Webinar on the Transit Agency Diesel-Fueled Bus and Engine Exemption Request under the Heavy-Duty Omnibus Regulation

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January 19, 2022

Webinar on the Transit Agency Diesel-Fueled Bus and Engine Exemption Request under the Heavy-Duty Omnibus Regulation

Webinar will be held on February 4, 2022

The California Air Resources Board (CARB) invites transit agencies and transit bus manufacturers to participate in a webinar on the requirements and process of requesting an exemption under the Heavy-Duty Engine and Vehicle Omnibus Regulation (Omnibus Regulation). Transit agencies can request an exemption for 2022 and subsequent models of diesel-fueled medium or heavy heavy-duty engines used in urban buses if they meet the requirements of title 13, CCR, section 1956.8(a)(2)(F) in the Omnibus Regulation.

The webinar will be held virtually at the following date and time. Please note that there is no in-person attendance option for this event. This webinar will be recorded.

Date:                 February 4, 2022
Time:                10:00 a.m. – 12:00 p.m. Pacific Time


CARB is preparing the Transit Agency Diesel-Fueled Bus & Engine Exemption Request Guidance Document that will summarize the conditions, requirements, and procedures of requesting an exemption. The Guidance Document will be available on the Innovative Clean Transit (ICT) website before the webinar.


The Omnibus Regulation was adopted on September 9, 2021, and became effective on December 22, 2021, to drastically cut smog-forming nitrogen oxides (NOx) from conventional heavy-duty engines. The Omnibus Regulation will significantly increase the stringency of NOx emissions standards and will also lengthen the useful life and emissions warranty of heavy-duty diesel engines for use in vehicles with a gross vehicle weight rating (GVWR) greater than 10,000 pounds. The more stringent NOx emission standards begin with the 2024 model year engines and become more stringent with 2027 and subsequent model year engines.

In 2020, the only manufacturer of diesel-fueled heavy-duty urban bus engines announced that it will no longer produce these types of engines to be certified in California, beginning with the 2024 model year, and plans to increase the price of the diesel-fueled urban bus engines starting with the 2022 model year. This creates a potential obstacle for transit agencies that are currently working diligently to comply with the ICT regulation. The ICT regulation requires all public transit agencies to gradually transition to a 100 percent zero‑emission bus fleet. The Transit Agency Diesel‑Fueled Bus and Engine Exemption Request (Exemption Request) was then added to the Omnibus Regulation (title 13, CCR, section 1956.8(a)(2)(F)) to support transit agencies with a smooth transition to zero-emission bus fleets. If an Exemption Request is granted, the transit agency can purchase or re-power buses with engines that are certified to both the federal emission standards for 2010 and later model year diesel-fueled medium heavy‑duty or heavy heavy-duty engines and vehicles.


Please send questions or comments regarding this webinar or the Exemption Request to the ICT@arb.ca.gov. If you wish to learn more about the Omnibus Regulation, please visit its rulemaking webpage and subscribe to its email list to receive the latest updates and notices of upcoming events.