS +2-DEGREES OF MANUFACTURER RECOMMENDED LEVEL.  
TOLERANCE roR IDLE CO ISfo. 5 PERCENT.       

-------
TABLE 3.113
I'fRCUUAGE Of VEIIICl£S WITII (NGINE PARAI1EHRS
/JUTS I OE lIf SPEC If I U fI ON I UlEKANCH. 3Y MILEAGE
All PitASI' 1 VEIIICLES
1915-1976 110UEl YEAR
 TOTAL TII1ING IDLE RPI1 IDLE CO fAiliNG All
"ILEACI' N N X I~ I I~ " N II
lESS THAtl 5000 12 4 n.) " n.) 5 41.1 2 16.1
5000 10 10000 H 18 5'0.5 7 21.2 17 S1.5 " 12.1
. 0000 TO 15000 25 15 60.0 I, 16.0 18 12.0 1 4.0
15000 TO 20000 23 8 3'0.8 4 17." II) (,9.6 2 8.7
GREAIER THAN 20000 18 9 50.0 I 5.6 9 50.0 0 0.0
PFRCENTACE Of IIflllCLES WITII ENGINE PARA"£TERS
IJUTSIOE OF SPEC If ICAT IUt! InlElIANCES * BY
PASSING PltA~f I VEHICLES
1975-1916 "lIUEl YEAR
MILEAGE
f-'
CO
U1
  TOT Al TII1HIG IDLE RP" IDLE (0 fAILING All
"IlEAGE N N X ... II Ij II II J
l I' 5 S TlIAN 5000 10 ) )0.0 " 40.0 4 100.0 2 20.0
5000 TO 10000 21 11 52." ) 14.) 7 H.) 2 9.5
10000 10 15000 IS 7 106.1 ) 20.0 8 5).) 1 6.7
15000 10 200011 H 6 42.9 2 14.3 7 ~O.O 2 14.)
GREATER IHAN 10000 12 5 41.7 1 8.) '0 H.) 0 0.0
I'I'IICENIAGE I)f VEltlClfS "'ITII ENGINE PARAl1fTERS
nuTS 101' or SP[C If ICUIOtI TllLERAtlCES * BY MILEAGE
OILING PIIASE I I fAILING PIIAH 1 VEIIICLES
1915-1976 "OO(l YEAR
 TOTAL III1IN& IDLE RI'I1 IIIL( (U FAiliNG All
11 Ilf AGE N N X N II II " N '
l I' H TIIAt~ 5000 " 1 25.0 1 25.0 ) 75.0 0 0.0
'000 TO 10000 27 IS 5S.b 5 lB.5 2'0 08.9 2 7.'0
10000 TO 15000 28 18 b'o.) 5 17.9 27 9(,.'0 ) 10.7
15000 Tn 20000 27 12 44.'0 ) 11.1 2b 96.) 0 0.0
GRlATER THAN 2uOOD )8 26 b8." 1 2.b )5 92.1 0 0.0
* TOLERANCE FOR IDLE RPM IS +150 RPM OF MANUFACTURER RECOMMENDED LEVEL.
TOLERANCE FOR TIMING IS +2-DEGREES OF MANUFACTURER RECOMMENDED LEVEL.
TOLERANCE FOR IDLE CO IS!O.5 PERCENT.

