Control of Air Pollution From New Motor Vehicles: Amendments to the Tier 2 Motor Vehicle Emission Regulations

EPA is taking direct final action to make minor amendments to the existing Tier 2 motor vehicle regulations (65 FR 6698, February 10, 2000, hereinafter referred to as the Tier 2 rule). These minor amendments are consistent with our intention, under the original Tier 2 rule, to provide interim compliance flexibilities for clean diesels in the passenger car market. While the automotive industry has made rapid advancements in light-duty diesel emissions control technologies and will, as a result, be able to produce diesel vehicles that can comply with the primary regulatory requirements of the Tier 2 program, diesel vehicles still face some very limited technological challenges in meeting the full suite of Tier 2 requirements. This action will provide two voluntary, interim alternative compliance options for a very limited set of standards for oxides of nitrogen (NO<INF>X</INF>), including only high altitude and high speed/high acceleration conditions. These temporary alternative compliance options are designed to be environmentally neutral, as manufacturers choosing them would then be required to meet more stringent standards in other aspects of the Tier 2 program. The alternative compliance options will last for only three model years, during which time advancements in diesel emissions control technologies will be further developed.