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Zero-Emission Bus Rollout Plan Guidance for Transit Agencies

Prepared for the ZEB Rollout Plan Assistance Session at the
2022 CalACT Spring Conference and Expo

The Innovative Clean Transit (ICT) regulation became effective on October 1, 2019 and requires all California public transit agencies to gradually transition their bus fleets to zero‑emission technologies. The ICT regulation applies to all transit agencies that own, operate, or lease buses with a gross vehicle weight rating (GVWR) greater than 14,000 pounds. It covers standard, articulated, over-the-road, double decker, and cutaway buses. The ICT regulation requires a percentage of new bus purchases to be zero-emission buses (ZEBs). The ZEB purchase requirement increases gradually over time. The ZEB purchase requirements begin in 2023 and 2026 for large[1] and small[2] transit agencies, respectively. Starting 2029, 100 percent of all transit agencies’ new bus purchases must be ZEBs, with a goal of complete transition to ZEBs (all buses in each transit agency’s fleet to be ZEBs) by 2040.

This document is created to facilitate the Zero Emission Bus Rollout Plan Assistance Session at the 2022 CalACT Spring Conference and Expo. This guidance document does not replace the adopted regulatory text, which takes precedence in all instances. The purpose of this document is to provide guidance on the content of the Rollout Plan, but transit agencies are not required to follow the exact format of this guidance document.  Successful transition of transit bus fleets to zero-emission technologies requires early planning which includes but is not limited to, route simulations, charging or hydrogen fueling site assessment, and identification and addressing of potential resource gaps, among the many preparatory steps. Transit agencies that have begun the transition to zero‑emission technologies stress that early communication and engagement with ZEB manufacturers, technology providers, infrastructure providers, fuel providers, and other related parties are key to a successful and well-coordinated transition.


[1] The ICT regulation defines a “Large Transit Agency” (13 CCR § 2023(b)(30)) as a transit agency that meets one of the following criteria:

  1. It operates either in the South Coast or the San Joaquin Valley Air Basin and operates more than 65 buses in annual maximum service; or
  2. It operates outside of these areas, but in an urbanized area with a population of at least 200,000 as last published by the Bureau of Census before December 31, 2017, and has at least 100 buses in annual maximum service.

[2] The ICT regulation defines a “Small Transit Agency” (13 CCR § 2023(b)(49)) as all other transit agencies that do not meet the definition of the “Large Transit Agency”.

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