Regulatory Background on the U.S. Mobile Source Emission Control Program

The U.S. Environmental Protection Agency's Motor Vehicle Compliance Program

Regulatory Authority

The Clean Air Act, as amended, both directs and authorizes the U.S EPA to establish standards regulating the emissions of mobile sources and to establish a compliance program to implement and enforce the mobile source emission control program. Mobile sources include, cars, trucks, and buses, as well as a variety of non-road vehicles and equipment, including construct, materials handling, and agricultural equipment, recreational equipment, marine vessels, locomotives and lawn and garden equipment. EPA was also given the authority to regulate the quality of fuels and fuel additives used for mobile sources. Over the years, EPA has adopted standards covering a variety of mobile sources and implemented the full set of tools provided by Congress to assure that vehicles meet standards -- most notably certification, assembly-line testing, recall, and warranty. Together, these compliance tools address, in a comprehensive fashion, the problem of controlling emissions from improperly maintained in-use cars. They assure that attention is paid to vehicle design before mass production begins, place constraints on quality assurance on the assembly line, and through the combination of recall and warranty, impose discipline on manufacturers to be concerned about emissions from in-use cars.

Standard Setting

In the Clean Air Act, as amended, Congress has given EPA varying degrees of guidance in setting emission standards. In some instances, as occurred with the emission standards for passenger cars established by the 1970 Clean Air Act Amendments, Congress give specific instructions regarding the pollutants to be regulated, the level of the emission standards, and the date the standards must be met ⬠usually stated in terms of vehicle or engine model years. In other cases, such as the 1977 Clean Air Act Amendments provisions relating to trucks and buses, Congress will direct EPA to establish emission standards and provide guidance on setting the levels of the standard, but Congress will leave the final decision to EPA on what the level of the standards will be. Finally, EPA is given the general authority to establish emission standards for a variety of sources including non-road equipment and engines upon a finding that emissions reductions from those sources are needed to protect the public health. Under this general authority, EPA may set standards more stringent for subsequent model years than those originally mandated by Congress or standards recommended by Congress. Examples where EPA went beyond standards originally mandated or recommended by Congress include the passenger car/light-duty truck Tier 2 standards that take effect beginning with the 2004 model year and the on-road heavy-duty engine (trucks and buses) that take effect beginning with the 2007 model year.

In setting emission standards under its general authority, EPA may choose a level more stringent than is technologically feasible at the time the standards are adopted, provide EPA can make the case that with sufficient lead-time technology can be developed to meet the standards, considering not only technological feasibility, but such factors as compliance costs, impact on energy consumption and vehicle or engine operation. EPA must also make a finding the standards are necessary to protect the public health.

As noted, Congress has given EPA the authority to regulate the quality of fuel and fuel additives used by mobile sources. Typically, Congress has given EPA considerable discretion in determining the specific of the fuel/fuel additive regulations. In regulating fuels and fuel additives EPA must act consistent with any guidance that may have been provided by Congress and also establish that the regulations are necessary to protect the public health either from the direct adverse effects and from the standpoint of where the fuel/fuel additive is being regulated to enable vehicles to meet applicable emission standards. Under the authority, EPA has established a number of fuel and fuel additive regulations. Some notable examples include the regulations requiring the phase-down and banning of lead and gasoline and setting sulfur content limits for both gasoline and diesel fuel.

Compliance Program

Below the various elements of EPA's compliance program are discussed.

Certification -- The Clean Air Act requires that each new vehicle or engine sold be certified as capable of meeting applicable emission standards. Section 206(a) of the Clean Air Act requires EPA to certify new vehicles or engines according to procedures prescribed by the EPA Administrator. Manufacturers are required to demonstrate that the vehicle or engine can meet the emission standard for a specified period. Today, for example, passenger cars must meet emission standards for 10 years or for 100,000 miles, which ever occurs first. Engines used in heavy trucks must meet standards for up to 435,000 miles. Vehicle and engine aging, maintenance, and testing are conducted by the manufacturers, but EPA reserves the right to test some certification vehicles or engines on a spot-check basis. Manufacturers' maintenance instructions are reviewed in conjunction with this program to assure reasonableness and necessity.

The advantage of the certification program is that it can affect vehicle or engine design before mass production. Obviously, it is better for overall air pollution control if manufacturers identify and remedy problems before production actually begins, when corrections are less costly. The certification process, however, must as a practical matter deal with prototype cars (sometimes almost hand-made) in an artificial environment (very careful maintenance and perfect driving conditions, with well-trained drivers using ideal roads or dynamometers, etc.)

EPA has taken steps over the years to streamline the certification process. For example, EPA now permits manufacturers to apply certification testing data to a number of models within a given model year and to apply that same data to subsequent model year vehicles where the agency has reasonable expectation that the models will perform similarly in use. In 1999, EPA implemented modifications to the passenger car and light-duty truck certification process by reducing upfront certification requirements while expanding the use of in-use testing to verify compliance.

Inspections/Investigations -- The inspection/investigation program allows EPA to conduct routine inspections of the manufacturers' certification records and facilities, to be followed up, in the case of suspected noncompliance, by investigations. The program essentially supports certification and is based on sections 208 and 206(b) of the Clean Air Act, which require manufacturers to provide EPA with access to records and information as well as right to enter the manufacturers premises to conduct "test". The inspection program was initiated in 1973 when a major domestic auto maker was alleged to be filing false certification reports. The Clean Air Act Amendments of 1990 expanded EPA's information-gathering authority.

Imports -- The imports program, which based on sections 203(a)(1) and 203(b) of the Act, also supports certification by preventing the entry of uncertified vehicles into the United States. A limited imports program began in 1968 with the Department of Health, Education and Welfare and was devoted to the investigation of commercial importers of vehicles. In 1973, the program was expanded by EPA and the Bureau of Customs to cover all imported vehicles and engines.

