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The data required by paragraphs 2 and 3 above shall be displayed in a table similar to the following:
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Trip type

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types as appropriate

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Indicate pollutant. • The table need contain only those entries appropriate to the transportation control measures included in the pen, 138 FR 16196, June 8, 1973]



1. General.—This appendix presents estimates of emissions reductions that, in the judgment of the Administrator, are likely to be achievable through application of inspection, maintenance, and retrofit measures to in-use motor vehicles. To tho extent possible, these estimates are based on empirical data. However, lack of data in some areas has necessitated some extrapolation of empirical data using engineering Judgment. It should be noted that, for inspection/maintenance, estimates of changes in oxides of nitrogen are not included in the discussion. In general, oxides of nitrogen were not significantly affected by Inspection/maintenance procedures. The sources of empirical data and the bases for judgments are discussed in paragraph 6 of this appendix.

The emissions reductions estimates presented herein are subject to considerable uncertainty. The emissions reductions actually realized in a transportation control program may be greater or less than the estimated reductions. The estimates should therefore be regarded as useful primarily for current planning purposes. Any transportation control plan incorporating in-use vehicle emis. sion control approaches, whether those specifically cited in this appendix or alternatives proposed by a State, must provide, as required by 40 CFR 51.19d, for fleld verification of the emissions actually achieved in the implemented programs and, as required by section 110(a) (2) (H) of the Act, for any revistons of the transportation control plan that may be indicated thereby.

The approaches to in-use vehicle emissions control cited herein are those judged to be most generally applicable by the Administrator considering the information currently available to him. States are encouraged to consider other approaches that may be applicable to their particular situations. Data and analyses supporting the emissions reductions claimed for alternative approaches must be submitted with the Transportation Control Plan. Several alternative approaches are discussed in a report entitled: "Control Strategies for In-Use Vehicles," available from EPA, Mobile Sources Pollution Control Program, 401 M Street sw., Washington, D.C. 20460.

States proposing inspection/maintenance or retrofit programs are encouraged to consider the effects on the implementation of their plans of inequities that may arise in connection with these programs. Such inequities may include premature fallure or inadequacy of retroit components, improper or inadequate workmanship at inspection and repair facilities, inconvenient numbers, locations, and operating schedules for inspection, retrofit, and repair facilities, and inadequate public notice of inspection maintenance and retrofit requirements.

The States are also encouraged to give consideration to transportation control mengures based on reductions in vehicle use and traffic flow measures. Nothing in this appendix is intended to suggest that transportation control approaches based on inspection, maintenance, and retrofit should necessarily be considered preferable to approaches based on reductions in vehicle use or traffic flow measures.

2. Definitions.--a. "Precontrolled vehicles" means light duty vehicles sold nationally

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Carbon monoxide

(except in California) prior to the 1968 model-year and light-duty vehicles sold in California prior to the 1966 model-year.

b. "Controlled vehicles" means light-duty vehicles sold nationally (except in Callfornia) in the 1968 model-year and later and light-duty vehicles sold in California in the 1966 model-year and later.

C. “Loaded emissions test" means a sampling procedure for exhaust emissions which requires exercising the engine under stress (1.e., loading) by use of a chassis dynamom eter to stimulate actual driving conditions. As a minimum requirement, the loaded emission test must include running the vehicle and measuring exhaust emissions at two speeds and loads other than idle.

d. “Idle emission test" means & sampling procedure for exhaust emissions which requires operation of the engine in the idle mode only. At a minimum, the idle test must consist of the following procedures carried out on a fully warmed-up engine: a verification that the idle revolutions per minute is within manufacturer's specified limits and a measurement of the exhaust carbon monoxide and/or hydrocarbon concentrations during the period of time from 15 to 25 seconds after the engine either was used to move the car or was run at 2,000 to 2,500 r/min with no load for 2 or 3 seconds.

e. "Retrofit" means the addition or removal of an item of equipment, or a required adjustment, connection, or disconnection of an existing item of equipment, for the purpose of reducing emissions.

