Portland Study Interim Analysis:
Observations on Six Months of Vehicle Operation
January 1979
Inspection/Maintenance Staff
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Office of Air, Noise, and Radiation
United States Environmental Protection Agency
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Introduction
Through the cooperation of the Oregon Department of Environmental
Quality (DEQ) and the contracted services of Hamilton Test Systems
(HTS), EPA is currently conducting the Portland Study, a large scale
vehicle testing program designed to study Oregon's motor vehicle inspec-
tion program. The primary goal of the study is to quantify the costs
and effectiveness of an ongoing "real life" inspection and maintenance
(I/M) program.
Due to the great demand for information on inspection and maintenance
programs, the following report is being prepared as data are still being
collected in the Portland Study. In a series of interim reports, results
from this study will be made available as soon as possible. The anal-
yses in this report are based upon data which were complete, edited, and
verified as of September 14, 1978 when they were placed on magnetic tape
in final form. Inquiries may be addressed to Janet Becker (313-668-
4351).
Summary
The main objectives of the Portland Study are as follows:
1. To determine the ability of an actual I/M inspection test to
correctly identify high emitting cars; i.e., cars which need
remedial maintenance;
2. To determine emission reductions achieved following mainte-
nance on so-identified cars, with maintenance performed by mechanics
in the field;
3. To determine the duration of emission reduction when compared
to non-I/M situation;
4. To determine the cost of maintenance for I/M vs. non-I/M
situation;
5. To determine the energy impact.
Preliminary conclusions regarding each of these objectives are listed
below.
1. Exhaust emission levels as measured by the complete Federal
Test Procedure of vehicles which failed the Oregon inspection test
are much higher than for vehicles which passed. For catalyst-
equipped, 1975 through 1977 model year vehicles, failing cars
emitted 2.18 times as much hydrocarbons and 2.96 times as much
carbon monoxide as passing cars. For 1972 through 1974 model year
vehicles, failing cars emitted 1.40 times as much hydrocarbons and
1.73 times as much carbon monoxide.
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-2-
2. Following maintenance, HC and CO FTP emissions of the failed
1975-77 model year vehicles* were reduced 47% and 54% and emissions
of the failed 1972-74 model year cars were reduced 34% and 33%,
respectively. For the fleet (including both passed and failed
cars), HC and CO emission reductions were 26% and 35% for the newer
cars and 15% and 16% for the older cars. Maintenance did not
affect NOx emission levels.
3. Averaged over six months, HC and CO emission reductions** for
the entire fleet were 27% and 32% for the newer cars, and 8% and
10% for the older cars.
4. The average cost of repair was $24 for the newer cars and $35
for the older cars. Fifty percent of all failed cars had repair
costs of $14 or less. Ninety percent of all cars had repair costs
of $70 or less. There is currently no quantitative comparison
between maintenance costs which would normally have been incurred
and those which were incurred specifically due to I/M. However,
such a comparison would reduce the net cost of I/M to the vehicle
owner.
5. The Portland Study shows on the average no fuel economy gain
or loss due to I/M maintenance performed on failed cars.
Program Design
In the Portland Study design, two basic study areas have been defined.
The first area, designated Element I, addresses the question of the
"correlatability" of short emissions test procedures with the Federal
Test Procedure (FTP). For Element I, some 2,000, 1975-77 model year .
light-duty vehicles are included in the study. They are tested accor-
ding to three short emission tests plus the FTP at the HTS laboratory,
and also are subjected to the Oregon State inspection test at an Oregon
State inspection lane. In addition, state personnel performed the two
loaded short tests on many of these vehicles.
The second study area, designated Element II, addresses questions
relating to the effectiveness and the cost of inspection and maintenance
as an in-use vehicle emission control strategy. This sample includes
approximately 600 light-duty vehicles. Approximately 400 of the Element
II vehicles were recruited from the Portland area, where I/M is required.
The other 200 were recruited from Eugene, Oregon, where I/M is not
required. Most of the remainder of this status report focuses on the
Element II vehicles.
*Includes only those failed vehicles which have been tested through six
months. These reductions are slightly different from those given on page 4
for all failed vehicles.
**These estimates are based on a comparison of 1) the Portland fleet's
emissions as they would be expected to deteriorate without I/M, with
2) the Portland fleet's emissions as measured in this program initially
and over the six months following inspection and maintenance.
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-3-
Table 1 describes the sample of vehicles in Element II in more detail.
Vehicles are divided into two main groups: 1972-74 and 1975-77 model
year vehicles. Emission control technologies are thus generally sepa-
rated into pre-catalyst and catalyst, respectively. Within each main
group, vehicles were subject to the same federal exhaust emission stan-
dards for FTP HC and CO. The pertinent standards are given in Table 2a.
Table 2b provides the applicable Oregon state inspection test (idle)
standards for Element II vehicles. Vehicles from Eugene, Oregon, are
intended to serve as a "control group" in the sense that I/M is not
required of these cars and they have been selected to match the Portland
vehicles with respect to model year, engine cubic inch displacement
(CID), and model type.
