# Control of Emissions From Nonroad Large Spark Ignition Engines, Recreational Engines (Marine and Land-Based), and Highway Motorcycles

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A00-30105

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** December 7, 2000
- **Citation:** 65 FR 76797

## Text

ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 86, 94, 1048 and 1051
[FRL-6907-6]
Control of Emissions From Nonroad Large Spark Ignition Engines, Recreational Engines (Marine and Land-Based), and Highway Motorcycles

AGENCY:

Environmental Protection Agency.

ACTION:

Advance notice of proposed rulemaking.

SUMMARY:

With this advance notice of proposed rulemaking (ANPRM), we are continuing with our process of establishing standards for nonroad engines and vehicles that cause or contribute to air pollution. The ANPRM addresses nonroad engines and vehicles that have yet to be regulated by EPA, including: Large spark ignition (SI) engines such as those used in forklifts and airport tugs; Recreational vehicles using spark ignition engines such as off-highway motorcycles, all-terrain vehicles, and snowmobiles; and Recreational marine diesel engines and marine spark ignition sterndrive and inboard engines.

These engines and vehicles contribute to ozone, carbon monoxide (CO), and particulate matter (PM) nonattainment. We are also concerned in some cases about personal exposure to high levels on CO, air toxics, and PM to persons operating or close to this equipment. With this ANPRM, we invite early input to the process to establishing standards and programs for these nonroad sources.

We are also seeking comment on whether EPA should pursue rulemaking to establish more stringent emissions standards for highway motorcycles. While standards are in place for highway motorcycles, the current standards were established more than twenty years ago. Since off-highway motorcycles are included this ANPRM as part of nonroad recreational vehicles, we believe it may be appropriate to consider standards for both types of motorcycles together.

DATES:

We request comment on this Advance Notice by February 5, 2001.

ADDRESSES:

You may send written comments in paper form and/or by e-mail. Send paper copies of written comments (in duplicate if possible) to the contact person listed below. You may also submit comments via e-mail to “nranprm@epa.gov”. In your correspondence, refer to Docket A-2000-01.

EPA's Air Docket makes materials related to this rulemaking available for review in Dockets A-2000-01 and A-98-01. These materials are located at U.S. Environmental Protection Agency (EPA), Air Docket (6102), Room M-1500, 401 M Street, SW, Washington, DC 20460 (on the ground floor in Waterside Mall) from 8:00 a.m. to 5:30 p.m., Monday through Friday, except on government holidays. You can reach the Air Docket by telephone at (202) 260-7548 and by facsimile at (202) 260-4400. We may charge a reasonable fee for copying docket materials, as provided in 40 CFR part 2.

FOR FURTHER INFORMATION CONTACT:

Margaret Borushko, U.S. EPA, National Vehicle and Fuels Emission Laboratory, 2000 Traverwood, Ann Arbor, MI 48105; Telephone: (734) 214-4334, Fax: (734) 214-4050, e-mail: borushko.margaret@epa.gov.

SUPPLEMENTARY INFORMATION:

Electronic Copies of Documents

This document is also available electronically from the EPA Internet Web site. This service is free of charge, except for any cost already incurred for internet connectivity. The electronic version of this document is made available on the day of publication on the primary web site listed below. We also publish
Federal Register
documents and related documents on the secondary web site listed below.

1.
http://www.epa.gov/docs/fedrgstr/EPA-AIR/
(either select desired date or use search feature)

2.
http://www.epa.gov/otaq/
(look in What's New or under the specific rulemaking topic)

Please note that due to differences between the software used to develop the document and the software into which the document may be downloaded, changes in format, page length, etc., may occur.

Table of Contents

I. Overview

II. Air Quality

III. Recreational Vehicles

IV. Highway Motorcycles

V. Recreational Marine Engines

VI. Large Spark Ignition Engines

VII. Public Participation

VIII. Regulatory Flexibility

IX. Administrative Designation and Regulatory Analysis

X. Statutory Provisions and Legal Authority

I. Overview

A. History of Nonroad Engine Regulations

The process of establishing standards for nonroad engines began in 1991 with a study to determine whether emissions of carbon mononxide (CO), oxides of nitrogen ( NO
X
), and volatile organic compounds (VOCs) from new and existing nonroad engines, equipment, and vehicles are significant contributors to ozone and CO concentrations in more than one area that has failed to attain the national ambient air quality standards for ozone and CO.
1

In 1994, EPA finalized its finding that nonroad engines as a whole “are significant contributors to ozone or carbon monoxide concentrations” in more than one ozone or carbon monoxide nonattainment area.
2

1
“Nonroad Engine and Vehicle Emission Study—Report and Appendices,” EPA-21A-201, November 1991 (available in Air docket A-91-24). It is also available through the National Technical Information Service, referenced as document PB 92-126960.

2
59 FR 31306 (July 17, 1994).

Upon this finding, EPA was tasked by the Clean Air Act (CAA or the Act) to establish standards for all classes or categories of new nonroad engines that cause or contribute to air quality nonattainment in more than one ozone or carbon monoxide (CO) nonattainment area. Since the finding in 1994, EPA has been engaged in the process of establishing programs to control emissions from nonroad engines used in many different applications. Nonroad categories already regulated include:

• Land-based compression ignition (CI) engines (e.g., farm and construction equipment),

• Small land-based spark-ignition (SI) engines (e.g., lawn and garden equipment, string trimmers),

• Marine engines (outboards, personal watercraft, CI commercial)

• Locomotive engines

B. Today's ANPRM

Today's ANPRM provides an initial overview of possible regulatory strategies for nonroad vehicles and engines that have yet to be regulated under EPA's nonroad engine programs. It is a continuation of the process of establishing standards for nonroad engines and vehicles, as required by CAA section 213(a)(3). If, as expected, standards for these engines and vehicles are established, essentially all new nonroad engines will be required to meet emissions control requirements. The rulemaking that begins with this ANPRM therefore is the final round of initial regulations for nonroad engines. The ANPRM covers diesel engines used in recreational marine applications. The ANPRM also covers several nonroad spark ignition (SI) engine applications, as follows:

• Land-based recreational engines (for example, engines used in snowmobiles,

off-highway motorcycles, and all-terrain vehicles (ATVs))

• Marine sterndrive and inboard (SD/I) engines
3

3
As a shorthand notation in this document, we are using “recreational marine engines” to mean recreational marine diesel engines and all gasoline SD/I engines, even though some SD/I applications could be commercial.

• Land-based engines rated over 19 kw (Large SI) (for example, engines used in forklifts); this category includes auxiliary marine engines, which are not used for propulsion.

We have found that the nonroad engines included in this ANPRM cause or contribute to air quality nonattainment in more than one ozone or carbon monoxide (CO) nonattainment area.
4

CAA section 213(a)(3) requires EPA to establish standards that achieve the greatest degree of emissions reductions achievable taking cost and other factors into account. We plan to propose emissions standards and related programs consistent with the requirements of the Act and, with this ANPRM, are seeking early input from interested parties.

4
See Final Finding, “Control of Emissions from New Nonroad Spark-Ignition Engines Rated above 19 Kilowatts and New Land-Based Recreational Spark-Ignition Engines” elsewhere in today's Federal Register for EPA's finding for Large SI engines and recreational vehicles. EPA's findings for marine engines are contained in 61 FR 52088 (October 4, 1996) for gasoline engines and 64 FR 73299 (December 29, 1999) for diesel engines.

In addition to the nonroad vehicles and engines noted above, today's ANPRM also reviews EPA requirements for highway motorcycles. The emissions standards for highway motorcycles were established twenty-three years ago. California recently adopted new emissions standards for highway motorcycles and new standards have also been proposed internationally. There may be opportunities to reduce emissions in a way that also allows manufacturers to benefit from harmonized requirements, which may reduce product lines and production costs. In addition, we believe it is important to consider the emissions standards for highway motorcycles in the context of setting standards for off-highway motorcycles. We are interested in providing regulatory programs for off-highway and highway motorcycles that are consistent, and which may also allow for the transfer of technology across product lines for manufacturers.

This ANPRM covers engines and vehicles that vary in design and use, and many readers may only be interested in one or two of the applications. There are various ways we could group the engines and present information. For purposes of this ANPRM, we have chosen to group engines by common applications (
e.g
, recreational land-based engines, marine engines, large spark ignition engines used in commercial applications). We have attempted to organize the document in a way that allows each reader to focus on the applications of particular interest. The Air Quality discussion which follows in section II is general in nature and applies to all the categories covered by the ANPRM. Sections III through VI of the ANPRM present self-contained discussions of standards and programs for each of the vehicle and engine categories. While some of the information may be repetitive among the discussions, we hope that this structure helps the reader focus on the categories and information of interest. The remaining sections VII through X are generally applicable to all of the engines and vehicles.

II. Air Quality

A. Overview

As directed by the Act, EPA has set National Ambient Air Quality Standards for, among other pollutants, ground-level carbon monoxide, ozone, NO
2
, and particulate matter.
5

States are divided into discrete areas for air quality planning purposes. Currently, 17 areas around the U.S. are classified as CO nonattainment areas. Additionally, 31 areas are not in attainment with ozone air quality standards.

5
See 42 U.S.C. 7409.

State and local governmental organizations charged with designing and implementing emission control programs to bring specific areas into attainment with these air quality standards have mounted significant efforts in recent years to reduce CO and ozone concentrations. Their state implementation plans, combined with federal stationary and mobile source emission control programs, have yielded encouraging signs of success. Emissions of the targeted pollutants have been significantly reduced in many areas. Average carbon monoxide and ozone levels, as well as the number of nonattainment areas, are beginning to decrease. We project, however, that emission increases accompanying general growth and economic expansion will eventually outpace per-source emission rate reductions. Increases in the number of sources, as well as increased use of existing sources, mean that even full implementation of current emission control programs may fall short of that needed to achieve long term attainment and maintenance of the air quality standards.

In addition to nonattainment concerns, we are also concerned about hazardous air pollutants (air toxics). In August 2000, we proposed a list of Mobile Source Air Toxics (MSATs) of concern, including those emitted from nonroad engines.
6

These pollutants are known or suspected to have serious health impacts. The engines and vehicles included in this ANPRM are sources of MSATs which are included on the proposed list, including diesel exhaust and several components of VOC emissions.

6
65 FR 48058, August 4, 2000.

B. Public Health and Welfare Concerns

The nonroad engines included in this ANPRM and highway motorcycles all contribute to air pollution with a wide range of adverse health and welfare impacts. The following sections contain a brief description of some of the health effects associated with ozone, PM, air toxics and CO and the importance of continuing to reduce the associated emissions. This section also contains a brief description of issues that are unique to the engines and vehicles being considered in this document. The NPRM will contain a more detailed discussion of the health and welfare benefits which can be expected from a program regulating these engines.

1. Ozone and its Precursors

Ground-level ozone, the main ingredient in smog, is formed by complex chemical reactions of volatile organic compounds (VOC) and nitrogen oxides ( NO
X
) in the presence of heat and sunlight. Ozone forms readily in the lower atmosphere, usually during hot, summer weather. VOCs are a broad group of compounds composed mainly of hydrocarbons (HC). Aldehydes, alcohols, and ethers are also present, but in small amounts. VOCs are emitted from a variety of sources, including motor vehicles, chemical plants, refineries, factories, consumer and commercial products, and other industrial sources. NO
X
is emitted largely from motor vehicles, nonroad equipment, power plants, and other sources of combustion.

Ozone is a highly reactive chemical compound which can damage both biological tissues and man-made materials. When inhaled, ozone can cause acute respiratory problems; aggravate asthma; cause significant temporary decreases in lung function of 15 to over 20 percent in some healthy adults; cause inflammation of lung tissue; may increase hospital admissions and emergency room visits; and impair the body's immune system defenses,

making people more susceptible to respiratory illnesses. In addition to human health effects, ozone adversely affects crop yield, vegetation and forest growth, and the durability of materials. Because ground-level ozone interferes with the ability of a plant to produce and store food, plants become more susceptible to disease, insect attack, harsh weather and other environmental stresses. Ozone causes noticeable foliar damage in many crops, trees, and ornamental plants (
i.e.,
grass, flowers, shrubs, and trees) and causes reduced growth in plants. Studies indicate that current ambient levels of ozone are responsible for damage to forests and ecosystems (including habitat for native animal species).