1. "Inspection maintenance" means & program to reduce emissions from in-use vehicles through identifying vehicles that need emissions control related maintenance and requiring that maintenance be performed.

g. "Idle adjustments" means a series of adjustments which include idle revolutions per minute, idle air/fuel ratio, and basic tim. ing.

h. "Initial fallure rate" means the percentage of vehicles rejected because of excessive emissions of a single pollutant during the first inspection cycle of an inspection/maintenance program. (If inspection is conducted for more than one pollutant, the total failure rate may be higher than the failure rates for each single pollutant.)

3. Inspection/maintenance of light duty vehicles.-(a) Reductions.-(1) Loaded emission tests. The following average annual reductions in vehicular exhaust emissions as & function of initial failure rates are estimated to be achievable through implementation of an inspection/maintenance program using a loaded emission test: Percent initial fallure rate --------------

-- 10 20 30 40 50 Emission reduction

(percent): Hydrocarbons ------ 8 11 13 14 15 Carbon monoxide - 4 7 9 11 12

(11) Idle emission test.-The following average annual reduction in vehicular ex

haust emissions as a function of rejection rate are estimated to be achievable through Implementation of an inspection/maintenance program using an idle test: Percent initial failure

rate ---------------- 10 20 30 40 60 Emission reduction

(percent): Hydrocarbons -----

Carbon monoxide---- 3 6 8 9 10 To obtain these reductions an inspection/ maintenance program must provide for inspection of each vehicle at least once per year. More frequent inspection and maintenance is expected to provide larger average emissions reductions, although at greater cost. During the first inspection cycle of an inspection/maintenance program, emissions reductions may be assumed only to the extent consistent with the portion of the vehicle population that has been inspected by that time. During subsequent years the full reductions shown in the tables may be assumed provided that the emissions levels which correspond to the appropriate initial failure rate are used as failure criteria.

(b) The average reductions cited above are applicable for all gasoline-powered lightduty motor vehicles (except motorcycles) which are included in the inspection/maintenance program. .

(c) Requirements.-An acceptable inspection/maintenance program must include:

(1) Provisions for regular periodic inspection of all vehicles for which emissions reductions are claimed.

(11) Provisions for the establishment of inspection failure criteria consistent with the claimed reductions..

(111) Provisions to insure that necessary vehicles receive the maintenance necessary to achieve compliance with the inspection standards. This might include sanctions against individual owners or repair facilities, retest of failed vehicles following maintenance, & certification program to insure that repair facilities performing the required maintenance have the necessary equipment, parts and knowledge to perform the tasks satisfactorily, a program to train mechanics and/or other measures.

(iv) A program of enforcement to insure that vehicles are not intentionally readjusted or modified subsequent to the inspection/maintenance in such a way as would cause them to no longer comply with the Inspection standards. This might include spot checks of idle adjustments and/or a suitable type of physical tagging.

(d) Alternative approaches.-Inspection/ maintenance programs employing approaches other than emissions testing may be capable of achieving emissions reductions for vehicles of certain model-years. Extensive engine parameter inspection and mandatory maintenance procedures are discussed in the Environmental Protection Agency report "Control Strategies for In-Use Vehicles." Inspection/maintenance approaches other than those using an emissions test, or emissions reductions greater than those cited in paragraph 3(a) will be acceptable only 1 sufficient data are provided to justify the emissions reductions claimed.

4. Retrofit of light duty vehicles.-(a) Reductions.—The following reductions in exhaust emissions per vehicle are estimated to be achievable through the installation of the cited types of retrofit devices on the classes of vehicles noted. These emissions reduction estimates are provided for planning purposes only. States including retrofit in their transportation control plans must determine, prior to the actual installation of retroit devices, that the specific devices selected (e.g., brand A oxidizing catalytic converters) satisfy the requirement of paragraph 4 (c)(1).

