Truck and Bus Regulation
Model Year Schedules and Options
Last Updated: December 2, 2014

This summary describes the compliance requirements by engine model year for vehicles that operate in California including an option that limits the number of 2010 engine upgrades in any one year. There are different schedules based on the weight category of your vehicles. This summary has been updated to describe amendments that were approved by the Air Resources Board (ARB/Board) on April 25, 2014. These requirements and options do not apply to school buses.

What vehicles are affected by the Truck and Bus Regulation?
The regulation applies to nearly all diesel-fueled trucks and buses with a gross vehicle weight rating (GVWR) greater than 14,000 pounds that are privately or federally owned and for privately and publicly owned school buses. The regulation does not apply to state and local government vehicles, solid waste collection trucks, and public transit buses because they are already subject to other regulations.

What are the compliance requirements for heavier trucks and buses?
Heavier trucks and buses with a GVWR greater than 26,000 pounds must comply with a schedule by engine model year or owners can report to show compliance with more flexible options.

Starting January 1, 2012, heavier trucks were required to meet the engine model year schedule shown to the left. Fleets that comply with the schedule must install the best available PM filter on 1996 model year and newer engines and replace the vehicle 8 years after the initial PM filter requirement date. Trucks with 1995 model year and older engines must be replaced starting January 1, 2015. By January 1, 2023, all trucks and buses must have 2010 model year engines with few exceptions. No reporting is required if complying with this schedule.

What are the requirements for lighter trucks and buses?
Lighter trucks and buses with a GVWR of 14,001 to 26,000 pounds have compliance requirements starting January 1, 2015. The Engine Model Year Schedule for Lighter Trucks shown in the table to the right lists the compliance dates by engine model year for existing lighter trucks. Starting January 1, 2015, lighter truck and buses with engines that are 20 years or older must be replaced with newer trucks (or engines). Starting January 1, 2020, all remaining trucks and buses need to be replaced so that they all have 2010 model year engines or equivalent emissions by January 1, 2023. No reporting is required with this schedule.

Can I upgrade with used trucks instead of upgrading with 2010 model year or newer engines?
Yes, replacements with a 2010 model year or newer engines meet the final requirements; but you may also replace with used trucks that have a future compliance date on the schedule. For example, if you replace a vehicle with one that has a 2007 model year engine – it will comply until 2023 if equipped with a PM filter. By January 1, 2023, it will need to be upgraded to a 2010 model year engine with few exceptions. 

While this document is intended to assist fleets with their compliance efforts, it is the sole responsibility of
fleets to ensure compliance with the Truck and Bus Regulation.

Can I still install PM filters on trucks that are required to upgrade to 2010 model year engines?
No, all owners had the opportunity to extend the use of an existing truck by installing a PM filter before January 1, 2014 regardless of fleet compliance option used. These vehicles comply until January 1, 2023 as long as the vehicle remains in the fleet and the owner reports their fleet information by January 31, 2015. Owners that did not install PM filters before January 1, 2014 and do not use flexibility options must replace existing trucks (or engines) according to the applicable model year schedule.

Are there any flexibility options I can use?
Yes, there are a number of compliance extensions for individual trucks within a fleet that can extend the compliance date for low mileage work trucks, agricultural vehicles, vehicles that are operated in certain areas with cleaner air, low use vehicles and for vehicles that were retrofitted with PM filters before January 1, 2014. Vehicle owners must meet the eligibility criteria and report by certain deadlines to use these flexibility options. Other fleet-wide compliance options began in 2012 and are no longer available to owners that did not opt-in; however, if the engine model year schedules require more than 25 percent of the fleet to be replaced in any year you may be able to limit the number of 2010 model year or newer engine upgrades per year. Information about these options is available at
http://www.arb.ca.gov/msprog/onrdiesel/documents.php.

What can I do if the model year schedule requires me to replace most of my trucks in one year?
You may be able to limit the number of trucks that need to be upgraded to 2010 model year or newer engines each year if you meet certain requirements. If you are complying with the engine model year schedules, you will not be required to upgrade with 2010 engines for more than 25 percent of the fleet, but no less than two trucks within a weight category per year. The limit applies separately for the fleet of lighter and fleet of heavier vehicles and requires reporting.

How can I limit the number of 2010 engine upgrades I need to make each year?
You need to retire a minimum number of existing vehicles and replace them with 2010 model year engines as required by the applicable model year schedule. The minimum number of upgrades is based on the total number of vehicles within the weight category in the fleet on January 1 of the prior year but not less than two. For example, if you had 10 heavier vehicles on January 1, 2014, then you will need to upgrade a minimum of 3 heavier vehicles (10*25%=2.5 and rounds up to 3) to meet the minimum requirements to comply on January 1, 2015. The minimum number of upgrades does not change if you use extensions or if you reduced the number of heavier trucks in your fleet compared to the prior year. You cannot use this option if you increased the number of heavier vehicles in your fleet or if you did not comply with the applicable engine model year schedule in the prior year. The limit applies separately for lighter vehicles. Reporting is required to use this flexibility option.

Can I still report to take advantage of the 2010 engine replacement limit?
You must report by January 31 of each year to demonstrate compliance for all of the vehicles in the applicable weight category. You need to report information about your fleet as it existed on January 1 of the prior year and as it currently exists. You must also report changes to the fleet within 30 days of purchasing or selling a vehicle and must continue reporting by January 31 of each year until all vehicles in the fleet comply with the applicable engine model year schedule. In order to report for January 2015 you need to report the fleet as it existed January 1, 2014 to claim the replacement cap.

Where can I get more information?
Fact sheets, compliance tools and regulatory documents about the Truck and Bus Regulation are available at www.arb.ca.gov/dieseltruck. If you have questions or wish to obtain this document in an alternative format or language, please call ARB’s diesel hotline at (866) 6DIESEL (634-3735). TTY/TDD/ Speech to Speech users may dial 711 for the California Relay Service.
While this document is intended to assist fleets with their compliance efforts, it is the sole responsibility of
fleets to ensure compliance with the Truck and Bus Regulation.