Optional Reduced NOx Standards for Heavy-Duty Vehicles | California Air Resources Board

Optional Reduced NOx Standards for Heavy-Duty Vehicles

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In 2013, CARB adopted optional low oxides of nitrogen (NOx) emission standards for on-road heavy-duty engines to encourage engine manufacturers to introduce new technologies to reduce NOx emissions below the current mandatory on-road heavy-duty diesel engine emission standards. Please see the information below for engines currently certified to the optional low NOx emission standards.
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Keep up to date with the latest information regarding the optional reduced NO_x emission standards for on-road heavy-duty engines.

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Optional Low NOx Certified Heavy-Duty Engines

Semi trucks

Evaluating Technologies & Methods to Lower Nitrogen Oxide Emissions

Low NOx Study

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Heavy-Duty Low NOx

GHG Standards for Medium- and Heavy-Duty Engines and Vehicles

Heavy-Duty GHG Phase 1 2013 Rulemaking Documents

California Phase 1 Background Materials

California Phase 1 Greenhouse Gas Standards

Truck and Bus Regulation