United States Air and Radiation EPA420-F-97-052
Environmental Protection August 1997
Agency
Office of Mobile Sources
&EPA Regulatory
Announcement
Minor Amendments to Inspection/
Maintenance Program Evaluation
Requirements
The U.S. Environmental Protection Agency (EPA) has proposed
changing the inspection/maintenance (I/M) rule's mandatory program
evaluation to require states to use a sound evaluation methodology
capable of providing accurate information about the overall
effectiveness of an I/M program. This proposal also clarifies related test
requirements.
Background Of The Rule
Under the 1990 Clean Air Act, EPA published on November 5, 1992, the
I/M rule. The Clean Air Act required that enhanced I/M programs con-
duct biennial program evaluations using methods established by the
Administrator. EPA established the criteria for this in the I/M rule. The
program evaluation was to include state-administered or -monitored
program evaluation tests on a random, representative sample of at least
0.1 percent of the annual subject vehicle population. The program
evaluation tests included measuring the gram-per-mile tailpipe emissions
using the IM240. Alternative, equivalent mass based transient emission
testing (METT) was allowed in place of the IM240, but these had to be
approved by EPA.
At the time the I/M rule was promulgated, it was anticipated that most
programs subject to the enhanced I/M requirement would opt to use
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IM240 as part of their routine testing program. Therefore, requiring
additional, state-administered or -monitored IM240s to confirm the
overall program's effectiveness did not require states to invest in addi-
tional program evaluation testing equipment and did not call for the
development of an alternative program evaluation testing methodology.
The National Highway System Designation Act (NHSDA) was enacted
on November 28, 1995, specifically prohibiting EPA from mandating the
test-only IM240 for program operation. EPA has since determined that
additional flexibility is desirable in order to better accommodate the
wider range of enhanced I/M program designs which states are in the
process of adopting and implementing, and which were not anticipated at
the time the original program evaluation criteria were promulgated. EPA
also believes that alternative, sound methods for meeting the Clean Air
Act's program evaluation requirement may exist, and the Agency intends
to work with states and other interested parties during the proposed
period of delay to identify and approve these alternatives.
What Are the Key Elements Of The Rule?
This Notice of Proposed Rulemaking:
• Amends the I/M program evaluation requirements to remove the
current requirement to conduct METT on 0.1 percent of the
subject fleet, beginning at the time of program start-up.
• Creates a new evaluation requirement that would require states to
conduct program evaluation testing on a minimum of 0.1 percent of
subject vehicles using a scientifically sound evaluation methodol-
ogy capable of providing accurate information about the overall
program effectiveness of an I/M program. Such program evaluation
testing is to begin by November 30, 1998, and is not required to be
coincident with program start up.
• Clarifies that "initial test" simply means that the test is conducted
before repairs for each test cycle, and does not therefore preclude
states from using alternative sampling methodologies such as
roadside pullover to sample the fleet.
• Proposes to amend the conditions on the program evaluation re-
quirements of the I/M State Implementation Plans for the Common-
wealths of Pennsylvania and Virginia and the State of Delaware.
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Who Will Be Affected By The Rule?
Only states that choose to utilize the additional flexibilities will be
affected by the proposed change. Modifications to a state's I/M program
as a result of this rule change may require a SIP revision. Of those af-
fected States, primarily the State I/M program authorities will be af-
fected. Program evaluation equipment suppliers and I/M contractors may
need to adjust to shifting requirements as states accept the new flexibility
and delay implementation of program evaluation.
How Does The Rule Provide Flexibility To The States?
The goal of the proposed rule change is to allow states additional flexibil-
ity to use not only IM240 but other approved alternative methodologies
for their program evaluation. This action may reduce the cost burden the
states would face if they were required to implement IM240 program
evaluation testing while at the same time choosing to implement a differ-
ent test type for the operating program. This action will allow the states
even greater flexibility in designing and implementing I/M program
evaluations which meet their local needs.
For More Information
For further information on this proposed rulemaking, please contact
Tracey Bradish at:
U.S. Environmental Protection Agency
Office of Mobile Sources
2565 Plymouth Road
Ann Arbor, Michigan 48105
(734) 668-4239
Additional documents on I/M programs are available electronically from
the EPA Internet server at:
http://www.epa.gov/OMSWWW/im.htm
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