-------
TABLE 3.114
I'fllCENIAGf Of VEIIICUS lum (NI>INE PAU"ETERS
ours IDE Of SPEClflCUlnll "'1(aANUS. a'l
All "lASE I VfHIHU
1975-191b "DUEL YEAR
ENGINE DISPLACEMENT
 TUTAl TI"ING IOLE RP" IOU CO fUllNG All
ClD ~I N S N S II II h I
LESS TlfAN 151 21 12 H.9 1 21.6 20 11." ) 10.1
1!H TO 259 11 10 SII.I " 2).5 10 5'.8 ) 17.6
,aUTEa TIIAN l59 (,b )2 "'.5 . 12.1 )5 5).0 ) ".5
....
Q)
0'1
PE-UNTAGE Of VUIICltS IInll UI'1t1E "U"EfUS-
QUTSIltE Of S'U If 1(1.1 ION TOUUNUS. BY
PASSING PHASE 1 VEHICLES
1975-1916 HODEL YEAR
ENGINE DISPLACEMENT
 TO'U TI " I NG IPIE R'H IbU Co F.\llING All
CID H H II N II It II It I
LESS THAN 151 18 10 55.6 5 21.1 11 bl.l J 16.1
151 TO 259 11 5 "'.5 2 11.2 I, )6.4 1 9.1
GREATfR THAN 259 H 11 )9.5 6 110.0 i5 )4.9 ) 7.0
'fRCENIAGE Of "fllIClES IIIfIl ENGINE "U"fJUS
""'SlbE Of S'U If IUTION 'OLEUMC:U * BY
tAILING PIIASf 1 / fAiliNG PIt'SE Z VElllCUS
1915-1916 "OUfl YEAR
ENGINE DISPLACEMENT
 IlITAl TI"ING IUIE aPH Hill Co fAILING All
CID " N I N S II I It I
LESS TItAN 151 2" 10 " I. 1 6 25.0 22 91.7 J 12.5
151 '0 259 U 12 66.1 ) 16.1 11 9"'." 2 11.1
GRUTER TIIAN 259 12 50 61.0 6 1.) 16 92.1 0 0.0
. TOLERANCE POR IDLE RPM IS +150 RPM or MANUFACTURE. RECOMMENDED LEVEL.
TOLERANCE FOR TIMING IS +2-0EGREES OF MANUFACTURE. RECOMMENDED LEVEL.
TOLERANCE 1'0. IDLE CO IS?'O. 5 PERCENT.

-------
HANUFACTURER
GENEltAl HOTORS
FORO
CURYSLEI'
AHERICAN HUIORS
fOREIGN
TOTAL
......
00
"
HAtlUfACTURER
GENERAL 1101 URS
fORO
CHRYSLER
AHERICAN MUTORS
FOREIG~I
TOUl
TABLE 3.115
1975 FEDERAL TEST PROCEDURE
ALL PHASE I VEHICLtS
TIHING A~O IDLE RPH
WITUIH SPECIFICATION TOL[KANCES
1975-1916 "UO~l YEAR
 HYORl1CARBUNS CAR801'1 I1IJNOXIO[ IIOX
~I MfAN SO 'IE Atl SO HtOAN Sl)
2) 1.86 0.91 42.40 2',.'}l 1.H 0.99
8 1.52 0.69 36.39 22.29 1.54 0.5.
3 3.32 1.35 79.88 49.86 1.60 0.08
2 I.R4 1.56 39.98 ',3.71 ".17 3.11
12 2.37 1.27 33.06 15.51 1.56 0.71
48 7..02 1.08 '. . .30 16.16 1.15 1.05
17
17-
12
4
13
63
1975 FEDERAL TEST PROCEDURE
All P/IASE . VElllClES
TIMING ANO IDLE RPH
OUTSIDE SPECIFICATION TOLERANCES
1975-1116 HOOEL YEAR
N
IIYOROCARBONS
HrAN SO
HEAN
2.')2
2."38
3.32
1.9"
2.18
2.51
CARUON HONLIXIOF
HF.MI su
1.47
2."9
1.19
0.61
0.53
1.63
t,? . 67
59.21
13.38
21.86
"0.83
51.06
1.39
1.58
1.80
2.18
1.16
1.69
38.15
66.71
30.63
10.8"
15.43
"3.15
TOLERANCE FOR IDLE RPM IS + OR - 150 RPM OF MFG. SPECS
TOLERANCE FOR TIMING IS + OR - 2 DEGREES OP MFG. SPECS
tlOX
SO
0.53
0.52
0.45
0.81
0.93
0.69
FUel ECONOHY
HEAN SO
13.53
12.01
12.91
1".67
17.85
14.11
2.19
2.31
3.1"
0.48
1.60
3.71
FUEl ECONOHY
HEAN SD
14.31
12.25
12.9"
11.59
20.11
14.'t1
3.16
2.55
1.71
2.14
3.U
],.79