All vehicles in Element II are subjected to several short emission
tests, a diagnostic inspection, the FTP, and the Highway Fuel Economy
Test (HFET). If a Portland area vehicle fails the state test, it returns
following maintenance and is retested according to the 1975 FTP, the hot
start FTP, the HFET, and the idle test to determine the immediate
effect of maintenance. Information on the type and cost of maintenance
performed and on diagnostics is also collected.
All vehicles in Element II are retested at approximately 3-month inter-
vals during the following year to obtain information on FTP emission
deterioration, idle emission deterioration, fuel economy deterioration,
and information on diagnostics and voluntary owner maintenance.
Following vehicle testing, data packets containing test-related infor-
mation such as strip charts, calibrations, etc., are manually reviewed
by EPA personnel assigned to Portland. When EPA approves the data
packets, the complete sets of data are placed onto computer files and
are computer-checked for reasonableness. Once this checking/editing
procedure is completed, the data are transferred onto magnetic tape for
data analysis. Analysis is carried out in Ann Arbor by the Inspection
and Maintenance Staff of the Emission Control Technology Division.
Preliminaries to the Analysis
This analysis is being prepared based upon data available from the
Portland Study as of September 14, 1978. At that time there were 1001
Element I test sequences and 1907 Element II test sequences available.
The distribution of the Element II test sequences is given in Table 3 by
vehicle group and test sequence type. Since the study is incomplete,
estimates and tentative conclusions are subject to revision pending
further analysis.
In the estimates which follow an attempt has been made where appropriate
to weight the sample of vehicles in the study to make it representative
of the population of vehicles in the Portland tri-county area. It was
possible to devise such a weighting scheme for the 1975-77 model year
vehicles, and this weighting scheme has generally been applied. Pre-
sently, sufficient information is not available to perform this weighting
for 1972-74 model year vehicles.
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-4-
Immediate Effects of Maintenance
The immediate effects of I/M on idle HC and CO, FTP HC, CO, and NOx, and
urban and highway fuel economy are indicated in Tables 4 and 5. The
idle measurements are the minimum of the two curb idle measurements at
the HTS lab. Results for 1975-77 model year vehicles have been weighted
in an effort to better reflect the experience of the Portland fleet of
1975-77 cars. Results for the 1972-74 model year vehicles are unweighted
sample means.
Table 4 gives the best current evaluation of immediate I/M effectiveness
in Portland. It is seen that initial HC and CO emission reductions are
substantial for failed 1975-77 vehicles: there is a 44% reduction in
FTP HC and a 53% reduction in FTP CO after maintenance. Fleetvride
average urban fuel economy improves slightly, highway fuel economy
decreases slightly, and NOx increases slightly though none of these
changes is very different from zero. The mean emission levels after
maintenance for the failed population are only slightly above the
appropriate federal exhaust emission standards (1.5 grams per mile (gpm)
HC, 15.0 gpm CO). Per inspected 1975-77 model year vehicle (including
both passed and failed cars), there is a 25% reduction in FTP HC and a
35% reduction in FTP CO after maintenance.
As indicated in Table 5 and the following summary tables, reductions of
FTP HC and CO for 1972-74 model year failed cars in the Portland Study
sample following maintenance are 25% and 38%, respectively. Fleetwide
reductions (considering both passed and failed cars) are 13% and 22%,
respectively. (Fleetwide estimates represent sample averages; no weights
have been applied for the 1972-74 model year cars.) As with the 1975-77
cars, fleetwide average fuel economy and NOx emissions do not appear to
be significantly affected by I/M maintenance.
Fuel Economy Results and FTP Emissions Before and After Maintenance
1972-74 Model Year Cars (Sample Means)
HC CO NOx City F.E. Highway F.E.
(GPM) (GPM) (GPM) (MPG) (MPG)
Before 4.04 55.3 3.15 14.41 20.79
After 3.02 34.4 3.26 14.62 20.65
Percent
Change -25% -38% +3% +1.5% -.7%
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-5-
Fuel Economy Results and FTP Emissions Before and After Maintenance
1975-77 Model Year Failed Cars (Weighted Means)
HC CO NOx City F.E. Highway F.E.
(GPM) (GPM) (GPM) (MPG) (MPG)
Before 2.87 40.9 2.32 16.42 23.37
After 1.60 19.4 2.37 16.59 23.03
Percent
Change -44% -53% +2% +1.0% -1.5%
Ongoing Effects of I/M
As seen above, I/M is initially effective in reducing FTP HC and CO
emissions as observed immediately after maintenance. Of extreme impor-
tance is whether the emission levels remain below levels which would be
experienced in the absence of I/M. A major question is whether cars
involved in an I/M program have emissions which deteriorate faster than
they would without I/M. This topic is being addressed in the Portland
Study by retesting the Element II vehicles during the year following the
initial test. All Element II vehicles are returned to the HTS lab for
retesting at quarterly intervals.
