California Air Resources Board

What is the ICT regulation and to whom does it apply?

The ICT regulation was adopted in December 2018 and requires all public transit agencies to gradually transition to a 100 percent zero‑emission bus (ZEB) fleet. Beginning in 2029, 100% of new purchases by transit agencies must be ZEBs, with a goal for full transition by 2040. It applies to all transit agencies that own, operate, or lease buses with a gross vehicle weight rating (GVWR) greater than 14,000 lbs. It includes standard, articulated, over-the-road, double‑decker, and cutaway buses.

What are the ICT regulation requirements?

The ICT regulation includes the following elements:

• A ZEB Rollout Plan required from each transit agency, approved by its Board, to show how it is planning to achieve a full transition to zero-emission technologies by 2040. Large transit agencies have to submit their Rollout Plan by July 1, 2020, and small transit agencies by July 1, 2023; 
• ZEB purchases with various exemptions and compliance options to provide safeguards and flexibility to transit agencies;
• Low NO_x engine purchases, unless the transit buses are dispatched from NO_x Exempt areas;
• Use of renewable diesel or renewable natural gas for large transit agencies, and
• Reporting and record keeping requirements.

Do the ICT requirements differ by transit agency fleet size?

Yes, the requirements differ for large and small transit agencies. A transit agency is considered large if it operates at least 100 buses in annual maximum service in an urbanized area with a population of at least 200,000. However, if it operates in either the South Coast or San Joaquin Valley Air Basins with more than 65 buses in annual maximum service, it is also considered a large transit agency. All others are small transit agencies. The number of buses in annual maximum service excludes demand response buses.

What are the ZEB purchase requirements?

As shown in the table, the ZEB purchase requirements begin in 2023 for large transit agencies and 2026 for small transit agencies, based on a percentage of new bus purchases each year that must be zero-emission. 

The ZEB purchase requirements for articulated, over-the-road, double-decker, or cutaway buses do not start until 2026 or later. These bus types remain exempt from the ZEB purchase requirements until they pass the Altoona testing. Note the 2023 ZEB purchase requirement will be discharged (the requirement will be removed) if California transit agencies collectively purchase at least 850 ZEBs by December 31, 2020. The 2024 ZEB purchase requirement will be discharged if at least 1,250 ZEBs are purchased by December 31, 2021.  ­­

ZEB Purchase Schedule (ZEB Percentage of Total New Bus Purchases)

Flexibility Options

Transit agencies may be able to take advantage of flexibility options to comply with the ZEB purchase requirements, including:

• Bonus credits for early ZEB purchases: to recognize transit agencies that took more risks by early purchases of innovative technologies; credit is based on each early acquisition of a zero-emission bus per the schedule in the regulation.
• Zero-emission mobility options: to encourage innovation in providing first- and last-mile connectivity and improved mobility for transit riders; and
• Formation of a joint ZEB group: to allow transit agencies to work together to collectively comply with the ZEB purchase requirements.

Note: To be eligible to form a joint ZEB group, two or more transit agencies must either share the use of infrastructure, be in the same air basin, be in the same air district, be under the same Metropolitan Planning Organization, or be under the same Regional Transportation Planning Organization.

Provisions for Exemptions of a ZEB Purchase

To ensure transit service is not adversely impacted, the regulation has exemptions for circumstances that are beyond a transit agency’s control. Providing that all required information is correct and complete, exemptions will be granted upon request under the following circumstances:

• When the needed ZEB type is not available;
• When daily mileage needs cannot be met;
• When gradeability needs cannot be met;
• When incremental capital or electricity costs for depot-charging battery electric buses cannot be offset after applying for all available incentive and funding programs;
• When there is a delay in infrastructure construction; or
• When a transit agency declares a financial emergency.

More Information

For questions, please contact CARB Innovative Clean Transit.