Besides their role as an ozone precursor, NO
X
emissions produce a wide variety of health and welfare effects.
7,8

Nitrogen dioxide can irritate the lungs and lower resistance to respiratory infection (such as influenza). NO
X
emissions are an important precursor to acid rain and may affect both land and water ecosystems. Atmospheric deposition of nitrogen leads to excess nutrient enrichment problems (“eutrophication”) in the Chesapeake Bay and several nationally important estuaries along the East and Gulf Coasts. Eutrophication can produce multiple adverse effects on water quality and the aquatic environment, including increased algal blooms, excessive phytoplankton growth, and low or no dissolved oxygen in bottom waters. Eutrophication also reduces sunlight, causing losses in submerged aquatic vegetation critical for healthy estuarine ecosystems.

7
“U.S. EPA (1995), Review of National Ambient Air Quality standards for Nitrogen Dioxide, Assessment of Scientific and Technical Information,” OAQPS Staff Paper, EPA-452/R-95-005.

8
“U.S. EPA (1993), Air Quality Criteria for Oxides of Nitrogen,” EPA/600/8-91/049aF.

Need for NO
X

and VOC Control.
Photochemical modeling highlights the fact that ozone pollution is a regional problem, not simply a local or state problem. Ozone and its precursors are transported long distances by winds and other meteorological events. Thus, achieving ozone attainment for an area, and thereby protecting its citizens from ozone-related health effects, often depends on the ozone and precursor emission levels of upwind areas. For many areas with persistent ozone problems, attainment of the ozone NAAQS will require control strategies for both NO
X
and VOC that extend beyond the areas' boundaries.

We expect that reducing NO
X
and HC emissions from engines that would be regulated under this potential program would help reduce the health and welfare effects of ozone.
9

Manufacturers and users of snowmobiles provided comments during the “finding” rulemaking indicating that snowmobiles should not be regulated for ozone precursors because snowmobiles are used during cold weather, when ozone is less of a health concern.
10

However, ozone precursors are also responsible for other pollution problems including air toxics, discussed below, and indirect PM. We are examining the need to reduce precursors of ozone in the context of this rulemaking and request comment. In particular, we request comment on whether EPA should distinguish snowmobiles from other recreational vehicles in regulating ozone precursors and whether emissions of ozone precursors such as NO
X
and VOC should in any case be regulated due to other pollution problems.

9
The emissions inventory contributions for these sources are provided in the Final Finding document referenced in footnote 4.

10
International Snowmobile Manufacturers Association, Docket A-98-01, document IV-D-03.

2. Particulate Matter

Particulate matter (PM) is the general term used for a mixture of solid particles and liquid droplets found in the air. These particles, which come in a wide range of sizes, originate from many different stationary and mobile sources as well as from natural sources. They may be emitted directly by a source (direct emissions) or formed in the atmosphere by the transformation of gaseous precursor emissions such as sulphur dioxide (SO
2
), nitrogen oxides (NO
X
), or organic compounds (secondary particles). Their chemical and physical compositions vary depending on source location, time of year and meteorology.

Scientific studies show a link between inhalable PM (alone, or combined with other pollutants in the air) and a series of significant health effects. Inhalable PM includes both fine and coarse particles. Fine particles can be generally defined as those particles with an aerodynamic diameter of 2.5 microns or less (also known as PM
2.5
), and coarse particles are those with an aerodynamic diameter between 2.5 and 10 microns. All particles 10 microns or smaller are called PM
10
. The health and environmental effects of PM are strongly related to the size of the particles.

Diesel particles are a component of both coarse and fine PM, but fall mostly in the fine range. Both coarse and fine particles can accumulate in the respiratory system and are associated with numerous health effects. Exposure to coarse fraction particles is primarily associated with the aggravation of respiratory conditions such as asthma. Fine particles are more deeply inhaled into the lungs than course particles. They are most closely associated with such health effects as decreased lung function, increased hospital admissions and emergency room visits, increased respiratory symptoms and disease, and premature death. Sensitive groups that appear to be at greatest risk to such effects include the elderly, individuals with cardiopulmonary disease such as asthma, and children.

In addition, PM causes adverse impacts to the environment. Fine PM is the major cause of reduced visibility in parts of the United States, including many of our National Parks. Other environmental impacts occur when particles deposit onto soils, plants, water or materials. For example, particles containing nitrogen and sulphur that deposit on to land or water bodies may change the nutrient balance and acidity of those environments. An ecosystem condition known as “nitrogen saturation,” where addition of nitrogen to soil over time exceeds the capacity of the plants and microorganisms to utilize and retain the nitrogen, has already occurred in some areas of the United States. When deposited in sufficient quantities such as near unpaved roads, tilled fields, or quarries, particles block sunlight from reaching the leaves, stressing or killing plants. Finally, PM causes soiling and erosion damage to materials, including culturally important objects such as carved monuments and statues.

Recreational marine diesel engines tend to be concentrated in specific areas of the country (ports, coastal areas, lakes and rivers), so the emissions contribution of these engines in local areas can be more important. Consequently addressing PM and other emissions from recreational marine diesel engines can be an important tool toward the goal of reducing health and environmental hazards.

Considerations For PM From Recreational Two-Stroke Gasoline Engines.
Two-stroke engines used in land-based recreational vehicles generally use a fuel and oil mixture to both produce power while lubricating the engine. As much as 30 percent of the intake charge passes through the engine unburned and exhausts to the atmosphere. As a consequence, PM emissions from these engines can be very high. Two stroke gasoline engines are commonly used in off-highway motorcycles and snowmobiles.

Snowmobile engine emissions are of particular concern in environmentally

sensitive areas, such as Yellowstone National Park. Snowmobiles are typically powered by 2-stroke engines that have high emissions of hydrocarbons (HC), carbon monoxide (CO) and PM compared to 4-stroke engines. Recent studies have concluded that particulate emission rates from a snowmobile engine are more comparable to those of older, pre-control diesel engines.
11,12

Particle diameters were found to be typically less than 0.1 microns, which is of respirable size and able to be delivered into the deepest and most sensitive areas of the human lung. While formation rates of secondary PM may be lower in the winter months, PM concentrations can be elevated under some meteorological conditions (
e.g.,
low mixing heights). We request comment on the health benefits of reducing PM emissions from recreational vehicle 2-stroke gasoline engines.

11
“Characterization of Snowmobile Particulate Emissions conducted for Yellow Stone Park Foundation Inc.,” James N. Carroll and Jeff J. White, Southwest Research Institute, June 1999.

12
“Emissions from Snowmobile Engines using bio-based fuels and lubricants conducted for the Montana department of Environmental Quality,” Jeff J. White and James N. Carroll, Southwest Research Institute, October 1998.

3. Air Toxics

These engines are also sources of a number of chemical species which we have proposed to list as mobile source air toxics (MSATs), that are known or suspected human or animal carcinogens, or have serious noncancer health effects.
13

They include pollutants such as diesel exhaust, benzene, 1,3-butadiene, formaldehyde, acetaldehyde, and acrolein, described in more detail below. While the harmful effects of air toxics are of particular concern in areas closest to where they are emitted, they can also be transported and affect other geographic areas. Some can persist for considerable time in the environment.

13
65 FR 48058, August 4, 2000.

Many of the air toxics discussed below are components of VOC and we expect that the HC standards discussed in this document would reduce exposure to air toxics and therefore reduce the incidence of cancer and noncancer health effects related to emissions from these engines. We request comment on the need to control air toxics emissions from the engines and vehicles included in this document.

Considerations for Diesel Exhaust
. Diesel exhaust emissions are a by-product of incomplete combustion and include gaseous and particulate components. Gaseous components of diesel exhaust include organic compounds, sulfur compounds, carbon monoxide, carbon dioxide, water vapor, and excess air (nitrogen and oxygen). Particulate components include many organic compounds that are mutagenic as well as several trace metals (including chromium, manganese, mercury and nickel) that may have general toxicological significance (depending on the specific chemical species). In addition, small amounts of dioxins have been measured in diesel exhaust, some of which may partition to the particle phase.

Because the chemical composition of diesel exhaust includes hazardous air pollutants, or air toxics, diesel exhaust emissions are of concern to the agency. There have been health studies specific to diesel exhaust emissions which indicate potential hazards to human health that appear to be specific to this emissions source. For chronic exposure, these hazards include respiratory system toxicity and carcinogenicity. Acute exposure also causes transient effects (a wide range of physiological symptoms stemming from irritation and inflammation mostly in the respiratory system) in humans though they are highly variable depending on individual human susceptibility.

The EPA draft Health Assessment Document for Diesel Exhaust was reviewed in a public session by the Clean Air Scientific Advisory Committee (CASAC) of EPA's Science Advisory Board on October 12-13, 2000.
14

The CASAC, in public session, found that the Agency's conclusion that diesel exhaust is likely to be carcinogenic to humans by inhalation, was scientifically sound. The comments provided by CASAC on the draft Assessment are being incorporated into the final Assessment to be released in late 2000 or early 2001. California EPA has identified diesel PM as a toxic air contaminant.
15

Several other agencies and governing bodies have also designated diesel exhaust or diesel PM as a “potential” or “probable” human carcinogen.
16,17,18

The International Agency for Research on Cancer (IARC) considers diesel exhaust a “probable” human carcinogen and the National Institutes for Occupational Safety and Health have classified diesel exhaust a “potential occupational carcinogen”. Thus, the concern for the health hazard resulting from diesel exhaust exposures is widespread. We request comment on the health benefits of reducing PM emissions from marine diesel engines.

14
U.S. EPA(2000) Health Assessment Document for Diesel Exhaust: SAB Review Draft EPA/600/8-90/057 Office of Research and Development, Washington, D.C. The document is available electronically at www.epa.gov/ncea/dieslexh.htm.

15
“Proposed Identification of Diesel Exhaust at a Toxic Air Contaminant, Health risk assessment for diesel exhaust,” California Environmental Protection Agency, April 1998.

16
“Carcinogenic effects of exposure to diesel exhaust,” NIOSH Current Intelligence Bulletin 50. DHHS, Publication No. 88-116, 1988.

17
“Diesel and gasoline engine exhausts and some nitroarenes,” Vol. 46, Monographs on the evaluation of carcinogenic risks to humans, International Agency for Research on Cancer, World Health Organization, 1989.

18
“Diesel fuel and exhaust emissions: International program on chemical safety,” World Health Organization, 1996.

Benzene
. Benzene is an aromatic hydrocarbon which is present as a gas in both exhaust and evaporative emissions from motor vehicles. Benzene in the exhaust expressed as a percentage of total organic gases (TOG), varies depending on control technology (e.g., type of catalyst) and the levels of benzene and aromatics in the fuel, but is generally about four percent from gasoline engines. The benzene fraction of gasoline evaporative emissions also depends on control technology (i.e., fuel injector or carburetor) and fuel composition (e.g. benzene level and Reid Vapor Pressure or RVP) and is generally about one percent.

The EPA has recently reconfirmed that benzene is a known human carcinogen by all routes of exposure (including leukemia at high, prolonged air exposures), and is associated with additional health effects including genetic changes in humans and animals and increased proliferation of bone marrow cells in mice.
19

Respiration is the major source of human exposure. Long-term exposure to high levels of benzene in the air has been shown to cause cancer of the tissues that form white blood cells. Among these are acute nonlymphocytic leukemia, chronic lymphocytic leukemia and possibly multiple myeloma (primary malignant tumors in the bone marrow). A number of adverse noncancer health effects, blood disorders such as preleukemia and aplastic anemia, have also been associated with low-dose, long-term exposure to benzene. People with long-term exposure to benzene may experience harmful effects on the blood-forming tissues, especially the bone marrow. Many blood disorders associated with benzene exposure may occur without symptoms.