As seen in Table 3, the current data set contains first quarterly
results for most vehicles in the study and second quarterly results for
well over half the vehicles while very few third quarterly results are
present. As a preliminary application of this data to the question of
deterioration over time, data were considered for those vehicles which
had completed testing through the second quarterly retest.
The effects of I/M on HC and CO emission levels for 1975-77 model year
vehicles over time can be seen in Figures 1-4. The figures indicate
that after maintenance on the failed Portland vehicles, the composite
means drop significantly below the Eugene (without I/M) mean emission
levels for HC and CO for both idle and FTP results. Following the
initial reductions these emissions appear to deteriorate along roughly
parallel paths thus preserving significant emission reductions at least
through the second quarterly retest.
Table 6 presents the weighted mean odometer readings, emission levels
and fuel economies for the 1975-77 model year vehicle Portland popu-
lation from which Figures 1-4 were derived. These estimates represent
the experience of vehicles through about six months from the time of a
passed state inspection test. The estimates are based upon all Element
II vehicles in the Portland Study which have completed the first two
quarterly test sequences. The results in Table 6 for the initial and
retest after maintenance test sequences are generally similar to those
seen in Table 4, even though Table 4 was based upon a greater number of
vehicles—all those which had completed initial and retest after main-
tenance sequences.
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-6-
Table 7 gives absolute changes (in gpm) and deterioration rates in gpm
per 10,000 miles for estimated mean FTP emissions for 1975-77 vehicles
through the second quarterly retest. For both HC and CO, the lower
deterioration rates for passed vehicles and higher rates for failed
vehicles yield a composite rate which is lower than that for Eugene
vehicles. This indicates that, at least through the second quarter, the
initial reductions due to I/M are well-sustained. EPA's best nationwide
estimates of emission deterioration rates, based on EPA's surveillance.
data, are labeled "predicted" and are presented here for comparison.
Table 8 presents sample mean odometer readings, emission levels, and
fuel economies for 1972-74 model year vehicles at test points through
approximately six months. Figures 5 and 6 present the FTP HC and CO
information graphically. Table 9 presents deterioration rates (gpm per
10,000 miles) calculated from the results in Table 8. Preliminary
indications are that, although substantial emission reductions due to
maintenance are occurring, fleet average hydrocarbon deterioration is
large for the 1972-74 model year cars in the months following main-
tenance. Much of the relatively rapid HC deterioration appears to be
due to ignition system problems. Further investigations relating to
this issue including a review of more detailed information on individual
vehicles and application of an appropriate weighting scheme to make the
1972-74 model year car sample more representative of the Portland popu-
lation are currently being planned.
Maintenance
Cost of maintenance information was requested on every failed Element II
vehicle following passage of the DEQ test. For the 1975-77 model year
cars, the sample average repair cost was $24.46. The average repair
cost weighted to represent the Portland population was $23.35. The
following table provides percentiles of cost which may be read as, for
example, 50% of the sampled 1972-77 model year vehicles had maintenance
costs of $14 or less, and 90% had costs of $70 or less.
Repair Costs
Model Years
1972-74
1975-77
1972-77
Sample Mean
$34.97
$24.46
$29.47
Percentiles
25
$5
$7
$6
50
$11
$14
$14
75
$41
$37
$38
90
$78
$59
$70
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Figure 1
Ongoing Effects: 1975-77 Model Year
Portland Population Estimated Means
IDLE HC VS. MILEAGE (VEHICLES WITH TWO QUARTERLIES)
400
J2Q
o
ac
EUGENE
22000 24000 26000 23900
HILEAGE
39000
32080
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Figure 2
Ongoing Effects: 1975-77 Model Year
Portland Population Estimated Means
IDLE CO VS. MILEAGE (VEHICLES WITH TWO QUARTERLIES)
02
o-
w
1
,m*m prmnHO
CC:i?C31
— CUGEKE
22000 24000 26000 28900 3G000
HILEflCE
?000
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-7-
It should be noted that the median (50 percentile) cost of maintenance
in the sample is far below the mean cost of maintenance. This pheno-
menon is further illustrated in Figure 7 which indicates frequencies of
maintenance costs. The implication of these results is that cost of
maintenance is skewed heavily to the low end and a relatively small
number of high costs are bringing up the mean. For the earlier model
year vehicles, there were five extreme examples which had extensive
tune-ups. For example, a $260 repair included a muffler replacement and
a $333 repair included replacement of the camshaft. In these and other
less extreme cases, repairs not necessary to pass the DEQ test may be
inflating average cost of repair for I/M failure. The median might
therefore be a more appropriate measure for estimating repair costs
which are due to I/M.
Review of the maintenance data indicates that the majority of cars in
the Portland Study required only minor tune-up work to pass the state
inspection test. Carburetor work in the form of repair, adjustment, or
replacement was indicated on a large proportion of the vehicles (88% of
the earlier and 90% of the later model year vehicles). Cost data indi-
cate that most of the carburetor work was adjustment. In addition to
carburetor work, spark plugs, choke, air filter, idle speed, timing, and
dwell were common maintenance items. Although higher cost parts and
repairs were observed they were infrequent. These costs undoubtedly
include some costs which would have been incurred for routine maintenance,
even in the non-I/M situation. A breakdown of "routine maintenance"
costs vs. I/M-related maintenance costs will be attempted for a subse-
quent report.