-------
TABLE 3.116
1975 FEDERAL TEST PROCEDURE
All PHASE I VEHICLES
IOlE CO
WITHIN SPECIFICATION TOLERANCES
1975-1976 HODEL YEAR
MANUFACTURER
 IIYDRnCAR80NS CARRnN HONUXIDE NOX
N HUN SO HEAN 51) HEAN SO
24 1.76 0.86 100.22 l2. 20 1.7) 0.91
12 1. J2 O.H 28.11 11.16 1.59 0.48
2 1.19 0.55 21.08 7.89 1.58 0.64
2 0.88 0.20 10.35 1.81 ".u 3 .10
6 2.12 1."" 22.16 9.21 1.61 0.66
"6 1.61 0.88 32.7) 19.25 1.18 1.04
GE"fRAl MOHJRS
FORD
CIIR YSl Eft
AHERICAN HOTURS
rOREIGN
TOTAL
~
CO
CO
1975 rEDERAL TEST PROCEDURE
All PHASE 1 VEHICLES
10LE CI]
OUTSIDE SPfClfICATIO" TOLERANCES
1975-1976 HUDtL YEAR
   tlYDkOCARBONS CARDON HONOXIDr NOX
HANUFACTURER N HEAN SO "EAN SO HEAN SO
CiEI4ERAL HOTORS 16 2.10 1."5 61.21 n.n 1.38 0.55
fORD  1] 2.8" 7.. 1't B.J2 72.81 1.55 0.55
CHkYSLER  13 3.65 0.810 02.92 26.9" 1.19 0.39
AHER leAN HOTURS 4 2.U 0.35 42.61 18.82 2.18 0.81
fOREIGN  19 2.32 0.11 101.82 1".32 1.68 0.88
1 OUl  65 2.19 1.56 62.6'. "2.12 1 . 61 0.11
TOUItANU FUR IDLE CO IS A HUSUREHEHT~.51
fUEL ECONUHY
HEAN SO
13.101
13.75
12.19
14.68
16.80
13.89
2.11
2.15
1.90
0.4'
0.15
3.10
FUEL ECONOHY
HEAN SD
14.63
11.03
12.91
11.58
20.16
14.63
3.]0
1.60
2.11
2.16
4.55
4.21

-------
MANUFACTURER
GENERAL MOTORS
fORD
CIIR Y SUR
AMERICAN HOTORS
fOREIGN
TOTAL
......
ex)
\0
HANUFACT\JRER
GENERAL MOTORS
fORD
CtiRYSlER
AMERICAN MOTURS
FOREIGN
TOTAL
TABLE 3.117
1375 FEDERAL TEST PROC~DORE
PASSING P""SE I IIEtllCLrS
rlHING AND IDLE RPM
WITHIN SPHIFlC/d ION TIlLERANCES
1975-1976 HIIOll YEAR
 tlYOROCARDONS CARootl HtJNOXJnF NOX
N HEAI~ SO tIE A'"  SO H[AN SO
19 1.60 0.74 36.105 22.07 1.85 1.06
7 1.34 0.50 30.05 14.27 1.52 O.H
2 2.63 0.88 51.18 5.14 1.58 0.10
I 0.71t 0.00 9.08 0.00 t..n 0.00
7 1.93 1.37 26.2U 13.32 1.1tl 0.54
36 1.65 0.88 31.28 19.21 1.81 1. 15
1975 FEDERAL TEST PROCEDURE
PASS INC PtI"SE 1 VElIIClES
TIHI~G ANO IOLE RPH
ours IDE SPECIFICA11IJN JIILERANCES
1975-197t. MUOEl YEAR
CARIlOtI HIlNOXIDr
"LAN SO
N
HYORIJCARRl1NS
HEAN SO
8
13
J
1
11
36
1.62
1.63
7..l0
1.02
2.08
1.00
M E At~
0.68
0.80
1.80
0.00
0.50
0.80
39.93
42.19
37.55
11.63
39.95
39.77
1.66
1.56
1.70
1.98
1.82
1.69
20.59
l3.00
29.07
0.00
I1t.Olo
19.90
TOlERANCE FIIR IDLE MPH 15 + OR - 150 RP" OF HFG SPE(~
TOLERANCE FOR TIHING IS + OR - 2 DEGREES ur "FG S~[(5
NOX
511
0.64
o.H
0.50
0.00
0.97
0.68
FUEL ECONOMY
MEAN SO
13.'.2
12 .410
15.3Z
15 .01
16.21
13.81
2.32
2.41
2.87
0.00
7.96
3.47
FUEl ECOIIOHY
HEAN SO
14.51
12.79
13.31
14.36
20.93
15.07
1.36
2.34
1.74
0.00
3.2it
3.72

