New standards apply to heavy-duty (HD) engines starting model year 2027

Required NOx reduction of 82.5% on existing FTP & RMC lab transient test cycles

New low load cycle adopted from California with tighter-than-CARB limits for full useful life

New methodology adopted for analyzing off-cycle emissions. Emissions will be analyzed using moving average window method and separated into 2 bins (vs. 3 in California). One bin for idle and low load emissions, another for high load emissions.

Full useful life extended from current 435,000 miles to 650,000 miles. Durability demonstration required out to 750,000 miles to account for real-world deterioration.

New SET cycle required for spark ignition engines. Same limits and useful life for compression ignition and spark ignition engines.

Warranty periods increased from 100,000 miles today to 450,000 miles for heavy HD engines. This increases the period under warranty from 23% to 70% of useful life.

Powertrain test cycles developed for hybrids and full powertrain testing of hybrids allowed for compliance

No NOx or PM emission credits for zero-emitting vehicles (ZEVs)

Standards will drive adoption of increased SCR volume and new technologies (e.g. close-coupled SCR with dual dosing, cylinder deactivation, heated urea dosing, electrically heated catalysts)