It is seen in Table 10 that nearly half of the newer cars had maintenance
performed at auto dealer service departments while for older cars the
most frequent maintenance facility was independent repair garage.
Preliminary analyses have not established any effects of where the
maintenance was done on emission reductions.
As an indicator of the use of diagnostic information supplied to mechanics,
Table 11 indicates the frequency of maintenance items for vehicles which
fail the state inspection test for HC only, for CO only, and for both.
These results indicate that certain adjustments are performed on most
vehicles regardless of the pollutant(s) failed. Carburetor adjustment
is an obvious example. However, "spark timing control devices" are
repaired, replaced, or adjusted approximately two or three times more
frequently for HC only failures then for CO only failures.
Tables 12 and 13 present mean emissions and fuel economies on pollutant-
specific failure for 1972-74 and 1975-77 Element II vehicles. Before
and after maintenance results are given in addition to percent reduc-
tions. In general, repairs to a vehicle failing only one pollutant do
not provide large FTP emission reductions on the other pollutant. The
exception is for 1975-77 model year vehicles failing only on idle CO,
where a 29% reduction in FTP HC occurs after maintenance. This result
is expected since the correct idle mixture setting increases the catalyst's
efficiency thus reducing emissions of both pollutants. This suggests
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-8-
that an area with only an oxidant problem will benefit from implementing
an I/M program with both HC and CO outpoints. This possibility is
currently receiving further evaluation.
SIT Efficiency in Identifying FTP Failures
Overall it appears that the Oregon state test is doing a good job of
identifying those vehicles which are high polluters and are in need of
remedial maintenance. The table below indicates how well the Oregon
State test is doing.
Oregon State Test's Ability to Detect High Emitters
(As Measured Relative to the Federal Test Procedure)
1972-77 Model Year Portland Vehicles
1972-74 Models 1975-77 Models
Passed Cars: Avg. FTP HC = 2.92 Avg. FTP HC = 1.20
Avg. FTP CO = 32.07 Avg. FTP CO = 12.92
Avg. FTP NOx- 3.45 Avg. FTP N0x= 2.40
Failed Cars: Avg. FTP HC = 4.09 Avg. FTP HC = 2.63
Avg. FTP CO = 55.53 Avg. FTP CO = 38.18
Avg. FTP NOX= 3.16 Avg. FTP NOX= 2.40
Fast Deterioration
As suggested by Figures 3, 4, 5, and 6, some of the vehicles in the
Portland Element II fleet appear to be deteriorating relatively rapidly
following maintenance. The phenomenon of rapid deterioration following
passage of the state inspection test was therefore investigated for the
whole sample (both passed and failed cars). As an initial investigation
into this phenomenon, Portland area vehicles in the data base were
identified as being possible "fast deteriorators" if their FTP or HFET
emissions had doubled from the time when the state inspection test was
passed until the first quarterly retest. Following the screening procedure,
all pertinent information available for these vehicles including emission
tests, engine diagnostics, and maintenance records was studied in an
effort to determine the reasons for the apparent deterioration. A
summary of the findings regarding probable causes is presented in Table
14. The majority (15 out of 26 1972-74 model year vehicles and 13 out of
20 1975-77 model year vehicles) appeared to have experienced some
carburetor adjustment between the two test points. Of the earlier model
year vehicles, 9 appeared to have spark plug or spark plug wire failure
as the likely cause for deterioration. For many of these vehicles,
driveability problems were observed at the test following the passed SIT
which were not observed at the first quarterly retest. This suggests
that driveability problems following certain I/M-related repairs may be
encouraging subsequent readjustments, thus decreasing I/M's potential
effectiveness. Whether the poor driveability is a result of the vehicle
design or improper engine parameter adjustment is yet to be determined.
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Figure 3
Ongoing Effects: 1975-77 Model Year
Portland Population Estimated Means
FTP HC VS. MILEAGE (VEHICLES WITH TWO QUARTERLIES)
3.69
2.55
1.5
1.08
r «.. > 1 I 1. : . -J
22000 24000
26000 28090
HUEflCE
8000 32000
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Figure 4
Ongoing Effects: 1975-77 Model Year
Portland Population Estimated Means
FTP CO VS. MILEAGE (VEHICLES WITH TWO QUARTERLIES)
48
=32
o
o
24-
16
„«.,.
22088 24888
26880 28G88
R1LERCE
30800 32000
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Figure 5
Ongoing Effects: 1972-74 Model Year Sample Means
FTP HC VS. MILEAGE (VEHICLES WITH TWO QUARTERLIES)
o
.7. 0.
