إجراء مقترح من الولايات المتحدة: المركبات وأجزاؤها

Proposed rule - The U.S. Environmental Protection Agency (EPA) is reconsidering the Tier 4 criteria pollutant standards for new motor vehicles promulgated within the final rule entitled 'Multi-Pollutant Emissions Standards for Model Years 2027 and Later Light-Duty and Medium-Duty Vehicles' (notified as G/TBT/N/USA/1991/Add.1). This reconsideration will occur in two separate, but coordinated, rulemakings. In this Part 1 rulemaking, the EPA is proposing to amend the phase-in schedule for the Tier 4 criteria pollutant standards for certain vehicles to address changing circumstances and feasibility concerns. These amendments, if finalized, would extend the Tier 3 standards for certain vehicles to model years (MYs) 2027 and 2028 such that the Tier 4 standards for these vehicles would phase in starting with MY 2029. The EPA is also proposing other changes to the test protocols used to evaluate emissions performance for certification and related regulatory issues. Potential amendments to the Tier 4 standards and other program elements will be proposed separately in a future Part 2 rulemaking. The EPA plans to hold a public hearing for this proposal on 3 June and 4 June 2026. If there is sufficient interest, an additional day of hearings will be held on the subsequent day. Information on the public hearing is available at Please also refer to this website for any updates regarding the hearings. The EPA does not intend to publish additional documents in the Federal Register…