Phase I GHG

This page last reviewed December 9, 2014


Truck imageCalifornia Air Resources Board (ARB) has adopted a new regulation for greenhouse gas (GHG) emissions from heavy-duty trucks and engines sold in California. It establishes GHG emission limits on truck and engine manufacturers and harmonizes with the recently adopted U.S. EPA rule for new trucks and engines nationally. Existing heavy-duty vehicle regulations in California include engine criteria emission standards, tractor-trailer GHG requirements to implement SmartWay strategies (i.e., the Heavy-Duty Tractor-Trailer Greenhouse Gas Regulation), and in-use fleet retrofit requirements such as the Truck and Bus Regulation.  In September 2011, the U.S. EPA adopted their new rule for heavy-duty trucks and engines. The U.S. EPA rule has compliance requirements for new compression and spark ignition engines, as well as trucks from Class 2b through Class 8. Compliance requirements begin with model year (MY) 2014 with stringency levels increasing through MY 2018. The rule organizes truck compliance into three groupings, which include a) heavy-duty pickups and vans; b) vocational vehicles; and c) combination tractors. The U.S. EPA rule does not regulate trailers.

What's New

Posted December 9, 2014:
The five heavy-duty related regulatory documents, including the Phase 1 Heavy-Duty Vehicle Greenhouse Gas Emission Standards and Test Procedures, have been approved by Office of Administrative Law.  The formal regulatory documents have been posted on the Heavy-Duty GHG Phase 1 2013 webpage.

Posted December 5, 2013:

Public hearing announced. The Air Resources Board will conduct a public hearing on December 12, 2013, in Sacramento, to consider five heavy-duty vehicle related proposals, including harmonizing with U.S. EPA’s Phase 1 GHG standards. The public hearing notice and staff report have been posted on the draft proposed regulations web page. ARB staff has posted additional background materials, calculations, and models to allow stakeholders to evaluate the emission and cost estimates presented.

Posted March 8, 2013:

The Phase I GHG regulation presentation for the public workshop in Sacramento on March 11, 2013, has been posted.

Posted February 14, 2013:

ARB invites you to participate in a public workshop in Sacramento on March 11, 2013, to discuss proposals for several regulations and regulation amendments related to on-road heavy-duty vehicles. The workshop will include discussion of Heavy-Duty Truck and Engine Manufacturer Greenhouse Gas Requirements (i.e., the Phase I GHG regulation). Additional details can be found in this public notice.


Monday, March 11, 2013


8:30 a.m. – 4:00 p.m.


Air Resources Board
Coastal Hearing Room
1001 I Street
Sacramento, California 95814


For more information, please contact:

Ms. Kim Heroy‑Rogalski, Manager, at (916) 327-2200.