2.0
1 5
....... PORTLflNO
COMPOSITE
CUCCNC
58080
52000 54000
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Figure 6
Ongoing Effects: 1972-74 Model Year Sample Means
FTP CO VS. MILEAGE (VEHICLES WITH TWO QUARTERLIES)
40
20
10
e
50000 52000 54000 56000 58008 66609
MILEAGE
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Figure 7
UJ
FREQUENCY OF HfllNTENfiNCE COSTS
24..
22
20
£. 18
£ 16
S 14
CE
° 8
2
0
0
MODEL YEflRS 1972-74
MODEL YE1RRS 1975-77
i HBEh HEU aaai
25 50 75 100
COST OF MfllNTENflNCE
125
150
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Table 1
Description of Element II Vehicle Groups
Group Description Number of Vehicles
1. Portland area 1972-74 model year 100
vehicles which passed the state
inspection test,
2. Portland area 1975-77 model year 100
vehicles which passed the
state inspection test,
3. Portland area 1972-74 model year 100
vehicles which failed the state
inspection test,
4. Portland area 1975-77 model year 100
vehicles which failed the state
inspection test,
5. Eugene, Oregon 1972-74 model year 100 •
vehicles,
6. Eugene, Oregon 1975-77 model year 100
vehicles.
TOTAL ELEMENT II VEHICLES ' 600
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Table 2a
Federal Exhaust Emission Standards Applicable to Element II Vehicles
Certification Standards (gpm)
Model Year Procedure HC_ C0_ NOx
1972 72 FTP* 3.4(3.0) 39.0(34.0) -
1973-1974 72 FTP* 3.4(3.0) 39.0(34.0) 3.0(3.1)
1975-1976 75 FTP 1.5 15.0 3.1
1977 75 FTP 1.5 15.0 2.0
Table 2b
Ranges in Oregon State Inspection Idle Test Standards
Applicable to Element II Vehicles
State Idle Standards
Model Year HC CO
1972-74 400-500 ppm 2.0-4.0%
1975-77 225-300 ppm 1.0-3.5%
*The 1972 FTP, which consists of bags 1 and 2 of the 75 FTP, was used to
determine whether a 1972-74 model year vehicle was correctly passed or
failed since these vehicles were certified when new on the basis of the
72 FTP. However, FTP emission results for all vehicles are presented
as 1975 FTP results. For comparison, the estimated equivalent 75 FTP
standards are provided in parentheses.
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Table 3
Number of Test Sequences Completed by Element II Vehicles
(as of 14 September 1978)
Retest After First Second Third
Initial Maintenance Quarterly Quarterly Quarterly*
Portland, Model Years 111 - 103 85 20
72-74, passed
Portland, Model Years 112 - 109 83 17
75-77, passed
Portland, Model Years 102 92 88 54 7
72-74, failed
Portland, Model Years 114 99 93 74 2
75-77, failed
Eugene, Model Years 111 - 93 59 0
72-74
Eugene, Model Years 109 - 95 75 0
75-77
*Third quarterly results have not been included in this report.
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Table 4
Immediate Effects of Maintenance*
1975-77 Model Year Cars
Portland Pass Portland Fail
After
Initial Maintenance % Change
Portland Composite
After
Initial Maintenance % Change
Eugene
Initial % Difference***
(Eugene to
Portland, initial)
% Difference**
(Eugene to
Portland, after
maintenance)
Odometer (Miles)
Idle HC** (PPM)
Idle CO** (%)
FTP HC (GPM)
FTP CO (GPM)
FTP NOx (GPM)
Urban Fuel Economy (MPG) 17.72
Highway Fuel Economy (MPG) 25.25
*A11 numbers have been weighted to give best estimates for the Portland tri-county vehicle population. Eugene vehicles do not
undergo I/M but are matched to the Portland sample and weighted to represent the Portland population in the absence of I/M.
**Based on measurements taken at the contractor's lab. The lower of the two curb idle measurements was used as the idle
level for each car.
***100 X (Portland Composite Average - Eugene Average)/(Eugene Average) where the Portland Composite Average is Initial
or After Maintenance, respectively.
23,508
69
0.24
1.16
11.23
2.56
17.72
25.25
24,583
325
3.09
2.87
40.87
2.32
16.42
23.37
25,455
80
0.17
1.60
19.36
2.37
16.59
23.03
3.5
-75.4
-94.5
-44.3
-52.6
2.2
1.0
-1.5
23,880
158
1.23
1.75
21.49
2.48
17.27
24.60
24,182
72
0.22
1.31
14.04
2.49
17.33
24.48
1.3
-54.4
-82.1
-25.1
-34.7
0.4
0.3
-0.5
23,053
150
1.34
1.90
25.16
2.75
17.28
24.77
3.6
5.3
-8.2
-7.9
-14.6
-9.8
-0.1
-0.7
4.9
-52.0
-83.6
-31.1
-44.2
-9.5
0.3
-1.2
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Table 5
Immediate Effects of Maintenance*
1972-74 Model Year Cars
a rass rorciana ran
After
Initial Maintenance '/.
