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Vehicle Inspection & Maintenance

Federal Requirements for Vehicle Inspection and Maintenance (I/M)

The Federal Clean Air Act Amendments (CAAA) of 1990 require New York to establish the Enhanced Vehicle Inspection/Maintenance (I/M) Program to ensure regular testing of vehicle emissions. Under the I/M program, vehicles undergo emissions testing in conjunction with the annual safety inspection or when a change of ownership occurs.

By requiring that vehicles with excess emissions be repaired or maintained, the enhanced emissions testing program is a significant element of New York's plan to meet federal air quality standards. The descriptions of I/M program components and quantifications of program outcomes linked from this page will be of interest largely to technical readers.

New York's I/M Program

New York's I/M Program is implemented jointly by DEC and Department of Motor Vehicles (DMV). DEC oversees statewide, comprehensive inspection and maintenance (I/M) emissions testing for all vehicles dating from model year 1981 or later. The department also is responsible for ensuring that the 4,000+ inspection stations administering the test comply with the regulations that govern emissions testing, and that the tests are conducted with approved and certified equipment and software.

Types of Emissions Testing

In the nine counties of the New York Metropolitan Area, most vehicles are subject to the New York Transient Emissions Short Test (NYTEST), which uses specialized equipment installed at vehicle inspection stations. NYTEST equipment has three components: a dynamometer, a VMASTM sampler, and an analyzer gas bench. New York State is the first state to implement a non-IM 240 Mass Emission Transient Test, a VMASTM based test that utilizes a trace comparable to the four minute IM-240 trace.

The second type of vehicle emissions testing program used in New York is known as NYVIP (New York Vehicle Inspection Program). This test reads the on-board diagnostic systems (OBD) that are found in most cars and light trucks on the road today. OBD-II, an upgraded standard for on-board diagnostics introduced in the mid-'90s, provides almost complete engine control and also monitors parts of the chassis, body and accessory devices, as well as the diagnostic control network of the car. New York's program provides statewide coverage of emissions inspections with OBD II technology.

Under the requirements of the National Highway Systems Designation Act of 1995, the state must quantify its I/M program performance on a long-term basis. Since 1998, this requirement has been fulfilled by a contractor recruiting in-use vehicles which are emissions tested at the contractor's testing facility in Long Island.

DEC ensures that New York's program meets evolving federal requirements by continually monitoring the standards used in the I/M program, and by initiating changes to state regulation as needed to conform with federal law. The I/M program is also responsive to issues raised by the public or legislature.

I/M Test Data

DEC stores all emissions data on inspections and maintenance in a database. Program data is subject to quality assurance checks to determine whether the data is being transmitted correctly. The data are analyzed and reported as necessary to comply with US EPA guidelines, and the department analyzes data to assess overall impacts of the program on air quality, costs to motorists, and identifying problem vehicles.

Quality Assurance

IM program data is subject to quality assurance checks to ensure that data is being transmitted correctly, that the I/M testing equipment produces valid data, and that the testing procedures are valid. The department periodically reviews the test methods and equipment to assure that they meet accepted quality standards.

The Quality Assurance program conducts equipment audits, including a gas audit using gases of known concentrations at least as accurate as those required for regular equipment quality control; comparing these known concentrations actual test readings assures testing accuracy.

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