19
“U.S. EPA, Carcinogenic Effects of Benzene: An Update,” National Center for Environmental Assessment, Washington, D.C. 1998.

OSHA recently conducted an industrial hygiene survey to examine park employee exposures during winter

at Yellowstone National Park.
20

They reported exposure to benzene above the NIOSH recommended exposure levels (REL) of 0.10 ppm. Since exhaust emission benzene levels generally decrease as HC emissions decrease, we expect new emission control technology to substantially reduce ambient benzene levels.

20
“U.S. Department of Labor, Industrial Hygiene Survey of Park Employee Exposures During Winter Use at Yellowstone National Park,” February, 2000.

1,3-Butadiene
. 1,3-butadiene is formed in engine exhaust by incomplete combustion of fuel. It is not present in evaporative and refueling emissions, because it is not present in any appreciable amount in gasoline fuel. 1,3-butadiene accounts for 0.4 to 1.0 percent of total exhaust TOG, depending on control technology and fuel consumption. Nonroad mobile sources contribute 15.2 percent to the 1,3-butadiene inventory (baseline NTI).

The Environmental Health Committee of EPA's Scientific Advisory Board (SAB), in reviewing the draft document, issued a majority opinion that 1,3-butadiene should be classified as a probable human carcinogen.
21,22

The Agency has revised the draft Health Risk Assessment of 1,3-butadiene based on the SAB and public comments. The draft Health Risk Assessment of 1,3-butadiene will undergo the Agency consensus review, during which time additional changes may be made prior to its public release and placement on the Integrated Risk Information System (IRIS).

21
“U.S. EPA Health Risk Assessment of 1,3-Butadiene,” EPA/600/P-98/001A, February 1998.

22
“An SAB Report: Review of the Health Risk Assessment of 1,3-Butadiene,” EPA-SAB-EHC-98, August 1998.

Formaldehyde
. Nonroad mobile sources contribute 23 percent to the formaldehyde inventory (baseline NTI). EPA has classified formaldehyde as a probable human carcinogen based on evidence in humans and in rats, mice, hamsters, and monkeys.
23

Epidemiological studies in occupationally exposed workers suggest that long-term inhalation of formaldehyde may be associated with tumors of the nasopharyngeal cavity, nasal cavity and sinus. Formaldehyde exposure also causes a range of noncancer health effects, including irritation of the eyes (tearing of the eyes and increased blinking) and mucous membranes. Sensitive individuals may experience these adverse effects at lower concentrations than the general population. In persons with bronchial asthma, the upper respiratory irritation caused by formaldehyde can precipitate an acute asthmatic attack.

23
“U.S. EPA Assessment of health risks to garment workers and certain home residents from exposure to formaldehyde,” Office of Pesticides and Toxic Substances, April 1987.

The OSHA industrial hygiene survey at Yellowstone, described above, reported exposure to formaldehyde at 0.033 ppm, which is above the NIOSH recommended exposure level of 0.016 ppm.

Acetaldehyde
. Nonroad mobile source emissions are responsible for 27 percent of the total acetaldehyde inventory (Baseline NTI). Acetaldehyde is classified as a probable human carcinogen and humans are exposed by inhalation, oral, and intravenous routes. The primary acute effect of exposure to acetaldehyde vapors is irritation of the eyes, skin and respiratory tract. At high concentrations, irritation and pulmonary effects can occur, which could facilitate the uptake of other contaminants.

Acrolein
. Nonroad mobile source emissions are responsible for 11 percent of the total acrolein invenory (Baseline NTI). Acrolein is extremely toxic to humans when inhaled, with acute exposure resulting in upper respiratory tract irritation and congestion. The Agency has developed a reference concentration for inhalation (RfC) of acrolein of 0.02 micrograms/m
3
. Although no information is available on its carcinogenic effects in humans, EPA considers acrolein a possible human carcinogen based on laboratory animal data.
24

24
“U.S. EPA Integrated Risk Assessment System (IRIS),” Office of Health and Environmental Assessment, Cincinnati, OH, 1993.

4. Carbon Monoxide (CO)

Carbon monoxide (CO) is a colorless, odorless gas produced through the incomplete combustion of carbon-based fuels. Carbon monoxide enters the bloodstream through the lungs and reduces the delivery of oxygen to the body's organs and tissues. The health threat from CO is most serious for those who suffer from cardiovascular disease, particularly those with angina or peripheral vascular disease. Healthy individuals also are affected, but only at higher CO levels. Exposure to elevated CO levels is associated with impairment of visual perception, work capacity, manual dexterity, learning ability and performance of complex tasks.

Several recent epidemiological studies have shown a link between CO and premature morbidity (including angina, congestive heart failure, and other cardiovascular diseases). Several studies in the United States and Canada have also reported an association of ambient CO exposures with frequency of cardiovascular hospital admissions, especially for congestive heart failure (CHF). An association of ambient CO exposure with mortality has also been reported in epidemiological studies, though not as consistently or specifically as with CHF admissions. EPA is reviewing these studies as part of the CO Criteria Document process.

The toxicity of CO effects on blood, tissues and organs have also been topics of substantial research efforts. Such studies provided information for establishing the NAAQS for CO. The current primary NAAQS for CO are 35 parts per million for the one-hour average and 9 parts per million for the eight-hour average. There are currently 17 designated CO nonattainment areas, with a combined population of 31 million. EPA estimated that emissions from nonroad gasoline engines and vehicles have increased by 24 percent from 1980 to 1998.
25

25
U.S. EPA (March 2000). “National Air Pollutant Emission Trends, 1900-1998,” Office of Air Quality and Standards.

In addition to concerns related to air quality standards for broad areas, exhaust emissions from indoor applications can cause CO poisoning from individual human exposure. These engines (for example, engines used in forklifts) routinely operate in warehouses and production facilities. Unregulated industrial SI engines frequently have exhaust CO concentrations over 30,000 ppm (3 percent). The maximum allowable time-weighted average 8-hour workplace exposure set by the Occupational Safety and Health Administration is 50 ppm. Manufacturers in some cases may adjust engine calibration for somewhat lower CO emission levels. Also, engines used indoors are often fueled with LPG, which typically has lower CO exhaust concentrations than gasoline-fueled engines. However, improper maintenance or poor calibrations can lead to even higher levels than the 30,000 ppm level noted above from any industrial SI engine.

The typical snowmobile, which utilizes a two-stroke engine, produces significantly more CO than a modern automobile on a unit of work basis. There has been an increasing concern that snowmobile emissions in and around some national parks are reaching significant levels. During the winters of 1994-95 and 1995-96, studies were conducted at Yellowstone, Flagg Ranch, and Grand Teton National Park which indicated that snowmobile tourists are potentially exposed to significant CO

levels.
26

While the studies did not record official exceedances of the CO NAAQs, levels near and in some cases above the 35 ppm NAAQS standard were observed. These measurements were not considered NAAQS exceedances because sampling methods and measurement locations did not meet the criteria for NAAQS measurements. However, the measurements were reported to be scientifically valid and an indication of potentially significant exposure to CO.

26
Exposure to Snowmobile Riders to Carbon Monoxide, Park Science Volume 17—No. 1, National Park Service, U.S. Department of the Interior.

A study of snowmobile rider exposure conducted at Grand Teton National Park showed that CO levels when trailing a single snowmobile at distances of 25-125 feet at speeds of 10-40 mph ranged from 0.5-23 ppm, with a maximum level of 45 ppm (as compared to the current NAAQS for CO of 35 ppm).
27

Since snowmobile riders typically travel in large groups, the riders towards the back of the group are likely to experience significantly higher exposures to CO. An additional consideration is that the risk to health from CO exposure increases with altitude, especially for un-acclimated individuals. Therefore, a park visitor who lives at sea level and then rides his or her snowmobile on trails at high-altitude is more susceptible to the effects of CO than local residents. In addition, the OSHA industrial hygiene survey mentioned earlier reported a peak CO exposure of 268 ppm for a Yellowstone employee, in exceedance of the NIOSH peak recommended exposure limit of 200 ppm.

27
Snook and Davis, 1997, “An Investigation of Driver Exposure to Carbon Monoxide While Traveling Behind Another Snowmobile.”

The U.S. Coast Guard reported cases of CO poisoning caused by recreational boat usage.
28

These Coast Guard investigations into recreational boating accident reports between 1989 to1998, show that 57 accidents were reported, totaling 87 injuries and 32 fatalities, that involved CO poisoning. We believe that controlling CO emissions from marine engines could provide some benefits to boaters.

28
Summarized in an e-mail Phil Cappel of the U.S. Coast Guard to Mike Samulski of the U.S. Environmental Protection Agency, October 19, 2000.

C. National Emissions Inventory

We have estimated the contribution of the sources included in this ANPRM to the nationwide emissions inventories for the 2000 and 2007 calendar years, as shown in Table II-1.
29

29
Inventory data is further provided in Tables 1 and 2 of the Final Finding (see footnote 4).

Table II-1.—Estimated Nationwide Annual Emission Levels
[in thousand short tons (percent of mobile source inventory)]

NO
X

Tons
Percent
HC
Tons
Percent
CO
Tons
Percent
PM
Tons
Percent

Year 2000:

Nonroad Sources in ANPRM
371
2.8
822
11.0

7,15
7

9.0
8.4
1.2

Highway Motorcycles
22
0.2
21
0.3
147
0.2
0.4
0.1

Year 2000 Total
393
3.0
843
11.3

7,30
4

9.2
8.8
1.3

Year 2007:

Nonroad Sources in ANPRM
444
4.3
870
16.6

7,53
6

9.7
9.2
1.5

Highway Motorcycles
25
0.2
26
0.5
171
0.2
0.5
0.1

Year 2007 Total
469
4.5
896
17.1

7,70
7

9.9
9.7
1.6

III. Recreational Vehicles

A. Background

1. What Recreational Vehicles Would be Included in This Rulemaking?

The vast majority of vehicles that fall into the land-based recreational vehicles category are snowmobiles, off-highway motorcycles (e.g., dirt bikes), and all terrain vehicles (ATVs).
30

The engines used in these vehicles are a subset of nonroad SI engines.
31

Engines used in recreational vehicles include both Small SI (at or below 19 kW) and Large SI engines (above 19 kW). These engines, however, were excluded from our Small SI program (for lawn mowers, chain saws, etc.) because they have different design characteristics and usage patterns than other engines in the Small SI category. This suggests that the recreational engines covered by this ANPRM should be tested differently than Small SI engines. We would similarly expect to treat them separately from our Large SI engine program (discussed later in this ANPRM). We therefore request comment on whether engines used in recreational vehicles should be tested and regulated differently from other small and Large SI engines.

30
ATVs are typically four-wheeled vehicles that are straddled by the operator.

31
Almost all recreational vehicles are equipped with SI engines. Any diesels used in these applications must meet our nonroad diesel engine standards.

In our rulemaking regulating Small SI engines (defined as nonroad SI engines below 19 kW), we established criteria that effectively excluded the types of engines used in the recreational vehicles listed above.
32

These criteria, such as normal range of operating engine rpm, can greatly affect the basic engine design and the opportunities for emissions control. Engines used in some other types of recreational vehicles may be covered by the Small SI standards, depending on the characteristics of the engines. For example, lawnmower-type engines used in go carts would typically be covered by the Small SI standards. Engines used in golf carts are also typically included in the Small SI program due to their design and

operating characteristics being similar to lawnmower-type applications.

32
See 40 CFR 90.1(b)(5) for the list of criteria.

There may be other types of recreational vehicles that should be included in the recreational vehicles program in addition to snowmobiles, off-highway motorcycles, and ATVs. For example, some small mopeds or motor scooters could be included in the program depending on their characteristics.
33

We are interested in information and request comment about other types of vehicles that may exist so that we may consider them in developing our proposals.