53,833
148
0.88
2.93
32.08
3.46
14.14
20.42
55,234
328
3.20
4.04
55.30
3.15
14.41
20.79
55,970
189
0.72
3.02
34.41
3.26
14.62
20.65
i Change
1.3
-42.4
-77.5
-25.2
-37.8
3.5
1.5
-0.7
After
Initial Maintenance %
54,486
230
1.93
3.43
42.60
3.32
14.26
20.59
54,801
167
0.81
2.97
33.41
3.37
14.36
20.52
Change
0.6
-27.4
-58.0
-13.4
-22.2
1.5
0.7
-0.3
Initial % Difference*** % Difference
(Eugene to (Eugene to
Portland, initial) Portland, after
maintenance)
54,630
209
2.77
3.60
48.25
3.63
14.44
21.11
-0
10
-30
-4
-11
-8
-1
-2
.3
.0
.3
.7
.7
.5
.2
.5
0
-20
-70
-17
-31
-7
-0
-2
.3
.1
.8
.5
.3
.2
.6
.8
Odometer (Miles)
Idle HCC** (PPM)
Idle CO** (%)
FTP HC (GPM)
FTP CO (GPM)
FTP NOx (GPM)
Urban Fuel Economy (MPG)
Highway Fuel Economy (MPG)
*A11 numbers are sample averages i.e., the sample has not been weighted to represent the Portland population.
**Based on measurements taken at the contractor's lab. The lower of the two curb idle measurements
was used as the idle level for each car.
***100 X (Total Portland Sample Average - Eugene Average)/(Eugene Average) where Total Portland Sample Average
is Initial or After Maintenance, respectively.
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Portland Pass
Table 6
Ongoing Effects of I/M*
1975-77 Model Year Cars
Portland Fail
Portland Composite
Eugene
Odometer (Miles)
Idle HC** (PPM)
Idle CO*'- (2)
FTP HC (GPM)
FTP CO (GPM)
FTP NOx (GPM)
Urban Fuel Economy
(MPG)
Highway Fuel Economy
(MPG)
Initial
22004
70
0.26
1.20
10.48
2.62
18.03
25.71
First
Quarterly
25408
90
0.34
1.19
10.66
2.76
17.74
24.86
Second
Quarterly
28174
114
0.47
1.27
12.41
2.60
18.16
25.93
Initial
24470
351
3.40
3.04
42.00
2.39
16.30
23.23
After
Maintenance
25144
80
0.16
1.62
20.26
2.37
16.34
22.68
First
Quarterly
27795
153
0.76
1.77
23.01
2.37
16.60
23.03
Second
Quarterly
30708
166
1.11
1.76
23.79
2.37
16.68
23.34
Initial
22830
164
1.31
1.82
21.04
2.54
17.45
24.87
After
Maintenance
23055
73
0.23
1.34
13.76
2.54
17.46
24.70
First
Quarterly
26207
111
0.48
1.38
14.80
2.63
17.36
24.25
Second
Quarterly
29022
131
0.68
1.43
16.22
2.52
16.66
25.06
Initial
22748
157
1.29
1.86
25.17
2.72
17.26
24.94
First
Quarterly
26222
178
1.55
1.96
26.37
2.69
17.26
24.45
Second
Quarterly
29494
185
1.52
2.04
28.49
2.47
17.47
24.93
*A11 numbers have been weighted to give best estimates for the Portland tri-county vehicle population. Eugene vehicles do not
undergo I/M but are matched to the Portland sample and weighted to represent the Portland population in the absence of I/M.
"Initial" and "After Maintenance" numbers differ from Table 4 because Table 6 includes only vehicles which have completed
the second quarterly retest.
**Based on measurements taken at the contractor's lab. The lower of the two curb idle measurements was used as the idle
level for each car.
-------
Table 7
FTP Emission Changes Through the First Six Months after Inspection
(1975-77 Model Year Vehicles Weighted to Reflect the Portland Fleet)
Increase from Initial* Test
To Second Quarterly
Change per 10,000 Miles
Portland
Pass
Portland
Fail
Portland
Composite
Eugene
Odometer
6170
5564
5967
6746
FTP HC
.07
.14
.09
.18
FTP CO
1.93
3.53
2.46
3.32
FTP NOx
-.02
0.00
-.02
-.25
Predicted**
FTP HC
.11
.25
.15
.27
.23
FTP CO
3.13
6.34
4.12
4.92
2.8
FTP NOx
-.03
0.0
-.03
-.37
.08
*Test after maintenance for failed vehicles.
**MOBILE1 estimates of I/M benefit are based on the use of equal with and
without I/M deterioration rates given by the predicted rates in this table
for 1975-77 model year cars.