-------
TABLE 3.118
1975 FEDERAL TEST PROCEDURE
PUSING PIIASE 1 VfHICLfS
IDLE CO
WlrHI" SP£CIFICArION TOLERANCES
1915-1916 HUOEL YEAR
   HYIUUJC AR8UNS CARBnt. HUNOI'.I nr NO I'. 
HANUFACTURER N HEAN SO HEAN 50 HEAN 50
GENERAl HIJTORS 21 1.55 0.61 35.57 18.39 1.80 1.02
FORD  12 a.32 0.1eS 28.71 11.16 1.59 0.40
CHRYSLER  2 1.19 0.55 21.08 1.89 1.58 {I.64
AHERICAN HOTORS 2 0.88 0.20 10.35 1. 81 4.18 3.10
FOREIGN  5 2.09 1.61 21.64 10.19 1 . "" 0.55
TOTAL  42 1.50 0.78 30.06 16.05 1.80 1.07
~
\0
o
HANUfACTURER
CENERAl HOTORS
FOItO
CUR VSl ER
AHE R I CAN HU rORS
fUREIGN
TOTAL
  1975 FEDERAL TEST PROCEDUIZ  
  PAU IIIG PIIASE 1 VI:HIClES  
  IDLE CO     
  OUTSIDE SPECIFICATIUN rUl~RANCES 
  1915-1916 HUOEl YEAR  
 HYUlttlCARBUtiS CARRON HUNUXIOf tlOX
N HfAN SD HEAtl 50 HEAN SO
6 1.92 0.80\ "4.18 30.64 1.79 0.10
u 1. as 0.92 51.79 H.8J 1.4B 0.52
3 ).16 1.12 51.62 ".81 1.69 0.21
o 0.00 0.00 O.UO 0.00 0.00 0.00
13 2.00 0.50\ 39.63 13.69 1.15 0.93
30 2.00\ ().8) 4~.5B 20.91 1.6B 0.73
TOlUANCE FOR liRE CO 15 A HEASUREHENT~.5X
FUel ECONOHY
HEAN SO
13.42
U.75
12.79
1't .68
16.25
U.83
2.10
2.15
1.90
0.0\6
9.04
3.01
FUel ECONOHY
HEAN 5D
1't.92
11.32
15.04
0.00
20.01
15.32
2.18
1.01
2.01
0.00
4.71
4.31

-------
TABLE 3.119
1975 FEDERAL TEST PROCEDURE
FAILING PtlASE I I FAILING PIIASE 2 VEIIIClES
TIHING AND IDLE RPH
WITIIIN SPECIFIC AT lOti fnLEKANCES
1975-1976 HUOlL YEAR
tlANUFAC TUnE It
 HYDROCARBONS CARIHIN HntlOX JOE NUX
N HEAN SO MEAN so HEAN SO
21 3.46 1.77 62.b8 35.21 1.30 0.4b
7 3.02 1.47 bO.b9 44.96 1.26 0.65
5 '.. bO 1.39 103.40 42.72 I. 10 0.44
2 2.57 0.53 57.37 19.11 2.35 0.53
8 2.80 0.77 44.77 17.55 1.72 0.83
4) 3.36 1.55 7'..58 37.09 1.40 0.62
GENERAL HUT fiRS
F()KD
CHRYSLER
AMERICAN MUTURS
FOREIGN
TOTAL
I-'
\.0
.....
FUEL ECONOMY
HfAN So
13.49
11.66
12.44
15.97
20.67
14.00
2.1lt
1.95
2.74
2.57
3.18
3.33
    1975 FEDERAL TEST PROCEDURE    
    fAILING PIIASE 1 I FA ILItIG !'IIASE 2 Vetil Cl E S  
    TIHING AND IDLE RPH    
    OUTSIDE SPECIFICATION TUlERANCES   
    1~75-1976 HODEL YEAR    
   IIYDROCAROUN5 CARDON HlINOXIDf  NOX fUEl ECONOHY
.'ANUfIlCTURER N Mf.AN SO HEAI~  so HEAN SO HEAN SO
GENERAL MOTORS 35 3.95 2.89 87.46 J2 .61 1.3l 0.48 13.39 2.70
FORD  9 3.76 3.02 86.37 89.94 1.89 0.b3 11.78 2.88
CHRYSLER  24 3.60 1.60 83.54 20.18 1. b8 0.51 13.02 2.1lt
AHERICAN MUTORS 7 2.52 0.59 '.b.35 1b.39 2.48 0.73 18.08 2.06
FOREIGN  b 3.09 0.87 53.14 20.31 1.23 0.41 21.33 .It .62
TOTAL  81 3.64 l.:n 80.35 41.50 1.58 0.62 13.76 3.24
TOLERANCE FOR IDLE RPH 15 + OR - 150 RPM OF HfG S!'ECS
TOLERANCE FUit TlHING IS + OR - 2 DEGREES UF HfG SPf(S