33
The definition of motor vehicle excludes “any vehicle that cannot exceed a maximum speed of 25 miles per hour over level, paved surfaces” (see 40 CFR 85.1703(a)(1)). Such vehicles are therefore considered nonroad vehicles.

There may be some uncertainty surrounding the use of “recreational” in distinguishing between vehicle types and in determining which set of standards a vehicle or engine must meet. ATVs, for example, may have some utility aspects to their use. We request comment how to best differentiate among engines types. We could establish a definition for “recreational”, for example, based on the primary intended use of the vehicle model. Under such an approach, vehicles primarily intended for utility or work use by the manufacturer would be part of either the Small or Large SI programs, as applicable. We could also differentiate engines based solely upon engine design and operating characteristics without regard to usage; this option might eliminate potential confusion over whether a particular engine should be appropriately certified as a “recreational” or “utility” engine.

Hobby engines.
The Small SI rule categorized engines used in model cars, boats, and airplanes as recreational engines and exempted them from the Small SI program.
34

Historically, we have exempted hobby engines from our regulations. The nonroad diesel engine final rule exempted hobby engines due to feasibility, testing, and compliance concerns related to regulating such small engines. Also noted in the nonroad diesel engine rule, because hobby engines are very small with very low power output relative to other nonroad engines and have low annual usage rates, they contribute very little to emissions inventories.
35

We request comment on how to proceed for SI hobby engines, including data and information that would allow us to further consider the potential for establishing standards for them or for exempting them from this rule.

34
80 FR 24292, April 25, 2000.

35
63 FR 56971, October 23, 1998.

2. Who Makes Recreational Vehicles?

Based on industry information available to us, the recreational vehicle industry appears to be dominated by eight manufacturers. Of these eight manufacturers, seven of them manufacture a combination of two or more of the three recreational vehicle sub-categories: off-highway motorcycles, ATVs, and snowmobiles. For example, there are four major companies that manufacture both off-highway motorcycles and ATVs. There are three major companies that manufacture ATVs and snowmobiles and one major company that manufactures all three. These eight companies represent approximately 95 percent of all domestic sales of recreational vehicles.

We are aware of five major companies that dominate sales of off-highway motorcycles. Four of these companies, Honda, Kawasaki, Suzuki, and Yamaha, are long established, major corporations that manufacture a number of products including highway and off-highway motorcycles. They have dominated the off-highway motorcycle market for over thirty years. The fifth major company, KTM, is also long established but has had a major impact in domestic sales over the last 10 to 15 years. These five companies account for approximately 90 to 95 percent of all domestic sales for off-highway motorcycles. There are also several relatively small companies that manufacture off-highway motorcycles, many of which specialize in racing or competition machines.

Based on available industry information, four major manufacturers, Arctic Cat, Bombardier (also known as Ski-Doo), Polaris, and Yamaha, account for approximately 99 percent of all domestic snowmobile sales. The remaining percent comes from very small manufacturers who tend to specialize in unique designs or racing machines. The ATV sector has the broadest assortment of major manufacturers. With the exception of KTM, all of the companies noted above for off-highway motorcycles and snowmobiles are significant ATV producers. These seven companies represent over 95 percent of total domestic ATV sales. The remaining 5 percent come from importers who tend to import inexpensive, youth-oriented ATVs from China and other Asian nations.

3. What Types of Engines Are Used in the Vehicles?

The engines used in recreational vehicles tend to be small, air- or liquid-cooled, reciprocating Otto-cycle engines that operate on gasoline.
36

They are designed to be used in vehicles, where engine performance is characterized by highly transient operation, with a wide range of engine speed and load capability. Maximum engine speed is typically well above 5,000 rpm. Also, the vehicles are equipped with transmissions to ensure performance under a variety of operating conditions.

36
Otto cycle is another name for a spark-ignition engine which utilizes a piston with homogenous external or internal air and fuel mixture formation and spark ignition.

These engines can be separated into two-stroke and four-stroke designs. The distinction between two-stroke and four-stoke engines is important for emissions because two-stroke engines tend to emit much greater amounts of unburned hydrocarbons (HC) and particulate matter (PM) than four-stroke engines of similar size and power. Two-stroke engines also have greater fuel consumption resulting in poorer fuel economy than four-stroke engines, but they also tend to have higher power output per unit displacement, lighter weight, and better cold starting performance. These advantages combined with a simple design and lower manufacturing costs tend to make two-stroke engines a popular choice as the power unit for recreational vehicles. Currently, snowmobiles use two-stroke engines almost exclusively, whereas about 63 percent of all off-highway motorcycles (predominantly in high performance, youth, and entry-level bikes) and 12 percent of all ATVs sold in the United States use two-stroke engines. Engine displacement for off-highway motorcycles and ATVs typically range from 50 cubic centimeters (cc) to 500 cc for two-stroke engines, and 50 cc to 650 cc for four-stroke engines. Snowmobile engines range from 100 cc to over 1,000 cc.

The basis for the differences in engine and exhaust emissions performance between two-stroke and four-stroke engines can be found in the fundamental differences in how two-stroke and four-stroke engines operate. Four-stroke operation takes place in four distinct steps: intake, compression, power, and exhaust. Each step corresponds to one up or down “stroke” of the piston or 180° of crankshaft rotation. The first step of the cycle is for an “intake” valve in the combustion chamber to open during the intake stroke allowing a mixture of air and fuel to be drawn into the cylinder while the piston moves down the cylinder. The intake valve then closes and the momentum of the crankshaft causes the

piston to move back up the cylinder compressing the air and fuel mixture. At the very end of the compression stroke, the air and fuel mixture is ignited by a spark from a spark plug, and begins to burn. As the air and fuel mixture burns, increasing temperature and pressure cause the piston to move back down the cylinder. This is referred to as the “power” stroke. At the bottom of the power stroke, an exhaust valve opens in the combustion chamber and as the piston moves back up the cylinder, the burnt gases are pushed out through the exhaust valve to the exhaust manifold, and the cycle is complete.

In a four-stroke engine, combustion and the resulting power stroke only occur once every two revolutions of the crankshaft. In a two-stroke engine, on the other hand, combustion occurs in every revolution of the crankshaft. Two-stroke engines eliminate the intake and exhaust strokes, leaving only compression and power strokes. This is due to the fact that two-stroke engines do not use intake and exhaust valves. Instead, they have intake and exhaust “ports” in the sides of the cylinder walls. With a two-stroke engine, as the piston approaches the bottom of the power stroke, it uncovers exhaust ports in the wall of the cylinder. The high pressure combustion gases blow into the exhaust manifold. As the piston gets closer to the bottom of the power stroke, the intake ports are uncovered, and fresh mixture of air and fuel are forced into the cylinder while the exhaust ports are still open. Exhaust gas is “scavenged” or forced into the exhaust by the pressure of the incoming charge of fresh air and fuel. In the process, however, some mixing between the exhaust gas and the fresh charge of air and fuel takes place, so that some of the fresh charge is also emitted in the exhaust. The loss of part of the fuel out of the exhaust during scavenging is one of the major reasons for the very high hydrocarbon emission characteristics of two-stroke engines. The other major reason for high HC emissions from two-stroke engines is their tendency to misfire under low load conditions due to greater combustion instability.

4. What Are the Pollutants of Interest for Each Type of Vehicle?

Recreational vehicles utilizing two-stroke engines, such as snowmobiles and some models of off-highway motorcycles and ATVs, emit significant quantities of fine particulate matter (PM), unburned hydrocarbons (HC), and carbon monoxide (CO). Recreational vehicles utilizing four-stroke engines, such as some models of off-highway motorcycles and most ATVs, also emit significant quantities of CO, however, they tend to emit considerably lower levels of HC and PM than their two-stroke counterparts. Both engine types emit oxides of nitrogen ( NO
X
). Two-stroke engines tend to emit very low levels of NO
X
whereas four-stroke engines emit greater quantities, similar to four-stroke HC emission levels. Exhaust hydrocarbon emissions also include significant quantities of toxic air contaminants including benzene, formaldehyde, acetaldehyde, and 1,3 butadiene. The most important source of recreational vehicle emissions is the engine exhaust, but HC emissions are also produced from the crankcase in four-stroke engines, by evaporation from the fuel system, and by vapor displacement during refueling.

5. What Programs Are in Place in California and Elsewhere To Control Emissions from Recreational Vehicles?

California established standards for off-highway motorcycles and ATVs which took effect in January 1997 (1999 for vehicles with engines of 90 cc or less). The standards, shown in Table III-1, are based on the highway motorcycle chassis test procedures. Manufacturers may certify ATVs to optional standards, also shown in Table III-1, which are based on the utility engine test procedure.
37

This is the test procedure over which Small SI engines are tested. The stringency level of the standards was based on the emissions performance of 4-stroke engines and advanced 2-stroke engines equipped with a catalytic converter. California anticipated that the standards would be met initially through the use of high performance 4-stroke engines.

37
Notice to Off-Highway Recreational Vehicle Manufacturers and All Other Interested Parties Regarding Alternate Emission Standards for All-Terrain Vehicles, Mail Out #95-16, April 28, 1995, California Air Resources Board (Docket A-2000-01, document II-D-06).

Table III-1.—California Off-Highway Motorcycle and ATV Standards for Model Year 1997 and Later
[1999 and later for engines at or below 90 cc]

HC

NO
X

CO
PM

Off-highway motorcycle and ATV standards (g/km)

a
1.2

15

HC + NO
X

CO
PM

Optional standards for ATV engines below 225 cc (g/bhp-hr)

a
10.0

300

Optional standards for ATV engines below 225 cc (g/bhp-hr)

a
12.0

300

Optional standards for ATV engines at or above 225 cc (g/bhp-hr)

a
10.0

300

a
Corporate-average standard.

California revisited the program in the 1997 time frame because a lack of certified product from manufacturers was reportedly creating economic hardship for dealerships. The number of certified off-highway motorcycle models was particularly inadequate.
38

In 1998, California revised the program, allowing the use of uncertified products in off-highway vehicle recreation areas with regional/seasonal use restrictions. Currently, noncomplying vehicles can be legally sold in California and used in attainment areas year-round and in nonattainment areas during months when exceedances of the state ozone standard are not expected. For enforcement purposes, certified and uncertified products are identified respectively with green and red stickers. Only about one-third of off-highway motorcycles sold in California are certified. All certified products are powered by 4-stroke engines.

38
Initial Statement of Reasons, Public Hearing to Consider Amendments to the California Regulations for New 1997 and Later Off-highway Recreational Vehicles and Engines, State of California Air Resources Board, October 23, 1998 (Docket A-2000-01, II-D-08).

California has not adopted standards for snowmobiles. In addition, EPA is not aware of emission control programs for nonroad recreational vehicles that have been adopted in other countries.

B. Technology

1. What Are the Baseline Technologies and Emissions Levels?

As discussed earlier, recreational vehicles are equipped with relatively small high performance two- or four-stroke engines that are either air- or liquid-cooled.
39

The fuel system used on these engines are almost exclusively carburetors. Two-stroke engines lubricate the piston and crankshaft by mixing oil with the air and fuel mixture. This is accomplished by most contemporary 2-stroke engines with a pump that sends two-cycle oil from a separate oil reserve to the carburetor where it is mixed with the air and fuel mixture. Some less expensive two-stroke engines require that the oil be mixed with the gasoline in the fuel tank. Four-stroke engines inject oil via a pump throughout the engine as the means of lubrication. With the exception of those vehicles certified in California, most of these engines are unregulated and thus have no emission controls. In fact, because performance and durability are such important qualities for recreational vehicle engines, they all operate with a “rich” air and fuel mixture. That is, they operate with excess fuel, which enhances performance and allows engine cooling which promotes longer lasting engine life. However, rich operation results in high levels of HC, CO, and PM emissions. Also, two-stroke engines tend to have high scavenging losses, where up to a third of the unburned air and fuel mixture goes out of the exhaust resulting in high levels of raw HC.

39
The engines are small relative to automotive engines. For example, automotive engines typically range from one liter to well over five liters in displacement, whereas off-highway motorcycles would range from 0.05 liters to 0.65 liters.

