Emissions Limits for Heavy Trucks

Heavy trucks are defined as having a Gross Vehicle Weight (GVW) of greater than 8,500 lbs. for 1979 and newer trucks, or greater than 6,000 lbs. for 1978 and older trucks. Heavy trucks are tested with the two-speed idle test rather than the I/M 240 test. Pollutants are sampled and measured in parts per million. Heavy duty trucks include most motorhomes.

The following chart shows the emissions limits for carbon monoxide (CO) and hydrocarbons (HC) by vehicle model year. Although emissions limits are listed here for only 1967 through 2001 model year vehicles, all older vehicles are subject to testing unless they fit certain testing exemption categories. Oxides of nitrogen (NOx) are not tested for heavy trucks.

View emissions limits for passenger cars and light duty trucks.
Back to I/M 240 Test page.
Back to Two-Speed Idle Test page.
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