Since retrofitted vehicles are expected to be subject to periodic inspection and maintezance (see paragraph 4(c)), the reductions cited are to be applied to a maintained vehicle emissions baseline. For example, la 12 percent reduction in hydrocarbon emissions is claimed for inspection/maintenance, the reduction in hydrocarbon emissions due to a retroit approach should be calculated after the vehicle's original emission rate for hydrocarbons has been reduced by 12 percent.

(1) Precontrolled vehicles:

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duty motor vehicles (except motorcycles) sold nationally (except in California) prior to the 1968 model-year or in California prior to the 1966 model-year.

The emissions reductions cited above for Installation of oxidizing catalytic converters on controlled vehicles are applicable to all gasoline-powered light-duty motor vehicles (except motorcycles) sold nationally (except in Cailfornia) in the 1968 through 1974 model-years or in California in the 1966 through 1974 model-years.

The emissions reductions cited above for installation of exhaust gas recirculation on controlled vehicles are applicable to all gasoline-powered light-duty motor vehicles (except motorcycles) sold nationally (except in California) in the 1968 through 1972 model-years or in California in the 1966 through 1971 model-years.

(c) Requirements.--An acceptable retrofit program must include:

(1) The use of a retrofit device whose potential capability for achieving the claimed emissions reductions has been demonstrated through testing and evaluation using the 1972 or 1975 Federal emission test procedure.

(11) A method of assuring the availability of installation facilities and personnel with the capability to perform the required installation tasks and a method of assuring the availabilty of an adequate supply of retrofit components.

(iil) Provisions for emissions testing at the time of retrofit installation or some other positive assurance that the retrofit device is installed and operating correctly.

(iv) Provisions for Inspection of each retrofitted vehicle at least once per year.

(v) Provisions for the establishment of in. spection standards for retrofitted vehicles consistent with the emissions reductions claimed. Particular attention must be paid in this regard to catalytic converter retrofits as the reductions cited in paragraph 4(a) do not include possible irreversible catalyst deterioration over time.

(vi) Provisions to insure that vehicles falling Inspection receive the maintenance necessary to achieve compliance with the inspection standards.

(vii) In the case of retrofit programs that include the use of catalytic converters requiring unleaded fuel, provisions to insure that vehicles utilizing this type of retrofit will not use leaded gasoline and that adequate supplies of lead-free gasoline of suitable octane value will be available if Federal regulations will not insure availability, and provided that such provisions are not in violation of section 211(c)(4) of the Act.

(vili) A program of enforcement to insure that vehicles are not intentionally adjusted or modified subsequent to retrofit installation in such a way as would cause them to no longer comply with the retroflt emissions standards. This might include spot checks, visual inspection, or other suitable techniques.

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(d) Alternative approaches.-Retrofit programs employing approaches other than those cited above may be capable of achieving emissions reductions for vehicles of certain model-years. For example, addition of vacuum spark advance disconnect to the air bleed to intake manifold approach may be feasible for precontrolled vehicles. Alternative retrofit approaches or retrofit emissions reductions greater than those cited in paragraph 4(a) will be acceptable only if sufficient data and analyses are provided to justify the emissions reductions claimed.

5. Inspection/maintenance or retrofit of vehicles other than light-duty vehicles. The inspection/maintenance and retrofit approaches discussed above may be applicable to certain classes of motor vehicles other than those cited. In particular, the States are encouraged to consider the application of such approaches to motor vehicles in the 6,000 to 10,000 lb GVW class. In many cases, these vehicles are constructed and operated in a manner similar to light-duty vehicles. However, the present lack of test data for application of inspection/maintenance or retrofit approaches to vehicles of this type prevents the inclusion of data on achievable emissions reductions for such vehicles in this appendix. Transportation control strategies employing inspection/maintenance or retrofit of vehicles other than light-duty vehicles will be acceptable only if sufficient data and analyses are provided to justify the emissions reductions claimed.