-------
TABLE 3.120
1975 FEDERAL T~ST PROCEDURE
fAiliNG PIIASE 1 I faILING PIIASE 2 VEHiClES
IDLE CO
W1T1I1N SPECIFICATION TOLERANCES
1975-1976 HUDEl Y[AM
ttAtlUFACTURER
 HYDROCARBONS CARRON HUNI)XIOf NOX
tl HEAN SO H[AN SO HEAN SO
" 7.ZIt 7.811 (.5.18 73.28 1.60 0.77
" 2.29 0.55 23.99 10.60 I.U 0.80
o 0.00 0.00 0.00 0.00 0.00 0.00
o 0.00 0.00 0.00 0.00 0.00 0.00
1 2.28 0.00 H.77 0.00 2.51 0.00
9 ".49 5.50 42.38 26.72 1.62 0.16
GENERAL HOTtJRS
FORD
CIIRYSlER
AH[RICAN HOTORS
FOREIGN
TOT Al
~
\D
.....,
1975 rzDERAL TEST PROCEDURE
FAILING PtlUE 1 I fAiliNG PIIASf 2 VEllIClES
I Dl E CO
llUTSIOE SPEC IF ICAf ION TIILERANCES
1915-1976 HUOEl YEAR
    IIYDROCARBUNS CARDON HUI!UX I OE NOX
ttAtlUF AC TUR E R N HUN SO HfAN 50 HEAN SD
GENERAL HOTORS 52 3.50 1.1t7 87.2It H.70 1.29 0.4le
f()RD   12 3.82 2.70 98.35 7".13 1.69 0.68
CHRYSLER   29 3.78 1.59 86.96 31.16 1.58 O.H
AHUICAN HOTtJRS 9 2.53 0.55 leD.DO 16.45 2."5 0.66
FORF.IGN   13 2.97 0.80 50."5 17.99 1.103 0.67
rOUL   115 3.1t7 1.59 '81.16 39.82 1.51 0.62
TOUltANCf. FUR IOI.E (II IS A t1USUREttEtIT ~..51   
fUEl [CONI1HY
HEAN 50
11.92
14.86
0.00
0.00
20.21
U.76
].0"
3.89
0.00
0.00
0.00
3.94
FUEL ECONOHY
HEAN SO
lJ.56
10.96
12.92
11.56
2 1 . 00
13.15
2.40
1.63
2.22
2.24
].84
3.22

-------
t-'
\0
W
TABLE 3.121

STUDENT'S t VALUES** FOR AVERAGE EMISSIONS OF VEHICLES OUTSIDE TOLERANCES
MINUS AVERAGE EMISSIONS OF VEHICLES WITHIN TOLERAN~ES
        Timing and Idle RPM  Idle CO 
       HC CO  NOX FE HC CO NOX FE
All Phase I            
General Motors    1. 63 1.89*  -1.44 0.94 2.33* 2.52* -1.45 1. 31
Ford      - -  - - 1.97* 2.18* -0.19 -2.99*
Foreign      -0.48 1. 25  0.61 1.18 - - - -
Total      1.98* 2.36*  -0.34 0.50 4.98* 4.98* -0.62 1. 07
Passing Phase I         
Total      0.76 1.41  -0.54 1. 49 2.79* 3.40* -0.57 1. 60
Failing Phases I and II         
General Motors    0.79 0.50  0.15 -0.15 - - - -
Total      0.80 0.78  1. 54 -0.39 - - - -
* Significant at the 95 percent level of confidence.
** A dash (--) in the table indicates that the sample size for that particular category
of vehicles is insufficient for valid t tests.