-------
Table 8
Portland Pass
Ongoing Effects of I/M*
1972-74 Model Year Cars
Portland Fail
Portland Total Sample
Odometer (Miles)
Idle HC** (PPM)
Idle CO** (Z)
FTP HC (GPM)
FTP CO (GPM)
FTP NOx (GPM)
Urban Fuel Economy
Initial
53657
148
0.94
3.11
34.18
3.43
14.27
First
Quarterly
56153
165
1.43
3.27
37.02
3.53
14.04
Second
Quarterly
58281
207
1.49
3.29
37.63
3.51
14.28
Initial
54837
346
2.91
3.99
49.06
3.26
15.13
After
Maintenance
55453
153
0.51
2.62
32.73
3.28
15.22
First
Quarterly
57647
220
1.59
3.41
41.26
3.41
14.81
Second
Quarterly
59849
293
1.86
4.13
40.61
3.26
15.08
Initial
54115
225
1.70
3.45
39.96
3.36
14.59
After
Maintenance
54355
150
0.77
2.92
33.62
3.37
14.64
First
Quarterly
56733
187
1.49
3.32
' 38.67
3.45
14.33
Second
Quarterly
58850
240
1.63
3.62
38.79
3.41
14.53
Initial
50510
202
2.85
3.35
46.52
3.93
13.95
First
Quarterly
53302
254
2.32
3.12
39.56
3.94
1 I
14.20 V
Second
Quarterly
56064
235
2.61
3.10
42.98
3.65
14.07
(MPG)
Highway Fuel Economy 20.62
(MPG)
20.09
20.69
21.81
21.50
21.91
21.50
21.07
20.96
20.50
21.00
20.35
20.26
20.47
*A11 numbers are sample averages, i.e., not weighted to reflect the Portland fleet. "Initial" and "After Maintenance" numbers
differ from Table 5 because Table 8 includes only vehicles which have completed the second quarterly retest.
**Based on measurements taken at the contractor's lab. The lower of the two curb idle measurements was used as the
idle level for each car.
-------
Table 9
FTP Emission Changes Through the First Six Months after Inspection
(1972-74 Model Year Vehicles, Unweighted)
Increase from Initial Test*
To Second Quarterly Change per 10,000 Miles
Odometer FTP HC FTP CO FTP NOx FTP HC FTP CO FTP NOx
Portland
Pass
Portland
Fail
Portland
Composite
Eugene
4624
4396
4535
5554
.18 3.45 .08
1.51 7.88 -.02 3
.70 5.17 .04 1
-.25 -3.54 -.28
Predicted**
.39
.43
.54
.45
.53
7.
17.
11.
-6.
6.
46
93
40
37
15
.17
-.05
.09
-.50
0.00
*Test after maintenance for failed vehicles.
**MOBILE1 estimates of I/M benefit are based on the use of equal with and
.without I/M deterioration rates given by the predicted rates in this table
for 1972-74 model year cars.
-------
Table 10
Repairs Performed on Vehicles Failing the State Inspection Test
Model Year Model Year
1972-74 Vehicles 1975-77 Vehicles
Total Number of Cars
Were the following items repaired,
Spark Plugs
Spark Plug Wires
Points and Condensor
Distributor Cap and Rotor
Spark Timing Control Devices
Carburetor
Choke
Intake System
Air Filter
Engine Oil
Idle Speed
Timing
Dwell
Air Injection System
EGR System
PCV System
Valves
Maintenance was performed by:
Auto Dealer Service Department
Independent Repair Garage
Service Station
Owner
Other
No Maintenance
92
replaced, or adjusted?
34
14
29
17
13
81
46
5
30
20
46
46
39
5
6
6
7
17
38
16
19
1
1
99
(yes)
34
27
11
10
20
89
35
7
38
17
70
65
9
6
5
4
2
48
21
18
12
0
0
-------
Table 11
Repairs Performed on Vehicles Failing the State Inspection Test (SIT)
(by pollutant failed)
Model Years
SIT CO Failure*
1972-74
1975-77
SIT HC Failure*
1972-74
1975-77
Both HC and CO Failure
1972-74
1975-77
Total Number Cars
Were the following items repaired,
64_ 34
replaced, or adjusted? (yes)
13
43
Spark Plugs
Spark Plug Wires
Points and Condensers
Distributor Cap and Rotor
Spark Timing Control Devices
Carburetor
Choke
Intake System
Air Filter
Engine Oil
Idle Speed
Timing
Dwell
Air Injection System
ECR System
PCV System
Valves
Maintenance Was performed by:
Auto Dealer Service Department
Independent Repair Garage