6. Bases for emissions reductions cited in paragraphs 3 and 4.-(a) Inspection/ main tenance.-The reductions cited in paragraph 3.a for inspection/maintenance were derived from test data obtained by EPA in evaluating the initial emissions reductions achieved when a fileet of precontrolled and controlled light-duty vehicles were subjected to emissions inspection tests and the vehicles falling the test were serviced in private maintenance garages. The observed average initial reductions were approximately twice the values shown in the tables in paragraph 3a.

It is expected that in an actual inspection/ maintenance program the average emissions reductions achieved will be substantially less than the initial reductions observed in the study, since there will be deterioration of emissions-related components and adjustments between periodic inspection and maintenance events. While the currently available data on such deterioration are inadequate to accurately predict the consequences of this effect, some correction for deterioration is necessary. Therefore, giving consideration to the current frequency of voluntary maintenance and the emissions reductions typically achieved by existing maintenance procedures, it has been assumed that linear deterioration to beforemaintenance emissions levels will occur over the 12-month period following maintenance, As a result, the average effectiveness for annual inspection is estimated to be one-hall

of the initial effectiveness following maintenance.

Data on the effectiveness of inspection/ maintenance programs in reducing emissions are available only for light-duty vehicles through the 1971 model-year. The effectiveness of inspection/maintenance programs in reducing emissions from future model year vehicles will depend primarily on the extent to which emissions from those vehicles increase in use as a result of repairable malfunctions and on the ability of the inspection test to accurately identify vehicles haping such malfunctions. These factors can be evaluated only after substantial numbers of such vehicles have been in use for some time. However, for implementation planning purposes, it has been assumed that emissions reductions estimated to be achievable for current light-duty vehicles will be applicable for future-model model years as well.

Inspection and maintenance programs using engine parameter inspection or mandatory maintenance approaches may also be effective for vehicles of certain model vears. However, such approaches must be tailored to relate to the specific engine and emissions control systems of the vehicles to be inspected and/or maintained. Depending upon inspection and maintenance procedures and the number and choice of engine parameters Included in the program, substantial variations in emissions reductions are to be expected. Generally applicable estimates of the emissions reductions that may result from such programs are not now available.

States considering Inspection and/or maintenance programs based on approaches not involving emissions tests should take the factors mentioned above into account where estimating and justifying emissions reductions expected from such programs. More detailed discussion of these matters may be found in the EPA report "Control Strategies for In-Use Vehicles."

(b) Retrofit.-(1) Precontrolled vehicles.The reductions cited in paragraph 4.a for precontrolled vehicles are based upon test data obtained in evaluating the initial emissions reductions obtained when various types of retrofit emission control systems were fitted to fleets of tuned, precontrolled, lightduty vehicles. The results of these studies are presented in the EPA report "Control Strategies for In-Use Vehicles." In each case, the mean emissions reductions observed hare been adopted as being most representative of the initial emissions reductions which may be achieved in an actual retrofit program.

Only very limited data are currently available on the deterioration of emissions performance of retrofitted vehicles. These data, which are discussed in the EPA report "Control Strategies for In-Use Vehicles," indicate the need for periodic inspection and maintenance of retrofitted vehicles it the attain. ment and maintenance of the retrofit emissions reductions cited in paragraph 4.a is to be assured. Based upon the available data and the requirements for inspection and

maintenance of retrofitted vehicles at least carbon and carbon monoxide emissions from once per year, and considering the nature controlled light-duty vehicles. While studies of the emissions control techniques employed of precontrolled vehicles have provided eviin each retrofit approach, it appears that the dence that retrofit catalysts may also achieve average annual emissions reductions per some reduction of nitrogen oxides emissions, retrofitted vehicle can approach the observed the extent of this reduction is too highly mean initial reductions if suitable inspec dependent on the air/fuel ratio in the tion and maintenance criteria are adopted. catalyst to be extrapolated to controlled veAccordingly, it has been assumed for plan hicles with reasonable certainty. ning purposes that the observed initial emis In experiments conducted to date, installasions reductions will not be affected by tion of retrofit catalysts on precontrolled deterioration.