-------
TABLE 3.122

CORRELATION CO~FICIENTS FOR PERCENT CHANGE IN EMISSIONS AND FUEL ECONOMY
VERSUS CHANGE IN ENGINE PARAMETERS FOLLOWING MAINTENANCE -- ALL PHASE I VEHICLES
....
\D
~
   HC   CO   NOX 
  Timing HPM Idle CO Timing RPM Idle CO Timing RPM Idle CO
197Z-1974         
FTP  0.05 -0. l6 0.34 - 0.18 -0.19 0.45 0.47 0.3l -0. II
Hot FTP O. lZ - O. 1.1. 0.38 -0.31 - O. 16 0.47 0.51. 0.36 - o. 1 3
Fed. Short Cycle 0.1.3 -0. 13 0.1.0 - 0.11. - O. 11 0.37 0.35 0.37 - O. 1. I
Fed. Three Mode (50) 0.1.4 -0.05 -0.03 -0.00 -0.16 0.08 0.2:7 0.15 - O. 08
Fed. Three Mode (30) 0.08 -0.17 0.01 -0.0 1 -0.09 o. 19 0.1.5 0.47 0.05
Fed. Three Mode (N) O.1.l -O.ll 0.30 -0.01. 0.37 0.35 - O. 10 0.37 - O. 44
Idle (1.1.50) 0.15 -0.05 -0.04 - 0.13 -0.06 0.05 0.11. 0.01 0.01
Idle (N) 0.1.0 -0.14 0.16 0.08 0.91 0.40 - O. 15 0.39 -0.48
1?7Z-1975         
FTP  0.19 -0.1.8 0.1.3 0.17 - 0.1.6 0.1.7 0.45 0.l6 0.1.0
Hot FTP 0.1.1 -0. 31 0.1.3 0.13 -0.1.5 0.1.0 0.43 0.31 0.l5
Fed. Short Cycle 0.1.5 -0. 17 0.30 0.07 -0.11. 0.09 0.38 0.31. 0.1.4
Fed. Three Mode (50) 0.1.7 -0.31. - O. 30 0.09 -0.17 -0.l4 0.17 -0.11 -0.06
Fed. Three Mode (30) 0.11. 0.03 0.11. -0.10 -0.01. 0.07 0.1.4 -0.07 0.05
Fed. Three Mode (N) 0.07 -0.07 0.1.0 0.14 - O. 11. 0.13 0.03 0.14 -0.03
Idle (l1.50) 0.13 0.01 0.1.1. 0.01 0.07 0.10 0.13 0.11 0.00
Idle (N) 0.01. - O. 1.5 0.18 0.06 0.01 0.17 - O. 05 0.1.1. -0.06
 Fue Economv 
 Timing RPM Idle CO
197Z-1974 0.36 -0.01 -0.1.5
1975-1976 0.1.8 -0.08 -0.16

-------
TABLE 3.123

MULTIPLE CORRELATIONS FOR PERCENT CHANGE IN EMISSIONS
VERSUS CHANGE IN ENGINE PARAMETERS DURING~INTENANCE
ALL PHASE I VEHICLES
    197Z-1974  1975-1976  
    Order of  Order of  
   R Significant Parameters R Significant Parameters 
 HC          
FTP   0.34 Idle CO  0.38 RPM, Idle CO  
Hot FTP  0.38 Idle CO  0.40 RPM, Idle CO  
Fed. Short Cycle 0.23 Timing   0.41 !dle CO. RPM, Timing 
Fed. Three Mode (501 0.24 Timing   0.55 RPM, Timing, Idle CO I
Fed. Three Mode (30) - None   - None    I
Fed. Three Mode (N) 0.37 Idle CO, Timing O. ZO Idle CO 
Idle (22 50)  - None   0.22 Idle CO  
Idle (N)  - None   0.3Z RPM, rdle CO  
 CO          
FTP   0.45 Idle CO  0.40 Idle CO, RPM  
Hot FTP  0.56 Idle CO, RPM 0.34 RPM, Idle CO  
Fed. Short Cycle 0.37 Idle CO  - None    
Fed. Three Mode (50) - None   0.24 Idle CO  
Fed. Three Mode (30) - None   - None    
Fed. Three Mode (N) 0.59 RPM, Idle CO - None    
Idle (2250)  - None   - None    
Idle (N)  0.39 Idle CO  - None    
 NOX          
FTP   0.56 Timing, RPM 0.51 Timing, RPM  
Hot FTP  0.62 Timing, RPM 0.52 Timing, RPM  
Fed. Short Cycle 0.51 RPM, Timing 0.49 Timing, RPM  
Fed. Three Mode (50) 0.27 Timing  - None    
Fed. Three Mode (30) 0.52 RPM, Timing 0.24 Timing  
Fed. Three Mode (N) 0.52 Idle CO, RPM - None    
Idle (2250)  - None   - None    
Idle (N)  0.56 Idle CO, RPM 0.22 RPM    
Fuel Economy 0.44 Timing, Idle CO 0.37 Timing, Idle CO 
195