Table III-2.—Typical Range of Exhaust Emissions for Recreational Vehicles

Recreational vehicle type
Engine type
HC
CO

NO
X

PM
Units

Snowmobiles
2-stroke
67-200
196-400
0.3-1.62
0.7-6.1
g/hp-hr

Off-highway Motorcycles/ATVs
2-stroke
8-26
16-37
0.01-0.1
0.002-0.025

g/km
a

4-stroke
0.4-3
7-50
0.03-0.2
0.006-0.025
g/km

a
Emission measurement for motorcycles is in grams per kilometer rather than grams per mile because the motorcycle industry, as well as Federal, California, and international motorcycle emission standards use “Système International d'Unitès” or SI units, which measure distance in kilometers rather than miles.

2. What Technology Approaches Are Available To Control Emissions?

A number of approaches are available to control emissions from recreational vehicles. The simplest approach would consist of modifications to the base engine, fuel system, cooling system, and recalibration of the air and fuel mixture. These could, for example, consist of changes to valve timing for four-stroke engines, changing from air to liquid cooling, and the use of advanced carburetion techniques and electronic fuel injection (EFI) in lieu of traditional carburetion systems. Other approaches could include using an oxidation catalyst alone or in conjunction with secondary air. The engine technology that may have the most potential for maximizing emission reductions from two-stroke engines is the use of direct fuel injection (DI). Direct fuel injection is able to reduce or even eliminate scavenging losses by pumping only air through the engine and then injecting fuel into the combustion chamber after the intake and exhaust ports have closed. The use of oxidation catalysts in conjunction with direct injection could potentially reduce emissions even further. Finally, because four-stroke engines emit significantly lower levels of HC than two-stroke engines, the conversion of two-stroke engine technology to four-stroke engine technology could be a desirable approach.

We request comment as to whether there are any other approaches to emission reduction for recreational vehicles that have not been discussed here. We are interested in information on feasibility, cost and corresponding emission reduction potential, and other issues associated with the above and other technologies. Specifically, we request comment on the effectiveness and durability of oxidation catalysts for these applications, the cost, corresponding emission reductions, and feasibility of direct fuel injection for two-stroke engine applications, and the cost and feasibility of switching from 2-stroke to 4-stroke engines. Any data on engines similar to those used in recreational equipment using these technologies is also requested.

3. What Level of Control May Be Feasible?

Calibration changes and engine modifications can reduce HC and CO emissions somewhat, in the range of 10 to 30 percent. While the precise level of control anticipated from recreational vehicles is not yet known, further HC reductions in the 70 to 90 percent range may be achievable from current two-stroke engines. We expect that the bulk of the HC reductions would occur through the elimination of scavenging losses, with additional reductions possible through the use of an oxidation catalyst. Because four-stroke engines already have low HC emissions relative to two-stroke engines, we would expect more modest HC reductions from four-stroke engines as a result of new emission standards. Control strategies that would reduce HC emissions would also generally reduce PM and toxics. This is especially true for 2-stroke engines where high levels of PM and toxics are the result of scavenging losses.

We believe that similar levels of control can be expected for CO emissions as for HC emissions. The bulk of CO reductions will come from improvements to the fuel system, either through enleanment (i.e., less fuel) of the air and fuel mixture, from now on referred to as A/F ratio, or the improvement of fuel atomization (i.e., smaller fuel droplets), with additional reductions possible through the use of an oxidation catalyst.
40-41

Such strategies are also likely to reduce HC and PM emissions as well.

40-41
Fuel atomization refers to the size of individual fuel droplets. The smaller the fuel droplet is, the better it is combusted or burned.

The NO
X
levels emitted from recreational vehicles, especially for those equipped with two-stroke engines, are very low since most recreational vehicles typically operate using a “rich” calibration (i.e., with excess fuel) for performance and durability purposes.

Some emission reduction techniques such as changes in engine design and calibration aimed at reducing HC and CO emissions may increase NO
X
. However, we expect that any increases

resulting from HC and CO standards would be minimal. To ensure continued low NO
X
performance, we request comment on the appropriateness of setting a capping standard for NO
X
emissions or combining NO
X
control with HC by setting a HC + NO
X
standard.

We request comment on the various strategies available to reduce emissions and the costs and potential corresponding emissions reductions of those strategies.

C. Standards and Program Approaches

Although off-highway motorcycles, ATVs, and snowmobiles are all categorized as recreational vehicles, we expect to establish separate emissions standards for them. The most fundamental reason for varying standards is that the operating characteristics are significantly different. Since we typically try to evaluate and control emissions performance under normal operating conditions, it is likely we will adopt different test procedures for the different applications. Also, the level of stringency and the timing of the standards may vary depending on the types of emissions control technology available, cost impacts, industry make-up, and other factors that we must consider in establishing the program. We request comments on the appropriateness of separate emission standards for off-highway motorcycles, ATVs, and snowmobiles.

Generally, we will be considering what level of emissions control is appropriate and the lead-time necessary for manufacturers to achieve those emissions reductions. There are a number of approaches that have been used in programs for other nonroad engines to effectively reduce emissions, both in the near term and long term. These approaches often incorporate some level of flexibility into the program which has allowed manufacturers to achieve lower overall emissions levels, perhaps at less cost. Programs have been tailored to the particulars of the engine categories and industries being regulated to achieve the overall goals of the program.

In many programs, we have established either a single set (tier) of standards, or multiple tiers of standards that progressively achieve further reductions over a number of years. We have also established corporate-average standards, including declining fleet averages where manufacturers must calculate fleet average emissions levels and reduce those emissions incrementally each year over several model years. Also, in some cases, standards have been phased-in over a number of years as a percentage of sales or by an engine characteristic such as size. Some programs also include averaging, banking and trading, discussed below in section III.C.4.

We have used such mechanisms, in part, to allow manufacturers to plan their research, development, and product introductions. Such program approaches may allow manufacturers to achieve long-term emission reductions that may not otherwise be achievable. For example, a declining fleet average approach over several years may provide near term reductions and also provide manufacturers with lead-time needed to employ advanced technology in an orderly and efficient manner. Also, averaging can provide flexibility by allowing manufacturers to certify some engines to levels above the standard as long as excess emissions are offset by sales of engines certified to emissions levels below the standard. However, such approaches may be of limited value to small businesses or companies offering only a few models and may not be justified for some programs. We encourage you to consider these approaches, and any others, in commenting on the standards discussed below.

1. Off-Highway Motorcycles and ATVs

We are considering establishing HC, NO
X
, and CO standards for off-highway motorcycles and ATVs. PM is discussed separately in section III.C.3, below. We expect the largest benefit in terms of reducing the ozone precursors NO
X
and HC to come from reducing HC emissions from two-stroke engines. Two-stroke engines have very high HC emissions levels. Baseline NO
X
levels are relatively low for engines used in these applications and therefore initial NO
X
standards may serve to cap NO
X
emissions. CO reductions can be expected from both 2-stroke and 4-stroke engines, as CO levels are somewhat similar for the two engine types.

HC Standard.
In the current off-highway motorcycle and ATV market, consumers can choose between 2-stroke and 4-stroke models in most sizes and categories. Each engine type offers unique performance characteristics. Some manufacturers specialize in 2-stroke or 4-stroke models while others offer a mix of models.

The HC standard is likely to be a primary determining factor for what technology manufacturers choose to employ to meet emissions standards overall. As described in the previous section, a variety of technological approaches appear promising to control HC emissions. HC emissions can be reduced substantially by switching from 2-stroke to 4-stroke engines. The California emissions control program for off-highway vehicles provides ample data on the emissions performance capability of 4-stroke engines in off-highway motorcycles and ATVs. Off-highway motorcycles certified to California standards for the 2000 model year have HC certification levels ranging from 0.4 to 1.0 g/km. The motorcycles have engines ranging in size from 50 cc to 650 cc and none of these motorcycles are equipped with catalyst technology.

Technologies are also available for the two stroke engine that may reduce HC emissions levels to near those provided by 4-stroke engines. Technologies such as direct fuel injection and catalysts have been applied to 2-stroke engines used in other applications, such as personal watercraft and outboard marine engines, in response to emissions control requirements. However, only vehicles equipped with 4-stroke engines have been certified to the California standards. Two stroke models are sold in California, but only under California's allowance for the sales and use of uncertified products under certain circumstances (discussed above in section III.A.5).

In determining what standards to propose, we will be carefully examining the feasibility and cost of both 2-stroke and 4-stroke technologies. Modest reductions (up to 30 percent) appear feasible through the use of engine modifications and calibration changes. We are also interested in approaches that would reduce HC emissions substantially (for example, 75 to 90 percent) from baseline 2-stroke engine levels. Clearly, switching to 4-stroke engines achieves this goal and some manufacturers would likely choose this approach to meeting such standards.

However, some manufacturers may want an opportunity to achieve HC reductions through the use of advanced technology 2-stroke engines. This approach may require more time and investment in research and development than switching to 4-stroke engines entirely, but could result in more cost effective emissions control in the long term. Also, if such engines were developed, consumers may benefit from having a variety of engine types from which to choose. We request comment on whether EPA should attempt to set standards in a manner that would encourage the development of clean 2-stroke technology, and if so, how that objective could best be accomplished.

We request comments on the appropriate level of HC control for off-

highway motorcycles and ATVs. We are interested in perspectives on whether an HC standard should be based on the capabilities of 4-stroke or 2-stroke engine emissions control technologies. We are also interested in comment on establishing separate standards for the two engine types. In making their recommendations, commenters are encouraged to consider the level of emission reductions currently achieved under the California emissions control program, described above, and the need and opportunity for further emissions reductions. Commenters are also encouraged to consider the benefits of aligning highway motorcycle HC standards, discussed in section IV below, with the HC standards for off-highway motorcycles and ATVs. We are interested in comments on technology, cost, corresponding emission reduction potential, necessary lead-time, phase-in, and performance implications, including supporting rationale and data, where possible. Commenters are also invited to address the cost and corresponding emissions reductions of various other potential strategies.

As described above, we may propose averaging approaches such as corporate-average standards and averaging, banking, and trading. We request comment on the appropriateness of averaging ATVs and off-highway motorcycles together, assuming they are required to meet the same standards, or standards of similar stringency. Comments on other aspects of averaging as it might apply to HC compliance are requested (for example, averaging recreational vehicles with other engines identified in this document).

NO
X

standard
. While the focus of the program would be on achieving HC reductions, we also request comment on the need for and appropriateness of NO
X
control for these engines. We are considering standards in the form of HC plus NO
X
. We would expect a small NO
X
increase when going from uncontrolled two-stroke engines to engine designs which meet new emissions standards. This NO
X
increase is due to engine efficiency improvements and emission control strategies available for 2-stroke engines. A NO
X
plus HC standard recognizes this trade-off. Also, 4-stroke engines typically have higher NO
X
emissions than 2-stroke engines.

When we established the HC plus NO
X
standard for personal watercraft, we adjusted the level of the standard to account for the inclusion of NO
X
. We request comment on this approach for establishing an HC plus NO
X
limit for motorcycles and ATVs. We also request comment on how much of an adjustment to the standard is needed to account for NO
X
emissions or what level would be appropriate for a NO
X
cap. We also request comment on a NO
X
plus HC standard in the context of averaging approaches for compliance. Finally, we request comment on the cost implications and corresponding emission reduction potential of NO
X
control strategies.

CO standard
. We expect to establish a CO limit for motorcycles and ATVs, along with HC and NO
X
standards. We will be considering the levels established by California for these vehicles and the standards for highway motorcycles. We request comment on what level of CO control would be appropriate for these vehicles, considering costs (and other statutory factors). We also request comment on whether or not the CO standard should be established as a separate technology driver or based on the performance of technologies likely to be needed to achieve low HC emissions levels. We request comment on the cost implications and corresponding emission reduction potential of CO control strategies. As with HC and NO
X
, we are interested in the usefulness of considering averaging approaches for CO emissions compliance.

