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 ------- 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. ------- -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. ------- -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. ------- -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% ------- -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. ------- -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 ------- 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 ------- 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 ------- -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 ------- -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. ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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. ------- 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. ------- 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 ------- 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. ------- 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. ------- |