-------
1.
2.
3.
4.
5.
6.
REFERENCES
Study of Exhaust Emissions from 1972 through 1975 Model Year
Light-Duty Vehicles in Denver, EPA Report, EPA-460/3-76-0l3,
October 1976.
High Altitude Emission Control Program, State of Colorado,
Department of Health Report, December 1974.
A Study of Emissions from 1975 Model-Year Vehicles, State of
Colorado, Department.of Health, March 1976.
Current draft of Appendix N to the "Requirements for
Preparation, Adoption, and Submittal of Implementation
Internal EPA Report, December 1977.
Plans,"
Automobile Exhaust Emission Surveilance -- Analysis of the
FY 72 Program, EPA Report EPA-460/2-74-00l.
Platte, Lois, "The Relationship Between FTP and Short Test
Emissions from 1975 Model Year Vehicles," Internal EPA
Report, September 1976.
7.
Letcher, Robert A., "On the Selection of Reject Rates for
I/M Programs: Ranking of Vehicles and Assessment of Impacts
on Emissions," Internal EPA Report, July 1977.
196

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                               -
           TECHNICAL REPORT DATA            
        (Please read IRumctions on the reverse before completing)          
1. REPORT NO.      12.          3. RECIPIENT'S ACCESSIOill'NO. 
EPA-460/3-77-018                      
4. TITLE AND SUBTITLE                6. REPORT DATE      
Evaluation of Potential Inspection/     ,..   . lQ77   
Maintenance Benefits on Vehicles Operated 6. PERf!"ORMING ORGANIZATION CODE
at Hiqh Altitudes                     
7. AUTHOR(S)                  8. PERFORMING ORGANIZATION REPORT NO.
 Alan P.  Berens and Michael  Hill                
I.PERFORMING ORGANIZATION NAME AND ADDRESS        10. PROGRAM ELEMENT NO.   
University of Dayton Research Institute            
300 College Park              11. CONTRACT/GRANT NO.   
Dayton, Ohio  45469                        
                      68-03-2384   -
12. SPONSORING AGENCY NAME AND ADDRESS          13. TYPE OF REPORT AND PERIOD COVERED
Environmental Protection Agency                 
Office of Air and Waste Management    14. SPONSORING AGENCY CODE 
Office of Mobile Source Pollution Control            
Emission Control Technology Division               
IS. SUPPLEMENTARY NOTES Ann ArDor, M~ch~gan 48105            
16. ABSTRACT                             
Inspection/Maintenance (I/M) is one of the transportation control 
strategies available to  state planners. Although I/M is needed in over
25 air quality control regions  (AQCRs), it has, to date, been effective
ly implemented  in only a small  subset of these regions. At the present
time, an effective I/M program has not been implemented in a high 
altitude region.                          
 Recently,  the EPA published in the Federal Register two signifi-
cant supporting documents for I/M. The first document was a Notice of
Proposed Rulemaking on the 207(b) Clean Air Act Warranty-  The second
documen twas a Notice of Proposed Rulemaking on Appendix N to the State
Implementation Plan Guidance Document. Appendix N presents I/M credits
for various  types of I/M programs. Although both of these documents
are expected to apply equally to high and low altitude regions, the
majori ty of  the data used to develop these documents have been collectec
at low al ti tude.                          
 This report presents a thorough analysis of data collected at high
altitude. The  data were not collected in a real life I/M program; they
are laboratory  data. As such,  they can be compared with laboratory dat
        (over)     
7.          KEY WORDS AND DOCUMENT ANALYSIS            
     DESCRIPTORS         b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
inspection and maintenance                     
motor vehicle emissions                       
high altitude                           
18. DISTRIBUTION STATEMENT           19. SECURITY CLASS (This Report)   21. NO. OF PAGES
 Unlimited           Unclassified     196 
          20. SECURITY CLASS (This page)   22. PRICE   
EPA Form 2220-1 (9-73)

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taken at low altitude and, in some subject areas, they can
extend the general understanding of the costs and effective-
ness of maintenance programs at both high and low altitude.
The prime analysis objectives of this study were threefold:
to estimate the effectiveness of 11M, to evaluate the correla-
tion between the Federal Test Procedure (FTP) and various
short inspection tests, and to examine any relationships
which exist between emissions, engine condition, and vehicle
usage.

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