vehicles has been accompanied by vacuum (11) Controlled vehicles.-Data which spark advance disconnect. In addition, a could serve as a basis for estimating emis lean idle air/fuel ratio adjustment has nor. sions reductions achievable through retrofit mally been included in the installation proting controlled light-duty vehicles are quite cedures. As neither of the latter two limited. As a result, the emissions reductions modifications is generally applicable to concited for this class of vehicles in paragraph trolled vehicles, it is prudent to anticipate 4.a were developed by extrapolating the data that reductions of hydrocarbon and carbon for retrofitting precontrolled light-duty monoxide emissions achieved by retrofit vehicles.

catalysts on controlled vehicles may be less The techniques of lean idle alr/fuel ratio than those observed with precontrolled adjustment, vacuum spark advance discon- vehicles. rect, and atr bleed to intake manifold are The cited emissions reductions of 50 pernot considered to be generally applicable to cent (hydrocarbons), 50 percent (carbon controlled vehicles. This is because these monoxide) and 0 percent (nitrogen oxides) emissions control approaches are either in are estimates consistent with the foregoing corporated into or may be inconsistent with considerations and the results obtained with emissions control techniques already applied precontrolled vehicles. to many controlled vehicles.

Exhaust gas recirculation (EGR) - EmisExhaust gas recirculation (EGR) is con.

sions reductions of 12 percent (hydrocarsidered generally applicable only to those ve. bons), 31 percent (carbon monoxide), and hicles not substantially controlled for nitro 48 percent (nitrogen oxides) have been obgen oxides emissions. Therefore, EGR as a served as a result of retrofitting precontrolled retrofit approach is applicable in 1968 light-duty vehicles with EGR accompanied through 1972 models sold nationwide (out

by vacuum spark advance disconnect. Expert

ence with 1973 emissions control systems for side of California), except for an insignifeant number of 1972 Vehicles already

new cars suggests that EGR retrofits can

achieve substantial reductions of nitrogen equipped with EGR. Incorporation of EGR

oxides emissions from controlled vehicles not into a significant number of 1972 models sold in Callfornia limits the general applica

already equipped with EGR or equivalent bility of this retrofit approach to 1966

nitrogen oxides emissions control systems. through 1971 controlled vehicles sold in

Much of the hydrocarbon control and California.

some of the nitrogen oxides control observed Oxidizing catalytic converters are consid

with EGR retrofits to precontrolled vehicles ered to be potentially applicable as retrofits

Is attributable to the vacuum spark advance through the 1974 model-year. Beyond the

disconnect. This is not generally applicable 1974 model-year, the presently anticipated

to controlled vehicles. In addition, the design design of emissions control systems required

features responsible for much of the carbon to meet Federal new car emissions standards

monoxide reduction observed with precon.

trolled vehicles are likely to be already inis considered to preclude retrofitting using currently available retrofit technology.

corporated into many controlled vehicles. It The following paragraphs describe the

is therefore prudent to expect that EGR basis for the emissions reductions cited for

retrofits to controlled vehicles may achieve retrofit of controlled vehicles.

somewhat smaller reductions of nitrogen Oridizing catalytic converters.-Test data

oxides emissions than have been observed Indicate that catalytic converter retrofits to

with precontrolled vehicles and no reductions precontrolled vehicles can achieve emissions of hydrocarbon and carbon monoxide reductions of 68 percent (hydrocarbons, 63emissions. percent (carbon monoxide), and 48 percent The cited emissions reductions of 0 percent (altrogen oxides) when combined with vac- (hydrocarbons and carbon monoxide) and 40 uum spark advance disconnect. Presently percent (nitrogen oxides) are estimates conavailable data suggest that deterioration sistent with the foregoing considerations and may not be significant with retrofit-type. the results obtained with precontrolled catalysts.

vehicles. Experience to date with prototype 1975 EGR and oxidizing catalytic converter emissions control systems suggests that retrofits for controlled vehicles affect differretrofit catalytic converters are capable of ent pollutants and operate independently on achieving substantial reductions of hydro- different parts of the engine. Therefore, when

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