Service Station
Owner
22 (34.4)**
8 (12.5)
20 (31.3)
13 (20.3)
8 (12.5)
59 (92.2)
34 (53.1)
2 (3.1)
20 (31.3)
14 (21.9)
32 (50.0)
33 (51. 6)
29 (45.3)
4 (6.3)
3 (4.7)
4 (6.3)
5 (7.8)
15 (23.4)
26 (40.6)
12 (1.8.8)
11 (17.2)
8 (23.5)
7 (20.6)
4 (11.8)
3 (8.8)
5 (14.7)
32 (94.1)
8 (23.5)
1 (2.9)
11 (32.4)
4 (11.8)
21 (61.8)
22 (64.7)
3 (8.8)
3 (8.8)
0 (0.0)
0 (0.0)
0 (0.0)
18 (52.9)
7 (20.6)
7 (20.6)
2 (5.9)
4 (50.0)
2 (25.0)
2 (25.0)
1 (12.5)
3 (37.5)
8 (100.0)
5 (62.5)
1 (12.5)
3 (37.5)
2 (25.0)
4 (50.0)
4 (50.0)
2 (25.0)
0 (0.0)
2 (25.0)
1 (12.5)
1 (12.5)
1 (12.5)
4 (50.0)
1 (12.5)
2 (25.0)
6 (46.2)
5 (38.5)
2 (15.4)
1 (7.7)
3 (23.1)
11 (84.6)
5 (38.5)
1 (7.7)
4 (30.8)
2 (15.4)
12 (92.3)
9 (69.2)
1 (7.7)
0 (0.0)
2 (15.4)
0 (0.0)
2 (15.4)
8 (61.5)
2 (15.4)
1 (7.7)
2 (15.4)
3 (33.3)
2 (22.2)
3 (33.3)
2 (22.2)
1 (11.1)
8 (88.9)
3 (33.3)
0 (0.0)
4 (44.4)
1 (U.I)
5 (55.6)
5 (55.6)
4 (44.4)
0 (0.0)
0 (0.0)
0 (0.0)
0 (0.0)
0 (0.0)
4 (44.4)
3 (33.3)
1 (11.1)
2
10
16 (37.2)
11 (25.6)
2 (4.7)
(4.7)
(23.3)
39 (90.7)
21 (48.8)
4 (9.3)
20 (46.5)
8 (18.6)
30 (69.8)
30 (69.8)
(9.3)
(7.0)
(4.7)
(7.0)
0 (0.0)
L9 (44.2)
10 (23.3)
9 (20.9)
5 (11.6)
'''Exclusive, i.e., includes vehicles which failed one and not the other of idle HC and idle CO.
"''•'Numbers in parentheses are percent of column total.
-------
Table 12
Sample Mean Emissions for 1972-74 Model Year Vehicles**
(By Pollutant Failure)
Idle CO Failure* (64 Vehicles)
Idle HC Failure* (8 Vehicles)
Fail Both HC and CO (9 Vehicles)
Idle HC
Idle CO
FTP HC
FTP CO
FTP NOx
Urban FE
Highway FE
Before
Maintenance
210.47
3.63
3.47
57.45
3.12
14.57
21.03
After
Maintenance
189.38
.75
3.22
36.75
3.18
14.63
20.75
%
Reduction
10.0
79.3
7.2
36.0
-1.9
-.4
1.3
Before
Maintenance
1187.50
.66
4.50
32.58
3.28
13.73
19.81
After
Maintenance
181.25
.22
2.70
30.62
3.11
14.10
20.13
7
/a
Reduction
84.
66.
40.
6.
5.
-2.
-1.
7
7
0
0
2
7
6
Before
Maintenance
912
5
9
94
3
13
18
.78
.99
.73
.45
.03
.09
.92
After
Maintenance
287.78
.68
3/00
35.06
3.92
14.32
19.31
%
Reduction
68
88
69
62
-29
-9
-2
.7
.6
.2
.9
.4
.4
.1
*Exclusive, i.e. includes vehicles which failed one and not the other of idle HC and idle CO.
**The values have not been weighted to better reflect the Portland fleet.
-------
Table 13
Mean Emissions for 1975-77 Model Year Vehicles**
(By Pollutant Failure)
Idle CO Failure* (34 Vehicles)
Idle HC Failure* (13 Vehicles)
Fail Both HC and CO (43 Vehicles)
Before After % Before After % Before
Maintenance Maintenance Reduction Maintenance Maintenance Reduction Maintenance
After %
Maintenance Reduction
Idle HC
Idle CO
FTP HC
FTP CO
FTP NOx
Urban FE
Highway FE
172.06
2.39
2.07
33.86
2.72
15.74
22.45
77.94
.30
1.47
17.84
2.96
15.86
22.25
54.7
87.4
29.0
47.3
-8.8
-.8
.9
310.00
.09
2.10
13.58
2.31
13.89
19.43
127.69
.02
1.43
14.40
2.47
13.26
19.02
58.8
77.8
31.9
-6.0
-6.9
4.5
2.1
476.23
4.83
1
3.44
50.16
2.16
15.17
21.24
91.98
.22
1.54
19.54
2.12
15.20
20.62
80.70
95.4
55.2
61.0
1.9
-0.2
2.9
*Exclusive, i.e., includes vehicles which failed one and not the other of idle HC and idle CO.
**These values have not been weighted to better reflect the Portland fleet.
-------
Table 14
Frequency of Fast Deteriorators and Likely Causes*
1972-74 Model Year Vehicles 1975-77 Model Year Vehicles
Total Identified in Sample 26 20
Carburetor Out of Adjustment 15 13
Distributor Malfunction 0 3
Choke Operation Failure 2 1
Spark Plug Failure 9 1
EGR Disabled 2 1
Unknown 0 3
*For some vehicles more than one likely cause was indicated.
------- |