Test procedures.
The form and numeric level of the standards depend on the test procedures and test cycle over which emissions are measured. As described above in section III.A.5., California off-highway motorcycle and ATV standards are based on the highway light-duty vehicle test procedure (the FTP). This is a chassis-based test procedure, which requires the vehicle to be tested rather than only the engine.

Some manufacturers have noted that they do not currently have chassis-based test facilities capable of testing ATVs. California provides manufacturers with the option of certifying ATVs using the engine-based, utility engine test procedure (SAE J1088), and most manufacturers use this option for certifying their ATVs. Manufacturers have facilities to chassis test motorcycles and therefore California does not provide an engine testing certification option for motorcycles. Manufacturers have noted that requiring chassis-based testing for ATVs would require them to invest in additional testing facilities which can handle ATVs, since ATVs do not fit on the same roller(s) as motorcycles used in chassis testing.

Currently, for off-highway motorcycles and ATVs, we are planning to use the FTP test cycle, as it appears to be the best available test cycle for these vehicles. We will be carefully examining the potential pros and cons of using an engine-based test procedure for ATVs and request comment on this issue. We request comment on whether or not the approach taken by California is suitable for the federal program, including the use of the above test procedures and their effectiveness in ensuring in-use emissions reductions.

We are particularly interested in comments on the use of the utility engine cycle for ATVs, and whether or not a different engine-based test cycle, such as the one being considered for snowmobiles (discussed below), may be more suitable. The utility engine cycle is a 5-mode steady-state test cycle which includes testing at only one engine speed (85 percent of rated speed). Such a test procedure is appropriate for engines used in lawn and garden applications, but may not be appropriate for engines used in vehicle applications. The snowmobile engine test procedure is also a 5-mode steady-state test procedure but the engine speed varies by mode along with torque. We believe this is generally more representative of how an engine behaves in a vehicle application.

2. Snowmobiles

Emissions standards established by EPA through this rulemaking will be the first for snowmobiles. Unlike off-highway motorcycles and ATVs, there are no emissions standards for snowmobiles in California to use as a point of reference. Snowmobiles are almost entirely equipped with two-stroke engines which have very high HC and CO emission levels. Our focus for snowmobiles will be to reduce those emission levels. NO
X
emissions are much less of a concern because of the seasonal nature of snowmobile use and low baseline levels.

CO standard
. CO emissions may be a larger concern for snowmobiles than for off-highway motorcycles and ATVs due to their high CO emissions levels and the general concern of high ambient CO level in some areas during cold weather. In initial discussions with the International Snowmobile Manufacturers Association (ISMA), manufacturers have suggested setting standards that would result in CO reductions of 10 to 30 percent, phased in over model years 2004-2006. As described in section III.B. above, promising technologies are available which have the potential to reduce emissions to significantly lower levels. These technologies go beyond minor engine modifications and calibration changes and may require additional lead time to implement. However, with

appropriate lead time, further CO emission reductions may be reasonably achievable.

We will be evaluating potential technologies and the costs of those technologies during the development of our proposal for snowmobiles. We will consider the timing of the standards in the context of the level of stringency we propose, recognizing that more lead-time would likely be needed to apply and prove-out the application of certain advanced technologies. Also, as described above, we will consider the value of implementation flexibilities such as averaging and phase-in schedules in allowing manufacturers to meet more stringent standards in an orderly manner. We request comment on what level of CO emissions control is feasible and appropriate for snowmobiles, on the cost and corresponding emissions reduction potential of various strategies, on the lead time needed to achieve new standards, and on the usefulness of implementation flexibility in meeting the standards.

HC standard.
As mentioned in section II, we received comments indicating that HC control for snowmobiles for purposes of reducing ozone may not be necessary due to their seasonal use. However, we believe that there may be a need to control HC emissions from snowmobiles. In particular, even if we accept the commenters' argument regarding ozone, HC emissions may result in increased exposure to air toxics. As discussed in section II, hydrocarbons are made up of numerous components, some of which have been identified as toxic air pollutants.

We anticipate that many of the technology approaches available to manufacturers to reduce CO emission levels would also reduce HC emissions levels. The two-stroke engines used in snowmobiles have very high HC levels and we believe that establishing standards to reduce those levels would be appropriate. Manufacturers have suggested an HC reduction of up to 30 percent by 2008, in addition to the 30 percent reduction in CO by 2006, discussed above. As with CO, we believe technology is likely to be available to achieve a greater degree of control, especially with several years lead time or phase-in. Reductions in CO and HC of 70 percent or more may be feasible.

We request comment on what level of HC emissions control is feasible and appropriate for snowmobiles, the cost and corresponding emissions reductions associated with such levels of emissions control, the lead time needed to achieve new standards, and the usefulness of implementation flexibility in meeting the standards. In particular, we request comment on the appropriateness of requiring any control of HC for snowmobiles given the seasonal nature of their use versus air toxic concerns for riders.

Test Procedures.
Snowmobile manufacturers, in conjunction with Southwest Research Institute, have developed a test procedure for measuring snowmobile emissions.
42

This effort was undertaken due to increasing interest in snowmobile engine emission levels and a lack of a test procedure based on a representative duty-cycle. The test cycle is a 5-mode steady-state cycle, with different engine speed and torque points chosen and weighted to reflect in-use engine operation (see table below). The study also found that the utility engine cycle (J1088), which had previously been used, was not appropriate for snowmobiles.

42
“Development and Validation of a Snowmobile Engine Emission Test Procedure,” Christopher W. Wright and Jeff J. White, SAE Paper 982017.

Table III-3.—Snowmobile Engine Test Cycle
(SAE paper 982017)

mode
1
2
3
4
5

normalized speed
1.0
0.85
0.75
0.65
idle

normalized torque
1.0
0.51
0.33
0.19
0

Weight, %
12
27
25
31
5

We request comment on the use of this test procedure as the basis of future snowmobile standards. This test procedure appears to be the best currently available for snowmobiles, but we request comment on the need for additional tests or test modes to ensure in-use emissions control. For example, idle CO emissions have been highlighted as a particular concern for snowmobiles and we request comment on the need for additional emphasis on idle CO emissions within the test procedure.

3. The Need for PM Standards

As discussed in section II, Air Quality, we are very concerned about current high particulate matter levels in snowmobile exhaust. High PM levels are primarily attributable to the use of traditional 2-stroke engines. PM emissions are also a concern for off-highway motorcycles and ATVs to the extent that 2-stroke engines are used in those applications.

We believe that the technology changes that would be needed to significantly reduce CO and HC levels, such as direct injection or 4-stroke engines, may also dramatically reduce PM levels. If HC and CO standards were established at a level only requiring minor modifications to the engines, PM could remain a problem for snowmobiles and a PM standard may be necessary. We request comment on whether or not we should establish a PM standard for snowmobile engines and what level of stringency would be appropriate. We also request comment on the cost implications (equipment costs, etc.) associated with measuring PM as part of the certification procedure.

4. Averaging, Banking, and Trading

Depending on the structure of the proposed program, the level of stringency of the proposed standards, and other considerations, we may propose averaging, banking, and trading provisions (ABT) for recreational vehicles/engines. We have established ABT programs in many of our engine-based emissions control programs in cases where we have set standards that require significant technology changes. The ABT programs allow manufacturers

to earn credits by introducing clean engines sooner than required or by certifying engines to levels below the standards. Manufacturers may use the credits to certify engines to levels above the standards in the same model year (averaging), keep the credits for use in a later model year (banking), or transfer the credits to another manufacturer (trading).

In some cases, we have not established ABT programs because we believed the standards we were adopting were achievable without the additional flexibility. In such cases, EPA found that the added complexity inherent in having an ABT program, both for EPA and the manufacturers, would outweigh the potential benefits of the program.

ABT can be beneficial in providing incentive to manufacturers for the early introduction of new technologies, allowing certain engine families to be trail blazers for new technology. This flexibility can allow us to consider a more stringent program than would otherwise be appropriate under CAA section 213. The programs also provide flexibility to manufacturers for product planning and can provide opportunity for more cost effective introduction of product lines. ABT is tailored to meet the specific needs of standards and programs being established. This is necessary to avoid issues such as windfall credits and the potential of stockpiling credits which could result in a significant delay of the standards being adopted or future standards not yet considered. We request comment on integrating ABT into the programs for recreational vehicles. We are interested in comment on the scope of ABT, including any particular issues we should consider in developing such a program, and whether or not credit trading among different vehicle types should be allowed.

D. Additional Program Considerations

1. Competition Off-Highway Motorcycles

Currently, a large portion of off-highway motorcycles are marketed as competition/racing motorcycles. These models often represent a manufacturer's high performance offerings in the off-highway market. Most such motorcycles are of the motocross variety,
43

although some high performance enduro models
44

are marketed for competition use. These high performance motorcycles are largely powered by 2-stroke engines, though some 4-stroke models have been introduced in recent years.

43
A motocross bike is typically a high performance off-highway motorcycle that is designed to be operated in motocross competition. Motocross competition is defined as a circuit race around an off-highway closed-course. The course contains numerous jumps, hills, flat sections, and bermed or banked turns. The course surface usually consists of dirt, gravel, sand, and mud. Motocross bikes are designed to be very light for quick handling and easy manueverability. They also come with large knobby tires for traction, high fenders to protect the rider from flying dirt and rocks, aggressive suspension systems that allow the bike to absorb large amounts of shock, and are powered by high performance engines. They are not equipped with lights.

44
An enduro bike is very similar in design and appearance to a motocross bike. The primary difference is that enduros are equipped with lights and have slightly different engine performance that is more geared towards a broader variety of operation than a motocross bike. An enduro bike needs to be able to cruise at high speeds as well as operate through tight woods or deep mud.

When used for competition, motocross motorcycles are mostly involved in closed course or track racing. Other types of off-highway motorcycles are usually marketed for trail or open area use. When used for competition, these models are likely to be involved in point-to-point competition events over trails or stretches of open land. There are also specialized off-highway motorcycles that are designed for competitions such as ice racing, drag racing, and observed trials competition. A few races involve professional manufacturer sponsored racing teams. Amateur competition events for off-highway motorcycles are also held frequently in many areas of the U.S.

Clean Air Act sections 216 (10) and (11) exclude engines and vehicles “used solely for competition” from nonroad engine and vehicle regulations. For purposes of past nonroad engine emissions control regulatory programs (for example, the nonroad CI, recreational marine, and Small SI programs), EPA has defined the term “used solely for competition” as follows:

Used solely for competition
means exhibiting features that are not easily removed and that would render its use other than in competition unsafe, impractical, or highly unlikely.

If retained for the recreational vehicles program, the above definition may be useful for identifying certain models that are clearly used only for competition. For example, there are motorcycles identified as “observed trials” motorcycles which are designed without a standard seat because the rider does not sit down during competition. This feature would make recreational use unlikely. Most motorcycles marketed for competition, however, do not appear to have physical characteristics that constrain their use to competition. Without such distinguishing characteristics, determining that a vehicle is used solely for competition becomes more challenging.

Manufacturers have recommended that EPA use the definition for competition motorcycle that EPA has previously established for purposes of exempting motorcycles from its noise regulations, as follows:

Competition motorcycle
means any motorcycle designed and marketed solely for use in closed course competition events.
45

45
40 CFR 205.151(a)(3).

Manufacturers further recommended that closed course competition include “any organized competition event covering a closed, repeated, or defined route intended for easy viewing of the route by spectators. Such events could include, but are not limited to, motocross, enduro, hare scrambles, observed trials, short track, dirt track, drag race, hill climb, ice race, and land speed trials * * *”. Manufacturers recommended that EPA require labels designating the vehicles for competition use only.
46

46
“MIC Recommended Definitions for Pending EPA Recreation Vehicle Exhaust Emissions Proposal,” Motorcycle Industry Council, Draft, June 1, 2000. Docket A-2000-01.