Selective Enforcement Auditing -- The Selective Enforcement Auditing (SEA) program was conceived in 1974 and took effect in 1976 to implement the assembly line testing authority provided in sec 206(b) of the Act. Rather than testing each vehicle coming off the assembly line, EPA identifies a number of production models for assembly line testing throughout a given model year. The vehicle or engine manufacturer conducts the actually testing.

The goals of the program are to enable EPA to identify certified production vehicles that do not comply with applicable emissions standards. If a pre-determined percentage of vehicles or engines fail to meet the emission standards the manufacturer must correct the problem or risk revocation of the certification. With some vehicle categories such as passengers, a manufacturer may be require to recall vehicles already sold to correct the defect or problem causing vehicles to fail.

Assembly line testing provides an additional check on mass produced vehicles to assure that the designs found adequate in certification are satisfactorily translated into production and that quality control on the assembly line sufficient to provide reasonable assurance that cars in-use will meet standards. The major advantage of the SEA program over certification is that it measures emissions from "real" production cars. However, a substantial and inevitable shortcoming in the program is that it provides no measure of vehicle performance over time. In response, EPA, over the years has streamlined the SEA process and placed increased emphasis on in-use testing.

Recall -- EPA's authority to order manufacturers to recall vehicles that have been introduced into commerce has been focused on light-duty vehicles such as passenger cars and light trucks. The recall program is intended to secure modification of properly maintained vehicles found to be nonconforming in-use and to deter the manufacture of such vehicles. The program is based on section 207(c) of the Clean Air Act and consists of four functional elements: surveillance, investigation, audit, and public reporting. Surveillance includes EPA surveillance testing, fleet owner contacts, state I/M data collection, manufacturer defect reporting, consumer complaints, assembly-line testing, and manufacturers' in-use testing to identify potential recall classes of vehicles. Investigation of a potential recall class requires inquiries to manufacturers, generation of any necessary additional EPA testing, gathering of corroborating data, and technical and legal analysis necessary to recommend a recall order. Auditing of the manufacturers' compliance with a recall order involves remedial plan approval and monitoring of the manufacturers, generation of any necessary additional EPA testing, gathering of corroborating data, and technical and legal analysis necessary to recommend a recall order. Public reporting simply entails assimilating emission-related recall activities into a form for public consumption.

The recall program measures emissions from "real" cars driven by actual consumers in the "real" world and is the ultimate test under the current act of how well manufacturers have designed and built durable emission controls.

In addition to identifying and bringing about the repair of vehicles, the recall program also provides a strong incentive to manufacturers to design and build vehicles properly so that the costs and burdens of recalls will be avoided.

Warranty -- The warranty programs are intended to provide effective recourse for consumers against manufacturers when individual vehicles do not meet standards in-use, as well as to deter the manufacture of such vehicles. The section 207(a) warranty is intended to assure that defects in design or workmanship that result in high emissions are remedied. The section 207(b) warranty in certain instances protects from liability, owners who, despite properly, maintaining and using their passenger vehicles or light-duty trucks, fail an EPA-approved Inspection/Maintenance (I/M) test. The 1990 Clean Air Act Amendments established, beginning with the 1995 model year, the warranty for the catalytic converter, electronic control unit, on-board diagnostic device, and other equipment designated by EPA, as a "specific major emission control component" will be 8 years or 80,000 miles; all other emission related parts will be warranted for two years or 24,000 miles. The warranty period for other categories of vehicles and engines are typically established by EPA as part of the standard-setting process.

Inspection/Maintenance (I/M) -- The Inspection/Maintenance (I/M) program, administered by the states, consists of a periodic emissions test of in-use vehicles. I/M programs are intended to detect and bring about the repair of in-use vehicles with excessive emissions by encouraging proper vehicle maintenance. A number of states have also implemented anti-tampering inspections. Under these programs, states are requiring consumers to replace damaged or missing control equipment.

The 1990 Clean Air Act Amendments required 27 new areas to adopt basic I/M programs, and 28 new areas to adopt enhanced I/M programs. Also, 47 of the 97 areas that currently had I/M programs, were required to upgrade them. EPA selected as its model I/M enhanced program a test-only program using the I/M 240 test procedure. In 1995, Congress enacted the National Highway System Designation Act which provided states added flexibility to design I/M programs. Individual states have adopted a variety of different approaches and test procedures for their I/M program. A detailed description of individual state programs can be found on this website.

Rulemaking Procedures

In establishing emission standards and elements of the compliance program, EPA must follow the requirements of the Clean Air Act and the Administrative Procedures Act in the Agency's rulemaking activities. EPA's rulemaking procedures are designed to provide ample opportunity for participation by interested stakeholders and the general public. Rulemakings are initiated in response to specific mandates or guidance contained in the Clean Air Act or upon findings by EPA that certain regulatory action in needed to protect the public health.

During the initial phase of the rulemaking process, EPA's Office of Transportation and Air Quality (OTAG) will develop a preliminary proposal, in consultation with interested stakeholders. In some cases public workshops are conducted to outline the initial concepts being developed and to receive input form stakeholders and the general public. EPA may publish in the Federal Register an Advanced Notice of Proposed Rulemaking (ANPRM) formally requesting comments. The next phase is for EPA, in consultation with other agencies of the federal government, to develop and propose in the Federal Register a Notice of Proposed Rulemaking. All interested parties are given an opportunity to provide written comments on the proposal and often one or more public hearings are held to provide opportunity for oral comments. Based on input from interested parties and further analysis by the agency, EPA issues in the Federal Register the final rule.

EPA is required by law to develop an administrative record to support the decisions made in the rule. This record usually will include a summary of comments received and EPA's responses to those comments.