# Control of Emissions of Air Pollution from 2004 and Later Model Year Heavy-Duty Highway Engines and Vehicles; Revision of Light-Duty On-Board Diagnostics Requirements
> **Rule** · Final rule. · Published 2000-10-06 · Effective 2000-12-05 · 65 FR 59896
## Document
- **Document number:** 00-20144
- **Category:** air-emissions
- **Federal Register citation:** 65 FR 59896
- **CFR reference:** 40 CFR 85
- **Publication date:** 2000-10-06
- **Effective date:** 2000-12-05
- **EPA docket:** AMS-FRL-6846-4
## Abstract

Today's action finalizes a major new program to reduce emissions from on-highway heavy-duty engines and vehicles. These reductions will provide for cleaner air and greater public health protection, primarily by reducing ozone pollution. This program is the first phase of a multi-phase strategy to reduce emissions from heavy- duty engines and vehicles. A key element of this action is a reaffirmation of the technical and economic feasibility of the non-methane hydrocarbon plus nitrogen oxide (NMHC+NO<INF>X</INF>) standard promulgated in October, 1997 for diesel heavy-duty engines. This previously-codified standard will therefore remain unchanged and effective starting with the 2004 model year for heavy-duty diesel engines. This standard represents about a 50 percent reduction in emissions of nitrogen oxides, as well as reductions in hydrocarbons, from diesel trucks and buses. Heavy-duty diesel engines and vehicles will also be subject to new test procedures and associated requirements beginning in the 2007 model year that will ensure that emission standards are met across a broad range of engine operating conditions. In addition, this action puts in place new more stringent emission standards and related provisions for heavy-duty Otto-cycle (e.g., gasoline-fueled) engines and vehicles, beginning in the 2005 model year or sooner under two optional programs finalized today. Vehicles in this category include large full size pick-up trucks and the largest cargo and passenger vans. Today's action does not affect vehicles classified as Medium-duty Passenger Vehicles (generally, large SUVs and vans), which are subject to the recently finalized Tier 2 program standards. For heavy-duty Otto-cycle engines and vehicles affected by today's action, emission standards for oxides of nitrogen and hydrocarbons are reduced by approximately 75 percent from current standards. We are also finalizing requirements for on-board diagnostics systems for all heavy-duty vehicles and engines at o

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2000/10/06/00-20144/control-of-emissions-of-air-pollution-from-2004-and-later-model-year-heavy-duty-highway-engines-and)
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