Based on confidential sales information, we believe that vehicles designated for competition by manufacturers could exceed 50 percent of total sales under their recommended approach. We believe that many “competition” style motorcycles are likely to also be used, at least by many end users, primarily or often for recreational riding. Section 216(10) of the Act excludes from the definition of nonroad engines vehicles used solely for competition. We are concerned that the approach suggested by manufacturers may be overly broad and therefore would not meet the conditions of this exclusion.

In a recent rulemaking for marine diesel engines, we addressed competition engines by providing exclusions for engines used in professional competitions only.
47

Engines used for amateur competition or occasional competition are not excluded under that rule. The exclusion is available both to manufacturers and to someone modifying an engine for professional competition use (normally, we would prohibit someone from making changes to a certified engine in ways that adversely affect emissions control). This would be one possible

approach to address the competition use issue for recreational vehicles.

47
64 FR 73305, December 29, 1999.

We are very interested in receiving input on the competition exemption issue described above. We request comment on ways the program can be established to provide an exclusion for motorcycles used solely for competition, consistent with the Act, without excluding vehicles that are often used for other purposes. Ideally, the program can be established in a way that provides reasonable certainty at time of certification. However, approaches could include reasonable measures at time of sale or in-use that would provide assurance that the competition exemption is being applied appropriately. We request information and data on the use of off-highway motorcycles for competition and recreation that would inform the rulemaking process.

2. Crankcase Emissions From Recreational Vehicles

We will be considering proposing the elimination of crankcase emissions from recreational vehicles. Venting the crankcase to the atmosphere is a source of HC emissions that has been cost effectively controlled in many other engine applications. Rather than venting these emissions to the atmosphere, they can be routed back to the engine for combustion. We believe that any effect on exhaust emission levels due to the additional hydrocarbons which are routed to the engine through the crankcase emissions control system can be substantially reduced, if not eliminated, through the recalibration of the engine. We are not aware of any issues particular to closing the crankcase on engines used in recreational vehicles. California has required the elimination of crankcase emissions on off-highway motorcycles and ATVs as part of their program. We request comments on the costs, emission reductions, and any other issues associated with requiring the elimination of crankcase emissions from recreational vehicles.

3. Compliance Measures

Along with emissions standards, we will be considering requirements to ensure in-use compliance with those standards over the useful life of the recreational vehicles/engines. The goal of these measures would be to promote high quality engine design, production, and in-use emissions performance. Compliance programs typically include certification, production line testing, and in-use testing components. Under these programs, manufacturers must submit data and other information prior to introducing the engine into commerce certifying that the engine meets applicable standards, and there is the ability to verify compliance through engine testing at the production line and in-use. We expect to examine the structure and effectiveness of compliance programs contained in other nonroad emissions control programs in determining what types of measures would be most appropriate for recreational vehicles.

Because of similarities in the applications, engine characteristics, and production volumes, we will carefully consider whether the compliance programs for recreational vehicles should be modeled after the programs adopted to control emissions from marine outboard engines and personal watercraft.
48

Some manufacturers making these marine products also make recreational vehicles, and are therefore familiar with the structure of the marine engines program.

48
61 FR 52088, October 4, 1996.

We encourage interested parties to review the compliance program in place for outboard engines and personal watercraft and provide input to EPA on the potential for applying the same types of compliance measures to these other recreational vehicles. In particular, we are interested in comments on requirements for manufacturer production line and in-use testing. For outboard engines and personal watercraft, the production line testing program requires manufacturers to test engines as they leave the production line. This process is used to provide a quality control check on the manufacturer's production processes to ensure that engines are routinely assembled in a way such that they continue to meet emission performance requirements when coming off the assembly line. The manufacturer in-use testing program requires manufacturers to select engines from the in-use fleet and test a portion of their engine families each year. These requirements focus resources on ensuring in-use compliance and are key components to the overall compliance program we have established for recreational marine engines.

4. Consumer Modifications

We are aware that consumers sometimes modify engines and exhaust systems on their recreational vehicles. Some of these changes are done to enhance operating performance. Others are to maintain optimal performance under varying operating conditions (
i.e.,
changes in altitude, weather, etc.). We request information on the types of modifications that are common for the different types of recreational vehicles and any information on their impact on emission performace. We are especially interested in those modifications that would affect the emissions performance of the vehicle, and could be considered tampering under the Act for engines certified to emissions standards. We also request information that would help us better understand how common these practices are for the different types of vehicles. Understanding the scope of these practices will help us establish standards and program requirements that achieve in-use emissions reductions.

5. Useful Life

For highway motorcycles, we currently have three distinct useful life categories that are based on engine displacement. The useful life for all three categories are five years or 12,000 km, 18,000 km, or 30,000 km depending on which category the motorcycle falls under. California has established a useful life of 5 years or 10,000 km for off-highway motorcycles and ATVs. For some of our nonroad engine regulations, we have based useful life on time (
i.e.,
hours). We request information that would help us determine the most appropriate method for establishing useful life for recreational vehicles. For example, a certain number of hours may be appropriate for snowmobiles and possibly ATVs, whereas a useful life similar to that used for highway motorcycles or California off-highway motorcycles may be more appropriate for off-highway motorcycles. We request comment on what the appropriate useful life levels and values would be for the various types of recreational vehicles.

6. Consumer Labeling

We request comment on the potential for a consumer labeling program for recreational vehicles. We are also interested in comment on this topic for recreational marine engines, as discussed in section V.E.10. The purpose of a labeling program would be to educate consumers so that they could make informed decisions concerning engine emissions when they purchase a recreational vehicle. One example of a consumer labeling program is the California Air Resources Board's requirement that personal watercraft and outboard engines sold in California starting in 2001 be labeled as either low, very-low, or ultra-low depending on their emission levels.

We request comment on the merit and cost of including such a program in our proposal for recreational vehicles and

whether the program should be voluntary or mandatory. We also request comment on programmatic aspect of labeling such as the content of the label, the number of tiers that would be useful in distinguishing among recreational vehicle models, and the pollutant(s) that should be used in establishing those tiers. Finally, we request comment on any other appropriate incentives for introducing new clean technologies that may be available.

IV. Highway Motorcycles

In addition to the nonroad vehicles and engines noted above, today's ANPRM also reviews EPA requirements for highway motorcycles. The emissions standards for highway motorcycles were established twenty-three years ago. California recently adopted new emissions standards for highway motorcycles and new standards have also been proposed internationally. There may be opportunities to reduced emissions in a way that also allows manufacturers to benefit from harmonized requirements, which may reduce product lines and production costs. In addition, we believe it is important to consider the emissions standards for highway motorcycles in the context of setting standards for off-highway motorcycles. We are interested in providing regulatory programs for off-highway and highway motorcycles that are consistent, which may also allow for the transfer of technology across product lines for manufacturers. Consequently, we request comment on the appropriateness of examining and potentially revising the highway motorcycle emission standards in the same time frame, and in the same rulemaking, in which we plan to address emission standards for recreational vehicles.

A. What Is a Highway Motorcycle, and Who Makes Them?

Motorcycles come in a variety of two-and three-wheeled configurations and styles. For the most part, however, they are two-wheeled self-powered vehicles. Federal regulations currently define a motorcycle as “any motor vehicle with a headlight, taillight, and stoplight and having: two wheels, or three wheels and a curb mass less than or equal to 680 kilograms (1499 pounds).” (See 40 CFR 86.402-86.478). Vehicles that otherwise meet the motorcycle definition but have engine displacements less than 50 cubic centimeters (cc) (generally, youth motorcycles, most mopeds, and some motor scooters) are currently not covered by federal regulations. Also currently excluded are motorcycles which, “with an 80 kg (176 lb) driver, * * * cannot: (1) Start from a dead stop using only the engine; or (2) Exceed a maximum speed of 40 km/h (25 mph) on level paved surfaces' (
e.g.,
some mopeds). Most scooters and mopeds have very small engine displacements and are typically used as short-distance commuting vehicles. Motorcycles with larger engine displacement are more typically used for recreation (racing or touring) and may travel long distances. Both EPA and California regulations further sub-divide highway motorcycles into classes based on engine displacement. Table IV-1 shows how these classes are defined.

The currently regulated highway category includes motorcycles termed “dual-use” or “dual-sport,” meaning that their designs incorporate features that enable them to be reasonably competent on and off road. Dual-sport motorcycles generally can be described as street-legal dirt bikes, since they tend to bear a closer resemblance in terms of design features and engines to true off-highway motorcycles than to highway cruisers or sport bikes. However, another category of motorcycle, referred to as “enduros,” are very similar in appearance to dual-sport motorcycles, but are typically equipped with higher performance engines and have traditionally been categorized as nonroad motorcycles and not been subject to the highway emission standards. Therefore, we request comment as to how we can better determine which motorcycles are street-legal and which are not.

Throughout this ANPRM the term “highway motorcycle” is intended to include all motorcycles covered by the current federal regulations; thus, dual-sport motorcycles are included in this definition. We currently believe that all highway motorcycle engines sold in the U.S., including those that power dual-sport motorcycles, are four-stroke engines.

Table IV-1.—Motorcycle Classes

Motorcycle class

Engine
displacement
(cubic
centimeters)

Class I
50—169.

Class II
170—279.

Class III
280 and greater.

Highway motorcycles are dominated by larger engines, with engine displacements exceeding 1000 cc for the most powerful “superbikes.” According to the Motorcycle Industry Council (MIC), in 1998 there were about 5.4 million highway motorcycles in use in the United States (only 565,000 of these were dual-sport), more than three-fourths of which had an engine displacement of over 449 cc.
49

Sixty percent had an engine displacement greater than 749 cc. Inclusion of the dual-sport motorcycles in this figure tends to skew the numbers somewhat, even despite the fact that their total numbers are relatively small, because their dirt bike heritage leads them to be weighted towards smaller engines. According to the MIC data, three-fourths of dual-sport motorcycles had an engine displacement of less than 350 cc, whereas two-thirds of the remaining motorcycles (those purely designed for road use) had a displacement of over 749 cc. Total sales in 1998 of highway motorcycles was estimated to be about 411,000, or about 72 percent of motorcycle sales. About 13,000 of these were dual-sport motorcycles. The remaining 28 percent of sales were strictly off-highway motorcycles, which are currently unregulated.

49
“1999 Motorcycle Statistical Annual,” Motorcycle Industry Council.

We are aware of a half-dozen companies, Honda, Harley Davidson, Yamaha, Kawasaki, Suzuki, and BMW, which account for near 95 percent of all motorcycles sold. Dozens of other minor players make up the remaining few percent. Based on available information, over half of all motorcycles sold in 1998 were made by Honda and Harley Davidson, with the two companies maintaining almost equal market shares of about 25 percent each.

B. What Is the Regulatory History?

1. Environmental Protection Agency Regulations

In 1974 EPA issued an advance notice of proposed rulemaking that discussed the possible implementation of emission controls for highway motorcycles for the first time and requested comment on a number of issues. Taking into account the comments received on the ANPRM, EPA issued an NPRM the following year for the control of exhaust and crankcase emissions from new motorcycles. The proposal addressed standards for HC, CO, and NO
X
, proposing a set of interim standards for 1978 and 1979 and final standards equivalent to the light-duty vehicle standards in effect at that time. The NPRM was followed by a Final Rule promulgated in 1977 (42 FR 1126, Jan. 5, 1977) which established interim standards effective for the 1978 and 1979 model years and ultimate standards effective starting with the 1980 model year. The interim standards ranged from 5.0 to 14.0 g/km HC depending upon engine displacement,

while the CO standard of 17.0 g/km applied to all motorcycles. The 1980 standards, which were more lenient than those that were proposed and which lacked a NO
X
standard, are essentially those that remain in effect today. While the final standards did not differ based on engine displacement, the useful life over which these standards must be met ranged from 12,000 km (7,456 miles) for Class I motorcycles to 30,000 km (18,641 miles) for Class III motorcycles. These standards were updated in 1989 to include methanol-fueled motorcycles starting with the 1990 model year, then again in 1994 to include natural gas-fueled and liquefied petroleum gas-fueled motorcycles starting with the 1997 model year. Crankcase emissions from motorcycles are also prohibited. There are no current federal standards for evaporative emissions from motorcycles. The current federal standards are shown in Table IV-2.

Table IV-2.—Current Federal Exhaust Emission Standards for Motorcycles

Engine size
HC (g/km)
CO (g/km)

All
5.0
12.0

2. Regulation by the California Air Resources Board

Motorcycle emission standards in California were originally identical to the federal standards that applied to the 1978 through 1981 model years. The definitions of motorcycle classes used by California continue to be identical to the federal definitions. However, California has revised their standards several times to bring them to their current levels. In 1982 the standards were modified to reduce the HC standard from 5.0 g/km to 1.0 or 1.4 g/km, depending upon engine displacement. California adopted an evaporative emission standard of 2.0 g/test for 1983 and later model year motorcycles. In 1984 California amended the regulations for 1988 and later model year motorcycles to further lower emission standards and provide additional compliance flexibility to manufacturers. The 1988 and later standards could be met on a corporate-average basis, and the larger (Class III) bikes (280 cc and above) were split into two separate categories: 280 cc to 699 cc and 700 cc and greater. These are the standards being met in California today. Like the federal standards, there are no currently applicable NO
X
standards for highway motorcycles in California. Under the corporate-averaging scheme, no individual engine family is allowed to exceed a cap of 2.5 g/km. Like the federal program, California also prohibits crankcase emissions.

Table IV-3.—Current California Highway Motorcycle Exhaust Emission Standards

Engine size (cc)
HC (g/km)
CO (g/km)

50-279
1.0
12.0

280-699
1.0
12.0

700 and above
1.4
12.0

In 1998 the California Air Resources Board (CARB) proposed new standards for Class III highway motorcycles that would take effect in two phases—a “Tier 1” to start with the 2004 model year, followed by a “Tier 2” that would take effect starting with the 2008 model year. These standards were finalized with minor modifications on November 22, 1999. Existing California standards for Class I and II motorcycles remained unchanged. As with the current standards, manufacturers will be able to meet the requirements on a corporate-average basis. Perhaps most significantly, this recent CARB action brings some level of NO
X
control to motorcycles by establishing a combined HC+NO
X
standard. No changes were made by the CARB action to the CO standard, which remains at 12.0 g/km. In addition, CARB is providing an incentive program to encourage the introduction of motorcycles compliant with the Tier 2 standard prior to the 2008 model year. This incentive program allows the accumulation of credits that manufacturers can use to meet the 2008 standards. Like the federal program, these standards will also apply to dual sport motorcycles.

Table IV-4.—Tier 1 and Tier 2 California Class III Highway Motorcycle Exhaust Emission Standards

Model year
Engine displacement

HC+NO
X
(g/km)

CO (g/km)

2004 through 2007 (Tier 1)
280 cc and greater
1.4
12.0

2008 and subsequent (Tier 2)
280 cc and greater
0.8
12.0

California also adopted a new definition of small volume that would take effect with the 2008 model year. Historically, California had a definition of small volume that applied to the 1984 through 1987 model years (5,000 units per model year), but no definition that has applied since. Thus, for the 1988 through 2007 model years, all manufacturers must meet the standards, regardless of production volume. Small volume manufacturers, defined in CARB's recent action as a manufacturer with combined California sales of Class I, Class II, and Class III motorcycles not greater than 300 units, do not have to meet new standards until the 2008 model year, at which point the Tier 1 standard applies. CARB intends to evaluate whether the Tier 2 standard should be applied to small volume manufacturers in the future.
50

50
CARB, October 23, 1998 “Proposed Amendments to the California On-Road Motocycles Regulation” Staff Report: Initial Statement of Reasons.

3. European Regulations

The European Commission recently proposed a new phase of motorcycle standards, which would start in 2003, and are considering a second in 2006. Whereas the current European standards make a distinction between two-stroke and four-stroke engines, the proposed standards would apply to all motorcycles regardless of engine type, leading to a technology-independent regulatory framework. The 2003 standards would require emissions to be below the values shown in Table IV-5, as measured over the European ECE-40 test cycle. The phase of standards being considered for 2006 are still in a draft form and have not yet been officially proposed, but in addition to taking another step in reducing motorcycle emissions, the 2006 standards are expected to incorporate an improved motorcycle test cycle, as noted in Section IV.D.2 below.

Table IV-5.—European Commission Proposed 2003 Motorcycle Exhaust Emission Standards

HC (g/km)
CO (g/km)

NO
X

(g/km)

1.2
5.5
0.3

C. Highway Motorcycle Emission Control Technology

1. Federal Standards

While highway motorcycles have had to apply some low-level control technologies to meet the current standards, the current federal standards require a technology mix comparable to the pre-catalyst stage for passenger cars. The standards that took effect starting in the 1980 model year precipitated the elimination of highway two-stroke engines and a transition to a fleet composed entirely of four-stroke engines. In general, the standards prompted the use of leaner air-fuel mixtures, electronic ignition systems, improvements in manufacturing tolerances in the carburetor and fuel handling systems, PCV valves to control crankcase emissions, and some engine redesign and modifications (changes to the camshaft, valve and ignition timing, and combustion chamber design).

2. California Standards

Despite the greater stringency of the current California standards (
i.e.,
those that apply in the current model year), most manufacturers have been able to comply without the use of catalytic converters, and only a few expensive high-performance motorcycles have used fuel injection systems. The majority of motorcycles have been able to meet these standards by using, in addition to the measures noted above for the federal standards, engine modifications and more advanced calibration strategies, with air injection systems being commonly used in the larger motorcycle models. A few models have been certified with 3-way catalytic converters and fuel injection systems.

The Tier 1 and Tier 2 standards taking effect in California in 2004 and 2008, respectively, will require some additional technologies.
51

Many of the control technologies that have been applied successfully to four-stroke engines in passenger cars may have some potential application to four-stroke motorcycle engines. Some, such as fuel injection and catalytic converters, have already been successfully used on some motorcycle engines, as noted above. Other passenger car technologies may arrive on motorcycles soon due to the upcoming California requirements. However, California did not base the Tier 1 standard effective in 2004 on the widespread application of catalytic converters. California has determined the 1.4 g/km HC+NO
X
standard will be largely feasible by reducing engine-out emissions using mostly engine systems (
e.g.
, fuel injection, pulse air injection, valve overlap changes), rather than relying on catalytic after-treatment. According to California, the Tier 2 standard will be more of a challenge to industry and existing technologies are likely to be modified and optimized for motorcycle application to achieve 0.8 g/km HC+NO
X
. They claim that such technologies could include computerized fuel injection, high-efficiency closed-loop two- or three-way catalytic converters, precise air-fuel ratio controls, programmed secondary pulse-air injection, low-thermal capacity exhaust pipes, and others which are available today or in the foreseeable near future. California has also suggested that some manufacturers may be able to meet the Tier 2 standards on some models without the use of catalytic converters.

51
California Air Resources Board, “Final Statement of Reasons for Rulemaking,” December 10, 1998.

D. Standards and Program Approaches

We have identified a number of key issues and decision points that may impact any action we may take regarding standards for highway motorcycles. We request detailed comments and data regarding the issue areas described in this section.

1. Exhaust Emission Standards

In general we request comment on the technological feasibility, cost, and appropriateness of implementing new more stringent emission standards for highway motorcycles. We also request comment on technologies that might enable reductions in motorcycle emissions, and the potential magnitude of such reductions. We request comment on the appropriate time frame for implementing new emission standards for highway motorcycles. In addition, we request detailed comments on the following specific issue areas.

Harmonization with California
. In many program areas, including light-duty and heavy-duty vehicles and engines, harmonization with California has frequently been a significant objective, and is often a desirable outcome for industry. When federal and California compliance programs are harmonized, manufacturers are more easily able to produce engine families that comply with both programs, rather than having to consider whether or how to design and market engine families separately for California and the remaining 49 states. In addition, historically any time the California program is significantly more stringent than the federal program there is a possibility that some individual states will elect to enforce the California program (as several states currently do with light-duty vehicles), further complicating compliance, marketing, and distribution for the manufacturers. Given that California has recently put in place technologically challenging standards for Class III motorcycles in a time frame that we would be likely to consider for a possible federal program, we are likely to look very closely at the pros and cons of harmonizing the federal program with the recently finalized California standards. We request comment on all aspects of the California program and whether the California standards are appropriate for a nationwide federal program. Commenters should address technological feasibility, cost, corresponding potential emissions reductions, appropriate time frame, structure (
e.g.
, a fleet average approach vs. something else), and potential advanced emission control technologies associated with California-level standards and with any other level of standards a commenter may consider appropriate.

As noted earlier, the recent action by California did not address emissions from Class I and Class II motorcycles. We request comment on the need to consider emission reductions from all classes of motorcycles, including Class I and Class II.

Harmonization with off-highway motorcycles
. Since we will be promulgating emission standards for off-highway motorcycles for the first time, it may make sense to have standards that apply to both, off-highway and on-highway motorcycles. This could be beneficial for manufacturers that produce both types of motorcycles, since they could spread their resources across both programs. In addition, the experience and knowledge used in developing emission compliant highway motorcycles could possibly be transferred to off-highway motorcycle applications. However, we also acknowledge that many off-highway motorcycles use two-stroke engines, where two-stroke engines are no longer used in highway applications and some of the information used in meeting highway standards may not be applicable. Therefore, we request comment on the appropriateness of harmonization of highway and off-

highway motorcycle emission standards and the costs and corresponding emissions reductions associated with this approach.

2. Test Cycle

The test cycle currently used to for compliance with the motorcycle emission standards, in both the federal and California programs, is the FTP-75. Motorcycles are tested on a specialized motorcycle chassis dynamometer on the traditional FTP, the same cycle used for light-duty vehicles and trucks, although the driving schedule speeds and accelerations are reduced for Class I and II motorcycles. It is now widely acknowledged that the traditional FTP does not adequately represent some high-emission modes that vehicles experience in actual use. When the cycle was first adopted for passenger cars in the early 1970's, the limited capabilities of the chassis dynamometers at that time made it necessary to limit the speeds and acceleration rates of the driving cycle. Thus, the top speed and acceleration rates seen on the FTP are much less than most vehicles—especially motorcycles—can achieve on the road. Consequently, we request comment on whether the existing US06 driving cycle for light-duty vehicles and trucks—or some other more representative driving cycle—may be appropriate for highway motorcycles, and if so, what standards might be appropriate. We request data on how motorcycles are driven in actual use that might support or reject the appropriateness of a high-speed/high-acceleration driving cycle for motorcycles.

In addition, there is an effort underway under the auspices of the United Nations/Economic Commission for Europe (UN/ECE) to develop a global harmonized world motorcycle test cycle (WMTC). The objective of this work is to develop a scientifically supported test cycle that accurately represents the in-use driving characteristics of motorcycles. The United States is also a participating member of UN/ECE. EPA has stated that present levels of environmental protection will not be lowered in order to achieve regulatory harmonization. In its recent proposal, the European Commission has announced its intention to consider a global test cycle for the second phase of its proposed standards, expected to take effect in 2006. We request comment on all issues related to pursuing a globally harmonized test cycle.

3. Evaporative Emission Standards

As noted earlier, the existing federal program does not require compliance with a limit on evaporative emissions from motorcycles, while California does. We request comments and supporting information on the appropriateness of harmonization with the California evaporative standards or whether other evaporative emission standards might be an appropriate element of the federal program. We also request comment on the costs and corresponding emissions reductions associated with adopting evaporative emission standards.

E. Additional Program Considerations

1. Addressing Currently-Excluded Vehicles

In addition, we may consider developing appropriate standards for those types of vehicles now excluded from compliance with emission standards. This would include mopeds and scooters that are under 50 cc or that otherwise can not meet the

[Text truncated at 120,000 characters. The full text is on the page linked above.]

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A00-30105. Public record. Not legal advice.